Communication use and protection of water bodies. Importance and protection of fresh waters. I was chosen as the coordinator of the project, as I have experience in the environmental direction of the regional scale
The main sources of water pollution are domestic wastewater and industrial effluents. Surface runoff (stormwater) is a variable in time, quantity and quality factor of water pollution.
Pollution of water bodies also occurs with waste from water transport and timber rafting. According to the Sanitary Norms and Rules for the Protection of Surface Water from Pollution (No. 4630-88), water bodies and drains (water bodies) are considered polluted if the indicators of the composition and properties of water in them have changed under the direct or indirect influence of production activities and domestic use of the population. The criterion for water pollution is deterioration in quality due to changes in organoleptic properties and the appearance of substances harmful to humans, animals, birds, fish, food and commercial organisms, as well as an increase in water temperature, which changes the conditions for the normal life of aquatic organisms.
Water use is divided into two categories: the first category includes the use of a water body as a source of centralized or non-centralized domestic and drinking water supply, as well as for water supply to food industry enterprises; to the second category - the use of a water body for swimming, sports and recreation of the population, as well as the use of water bodies located within the boundaries of populated areas. Points of water use of the first and second categories are determined by the bodies and institutions of the sanitary and epidemiological service with the obligatory consideration of official data on the prospects for using a water body for drinking water supply and cultural and domestic needs of the population.
When wastewater is discharged within the city (or any settlement), the first point of water use is this city (or settlement). In these cases, the requirements established for the composition and properties of the water of a reservoir or watercourse should apply to the wastewater itself.
The main elements of water and sanitation legislation are hygienic standards or MPCs - the maximum allowable concentrations at which substances do not have a direct or indirect effect (when exposed to the body throughout life) and do not worsen the hygienic conditions of water use. MPCs serve as the basis for preventive and ongoing sanitary surveillance. The limiting sign of harmfulness, according to which the traffic rules are established: sanitary-toxicological (c.-t.), general sanitary (gen.) and organoleptic (org.). The limiting sign of harmfulness is taken into account with the simultaneous content of several harmful substances. If several substances of I and II hazard classes are present in the water, the sum of the ratios of these concentrations (C1, C2, Cn) of each of the substances in the water body to the corresponding MPC should not exceed one:
In accordance with the classification of chemicals according to the degree of danger, they are divided into 4 classes: Class I - extremely hazardous, Class II - highly hazardous, Class III - hazardous, Class IV - moderately hazardous. The classification is based on indicators that characterize the degree of danger to humans of substances that pollute water, depending on the general toxicity, cumulativeness, and the ability to cause long-term side effects.
The composition and properties of the water of the water body at the points of household and drinking and cultural and household water use should not exceed the standards presented in Table. 16-18; water bodies for fishery purposes - in table. 19 (standards approved on 10/24/83; No. 2932-83-04.07.86; No. 42-121-4130-86).
| Table 16 |
*" Within limits calculated for the content of organic substances in the will of water bodies and in terms of MIC and dissolved oxygen.
*2 Harmful by skin contact.
*3 For inorganic compounds
*4 Including oxygen regime for winter conditions.
*5 MPC of phenol-0.001 mg/l - indicated for volatile phenols that give water a chlorophenolic smell during chlorination (trial chlorination method); MPC refers to water bodies for domestic and drinking water use, provided that chlorine is used to disinfect water in the process of water treatment at waterworks or when determining the conditions for the discharge of wastewater subjected to disinfection with chlorine. 1 mg/l.
*6 This refers to fluorine also in compounds.
*7 Taking into account the chlorine absorption of water in reservoirs.
*8 Simple and complex cyanides (excluding cyanoferrates) calculated as cyan.
Table 17
Table 18. General requirements for the composition and properties of water in water bodies at points of drinking and domestic water use
Table 19. General requirements for the composition and properties of water in water bodies used for fishery purposes
Sanitary protection of small rivers. A high anthropogenic load causes a potential danger of water quality deterioration and violation of water use conditions in certain sections of small rivers (watercourses up to 200 km long), increases the risk of intestinal infections and intoxication among the population due to the inflow of wastewater containing pathogenic microorganisms, pesticides, heavy salts. metals, etc.
Small rivers usually have low water flow, low water supply and depth, low flow velocity, which leads to relatively unfavorable conditions for mixing and, accordingly, dilution of pollution. Small rivers, being the initial link in the river network, have an impact on the entire hydrographic network; it is possible to spend a significant part (of the entire runoff) for local economic needs, to retain it in watersheds (reservoirs, ponds).
The formation of reservoirs and ponds has a positive value (increase in volume, natural settling and aeration of water). At the same time, a decrease in the flow of water bodies under the conditions of economic activity can adversely affect the intensity of self-purification processes, worsen the dilution of contaminants, be accompanied by "blooming" with a deterioration in the organoleptic properties of water, and during the period of algae's death - to the appearance of toxic products of their decomposition in the water.
The main tasks of the state sanitary supervision are: characterization of the state of the river and assessment of water quality; identification of the main sources of pollution; substantiation of hygienic measures to protect small rivers from pollution and ensure favorable conditions for the population's water use; control over their implementation.
From a hygienic point of view, special attention should be paid to determining the water quality of small rivers at control points, which should be established in accordance with the existing and planned use of the river, the presence of a pollution source upstream from the water use point: in areas used for domestic and drinking water supply; within the city limits; in places of mass recreation of the population. Observation sites should be located 1 km upstream from the points of household and drinking water use and places of mass recreation (the exception is cases when the sanitary situation requires closer placement). For each site, it is necessary to have information about the distance from the nearest source of pollution and the average water flow per year 95% security.
Sanitary characteristics are given on the basis of: the results of laboratory studies of water quality in control sites; data on sources of pollution and composition of wastewater; the results of analyzes of wastewater entering water bodies in order to determine the compliance of the discharge with the requirements of the Sanitary Norms and Rules for the Protection of Surface Water from Pollution No. 4630-88; obtaining the necessary information from the bodies and institutions of the Ministry of Water Resources, the State Committee for Hydrometeorology, and other institutions exercising control over the use and protection of waters; survey of the population and analysis of citizens' statements on the conditions of water use.
In areas of recreational water use, water is examined 2 times before the start of the bathing season and 2 times monthly during the bathing season; analyzes can be limited to organoleptic (smell, color, floating impurities, film) and bacteriological (coli-index) indicators.
In cases of centralized domestic drinking water use, the frequency of sampling and the list of water quality indicators are established in accordance with the requirements of GOST 2761-84 “Sources of centralized domestic drinking water supply. Hygienic, technical requirements and selection rules "(at least 12 times a year monthly).
Within the boundaries of populated areas, the frequency of sampling is established by the local bodies of the sanitary and epidemiological service, depending on the sanitary and epidemiological situation.
Preventive sanitary supervision over the sanitary condition of small rivers is carried out when considering projects for sanitary protection zones of sources of centralized domestic drinking water supply and coastal strips (zones), norms for maximum allowable discharges (MPD) and other project materials submitted for approval.
When assessing the sanitary condition of small rivers and monitoring the implementation of measures for their protection, first of all, the main (priority) types of their pollution should be taken into account; effluents from livestock complexes, farms, poultry farms, grazing and watering places for livestock; surface runoff from residential, agricultural and industrial areas, and in the southern regions - return and collector-drainage water; wastewater from health facilities; dewatering at mining sites (ore, coal, oil), discharge of blowdown water from circulating water supply systems of large industrial facilities, wastewater from dry cleaners, etc.; industrial effluents in the areas of location of territorial-industrial complexes, individual large industries and industrial centers; use of sections of small rivers by the population for recreational purposes. Discharge into small rivers of wastewater from livestock (pig-breeding) complexes and poultry farms without complete biological treatment is prohibited (for details, see "Guidelines for the hygienic assessment of small rivers and sanitary control over measures for their protection in places of water use" No. 3180-84).
Sanitary protection of coastal waters of the seas. According to the "Rules for the Sanitary Protection of Coastal Waters of the Seas" (No. 121074; see also "Methodological Guidelines for the Hygienic Control of Marine Pollution" No. 2260-80), the coastal protected area of the sea is determined by the boundaries of the area of actual and prospective marine water use of the population and two belts of the zone sanitary protection (ZSO): area of direct water use - areas of the sea used for cultural, community and health-improving purposes with a width towards the sea of at least 2 km; belt I of the WSS - to prevent exceeding the normative indicators of microbial and chemical water pollution within the limits of actual and prospective water use from organized wastewater discharges (along the coastal length and width towards the sea at least 10 km from the border of the water use area); zone II ZSO - to prevent water pollution of the water use area and belt I ZSO from the sea from ships and industrial facilities for the extraction of minerals. The boundaries of this belt are determined seaward by the boundaries of territorial waters for the internal and external seas in accordance with the requirements of the international conventions adopted by the USSR.
It is prohibited to discharge into the sea sewage that can be eliminated by rational technology, maximum use in recycling and re-water supply systems or through the installation of drainless production facilities; containing substances for which maximum permissible concentrations (MACs) have not been established. Discharges of treated industrial and domestic wastewater (including ship wastewater) within the boundaries of the water use area are prohibited. See Table 20.
In places of mass bathing, an additional indicator of pollution is the number of staphylococci in the water; signal value - an increase in their number of more than 100 in 1 l (in places of water intakes of swimming pools with sea water, the number of bacteria of the group of E. coli and enterococci, respectively, is not more than 100 and 50 in 1 l).
For zone I of the WZO, the coli-index of wastewater is not more than 1000 at a concentration of free chlorine of at least 1.5 mg/l. When wastewater is discharged from the shore beyond the boundaries of the 1st zone of the WSS, the microbial contamination of sea water at the border of the 1st-2nd belts of the zone should not exceed 1 million tons according to the coli index.
MPCs for harmful substances apply to water intakes for domestic and drinking and health-improving and therapeutic use of sea waters and areas of sea water use (temporarily until the development of standards for coastal waters of the seas).
For coastal areas of the seas with specific hydrological conditions and unsatisfactory sanitary, hydrophysical and hydrological features of the area from a hygienic point of view, causing stagnation or concentration of pollution in coastal waters, the requirements and standards for the I zone of the WSS should be attributed to wastewater without taking into account possible mixing and dilution their sea water.
In order to prevent pollution of the coastal protected area of the sea from ships in ports, port points and from ships in roadsteads, it should be possible to discharge sewage (through discharge devices, sewage disposal vessels, etc.) into the citywide
Table 20. Requirements for the composition and properties of sea water in the water use area 1 and belt I
sewerage; solid waste, waste and garbage are to be collected in special containers on board the ship and delivered ashore for subsequent disposal and neutralization.
To clean the sea from oil (oil products), ports and port points must have equipment - special mechanisms, ships or watercraft that ensure the collection of oil and the subsequent disposal of oil residues.
When exploring and developing the resources of the continental shelf, it is necessary to provide for protective measures to prevent pollution of the shelf and the water environment above it by industrial and household waste products.
Conditions for the descent of ocular waters. Requirements for the conditions for the discharge of wastewater into water bodies apply to the release of all types of industrial and domestic wastewater from populated areas (urban, rural)
and detached residential and public buildings, including mine water, waste water cooling water, hydraulic ash recovery, oil production, hydraulic stripping, waste water from irrigated and drained agricultural areas, including those treated with pesticides, and other wastewater of any objects, regardless of their departmental affiliation (requirements apply to storm sewers).
The conditions for the discharge of wastewater into water bodies are determined taking into account the degree of possible mixing and dilution of wastewater with the water of a water body on the way from the place of wastewater discharge to the settlement (control) site of the nearest points of household and drinking and fisheries water use "water quality of reservoirs and watercourses above the place projected discharge of wastewater.It is allowed to take into account the processes of natural self-purification of waters from substances entering them if the process of self-purification is sufficiently pronounced and its patterns have been sufficiently studied.
Sanitary supervision of sewage treatment facilities. Sewerage is understood as a complex of sanitary measures and engineering structures that ensure the collection and removal of wastewater, their purification, neutralization and disinfection. During mechanical treatment, the liquid and solid phases of wastewater are separated: grates, sand traps, settling tanks, septic tanks, two-tiered settling tanks. The liquid part of wastewater is subjected to biological treatment (natural or artificial): natural - in filtration fields, irrigation fields, in biological ponds; artificial - in biofilters, aerotanks. The treatment of sludge (sewage sludge) is carried out at sludge beds, in digesters or at mechanical dehydration and thermal drying plants.
Sanitary supervision includes an inspection of treatment facilities and an assessment of their performance through systematic visits to facilities, laboratory control, and identification of the impact on the sanitary condition of a reservoir. The sizes of the land plots of structures, sewers during artificial biological treatment are given in Table. 21.
| Table 21 |
For the dimensions of the sanitary protection zones between sewage treatment plants and residential areas or food enterprises, see SN 245-71.
The territory of the treatment facilities should be landscaped, landscaped, lit and fenced. Facilities for mechanical wastewater treatment include gratings, sand traps, settling tanks.
When examining the screens, it is important to pay attention to the timeliness of removing retained substances from the screens (clogging of the screens is detected externally by the amount of waste on the screen and by raising the level of the waste liquid in front of the screen by 5-8 cm).
The correct operation of the sand trap is ensured by the timely removal of sediment; with the accumulation of sediment, the removal of suspended solids from the sump occurs.
Settling tanks are used for preliminary wastewater treatment (if biological treatment is required) or as independent facilities (if only mechanical impurities need to be separated from wastewater). Depending on the purpose, sedimentation tanks are divided into primary and secondary. The primary ones are installed before the biological wastewater treatment facilities, the secondary ones - after these facilities. According to their design features, sedimentation tanks are divided into horizontal, vertical and radial.
Primary settling tanks can provide the effect of clarification of the liquid up to 60% (more often within 30-50%).
Sewerage sludge treatment facilities include septic tanks, settling tanks and clarifiers, decomposers, digesters, sludge pits. Septic tanks are facilities in which sewage liquid clarification, long-term storage and decay of the precipitated sludge occur simultaneously (the sludge is stored for 6 to 12 months and under the influence of anaerobic microorganisms are destroyed, insoluble organic substances are converted partly into a gaseous product, partly into soluble mineral compounds); the waste liquid is clarified within 1-3 days, which provides a relatively high clarification effect. Two-tier settling tanks are used for treatment plants with a capacity of up to 10,000 m3 / day. The sediment that has fallen into the sludge chamber is fermented under the influence of anaerobic bacteria with the formation of methane, carbon dioxide and hydrogen sulfide.
Normally, the process of anaerobic destruction of organic substances proceeds in an alkaline environment (pH 8.0). The acidity of the environment serves as an indicator of the normal operation of these structures. The process of sediment decay takes a long time (60-180 days). The sludge is considered technically mature when it easily releases moisture during drying and does not emit a bad odor. Well rots the sediment of domestic water.
The clarifier-decomposer consists of a clarifier with natural aeration and a decompressor located concentrically around it. The methane tank is a cylindrical or rectangular reinforced concrete tank with a conical bottom. In digesters, the gas resulting from fermentation is collected in a hood located in the upper part of the gas-tight ceiling, from where it is discharged for use. To speed up the fermentation processes, various methods are used, for example, heating the sludge and mixing it. The digested sludge has a high moisture content. There are various methods for drying the sludge; the most common is drying on silt pads. Silt pads consist of planned plots of land (maps) surrounded on all sides by earthen ridges.
When examining sludge sites, it is necessary to pay attention to the general mode of operation of the sites (number of maps) - the thickness of the accepted load layer, periods of drying, the degree of drying, the system for the removal and use of precipitation, the absence or presence of overloading of sites with precipitation. The silt layer on the maps should be 20-30 cm in summer and 10 cm below the height of the ridges in winter. When reloading, the drying period is reduced, the soil of the sites becomes silted, working conditions for removing precipitation from the sites and its removal are difficult.
Irrigated agricultural fields (AIP) are intended for round-the-clock and year-round neutralization of wastewater, which is used for irrigation and fertilization of crops. According to the “Sanitary Rules for the Arrangement and Operation of Agricultural Irrigated Fields” (No. 3236-85), it is not allowed to set up a ZPO on the territory of the I and II belts of the sanitary protection zone of sources of centralized domestic drinking water supply; on the territory of wedging out aquifers and fractured rocks and karsts; within the district of sanitary protection of resorts; at a depth of groundwater from the earth's surface of less than 1.25 m on sandy and sandy loamy soils and less than 1 m on loamy and clayey soils.
To collect drainage water and then use it for irrigation, it is necessary to provide for the construction of storage ponds.
A sanitary protection zone is established between settlements and the territory of the ZPO, the width of which depends on the method of irrigation and should be (at least): for subsoil irrigation - 100 m; for surface irrigation - 200 m; when sprinkling: a) short-jet devices - 300 m, b) medium-jet - 500 m, c) long-range - 750 m. The sanitary protection zone to main roads should be at least 100 m, including the right-of-way.
Along the borders of irrigated fields from the side of settlements, it is planned to install sanitary-protective forest belts with a width of at least 15 m, and along main roads - 10 m.
Filtration fields are used to treat the liquid phase of wastewater. When choosing a territory for their location, they are guided by the same rules (see above, No. 3236-85). The most suitable soils for filtration fields are sands and sandy loams.
During sanitary supervision of the operation of irrigation fields and filtration fields, attention should be paid to the conditions for filtering the sewage through the soil (ensuring a normal filtration rate): the frequency of sewage inlet, the correct planning of sites, the systematic plowing of the soil of the sites, the timeliness of cutting furrows, weed control, no overload of fields and their individual sites (maps) with sewage. It is important to maintain trays and channels that supply liquid to the fields and individual field maps, which must be free from blockages and grass thickets. Gate valves for switching the fluid supply to different sites must be in good condition. The system of rollers must reliably protect against spillage of wastewater onto the territory surrounding the map. It is necessary to systematically monitor the rise in the level of groundwater under the influence of irrigation.
Biological filters consist of an impermeable base, drainage, side walls, filter material and distribution devices. The biofilter consists of a container; filter loading; a distribution device that provides uniform (at short intervals) irrigation of the surface of the filter load; bottoms with drainage, through which purified water is discharged and through which the air necessary for the oxidizing process enters the body of the biofilter. The material of the filter bed must be sufficiently porous, strong and resistant to destruction from mechanical and chemical influences (boiler slag, certain grades of coal, coke, gravel, hard rock crushed stone and well-burnt expanded clay). Passing through the filtering load of the biofilter, contaminated water leaves suspended and colloidal organic substances (not settled in the primary settling tanks) in it due to adsorption, which create a biofilm populated by microorganisms. Biofilm microorganisms oxidize organic matter. Thus, organic substances are removed from the wastewater, and the mass of the active biological film in the biofilter body increases (the spent and dead film is washed away by the flowing wastewater and removed from the biofilter body). The effect of cleaning biofilters is very high (according to BODb 90% or more). Laboratory control over the operation of biofilters is carried out by sampling the incoming and outgoing waste liquid (average samples taken in separate portions every 30 minutes for 4-6 hours). Temperature, appearance, smell, transparency, insoluble substances and their ash content, oxidizability, BOD, stability, dissolved oxygen, ammonium nitrogen, nitrates, nitrites, chlorides are determined. On efficient filters, the waste liquid becomes transparent, turbidity disappears; the fecal smell of water changes to earthy; transparency increases to 20-30 cm according to Snellen; the amount of insoluble substances decreases slightly, since the water as a biofilter comes already settled; oxidizability drops by 60-80%; biochemical oxygen demand is reduced by 80-95%; relative stability increases to 80-90%; ammonium nitrogen almost completely turns into nitrate nitrogen, and nitrites are in small quantities (up to fractions of a milligram in 1 liter); dissolved oxygen appears in the amount of 3-8 mg/l; the concentration of chlorides in the waste liquid does not change.
The air filter is intensively blown from the bottom up with air, so the oxidation process is more intense than in biofilters (approximately 2 times), and, therefore, the amount of waste liquid to be treated in this case can be much higher. Depending on the climatic zone and the capacity of the building, bio- and air filters should be placed in heated rooms or unheated rooms of lightweight construction. When monitoring the operation of bio- and air filters, it is necessary to monitor the uniform distribution of the waste liquid over the surface of the biofilter, the good condition of the feed material, the maintenance of clean drainage space under the filter and discharge trays. In case of surface silting of the filter material and water stagnation on the filter surface, wetlands should be loosened and washed with a jet of water under pressure.
The aerotank is a reservoir in which a mixture of activated sludge and treated waste liquid slowly moves (constantly mixed with compressed air or special devices). Activated sludge is a biocenosis of microorganisms - mineralizers capable of sorbing on its surface and oxidizing organic substances of the waste liquid in the presence of atmospheric oxygen. The mixture of waste liquid with activated sludge must be aerated throughout the aeration tank (blowers). When controlling the operation of the aeration tank, it is necessary to monitor, first of all, the observance of the duration of the waste liquid in it, the content of the required amount of activated sludge and the mode of air supply over the entire area of the aeration tank, the timely removal and processing of excess activated sludge. Laboratory control of the efficiency of the aerotank is carried out according to the same indicators as on biological filters.
Secondary settling tanks are designed to retain the biological film from the waste liquid after biofilters or activated sludge coming with the liquid after the aerotanks. In addition, they are used as contact tanks when a chlorine solution is supplied to the waste water. Secondary clarifiers, which are technologically related structures with aerotanks, serve only to separate activated sludge from wastewater treated in the aerotank. The duration of sedimentation of the sludge mixture in the secondary clarifier is 1-0.5 hours (sludge is completely removed from the secondary clarifier). It is necessary to observe the uniformity of the inflow and outflow of wastewater from the secondary clarifier (less than 1 mg/l).
Biological, or treatment, ponds are used as independent treatment devices or as facilities for the post-treatment of wastewater previously treated in biological facilities (biofilters, aeration tanks). In the first case, the wastewater, having passed the settling tanks, is diluted before it enters the ponds with 3-5 volumes of technical or domestic and drinking water. During the operation of ponds, the load on them is taken: for settled wastewater without dilution - up to 250 m3 / ha per day, for biologically treated - up to 500 m3 / ha per day. The average depth in biological ponds should be no more than 1 m and not less than 0.5 m. In the spring, before the biological ponds are put into operation, their bottom is plowed, the ponds are filled with waste water and kept until almost the complete disappearance of ammonium nitrogen from it. The period of "ripening" of ponds for the middle zone of the USSR is at least 1 month. In autumn, after the end of the work of biological ponds, water is released from them (in winter, biological ponds are exploited by freezing ice on them).
Since the waste water of any settlement must be regarded as containing pathogenic microbes, disinfection must be provided for in all cases of artificial treatment. Currently, wastewater disinfection is provided for both after mechanical and biological treatment. Disinfection is carried out with liquid chlorine: the dose of active chlorine after mechanical cleaning is at least 30 mg/l, after incomplete biological cleaning - 15 m/l, after complete artificial biological cleaning - 10 mg/l. At small treatment facilities with a capacity of up to 1000 m3 / day, the use of bleach is allowed.
Waste liquid chlorination is carried out in special contact tanks, arranged as horizontal or vertical settling tanks. The duration of contact of chlorine with the liquid should be at least 30 minutes, so if the treated water passes from the treatment station to the reservoir for 30 minutes or more, then contact tanks can be omitted. The content of residual active chlorine in the waste liquid of at least 1.5 mg/l serves as an indicator of the sufficient depth of its disinfection.
When monitoring the operation of a chlorination plant, it is necessary to take into account the thorough mixing of chlorine with the waste liquid, the uniformity of the supply of chlorine, and the contact time of chlorine with the waste liquid. Sediment accumulating at the bottom of the contact pools must be removed after 2-3 days. For each installation, it is mandatory to draw up instructions for chlorination of wastewater, storage of chlorine and safety precautions.
When solving the issue of sewerage, treatment and disposal of wastewater from an industrial enterprise, depending on specific local conditions, the possibility and expediency of using wastewater in the system of recycling and re-water supply of enterprises or workshops should be considered.
Drawing up a project for sewerage, treatment, neutralization and disinfection of wastewater should be based on taking into account the quantity, composition and mode of disposal of wastewater; sanitary condition of the water body in the area of the projected facility; the sanitary situation above and below the wastewater discharge of this facility; the use of a water body for domestic and drinking water supply and cultural and domestic needs of the population and for fisheries and other purposes at the present time and in the future. In the absence of established standards, by the beginning of the design, water users must ensure that the necessary studies are carried out to study the degree of harmfulness of substances contained in wastewater and substantiate the MPC for them in the water of water bodies in accordance with the nature and category of water use.
Sanitary protection of water bodies from pollution by sewage of large livestock and poultry complexes. Effluent from livestock complexes is dangerous in sanitary and epidemiological terms (contains typical and atypical cultures of microbes of the Salmonella group, enteropathogenic Escherichia coli, Proteus, Pseudomonas aeruginosa, etc.). The total amount of manure runoff from livestock complexes and industrial type farms is calculated taking into account the volume of excrement (feces, urine) of animals; water for their removal from production facilities; water used for washing floors, equipment; water leaks from drinkers; hourly and daily coefficient of non-uniformity of water consumption.
Approximate daily amount of manure generated at the pig farm from one animal is 40 liters, and from the pig farm for 108 thousand years per year - 3000 m3, for 54 thousand heads per year - 1500 m3. With stall and pasture keeping of animals, the amount of manure is reduced by 50% due to loss in pastures and by 12% - in walking areas. The volume of sewage from milking parlors is 62 liters per head (the proportion of excrement in it is 8-10%).
Manure from livestock complexes can be a factor in the transmission of more than 100 infectious diseases (brucellosis, tuberculosis, etc.). Between 11 and 21 strains of enteropathogenic Escherichia coli and between 22 and 59 strains of Salmonella are isolated from the liquid fraction of pig manure (see also Chapter 17).
The epidemic danger of manure from livestock complexes is not only the presence of pathogenic microorganisms and their high concentration, but also long-term survival. The survival rate, for example, of Brucella in undiluted manure at a temperature of 25 ° C is 20-25 days, of Mycobacterium tuberculosis - 475 days. With an increase in manure moisture, the survival time of pathogenic bacteria increases. Manure and manure of pigs may contain viable eggs and larvae of helminths dangerous to humans. In warm weather, when manure is stored in manure storage facilities, the survival rate of helminth eggs reaches 4 months. In cold weather, even a longer period of holding effluents does not ensure their complete deworming. 80-90% of viable helminth eggs (ascarids) remain in manure and manure.
The collection and removal of manure and manure from livestock buildings is carried out by mechanical, pneumatic, hydraulic (flushing, gravity) methods. Gravity system is used for bedless keeping of animals on slatted floors. Manure channels must have reliable waterproofing. The settling-tray system is recommended for keeping animals without bedding on slatted floors, which provides for the periodic accumulation of animal excrement in manure canals (7-14 days) when they are filled with water to a height of 15 = 20 cm. The flush system provides for the daily use of water to remove animal excrement from manure canals.
The most appropriate way to transport manure and manure from livestock complexes and industrial farms to storage and processing sites is to supply them through a closed pipeline. In some cases, it is allowed to use mobile transport to transport liquid manure to the place of application to the soil, for which the projects must provide appropriate justifications. For storage and dehydration of bedding manure, non-buried waterproof areas or containers with a depth of 1.8-2 m are provided.
Facilities for the storage of liquid manure and manure runoff must meet the following requirements:
Ensure the prevention of the spread of infectious diseases ("intermediate" quarantine keeping);
Prevent infiltration into soil and groundwater,
The total capacity of manure storage facilities should be calculated for the period ensuring the release of manure from pathogenic microorganisms and helminth eggs (at least 6 months) from the moment their last portions arrive.
The terms of quarantine keeping of manure should be at least 6 days, which corresponds to the incubation period of infectious diseases.
Manure infected with resistant pathogenic microorganisms in quarantine containers (causative agents of anthrax, plague, rabies, tuberculosis, etc.) is burned after preliminary moistening with disinfectant solutions. Disinfection of liquid manure with formaldehyde during an epizootic should be carried out in quarantine containers, based on the consumption rate of reagents and contact time: for manure infected with salmonella and colibacilli, from 0.04 to 0.16% of the volume of manure with a contact time of 24 hours and homogenization for 3 hours; for manure infected with pathogens of foot-and-mouth disease and Aujeszky's disease - 0.3% of the volume of manure with a contact time of 72 hours and homogenization for 6 hours.
Mechanical treatment of liquid manure is used to isolate solid particles from its mass.
Currently, manure and manure runoff generated at livestock complexes and farms are mainly used for fertilizing and irrigating agricultural fields. The main hygienic requirements aimed at ensuring the complete neutralization of manure are: the availability of a sufficient amount of land for disposal, favorable soil and climatic, hydrological and hydrogeological conditions.
Irrigation fields are arranged on chernozem, sandy, sandy loamy, loamy soils and drained peat bogs. The groundwater level must be at least 1.5 m. If the groundwater depth is less than 1.5 m, a drainage device is required. Drainage water must not be discharged into water bodies (it is recommended to reuse it for irrigation or dilution of manure and manure before it is supplied to the fields).
In cases where soil methods cannot be applied, it is recommended to install facilities for artificial biological wastewater treatment with subsequent post-treatment in biological ponds and discharge into water bodies or use them for irrigation. To ensure the efficient operation of artificial biological treatment facilities, the dose of activated sludge should be at least 10-12 g/l. The BODb load on sludge should not exceed 100 mg/g sludge per day. The sludge index of such sludge is 60-120 mg/g. The increase in activated sludge is 40% of COD at a moisture content of 96-97%.
The solid fraction of manure (with a moisture content of not more than 70%) is subjected to composting or piling on special waterproofed sites with a slope towards drainage ditches (deepening of the sites into the ground up to 1 m). The liquid released from the solid fraction of manure, together with atmospheric precipitation, is sent to a slurry collector for further processing.
The time of keeping the solid fraction of manure in piles is at least 6-8 months. It is recommended to cover the piles with sawdust, peat or soil in summer with a thickness of 15-20 cm, in winter 30-40 cm. This ensures that the temperature in all layers of the piles rises to 60 ° C, which is detrimental to pathogenic microflora and helminth eggs. After neutralization, composts are taken to the fields as fertilizer.
To dilute manure and manure in irrigated fields, it is necessary to have reliable water sources (drainage water from irrigated fields can be used). On irrigation fields, measures should be taken to prevent the ingress of manure and manure runoff into open water bodies (arrangement of rollers, storage ponds, drainage and bypass channels, etc.). The capacity of storage ponds is determined taking into account the accumulation of the total amount of wastewater within 6 months.
The distribution of preparatory manure runoffs on irrigated fields is allowed by irrigation along furrows and strips with low-directional sprinklers, mobile devices (with appropriate justification) and underground (subsoil) irrigation. The rates of application of manure and manure to irrigated fields should be calculated taking into account the type of crops, their removal with the harvest and natural losses in the irrigation process (20-30%). When supplying liquid manure to irrigation fields, special flow meters (water meters) must be used, built into the facilities for the release and supply of wastewater for irrigation or into sewer pipes.
Lands irrigated with manure from livestock complexes may only be used for fodder grasses, fodder-tillage and grain-fallow crop rotations (feeding of fodder crops is allowed after ensiling or heat treatment, i.e., processing for vitamin flour).
Bodies and institutions of the sanitary and epidemiological service (sanitary and epidemiological stations of autonomous republics, territories and regions) carry out sanitary supervision at the stage of choosing a land plot for the construction of livestock complexes, linking projects of livestock complexes and projects of manure and manure treatment systems to the site, and also consider systems for using manure and manure for fertilization and irrigation of agricultural land.
When considering projects for irrigation fields for the use of manure and manure runoff from livestock complexes, it is necessary to pay attention to the correspondence of the allotted areas of land plots to the amount of generated manure runoff. The calculation of the areas is carried out in accordance with the permissible load standards and additional allocation of areas for driveways, dikes, canals, etc. (15-25% of the total area). Manure processing facilities are located below the water intake facilities and the production area.
During the implementation of state sanitary supervision during the construction of systems for the collection, removal, storage, disinfection and use of manure and manure, it is necessary to pay attention to the compliance of facilities and structures with the approved project; the timing of construction, bearing in mind that the commissioning of treatment facilities should precede the completion of the construction of the livestock complex.
Current sanitary supervision is carried out in the following areas: a) the conditions for the formation of manure and manure runoff at livestock complexes, their quantitative and qualitative characteristics in dynamics: upon completion of the construction of facilities and during operation;
b) evaluation of the effectiveness of manure and manure treatment systems in terms of sanitary-chemical, bacteriological, helminthological and other indicators; c) the effect of manure and manure runoff on the state of soil, open water bodies, groundwater and atmospheric air; d) study of the sanitary living conditions of the population in the areas where the livestock complex is located. Continuous monitoring of the operation of facilities for the treatment and disinfection of wastewater from livestock complexes, their impact on surface water bodies and groundwater, atmospheric air, soil and plants is provided by a departmental production laboratory.
Sanitary protection of water bodies from pesticide pollution. Pesticides enter water bodies with rain and melt water (surface runoff); during air and ground processing of agricultural land and forests; at direct processing of reservoirs by pesticides; with drainage-collector waters in the cultivation of cotton and rice; with wastewater from pesticide factories and agricultural wastewater from the use of pesticides (see also Chapter 17).
Water samples are taken quarterly (if necessary, more often). During the period of application of pesticides in agriculture, monitoring of water quality and the sanitary regime of water bodies in the immediate vicinity of the fields is established (water samples are taken before and after treatment, after work with pesticides is completed). The content of pesticides in drainage-collector waters is systematically monitored (sampling frequency is set depending on local conditions). Simultaneously with water intake, sludge samples are examined. In water samples from artesian wells, wells, cappings in the nearest and more remote areas, where, according to local conditions, a deterioration in water quality can be expected, drinking water is analyzed by general indicators and specific determinations for the presence of pesticides used in the treatment process. Drainage-collector waters in the presence of pesticides in concentrations above the maximum allowable are prohibited from being reused for irrigation.
When choosing the form of the drug from the standpoint of the sanitary protection of water bodies, preference should be given to granular forms, since in this case the risk of the drug being carried into the reservoir is significantly reduced, and a gradual release of the pesticide into the external environment is ensured when the granules are destroyed. The least favorable in this respect are dusts.
The treatment of agricultural areas with pesticides may be allowed if it is possible to maintain a sanitary-protective gap of at least 300 m between the lands and water bodies.
Our reservoirs and their protection (E. S. Liperovskaya)
Water conservation and school
The importance of reservoirs in the national economy. In school curricula, little attention is paid to such an important object of the national economy as water bodies.
Meanwhile, the water resources of our country are enormous. In the Soviet Union there are more than 250,000 lakes with an area of more than 20,000,000 hectares and 200,000 rivers. The total length of our medium-sized rivers is 3 million kilometers. The volume of the annual runoff of the rivers of the USSR reaches 4,000 billion cubic meters. Hundreds of thousands of kilometers of rivers are used for water transport. Since ancient times, rivers have been the main means of communication, trade and cultural ties between peoples, and cities arose along their banks.
In terms of reserves of hydraulic energy, the USSR ranks first in the world. Hydroelectric power plants with a capacity of about 300 million kilowatts can be built on the large and medium rivers of the USSR. Even on small rivers there is an energy reserve of 20-30 million kilowatts, which ensures the construction of collective farm power plants.
The construction of dams, sluices, hydroelectric power stations contributes to the integrated use of rivers: navigation conditions are improved, fields are irrigated, river flow is regulated, and settlements are provided with water. The construction of large dams and hydroelectric power plants is transforming the entire region. Canal construction. Moscow made it possible to turn part of the Volga waters to Moscow and created a navigable route, turning Moscow into a major river port of three seas: the Caspian, White and Baltic. The construction of a powerful HPP named after Lenin in the area of the city of Kuibyshev and the Volgograd HPP, generating about 10 billion kilowatts per year each, makes it possible to supply energy to Moscow, the Donbass, the Urals, Kuibyshev, to electrify railways, to provide irrigation of lands and navigation.
Reservoirs are sources of water supply, fishing, hunting, commercial use of useful aquatic animals and plants.
Rivers and lakes are also places of recreation and tourism.
Participation of schoolchildren in the protection of water bodies. We must know well, protect and increase our water resources.
Article 12 of the Law on the Protection of Nature of the RSFSR, devoted to the protection of water bodies, poses tasks of great importance to every Soviet citizen.
Of great importance is the promotion of the protection of natural waters among schoolchildren. Already in the elementary grades, the teacher should educate students in an attentive and careful attitude to water sources, teach them to keep clean at wells and other sources of water supply, not pollute the water with garbage when boating, explain the importance of water sources for health and the national economy.
In secondary schools, the topic of water protection can be the subject of special excursions, in which the teacher must show the relationship of water bodies with the surrounding landscape and the dependence of aquatic animals and plants on the state of pollution of water bodies.
In the upper grades, students can not only get acquainted with the life of reservoirs, but also actively contribute to their protection. Regular observations of the regime of local water bodies by schoolchildren can be of considerable benefit.
Accounting for all water resources, including rivers, is carried out by the Main Directorate of the Hydrometeorological Service under the Council of Ministers of the USSR. Rivers and their regime are monitored at special hydrometeorological posts and hydrometeorological stations. The number of such stations was 5510 in 1957 and has now increased greatly. These stations record water levels, discharges, temperature, ice phenomena, sediments, chemical composition of water and other data on a daily basis. All this information is summarized and published in the periodical of the Hydrometeorological Publishing House, called the "Hydrological Yearbook". The data obtained are used for planning the national economy. Along with this, the study of rivers by local organizations, including school organizations, can be of great importance, and all observations obtained in this way should be reported to the organizations of the hydrometeorological service - best of all, to the nearest water measuring post.
In order to successfully familiarize students with the life of our reservoirs and participate in their protection, the teacher himself must learn the basic information about this area.
Nature and life of reservoirs
River runoff. The movement of water in the river. The movement of water in rivers has a number of features and is characterized by complex phenomena that are specific only to rivers.
River runoff is formed from atmospheric precipitation flowing into the river along the surface (surface runoff) and seeping through the soil (underground runoff). The unevenness of precipitation and snowmelt, both within one year and in different years, causes continuous changes in flow rates and water levels in rivers. In accordance with this, periods of prolonged standing of low levels, the so-called low water, are observed in the rivers, when the river is fed mainly by groundwater, and seasonal long-term rises in levels (usually with the release of water on the floodplain) caused by snowmelt, called floods. In contrast to floods, irregular, relatively short-term significant rises in water levels can also occur in the river - floods resulting from heavy downpours, continuous rains. Floods can occur at any time of the year, depending on local geographical and climatic conditions. They reach a special force in the destruction of forests in the river basin, regulating the spring snowmelt and weakening the erosive washout from the soil surface. That is why the protection and proper exploitation of the forest is one of the most important tasks in the regulation of river flow.
The main force that determines the translational movement of water in rivers is gravity due to the slope of the river from the source to the mouth. In addition to gravity, the mass of water in the river is affected by inertial forces, called Coriolis forces, resulting from the rotation of the Earth, since points on the surface of the globe located closer to the poles move in a circle more slowly than those lying near the equator. The mass of water flowing in the northern hemisphere from north to south passes from lower to higher velocities, i.e., it will receive acceleration. Since the rotation of the Earth occurs from west to east, the acceleration will be directed to the east, and the forces of inertia in the opposite direction - to the west and will press the flow to the western (right) bank. When the flow moves from south to north, it will receive a negative acceleration directed against the direction of the Earth's rotation - from east to west. In this case, the forces of inertia will press the river against the eastern, i.e., also right, bank. Also, a stream flowing along the parallel will be pressed against the right bank. Thus, it turns out that the Coriolis forces in the northern hemisphere always push the flow to the right bank, regardless of the direction of the river flow, and vice versa in the southern hemisphere. Coriolis acceleration, acting on a moving mass of water, causes the appearance of a transverse slope of the water surface of the stream.
The centrifugal force acting in the course of the river at bends, similarly to the Coriolis force, also creates a transverse slope in the river. As a result, the movement of water begins in the plane of the living section of the river. At the same time, at the concave coast, water particles move from top to bottom, then along the bottom to the convex coast and further, at the surface, from the convex coast to the concave one. These internal currents are called transverse circulations. The movement of water in the river in the longitudinal direction is combined with transverse circulations, and as a result, the paths of movement of individual water particles take the form of spirals elongated along the channel (Fig. 1).
Formation of the river channel. Despite the fact that the transverse velocities of water movement are many times less than the longitudinal velocity of the flow, they have a serious effect on the internal structure of the flow and on the deformation of river channels. Since soils are usually heterogeneous, in the place where they are most susceptible to erosion, the coast will begin to collapse. The river will take a characteristic winding shape. The bends of river channels, formed in the process of erosion and deposition of soil particles by a stream, are called meanders (meo in Latin - flow, I'm moving).
In the process of their gradual development, the branches of the meander can approach each other so close at the base that at high water levels (during floods and spring floods) the remaining isthmus will break through (Fig. 2), the channel will straighten in this area and the flow will go along a shorter path. The flow velocities in the left side of the bend will drop sharply, and sedimentation will begin at the beginning and end of it. These sediments can, over time, completely separate the bend from the main channel. An isolated section of the old channel is formed - the oxbow lake. A stream going along a straightened section with a greater slope will increase its speed, the process of meandering of the channel will continue, and the formation of new bends will begin.
As a result of intensive circulation of water at bends, the concave banks are washed away and deep-water sections of the channel-reach are formed near them, and at the convex banks, the current slows down and shallow-water areas are created - shoals. Gradually growing downstream, they can lead to the formation of shoals and spits near the convex coast. Since the stretches are formed alternately near the right and left banks, the transverse circulation of one direction is transformed into the circulation of the opposite direction. This leads to the fact that the transverse circulations at the point of transition from one stretch to another weaken and break up into two (or more) independent equally directed circulations. Sediments begin to settle across the entire width of the river and form shallow areas - riffles that cross the river from coast to coast and completely or partially connect two adjacent shallows. The river, as it were, slides down the river valley and gradually processes all the soils that make up the floodplain.
Floodplains can be of different widths. On the Oka River near Kashira, the width of the floodplain is 1 km, near Ryazan - 15 km, and on the Volga between Volgograd and Astrakhan there is the Volga-Akhtuba floodplain, the width of which varies from 30 to 60 km.
Poem meadows are very fertile, as every year they are fertilized with river silt. In shallow flood waters, which mostly dry up in summer, a lot of aquatic animals are bred, which are washed into the river during floods.
Lake formation. A lake is a natural reservoir, which is a large mass of water inside a closed pit, constantly resting or slowly flowing. The formation of lake depressions (otherwise called a bed or a pit) in the Moscow region depends on the following main reasons:
1) damming of the river with accumulating sediments; 2) the formation of dips in place of dissolving calcareous rocks; 3) excavation of soil from quarries; 4) glacier activity.
Most of the lakes of the Moscow region are of glacial origin. During its movement, the glacier made a channel, rolling stones, sometimes of considerable size. Glacial lakes can be recognized by the presence of ramparts of huge smooth boulders along the shores and at the bottom of the lake.
Over time, the lake changes, having a significant impact on the shores. As a result of the processes of erosion and sedimentation in the lake, the following series of zones is formed in the direction from the shore to the depth (Fig. 3):
1) surf zone (already) - at the water's edge;
2) coastal stranded (zhz);
3) underwater slope (sg);
4) deep-water zone - in the middle of the lake (where).
Lake dwellers. The bottom and water column of the lake are inhabited by animals and plants; among them, two main groups are distinguished depending on the habitat: benthic - benthos and organisms of the water column - plankton. The organism of benthos (animals and plants) spend their whole lives at the bottom of the lake. Planktonic organisms float or, as it were, float in the water without sinking to the bottom (A.N. Lipin, 1950).
Plants in the reservoir are common in the zone of the so-called littoral, which is located along the coastal shoal and partially enters the underwater slope. The littoral is limited by the range of penetration of sunlight under water. As can be seen in Figure 4, plants grow closer to the shore, rooting at the bottom, whose hard leaves rise above the water: reed, reed, lake horsetail, cattails.
Further in the direction from the shore to the middle of the reservoir, plants with floating leaves live: water lilies, egg capsules, duckweeds, and even further submerged plants - pondweed, villain, hornwort, which are completely under water and expose only flowers to the air.
The smallest lower plants, such as blue-green, green and diatom algae, form plant plankton, causing the so-called flowering of the reservoir during periods of their strong reproduction. When blooming, all water appears to be colored green.
Water chemistry. Fresh water contains small amounts of salt - from 0.01 to 0.2 g per liter, in contrast to sea water, where the salt concentration reaches 35 g per liter.
In fresh waters, calcium salts predominate, forming the skeletons of fish and the shells of some invertebrates. There are also iron salts in the water. Iron deposits can be seen in the form of rust spots along the banks of rivers or lakes where springs come to the surface. With a high iron content in drinking water, an unpleasant rusty aftertaste occurs and a brown precipitate forms.
For aquatic organisms, gases dissolved in water - oxygen and carbon dioxide - are of great importance. Oxygen comes from the air and is released by aquatic plants; it is consumed in the processes of respiration of organisms. Carbon dioxide is produced during respiration and fermentation and is consumed by plants to assimilate carbon. As the temperature rises, the amount of gases dissolved in water decreases. Boiling water can be freed from all dissolved gases, including oxygen, and therefore a fish dipped into boiled chilled water instantly dies from suffocation.
Reservoirs are sources of water for drinking and industrial water pipelines. At the place of water intake for the water supply system, a security zone is arranged, within which it is prohibited to release sewage, bathing, watering livestock and any pollution of the banks. The place of water intake should be located along the river above the city, away from large factories, baths, sewers, and, if possible, away from tributaries that can bring pollution from the upper reaches. The degree of purity is controlled by water analysis. At the place of water intake from the reservoir, pumps for pumping water are installed. Water is taken from a depth of at least 2.5 m, passes through large gratings to retain plant residues and large suspensions, and then flows through pipes for treatment. Aluminum sulphate is usually added to precipitate turbidity. After partial separation from the turbidity in the settling tanks, the water enters the filters. Slowly passing through the sandy layer, it is freed from suspended particles and algae. Purified water is disinfected by chlorination and is fed into a clean water tank, and from there it is pumped to the water supply network.
Fish from our ponds. Numerous lakes and rivers of the USSR are rich in valuable species of commercial fish. In large rivers, for example, sturgeon, stellate sturgeon, beluga, sterlet, pike perch, carp, bream are found. However, large fish are caught only with special gear, and amateur anglers, including schoolchildren, usually catch smaller fish: roach, bleak, rudd, dace, asp, perch, pike, ruff, crucian carp, burbot, tench.
In order to protect fish stocks in reservoirs and catch fish correctly, you need to know how the fish live. Unfortunately, there are still frequent cases of predatory fishing - poaching. Often, children also catch fish by illegal methods. Therefore, in those schools where there are many amateur anglers among the students, the teacher must either explain to them the rules of fishing himself, or invite a knowledgeable angler to do this.
Schoolchildren need to be educated in the spirit of the fight against poaching. Catching juveniles of valuable species of fish brings great damage to the fish industry; in the same way, predatory fishing by poachers during spawning undermines the fishery. Therefore, the law prohibits fishing with a fine-mesh net, fishing with a spear net, and fishing with large spawners during spawning.
The teacher of the Moscow region should have an idea about the main types of local fish (Fig. 5, 6, 7); it can be compiled from the literature (Cherfas B.I., 1956, Eleonsky A.N., 1946).
Fish are bottom (for example, bream, crucian carp, tench, burbot) and pelagic, i.e., living in the water column (perch, pike, roach, dace). There are also peaceful and predatory fish. Predatory are those that feed on other fish, while peaceful fish eat algae and invertebrates, molluscs, worms, and insect larvae.
Bream it has a body strongly laterally compressed, its head and mouth are small, there is a characteristic narrow keel in front of the dorsal fin. It is found both in lakes and in rivers, keeps in reservoirs near the bottom, sometimes reaches a length of 45 cm.
carp usually lives at the bottom in slow-flowing ponds. This fish is sluggish, inactive, but extremely hardy. The crucian carp is easy to distinguish by the golden hue of the scales and the jagged ray of the dorsal fin.
asp it is distinguished by a long lower lip, which is bent like a bird's beak; in the upper lip there is a notch where this beak enters. Fins gray or slightly reddish. The fish is strong, living in a fast current. It feeds on dace, gudgeon, bleak.
catfish- voracious predator, eats not only live prey, but also carrion. It is caught on pieces of meat and frogs. Usually lies in pits under snags, only in hot weather it swims up to the middle of the whirlpool. Slow settled fish. Reaches a weight of 20 kg.
Zander also a predator (Fig. 6). Its scales are grayish on the back, the sides are golden with dark stripes. The dorsal fin is in the form of a prickly fan. Found in rivers and lakes in deep places and pits, on clean sandy or rocky ground. Spawns in mid-May. It is caught only at dawn on the nozzle of small live fish: bleak, minnow, ruff.
Pike characterized by spotted sides, while the back is black and the abdomen is white (Fig. 7). Fins are orange. The elongated head ends with a flattened, as if duck nose. The mouth is full of many very sharp teeth of various sizes - from the smallest to large fangs with hard enamel. The teeth are bent inward towards the pharynx. Each of the teeth is mobile, as if on a hinge, but does not fall out. The pike is a large predator. Pike can be found everywhere, but it prefers calm water near grass and snags, where it hides, lying in wait for prey. It is caught on live bait, even on small squints.
Rudd distinguished by red fins. The eyes are red-yellow. Lives in thickets of plants.
Tench has rounded fins and a small mouth pointing upwards. The body is dark, always thickly covered with mucus, the eyes are red. Lives in lakes, bays and oxbow lakes on a muddy bottom. The fish is calm and lethargic, but strong and tenacious (Fig. 5).
At the burbot very small scales are covered on the outside with a thick layer of mucus. The body is dark with light spots, the eyes are also dark, lives in rivers at the bottom under snags. It feeds on fish and caviar, which it eats a lot. Hunts at night. Caught on pieces of fish or frogs. The fish is strong.
Ruff- small fish, up to 15 cm in length. It has one dorsal fin, the anterior part of which is prickly and the posterior one is soft. There is a spine on the ventral fin. In spring it eats fish eggs. Caught on an earthworm.
Perch has two dorsal fins and small scales. The body is green-yellow with black stripes on the sides. Eats caviar and small fish.
Pike and pike perch feed on young fish. Pike, eating up to 30 kg of small things of other fish, increases in weight by only 1 kg. Pike perch use food better: it gives a weight gain of 1 kg instead of 15 kg of small things eaten. Pike perch is beneficial in that it does not stay in the coastal strip, but on the reach and feeds on low-value fish species (Verkhovka).
With regard to harmful, i.e. predatory, fish, measures must be taken to reduce their numbers by catching during the spawning period. But even peaceful fish need control, since overpopulation of a reservoir by them can lead to their grinding due to lack of food.
fish ponds. Many fish ponds have been built in the USSR, but many collective farm ponds and peat quarries can still be equipped for fish farming and stocked with fish, and thereby increase the output of fish in the country.
About 250,000 centners of fish are currently being produced in the ponds alone; however, this does not even reach 1% of the production of all fish in the USSR. And by the end of the seven-year period, in 1965, it is planned to increase the yield of pond fish to 2.6 million centners (Gribanov L.V., Gordon L.M., 1961).
A common form of fish ponds is carp farming (Eleonsky A.N., 1946). For carp spawning, stagnant or low-flowing, shallow water bodies well warmed by the sun, located on fertile soil, with aquatic vegetation, are suitable. Spawning of carp occurs at the end of May, when the water heats up to 18-20°C. Caviar is attached to aquatic plants, and after 4-6 days tiny fry emerge from it, soon beginning to feed on small aquatic animals. Growing up, they switch to feeding on worms and larvae. The favorite food of an adult carp is a red bloodworm. Carp is characterized by rapid growth: in spring it weighs 20-30 g, and by autumn it reaches 500-700 g.
Carp ponds have an average productivity of 2 centners of fish per 1 ha, in other words, 300 pieces weighing up to 600 g. A pond can produce such products due to the use of fish to feed living aquatic organisms. But thanks to the use of measures to intensify the economy - fertilizing ponds, feeding with grain, vitamins, microelements, combined compacted planting (carp along with silver carp, crucian carp and tench) - it is possible to increase the productivity of ponds by five, ten or more times. For example, on a collective farm in the village of Dedinova, Podolsky district, Moscow region, about 9 centners of fish were raised and at the same time received an income of 5.7 thousand rubles per 1 ha of a pond (Gribanov L.V., Gordon L.M., 1961). And in the fish farm "Para" of the Sarayevsky district of the Ryazan region, in ponds with an area of 140 hectares, even 19.1 centners of fish were grown from 1 hectare of the pond (Pravda, July 4, 1962).
Water pollution and water treatment. Huge harm to fisheries, water supply and the use of water bodies for any other economic purposes is caused by pollution introduced by wastewater from factories and enterprises. A number of our rivers (this applies especially to small rivers) are polluted to the extreme. In many places, fish have ceased to be found, watering of livestock is dangerous, bathing is prohibited, and pollution threatens to reach such proportions that even after the cessation of sewage discharge, such reservoirs will be unsuitable for national economic purposes for a long time to come. Water pollution is constantly increasing. The diversity of wastewater is increasing. If in pre-revolutionary Russia the main pollutants were household, textile and leather effluents, then at the present time, in connection with the development of industry, effluents from oil, artificial fiber, detergents, metallurgy, paper and cellulose have become important. Effluent from industrial enterprises may contain toxic substances: compounds of arsenic, copper, lead and other heavy metals, as well as organic substances: formalin, phenol, petroleum products, etc.
The reservoir has the ability to self-purify. Organic contaminants, getting into the water, are subjected to bacterial decay. Bacteria are consumed by ciliates, worms and insect larvae, which in turn are eaten by fish, and organic pollution disappears from the reservoir. It is much more difficult to get rid of toxic substances: some substances, when absorbed by fish, make fish meat unpleasant to taste or even harmful to eat. Therefore, the sanitary inspectorate provides for the norms for the release of toxic substances into water bodies, above which the descent is prohibited, and monitors their implementation.
Wastewater containing a lot of organic contaminants is treated biochemically. Depending on the nature of the pollution, wastewater treatment proceeds in two ways: 1) oxidation of pollutants by atmospheric oxygen or 2) anoxic fermentation with the release of methane formed from the carbon of organic compounds.
Of the oxidizing cleaning methods, the oldest is cleaning in irrigation fields. The disadvantage of this method is that the field area is too large. Soviet scientists have developed more intensive cleaning methods at facilities that occupy a smaller area: at aerotanks or biofilters, where cleaning is carried out using activated sludge when blown with air. Activated sludge is similar to sludge from the bottom of reservoirs: it develops the same microorganisms (ciliates, rotifers and flagellates) that can usually be found at the bottom of a reservoir, but due to the abundant continuous influx of organic matter with the waste liquid, which serves as food for microorganisms, and a good aeration condition , an excessively large number of bacteria and protozoa develop in the aerotank. They intensively consume organic matter and thereby purify the waste liquid. After staying in the aeration tanks, the water settles to separate from the silt and, already purified in this way, descends into the reservoir.
Excursions to reservoirs
Purposes of excursions. Familiarization of students with reservoirs can be carried out on one-day school excursions, in the summer in the camp, during agricultural practice and on hiking trips. To see different types of water bodies (lake, reservoir, pond, river), you need to conduct at least 3-4 excursions. It is also desirable to visit a fish farm, a waterworks and a wastewater treatment plant.
The goals of excursions with students to the reservoirs are as follows:
1. Show the importance of water bodies in the life of the region - the benefits they bring and the beauty they give to their native nature.
2. To instill in schoolchildren a love for water bodies, the habit of treating them with care and striving to increase their natural wealth.
3. In the process of observing aquatic animals and plants, develop students' observation skills, the ability to analyze nature and establish patterns of life of organisms in communities.
4. Show how animal and plant communities are closely related to the surrounding habitat conditions, to the landscape.
5. Involve students in the correct use of this reservoir.
Preparing for excursions. Equipment. When organizing an excursion to a reservoir, the teacher must first familiarize himself with it and find out what the surrounding landscape is like, especially vegetation and soil, the nature of the banks, and, if possible, determine the origin of the reservoir. He must find out from the local population the prevailing depths, dangerous places and pits, marshy shores, the nature of the bottom soil, and find out the possibility of a trip by boat.
From a conversation with fishermen, the teacher finds out what breeds of fish are found in the reservoir, which were found before, what are the reasons for their disappearance; where the effluents of industrial enterprises or domestic effluents are located along the banks.
From plants and animals, it is advisable to collect some of the most common species and determine them yourself by determinants or learn their names from specialists.
Before going on an excursion, the teacher conducts a conversation in which he explains its purpose - acquaintance with reservoirs, their life and significance for a person.
The teacher explains how each participant in the tour should keep a diary. The recording must be accurate and is always done immediately, on the spot, under the fresh impression of the observed phenomenon. The initiative of students in the search for new original forms of notation should be welcomed.
In advance, together with the students, the teacher prepares equipment for the excursion (Fig. 8, 9, 10).
To remove the plan of the lake you need: tape measure, milestones. As milestones, you should stock up on special sticks, and not break trees, you also need a home-made compass. To make a compass, you need to take a ruler, draw a straight line on it and attach a compass in the middle so that the north-south compass needle coincides with it. At the ends of the line, two pins should be stuck strictly vertically. The resulting compass must be strengthened on a tripod.
A lot is needed to measure the depths. To do this, the rope is marked with colored ribbons for meters and half meters, a weight or stone is tied at the end. The lower surface of the load is rubbed with lard so that pieces of soil stick when the lot falls to the bottom.
It is better to take a thermometer with divisions into tenths of a degree or at least half a degree. The end of the thermometer is tied with rope hemp, like a brush. Then, when quickly rising from a depth, the thermometer retains the temperature of the water in which it was immersed for several minutes for the time of counting degrees.
The Secchi disk is used to measure the transparency of water. A metal round plate the size of a plate is painted with white oil paint and tied horizontally in the center with a rope. When the disk is immersed, the depth at which it is not visible is taken into account.
Plankton mesh is made from silk mill gas, which is distinguished by its strength and uniformity of the size of the holes (cells); the gas number corresponds to the number of cells per 10 mm of fabric. To collect daphnia, you can use gas No. 34, and for small plankton - No. 70. The grid consists of a metal ring with a diameter of 25 cm, bent from thick copper wire, and a cloth cone. At the end of the cone is attached a funnel (like kerosene) made of stainless material with a clamp or tap at the end. The grid pattern is made from a square piece of matter (Fig. 8). Before sewing both halves of the cone, it is necessary to make arc strips (a) from coarse calico or canvas using the same pattern and sew them onto the gas.
The dredge for collecting benthos consists of a metal frame to which is attached a bag of rare burlap and a rope. The frame is made of an iron strip 2 mm thick, 30 mm wide and 1 m long, bent into a triangle and fastened at one end.
The net is made from a metal hoop with a diameter of 20-30 cm. The hoop is mounted on a stick. The bag of the net is made of burlap or mill gas, rounded towards the end part (for its pattern, see the first article).
The scraper is used to collect fouling and organisms living in thickets of plants. It is a kind of net, but it has a flat steel strip 2-3 cm wide. To attach the bag, holes are made on one side of the steel strip. The bag is made of coarse mill gas. To collect organisms, you need to have several jars with corks and alcohol or formalin.
Excursion to the well. You can start a cycle of excursions by getting acquainted with the nearest well, from which drinking water is taken. The well differs from the artesian well in the lower depth of the aquifer. In this regard, pollution from the soil can penetrate into the well, and when building wells, they are located away from garbage cesspools, cemeteries and sewers.
Exploring the well, you can get acquainted with the influx of groundwater. To do this, you need to measure the depth of the well with a rope with a heavy metal glass at the end, attached to it upside down. When hitting the water in the well, a loud sound is made. In the morning and in the evening, the water levels in the well are different due to water consumption and groundwater inflow. A bottle of water is taken from the well for chemical analysis in the school office.
Excursion to the river. Going on an excursion to the river, you need to familiarize yourself with the map of the river and its basin. If this river is small, with high school students, you can measure the speed of the current and its flow.
The flow rate is measured with floats. Choose two alignments - upper and lower. The distance between the gates is taken so that the duration of the float along the rod of the river between them is not less than 25 seconds. Above the upper alignment at a distance of 5-10 m, another launching alignment is selected. It is done so that the float thrown in this alignment, when approaching the upper alignment, takes the speed of the stream jets. After laying out the alignments, the areas of living sections are measured at two alignments. The measurement of living sections is carried out by measuring the depths with a rail or pole with divisions at regular intervals, usually at 1/50 or 1/20 of the width of the river, along the towline, which is pulled on each alignment from coast to coast. The open area can be calculated by the formula: W \u003d (n 1 + n 2 + n 3 ... n n ⋅ b, where n are the measured depths, b are the intervals between measurements in meters. Wooden circles are used as floats, sawn off from a log with a diameter of 10-25 cm and having a height of 2-5 cm.For better visibility, the floats are painted with bright paint or provided with flags.It is desirable that the float protrude as little as possible above the surface of the water to avoid the action of the wind.
On rivers up to 20 m wide with a more or less fast current, at the launch site, 10-15 floats are successively thrown into the pitch area. The moments of the passage of each float through the upper and lower sections are marked by a stopwatch, and the duration of the float T between the sections is calculated.
The float speed V pop is found by the formula
| V pop | L | , |
| T |
where L is the distance between the gates, T is the float passage time in seconds. Of all the floats, two are selected that have the highest speeds, and V max is derived from them. pov. - the average maximum surface velocity of water in the river. Then calculate the average flow velocity of the entire river V cf = 0.6 V max. pov. and the average free section area W for two alignments - upstream and downstream. The flow rate of the river Q is determined by the formula
Q \u003d V cf × W.
For example, we point out that the discharge of the Moskva River near Pavshin is on average about 50 m 3 per second.
On the river, the temperature and transparency of the water are measured in deep places, near the shore, near springs and tributaries. Differences indicate the presence of flow jets.
It is useful to have students talk with local fishermen. It is advisable to visit fishing with a net carried out by the local population and see representatives of the local ichthyofauna.
When observing small river organisms, attention should be paid to adaptations to life in fast-flowing water. Thus, mayfly larvae, which can be found under stones, have a flattened shape that protects them from being moved by the current. Mayfly larvae differ from similar stonefly larvae in three tail filaments.
The adaptations of caddisfly larvae consist in the formation of strong houses from the surrounding material (grains of sand, leaves, sticks), thanks to which the animal is protected from damage when rolling along the bottom. In addition, caddisfly larvae have strong hooks with which they can cling to plants or other hard substrate. Among the larvae of caddisflies there are predators, so it is dangerous to place them in the same aquarium with fish fry.
Near the banks in the rivers you can find large bivalve mollusks (toothless and barley), crawling along the bottom in places with silt rich in organic matter. They partially burrow into the silt, exposing their respiratory siphons into the water above the silt to draw clear water to their gills.
Excursions to the lake or pond. There are several excursions to the lake:
1) for plan shooting; 2) for depth measurement; 3) to get acquainted with plants and animals. An excursion to the lake can be replaced by a visit to a quiet backwater of the river, which, according to the regime, approaches it.
The first excursion to the lake is carried out along the banks.
If the lake or pond is small, then it is quite possible to shoot its plan with high school students. It is recommended that you familiarize yourself with the methodology of this case according to Lipin's book and use the method in which the compass is used. Two people work with the compass, the rest set milestones and measure distances. Coastal places are applied to the plan: villages, arable land, vegetable gardens, forests, streams flowing into a reservoir. At home, students draw a plan on a certain scale. The task is to calculate the area of the lake.
The next excursion to the lake is by boat. This excursion, as well as the previous one, should be carried out with older students. Having chosen a stable flat-bottomed boat, they swim across the lake in a straight line. If we measure the depth at several points along the course of the boat, we will obtain data for compiling a longitudinal profile of the lake.
During the next trip, temperature and water transparency are measured and living material is collected. Five students are needed to collect material, at least three students and a teacher: a rower, a helmsman, a planktonist, a collector of plants and bottom organisms, and one person for all records. In no case should you overload the boat with extra people above the norm.
The work is distributed as follows: the rower rows and at certain intervals, at the command of the leader, stops the boat. It's good to have an anchor that keeps the boat in place while you work. The helmsman gives the direction of the boat, he can also make entries in the diary and write labels. When the boat stops, one person measures the temperature (first the air in the shade, then the water), depth, and transparency.
The plankton net is lowered into the water by the planktonist at a quiet speed of the boat and, holding it barely under the surface of the water for 5-7 minutes, pulls it behind the boat. After that, the mesh is taken out, the contents are concentrated in the lower funnel of the mesh, washed off into a bottle and immediately fixed on the boat with alcohol, adding 1 part of alcohol to 2 parts of water. It can also be fixed with formalin (5 cm 3 per 100 cm 3 of water) or even table salt solution (about 1 teaspoon per 100 cm 3 of water). Organisms are well preserved in formalin, but it is necessary to work with it with caution and in no case should it be given undiluted to children, since it is very caustic; this fixator can be used when working only with those students who can be relied upon.
One of the participants in the boat trip should be busy collecting plants, as some plants cannot be obtained from the shore. When collecting plants, the teacher draws the attention of students to the location of plants in zones.
Plants on the boat can be collected in wet pieces of gauze, provided with labels written in pencil on parchment paper, and placed in a herbarium folder when they return to shore.
In order to beautifully arrange small filamentous algae on paper, you must first immerse them together with paper in water and then carefully remove them; then the individual threads will lie flat on the sheet, after which they can be dried.
During a detour on a boat, the teacher draws attention to the flowering of the reservoir. If the flowering is intense and gives the water a thick color, you can directly scoop the water into a bottle, fix it with alcohol and then examine it in the laboratory under a microscope.
A special excursion is carried out along the shore on foot to explore the littoral of the lake, i.e., the coastal zone of higher vegetation. Plants are collected for the herbarium, the rhizomes of aquatic plants are dug out, green threads are taken into jars. The definition of plants can be carried out according to the books of Yu. V. Rychin (1948) and A. N. Lipin (1950) or other plant determinants. Not only older, but also younger students (grade IV) can participate in such an excursion, but the teacher can change the program of the excursion in accordance with the level of knowledge of students.
The littoral zone with thickets of plants is the most lively and rich in organisms, since plants are a solid substrate for attaching organisms, they release the oxygen necessary for respiration and, when they die, give organic remains that serve as food for aquatic animals.
Among the vegetation, one can find water beetles and other insects, as well as their larvae, visible with the naked eye or through a magnifying glass.
Before catching animals, the student observes their behavior underwater. He records on which plants or on what soil a given specimen was found. On a quiet summer day, the underwater population is clearly visible along the banks of shallow reservoirs. Let the students try, by observing a beetle, worm, or insect larva, to decide how this organism eats, how it breathes, whether it is a predator or itself becomes a victim of others. Back at school, you can examine in more detail the signs of each organism under a microscope.
Approximate tasks for individual links of excursionists can be the following: 1) catching nets between plants; 2) scrapings of organisms attached to stems, leaves of plants and pitfalls; 3) collection by dredge of benthic organisms living in silt. The material obtained in this way is easy to systematize according to the habitats of animals and to link the distribution of organisms with living conditions.
To extract the organisms, the sludge collected by the dredge is washed through a sieve (the size of the sieve mesh is 0.5 mm). Silt should be taken from the surface layer, since it is here that there are most organisms. Usually, red bloodworm larvae, worms and small mollusks live in the silt, which must be viewed through a tripod magnifier and under a microscope, it is better to live, and before that it should be kept in a jar of water. If the day is hot and the laboratory is far away, they should be preserved in alcohol or other fixative.
When examining the water surface, water striders and small dark shiny beetles are striking. Consider the eye of a bug under a magnifying glass: when swimming, the lower half of their eye is immersed in water, and therefore it is arranged differently than the upper one. Of the large beetles, the water-loving, swimmer and their larvae are most often found. Water beetles breathe atmospheric air. They are good swimmers, as indicated by the structure of their limbs (Fig. 11).
Water bugs - smooth, comb, water scorpion - are distinguished by a sucking proboscis at the mouth.
Mollusks crawl on the floating leaves of plants (a large pointed pond snail, a coil, a lawn - all these mollusks belong to gastropods) and mollusk caviar is attached in the form of transparent mucous strands and rings.
Acquaintance with the signs of water pollution. When bypassing the banks and collecting material, you need to pay attention to whether there are signs of pollution of the reservoir. The teacher, together with the students, can be of direct benefit by reporting to the district sanitary inspectorate or the branch of the Nature Conservation Society about the presence of pollution in a given place.
Cemeteries, settlements, factories, barnyards are all sources of pollution. However, both high school and junior high school students should be aware that river currents sometimes carry pollutants downriver away from pollution sources and deposit them in quiet backwaters.
According to the requirements of the state standard (GOST), clean water of the reservoir should not have a foreign smell, its color when observed in a layer 10 cm high should not be clearly expressed, continuous floating films should not form on the surface in the reservoir. These requirements of GOST must be taken into account. On the tour, you can scoop up water in a bottle for research in the laboratory.
If traces of oil are visible on coastal plants and stones near the shore of a reservoir, if an extraneous smell is felt, for example, phenol, hydrogen sulfide, oil, etc., oil and litter films float on the surface of the water, or even clusters of blue-green or black cakes form - this means that the reservoir is polluted. It is forbidden to drink water from polluted reservoirs, swim in them, and samples must be collected carefully so as not to get harm. A sample from the accumulations of blue-green algae on the surface of the water should be taken into a jar for viewing under a microscope. Accounting for the degree of contamination by chemical analysis or microscopy of samples is available for students not lower than grade VII.
One of the ways to distinguish clean water bodies from polluted ones is microscopic analysis of the composition of coastal fouling that forms a border on underwater objects near the water's edge.
Practically pure reservoirs are characterized by bright green fouling of algae from the green group (cladophora, edogonia, etc.) or a brownish coating of diatoms. In clean reservoirs, there is never a white flocculent fouling, characteristic of polluted reservoirs.
Fouling of blue-green color, consisting of algae of the blue-green group (a number of species of oscillatoria), characterizes not clean, but polluted water (with an excess of organic pollution). Similar fouling occurs in runoff with an excess of total salinity.
Fecal sewage gives white-grayish flocculent fouling, consisting of attached ciliates (carhezium, suvoyki). Such fouling indicates poor treatment of wastewater after treatment plants.
The whitish-yellow mucous deposits of filamentous spherotilus bacteria, which also develop in the zone contaminated with organic substances, almost do not differ from them in appearance. Spherotilus sometimes produces powerful, felt-like pillows.
Poisonous effluents entering the reservoir in high concentrations can cause the complete or partial death of living organisms. Therefore, a comparison of the composition of animals above the release and below the release of polluted water will give us an idea of the degree of the harmful effect of runoff on the reservoir. The complete absence of fouling below the drain also indicates a strong (poisonous, toxic) effect of the drains.
When examining, attention should be paid to the state of higher (flowering) aquatic vegetation - pondweeds, reeds, reeds, etc. Poisonous drains can inhibit vegetation, and, conversely, the presence of biogenic salts (nitrogen, phosphorus, as is the case, for example, phosphorite mines) causes excessive development of vegetation.
If the familiarization with the lake or river can be continued in winter, then the degree of pollution can be more reliably established. The winter season is, as it were, a touchstone, since in winter the reservoir is isolated from the air by ice and the supply of oxygen in case of severe pollution may be insufficient for a long winter. With a lack of oxygen, a freeze occurs, and the sleeping fish emerges in the holes.
Hot at times for the protection of water bodies for schoolchildren and young naturalists should be spring, before the flood. At this moment, the snow melts and all the pollution along the banks of the reservoirs is exposed. If time does not take care of cleaning the shores, then the spring melt water and high water will wash away all the dirt into the reservoir, harming the fish industry, and for a long time will deprive the population of the opportunity to use water. The task of schoolchildren is to organize, together with the teacher under the guidance of a sanitary doctor, local residents for the timely cleaning of industrial and household waste from the banks of the reservoir.
Water pollution has a detrimental effect on fish. From a lack of oxygen in the water or a large amount of toxic substances, fish die - suffocation, and without visible changes in organs and tissues. When heavily contaminated with toxic substances, the fish sometimes rush about randomly, float to the surface, lie on its side, make sharp movements in a circle or jump out of the water and, as if exhausted, sink to the bottom with wide open gill covers.
In the case of chronic poisoning of carp, bream, ide, the phenomenon of dropsy is noted: ruffling of the scales with a large accumulation of fluid under it. Bulging is often noticeable. Changes in the internal organs are also noticeable: instead of a normal cherry color and a relatively dense consistency, the liver becomes dirty whitish, sometimes marbled, flabby, in some cases it is a shapeless mass. The kidneys are also often off-white in color and flabby in texture. However, similar changes are also observed when fish are infected with rubella.
All these signs of poisoning can be observed on fish, which the guys can either catch themselves or inspect with fishermen. It is useful to tell the fishermen about the listed signs of fish poisoning. Seventh grade students who are familiar with the anatomy of fish can conduct such conversations themselves.
Excursion material processing
Material Definition. After the tour, the collected material must be put in order and processed at the school.
Sixth grade students identify aquatic plants by determinants. It can be determined not only by flowering specimens, but also by one leaf (according to the book by Yu. V. Rychin, 1948).
In order to quickly understand the structural features of organisms, the teacher first determines the mass forms, writes down their main features, and then distributes to each of the students a copy of the same species for examination under a magnifying glass or microscope.
As an example, let's consider the dragonfly larva "rocker" (with students of grades VI-VII). This is a large larva. It has three pairs of jointed legs, like all insects. The shell of the larva is hard chitinous. Let's put a live larva in a deep saucer with water and observe its movement. It has a jet mode of movement: a jet of water is ejected from the posterior end of the intestine, and the larva thereby makes a jump forward. Sometimes you can find empty skins of larvae, from which an adult dragonfly has already been released. The larva on the underside of the head has a mask covering the lower jaw. If you carefully take an inanimate larva in your left hand, then you can pull the mask forward with tweezers or a stick. It serves the larva for catching prey.
If students, for lack of time, cannot use the guides, then it is enough for them to tell the names of individual large representatives of the fauna and indicate only some of the most characteristic features. It is very useful to sketch animals, at least 2-3 copies. Sketches must be approached strictly: the drawing should not be made from a book, but from life, similar to an object and reflect characteristic features.
For pupils of the sixth grade, it is available to examine beetles, water bugs, insect larvae, small mollusks, leeches under a tripod magnifying glass.
Independent work with a microscope and sketches of preparations can be entrusted to older students only after they have acquired the skill in a circle.
Under a microscope, consider: 1) algae that create a blooming reservoir; 2) contaminated films with accumulations of algae; 3) filamentous algae; 4) contaminated growth removed from objects in the coastal part of lakes and rivers; 5) small organs of aquatic animals that are characteristic features of the species, such as mayfly gill filaments; 6) daphnia (they are considered as a whole and better in a live form); 7) plankton (examined in a drop in a living form or fixed in alcohol).
Under the microscope, it can be seen that the fouling, which is green, consists of filamentous green algae (should be viewed under a high magnification of the microscope; the preparation is being prepared by the teacher). Filamentous algae in each cell have a green chromatophore in the form of a plate, spiral or grains.
Colorless filaments of fungus, mold or filamentous bacteria are found in the contaminated area. These threads are very thin, sometimes only a few microns in diameter (1 micron is equal to 1/1000 of a millimeter). The threads show division into cells (at high magnification).
Whitish fouling also occurs in the polluted area. Under a microscope, among them one can distinguish ciliates - suvoek, and others, having the shape of a bell, attached with a thread-like leg to a solid substrate.
Observations and experiments on living objects. Some animals can be placed in an aquarium to observe their movement, breathing and feeding. This can be done with beetles, dragonfly larvae, water bugs, clams, coil and pond snail. In order to determine the toxicity of river water as a result of industrial runoff entering it, in high school it is quite possible to put a three-day experiment on the survival of aquatic organisms in this water. Daphnia is best used for testing, but leeches or molluscs can also be used; mayfly larvae and bloodworms are not suitable for this, since these latter do not live well in laboratory conditions. Daphnia are caught in any small pond and kept until experience in a jar of clean water. In small cones, they pour the water from the reservoir that they want to test for toxicity. For comparison, obviously pure river water is poured into other exactly the same cones. 10-12 pieces of daphnia are placed in each cone. Daphnia should be transplanted with a small sparse mesh quickly and carefully, trying not to dry or crush the crustaceans. Immediately after transplantation, check whether the crustaceans are well preserved, and exclude those flasks where they are poorly preserved from the experiment. In the remaining flasks, observe the state of the organisms for 2-3 days. If daphnia both in the experiment and in the control swim normally, then the water is harmless to the reservoir.
Chemical analyzes of water. If there is a chemical laboratory in the school, some chemical analyzes of water can be carried out, for example, determining the active reaction (acidity and alkalinity) of water. For this, one sample is taken from a reservoir near the wastewater outlet and, for comparison, another sample is taken from its clean area. In both samples, add 2-3 drops of the methyl orange indicator, which changes color from red in an acidic environment to yellow in an alkaline one. In the case of contamination by industrial effluents, the color of the test and control samples will be different.
The color of water is determined in cylinders 10 cm high, comparing contaminated water with distilled water.
Determination of the hardness of water from a well is carried out with soap suds. You need to make a solution of soap in alcohol. Pour water from different wells into a row of cones or bottles, and distilled water into one of them. Then you should gradually add a soapy solution from a burette or pipette, shaking the liquid in the flask. In distilled water, foam is formed from a few drops of soap, and the harder the water, the more soap is needed to form foam.
Material design. The materials collected on the excursion are arranged for the school museum in the following way.
Aquatic flowering plants are collected in a herbarium on sheets in a folder or on a stand under glass. You can make a poster-scheme of the distribution of aquatic vegetation of the pond by zones (see Fig. 4).
The results of surveying the plan of the pond and measuring the depths are drawn in the form of a drawing-scheme, as well as a model of the pond, with the application of the coastal landscape and coastal settlements.
Calculations of the area of the lake, the amount of water in the lake, the flow of water in the river, the velocity of the river can be compared with the measurement data of the district water gauge.
Collections of aquatic insects are made dry on pins in boxes, insect larvae are stored in test tubes or jars of alcohol, filled with paraffin, with labels.
Drawings of microscopically small forms and drawings made when identifying species, indicating the distinguishing features, are drawn up in the form of an album. An album or an exhibition of photographs taken by the students themselves on the pond is also compiled.
The final conversation of the teacher is devoted to the national economic significance of this reservoir, the possibility of breeding fish or fishing in it, the degree of pollution of the reservoir and measures for its protection.
Literature
Gribanov L. V., Gordon L. M., Increasing the intensity is the main thing in the development of pond fish farming in the USSR, Sat. "The use of ponds for intensive fish farming", M., 1961.
Dorokhov S. M., Lyaiman E. M., Kastin B. A., Solovyov T. T., Agricultural fish farming, ed. Moscow Union of Artists, Moscow, 1960.
Eleonsky A. N., Pond fish farming, Pishchepromizdat, M., 1946.
Life of fresh waters of the USSR, ed. Zhadina V.I., ed. Academy of Sciences of the USSR, M. - L., 1940-1956.
Kulsky A. A., Chemistry and technology of water treatment, 1960.
Landyshevsky V.P., School and fish farming. State. uch. ped. ed., M., 1960.
Lipin A.N., Fresh waters and their life, M., 1950.
Martyshev G. V. et al., Pond fish farming on collective farms and state farms, 1960.
Polyakov Yu. D., A guide to hydrochemistry for fish farmers, Pishchepromizdat, M., 1960.
Raikov B. E. and Rimsky-Korsakov M. N., Zoological excursions, 1938.
Rychin Yu. V., Flora of hygrophytes, 1948.
Skryabina A., My work with young naturalists, ed. "Young Guard", 1960.
Cherfas B.I., Fish farming in natural reservoirs, Pishchepromizdat, M., 1956.
Zhadin V.I., Gerd S.V., Rivers, lakes and reservoirs of the USSR, their fauna and flora, Uchpedgiz, 1961.
Most of the surface of the Earth is covered with water, which as a whole makes up the oceans. On land there are sources of fresh water - lakes. Rivers are the lifeblood of many cities and countries. The seas feed a large number of people. All this suggests that there can be no life on the planet without water. However, man neglects the main resource of nature, which has led to huge pollution of the hydrosphere.
Water is necessary for life not only for people, but for animals and plants. Spending water, polluting it, all life on the planet is put under attack. Water reserves on the planet are not the same. In some parts of the world there is a sufficient number of water bodies, while in others there is a large shortage of water. Moreover, 3 million people die every year from diseases caused by drinking poor quality water.
Causes of water pollution
Since surface waters are the source of water for many settlements, the main cause of water pollution is anthropogenic activity. The main sources of pollution of the hydrosphere:
- domestic waste water;
- operation of hydroelectric stations;
- dams and reservoirs;
- the use of agricultural chemistry;
- biological organisms;
- industrial water runoff;
- radiation pollution.
Of course, this list can be continued indefinitely. Quite often, water resources are used for some purpose, but when they are discharged into water, they are not even cleaned, and polluting elements extend the range and deepen the situation.
Protection of water bodies from pollution
The condition of many rivers and lakes of the world is critical. If the pollution of water bodies is not stopped, then many aquatic systems will cease to function - to clean themselves and give life to fish and other inhabitants. Including people will not have any water supplies, which will inevitably lead to death.
Until it's too late, water bodies need to be taken under protection. It is important to control the process of water discharge and the interaction of industrial enterprises with water bodies. It is necessary for every person to save water resources, since excessive water consumption contributes to the use of more of it, which means that water bodies will become more polluted. The protection of rivers and lakes, the control of resource use is a necessary measure in order to preserve the planet's supply of clean drinking water, which is necessary for life for everyone without exception. In addition, it requires a more rational distribution of water resources between various settlements and entire states.
Cleanliness of water bodies: pollution, self-purification, protection
Introduction
At all times, water was considered the priceless moisture of life. And although those years are far behind when it was necessary to take it in rivers, ponds, lakes and carry it several kilometers to the house on yokes, trying not to spill a single drop, a person still treats water with care, taking care of the cleanliness of natural reservoirs, of good condition of wells, columns, plumbing systems. In connection with the ever-growing needs of industry and agriculture in fresh water, the problem of preserving existing water resources is becoming increasingly acute. After all, water suitable for human needs, as statistics show, not so much on the globe. It is known that more than 70% of the Earth's surface is covered with water. About 95% of it falls on the seas and oceans, 4% - on the ice of the Arctic and Antarctic, and only 1% is fresh water of rivers and lakes. Significant sources of water are underground, sometimes at great depths.
About 4.5 thousand km3 - a sea of water - this is the annual flow of our rivers. However, the distribution of water resources throughout the country is uneven. Consumers, using water, pollute it, this gradually leads to the depletion of clean fresh water and the need to take measures to protect it. Such water use, without affecting the amount of water, significantly affects its quality. The Party and government pay great attention to questions of nature protection and the rational use of its resources, including water. This is evidenced by such laws on nature protection adopted in the USSR, such as the “Fundamentals of Water Legislation of the USSR and the Union Republics”, the resolution of the Central Committee of the CPSU and the Council of Ministers of the USSR “On additional measures to ensure the rational use and conservation of the natural resources of the Baikal basin” (1971) .
In recent years, many powerful treatment facilities have been put into operation, the efficiency of cleaning wastewater discharged into water bodies has been increased, and the responsibility of economic bodies has increased. A difficult task, which required billions of dollars, was the protection of the river. Volga and Ural, lake. Baikal and our other reservoirs from industrial pollution. Water in our country is a nationwide property, and care for it should be nationwide and constant. Not only the development of industrial and agricultural production, but also the life and health of Soviet people today and in the future depend on the rational use of water resources, on a careful, economical attitude towards them. Our country - world leader in scale and the pace of water management construction, the creator of a comprehensive sanitary and epidemiological service and public health, its preventive direction. The most important property of water is its continuous circulation. There are two circles in it - horizontal and vertical. The exchange of water in the horizontal direction is carried out by sea currents and rivers. The mighty ocean current alone, the Gulf Stream, carries 25 times more water from south to north for thousands of kilometers in a year than all the rivers of the land.
The vertical circulation is made up of evaporation from the surface of the oceans, seas, lakes and atmospheric precipitation falling both on the water surface and on land. The energy of the sun's rays makes the oceans release 355,000 km3 of water to the atmosphere per year. Only 1/10 of this amount falls over land in the form of rain or snow, the rest returns to the oceans. But the whole life of the continents is largely due to these precipitations. Huge volumes of water pass living organisms, using it for life processes. Not a single life process in the human or animal body can take place without water, and not a single cell is able to do without an aquatic environment. With the participation of water, almost all functions of the body proceed. So, evaporating from the surface of the skin and respiratory organs, water takes part in the processes of thermoregulation.
But you need water of course, not only for drinking: it also helps to keep a person's dwelling and habitat clean. Water is the best hygienic agent for facial skin care. When washing, the cells of the stratum corneum of the skin swell and are rejected along with the dust, dirt, fat, and sweat residues that have settled on them. Patting and stroking the face while washing enhances the cleansing effect of the water. At the same time, blood circulation increases, metabolism increases, nutrition and skin tone improve. Water in the human body is both a medium and a direct participant in physiological and biochemical reactions. Various substances formed as a result of the metabolism of substances are excreted from the body with water. Imagine that such polluted water directly from a river or lake is used for drinking. The causative agents of diseases, getting into the human intestine, find favorable conditions for reproduction there, as a result of which an acute intestinal disease occurs. Since a large number of people usually use one source of water supply, the way the disease spreads through water is the most massive, and therefore the most dangerous.
Self-purification of reservoirs
The most interesting phenomena of nature are the ability of water bodies to self-cleanse and the establishment of the so-called biological balance in them. It is provided by the combined activity of the organisms inhabiting them: bacteria, algae and higher aquatic plants, various invertebrate animals. Therefore, one of the most important conservation tasks is to maintain this ability.
Each reservoir is complex living system, where plants live, specific organisms, including microorganisms that constantly multiply and die. If bacteria or chemical impurities get into the reservoir, then in the conditions of virgin nature, the process of self-purification proceeds quickly and the water restores its original purity. The factors of self-purification of water bodies are numerous and diverse. Conventionally, they can be divided into three groups: physical, chemical and biological. An important physical factor in the self-purification of water bodies is the ultraviolet radiation of the sun. Under the influence of this radiation, water is disinfected. The disinfection effect is based on the direct destructive effect of ultraviolet rays on protein colloids and enzymes of the protoplasm of microbial cells. Ultraviolet radiation can affect not only ordinary bacteria, but also spore organisms and viruses.
Of the chemical factors of self-purification of water bodies, oxidation of organic and inorganic substances should be noted. Self-purification of a water body is often assessed in relation to easily oxidized organic matter (determined by biochemical oxygen demand - BOD) or by total organic matter (determined by chemical oxygen demand - COD).
Algae, molds and yeasts are involved in the process of self-purification of the reservoir. bivalves- permanent inhabitants of water bodies - are orderlies rec. Passing water through themselves, they filter out suspended particles. The smallest animals and plants, as well as organic residues, enter the digestive system, inedible substances settle on a layer of mucus covering the surface of the mantle of bivalves. Mucus, as it gets dirty, moves to the end of the shell and is thrown into the water. Its lumps are a complex concentrate for the nutrition of microorganisms. They complete the chain of biological water treatment.
Sources of pollution
The main cause of pollution of water sources is the discharge of untreated or insufficiently treated wastewater into water bodies by industrial enterprises, as well as municipal and agricultural enterprises. Irrational agriculture also contributes to the pollution of water sources: the remains of fertilizers and pesticides washed out of the soil enter water bodies and pollute them. Although the loss of water in many industrial processes (due to evaporation and leakage) is small, in total, industrial enterprises consume a huge amount of water, and some of it is lost forever or is not subjected to any treatment.
With the ability of rivers to cleanse themselves thanks to the biological processes taking place in them, it made it possible to cope with waste. The fact that most cities, and with them large enterprises, were built on watersheds and in the upper reaches of rivers, was previously perceived only as a historical landmark. Cities grow like people, only more slowly. And a person in his life does not always have time to assess how the needs of the city in water have changed. And there are changes, and sometimes quite significant ones. After all, reservoirs in the current conditions are a place not only for water intake (withdrawal of water for industrial, drinking and other needs), but also for receiving wastewater. Modern agricultural production, like industry, can be a source of pollution. Mineral salts washed out from irrigated lands pollute water bodies, pesticides, phosphorus and nitrogen fertilizers are often used uncontrollably. Excess chemicals poison the animal and plant world of reservoirs. In addition, chemicals can accumulate in products, thereby posing a considerable threat to human health.
The sources of water pollution in rural areas also include large livestock complexes. The source of pollution of water bodies with harmful substances is the sewage of ships. In recent years, reservoirs and rivers have received many thousands of units of the so-called small size fleet: boats, various boats with outboard motors. With a roar, with a white surf trail, with circular turns, throwing out exhaust gases, they rush back and forth across the blue waters. It is known that 1 g of petroleum products spoils 100 liters of water. Wherein the content of oil products exceeds the permissible level. A wave raised by a rapidly rushing boat reaches the shore, destroys it, the shore is intensively eroded. There is still a very significant source of water pollution, which is practically uncontrollable. These are storm and snow runoff from the territory of the forest, agricultural land, etc. In terms of pollution, such waters flowing from vast territories are often comparable to city sewer waters.
Sanitary protection of the reservoir
In accordance with the Fundamentals of the Water Legislation of the USSR and the Union Republics, which were adopted in December 1970 by the Supreme Soviet of the USSR, schemes for the integrated use and protection of waters are being developed. All measures should ensure the most efficient use of water for the national economy (taking into account the priority satisfaction of the population's water needs) by regulating the flow of water, taking measures to conserve water and stop the discharge of untreated wastewater through improved production technology. -stva and schemes of water supply (use of waterless technological processes of air cooling, circulating water supply and other technical methods). The Fundamentals of the Water Legislation of the USSR and the Union Republics states that all waters, water bodies are subject to protection from pollution, clogging and depletion that affect water quality in such a way that they can harm public health, lead to a decrease in fish stocks, worsen conditions of water supply and cause other unfavorable consequences as a result of changes in the physical, chemical, biological properties of water, a decrease in the ability to naturally purify, a violation of the hydrological and hydrogeological regimes. The definition of the concept of “water pollution” in the legislation requires all water users to comply with the necessary requirements, which are set out in the “Rules for the Protection of Surface Waters from Wastewater Pollution” (1974).
The most important component of modern Soviet water and sanitary legislation is hygienic standards - the maximum permissible concentrations (MPC) of harmful substances in the water of reservoirs. Compliance with these MPCs creates safety for public health and favorable conditions for sanitary and household water use. They are a criterion for the effectiveness of various measures to protect water bodies from pollution, stimulate progress in the field of industrial technology for the most complete compliance with regulatory requirements corresponding to the favorable sanitary condition of water bodies. The role of hygienic MPCs in the implementation of the examination of projects and in determining the conditions for the discharge of wastewater into a reservoir in order to predict its sanitary condition is enormous. Hygiene standards are an important part of “ Rules for the Protection of Surface Waters from sewage pollution. Hygienic MPCs provide safe and normal conditions for the use of water by the population (drinking and cultural and domestic). MPCs of harmful substances in the water of reservoirs as hygienic standards make it possible to distinguish levels of pollution that directly or indirectly affect the sanitary conditions of water use and public health, from levels of pollution that affect not so much the interests of health as other national economic interests of the population.
Developed in the late 1940s by Prof. S. N. Cherkinsky, the methodological scheme for the hygienic study of the possible influence of industrial effluents entering water bodies and the harmful substances contained in them has become generally recognized. Such a study should be multifaceted and complex. It should characterize regulated substances according to the main three indicators of harmfulness - the impact on the general sanitary regime of water bodies, on the health of the population and the organoleptic properties of water, when taste, color, smell are determined using the senses. The hygienic criterion of harmfulness is based on the degree of restriction on water use caused by pollution that poses a danger to health or worsens the sanitary living conditions of the population.
According to the "Rules for the Protection of Surface Water from Pollution by Sewage", water bodies and watercourses (water bodies) are considered polluted if the indicators of the composition and properties of water in them have changed under the direct or indirect influence of production activities and household use by the population and have become partially or completely unsuitable for one of the types of water use. The criterion of water pollution is the deterioration of its quality due to changes in its organoleptic properties and the appearance of harmful substances for humans, animals, birds, and fish. An increase in water temperature changes the conditions for the normal life of aquatic organisms. The suitability of the composition and properties of surface waters used for domestic and drinking water supply and cultural and household needs of the population, for fishery purposes, is determined by their compliance with the requirements and standards set out in the document mentioned above.
There are two categories of water use. First category- use of a water body as a source of centralized or non-centralized domestic and drinking water supply and for water supply to food industry enterprises; the second category is the use of a water body for swimming, sports and recreation of the population, the use of water bodies within the boundaries of populated areas. The water use points of the first and second categories closest to the place of wastewater discharge are determined by the bodies and institutions of the sanitary and epidemiological service with the obligatory consideration of official data and prospects for the use of a water body for drinking water supply and cultural and domestic needs of the population.
Composition and properties of water and water bodies must comply with the standards in the site (a certain section of the reservoir) located on water currents 1 km upstream of the nearest water use point (water intake for domestic and drinking water supply, bathing places, organized recreation, the territory of a settlement, etc. . p.), and on stagnant water bodies and reservoirs - 1 km on both sides of the water use point. When wastewater is discharged within the city (or any settlement), the first point of water use is this city (or settlement). In these cases, the established requirements for the composition and properties of the water of a reservoir or watercourse should apply to the wastewater itself. The composition and properties of a water body at points of domestic drinking and cultural and domestic water use, or according to one of the indicators, should not exceed the MPC of harmful substances in water objects of domestic drinking and cultural and domestic water use. MPCs are currently set for bolt 800 substances.
One of the essential structures for the protection of water bodies is sewerage, which is a complex of sanitary and engineering structures that ensure the collection and rapid removal of polluted wastewater from populated areas and industrial enterprises, their purification, disinfection and neutralization. Domestic wastewater treatment methods are divided into mechanical and biological. For mechanical cleaning wastewater is the separation of the liquid and solid phases of wastewater. For this purpose, the following structures are used: gratings, sand traps, settling tanks (horizontal and vertical), septic tanks, two-tiered settling tanks. The liquid part of wastewater undergoes biological treatment, which can be natural or artificial. Natural biological wastewater treatment is carried out in filtration fields, irrigation fields, biological ponds, etc. For artificial biological treatment, special facilities are used - biological filters, aerotanks. Sludge treatment. produced in sludge beds or digesters.
The regulation provides that state control over the use and protection of waters must ensure that all ministries, departments, enterprises, institutions, organizations and citizens comply with the established procedure for the use of waters, fulfill their obligations to protect them from pollution, clogging and depletion. It is necessary to comply with the rules for accounting for the use of water established by the Fundamentals of the Water Legislation of the USSR and the Union Republics. The work on the sanitary protection of water bodies is carried out by the epidemiological service in accordance with the "Regulations on State Sanitary Supervision in the USSR" of 1973. The bodies of the sanitary and epidemiological service of the Ministry of Health of the USSR are responsible for the protection of water bodies - an aspect that affects the interests of health and sanitary living conditions population. The healthcare system has 4260 sanitary and epidemiological stations. By the Decree of the Central Committee of the CPSU and the Council of Ministers of the USSR "On measures to further improve health care and the development of medical science in the country" (1968), a wide network of sanitary laboratories was created at enterprises to study the composition of wastewater and the quality of water in reservoirs. Each laboratory conducts tens of thousands of analyzes of water and water of reservoirs a year.
The sanitary laboratory and its branches at the treatment facilities work according to a single plan approved by the management of the enterprise after detailed coordination with the sanitary and epidemiological service. The objects of sanitary observations are reservoirs that are used for household, drinking and cultural needs of the population. At the same time, the observation sites are timed to the points of sanitary and household water use. Sanitary condition of reservoirs, having a fishery significance, and the implementation of measures for their protection is controlled by the fish protection authorities of the USSR Ministry of Fisheries. Control over the use and protection of underground waters, as well as the study of their condition, is carried out by the USSR Ministry of Geology. When conducting sanitary observations of the state of water bodies, it is necessary to collect information about the main sources of pollution. At the same time, the issues of sanitary improvement of the settlement, the conditions for the disposal of its wastewater, data on other sources of pollution, in particular on industrial and other facilities that discharge wastewater, the quality and composition of discharged wastewater, the nature of treatment and disinfection, etc. d.
Materials on the quality of water in reservoirs are linked with data on their hydrogeological regime, which makes it possible to evaluate the results of sanitary laboratory studies and use them in predicting the quality of water in reservoirs. In conditions of water pollution, it is necessary to find more effective means of monitoring water quality. An automated water quality control system for the entire Moscow water basin - ANKOS - V (automatic monitoring of environmental control - water) was created. It provides automatic measurement and data transmission to the information processing center from an electronic computer, and from there through the control room directly to consumers. ANKOS-V will allow not only to quickly fix the level of water pollution, but also to regulate the quality of water when docked with an automated wastewater control system, to quickly evaluate the effectiveness of measures to protect the aquatic environment. ANKOS - V will serve as a prototype of similar systems throughout the country.
Posts on the banks of the rivers
In every Union republic there are nature protection societies, numbering about 35 million members, which help government bodies in the implementation and control of the use of legislation, as well as in planning measures for nature protection.
Concern for the purity of water opens up a wide field of activity for the public, members of the Society for the Protection of Nature.
Concerns about nature are rewarded with its generosity, the growing economy, and the joy of people. An example of this is the complex transformation of the Desna basin, which is organically linked with the program for the renewal of the Non-Chernozem Region, with five-year and long-term plans for the region.
Over the past decade, detachments of "green" and "blue" patrols, school forestries, detachments to combat soil erosion have become widespread. Only in the Russian Federation there are 7 thousand school forestries, about 100 thousand "green" patrols and 17 thousand "blue ones".
Bibliography:
Yu. V. Novikov. "Keep waterways clean"
REPORT ON THE TOPIC: "PROTECTION OF WATER BODIES"
Plan:
Meaning, role in nature.
Causes of pollution.
Protection of water bodies:
For you to take.
What is a body of water???
Water - permanent or temporary accumulation of standing or with reduced in natural or artificial depressions ( , , etc.). In a broad sense, also - the designation and . Science studies water bodies .
By the way, about 71% of the surface covered with water , , , , ice) - 361.13 million km. On Earth, approximately 96.5% of water is in the oceans, 1.7% of the world's reserves are groundwater, another 1.7% are glaciers and ice caps and , a small part is found in rivers, lakes and , and 0.001% in clouds (formed from particles of ice and liquid water suspended in the air) .
There are reservoirs: artificial and natural
Natural water bodies include: stream, river, lake, sea
Artificial reservoirs include: reservoirs, pond, canal
Meaning, role in nature.
Great importance of reservoirs. Reservoirs are reservoirs of water, which is necessary for all living things. In addition, the water of reservoirs participates in the water cycle.The role of water in the formation and maintenance of on Earth, in the chemical structure of living organisms, in the formation and . Water is the most important substance for all living things on the planet. . And for those plants and animals that live in water bodies, this is the only home.
When you approach a reservoir in warm weather, you see only some of its inhabitants. It is impossible to see everyone. But there are a lot of them! A reservoir is a place where a wide variety of living beings live.
The role of plants in the reservoir is great. They serve plants and animals, release oxygen into the water, which is necessary for the respiration of organisms. Underwater thickets of plants serve as a refuge for animals.
There are many animals whose life is connected with water. These are animals, birds, fish, various small animals. Each reservoir creates its own living conditions. They depend on the size of the reservoir, its depth, water temperature, the flow of rivers and many other reasons. But all the animals living in the reservoir have adapted to its conditions.
When the plants and animals of the reservoir die, their remains fall to the bottom. Here, under the action of microbes, the dead remains rot and are destroyed. They form salts. These salts dissolve in water, and then they can be used to feed new plants.
Pollution of natural waters - this is a decrease in their biospheric functions and economic significance as a result of the entry of harmful substances into them.
Causes of pollution.
There are natural and anthropogenic pollution. Natural pollution occurs as a result of natural causes - volcanic eruptions, earthquakes, catastrophic floods and fires. Natural (natural) pollution - pollution of the environment, the source of which is natural processes and phenomena not directly caused by human activity: volcanic eruptions, dust storms, floods, natural fires, etc.
Anthropogenic (artificial) pollution
- the result of human activity. At present, the total power of anthropogenic pollution sources in many cases exceeds the power of natural ones.
Artificial (anthropogenic) pollution of water bodies is mainly the result of the discharge of sewage into them from industrial enterprises and settlements. Pollution entering the reservoir, depending on their volume and composition, can have a different effect on it:
1) the physical properties of water change (transparency and color change, odors and tastes appear);
2) floating substances appear on the surface of the reservoir and deposits are formed (sediment at the bottom);
3) the chemical composition of water changes (the reaction changes, the content of organic and inorganic substances changes, harmful substances appear, etc.);
4) the content of dissolved oxygen in water decreases due to its consumption for the oxidation of incoming organic substances;
5) the number and types of bacteria change (pathogenic bacteria appear), introduced into the reservoir along with wastewater. Polluted reservoirs become unsuitable for drinking, and sometimes for technical water supply; fish die in them.
In the first decade of the 21st century, anthropogenic pollution of natural waters has become global in nature and has significantly reduced the available exploitable fresh water resources on Earth.
Mankind consumes a huge amount of fresh water for its needs. Its main consumers are industry and agriculture. The most water-intensive industries are mining, steel, chemicals, petrochemicals, pulp and paper, and food. They take up to 70% of all water used in industry.
One of the main water pollutants is oil and oil products. Oil can get into the water as a result of its natural outflows in the areas of occurrence. But the main sources of pollution are associated with human activities: oil production, transportation, processing and use of oil as fuel and industrial raw materials.
Among industrial products, toxic synthetic substances occupy a special place in terms of their negative impact on the aquatic environment and living organisms. They are increasingly being used in industry, in transport, and in public utilities. The concentration of these compounds in wastewater, as a rule, is 5-15 mg/l at MPC - 0.1 mg/l. These substances can form a layer of foam in reservoirs, which is especially noticeable on rapids, rifts, locks. The ability to foam in these substances appears already at a concentration of 1-2 mg / l.
Other contaminants include metals (eg mercury, lead, zinc, copper, chromium, tin, manganese), radioactive elements, pesticides from agricultural fields, and runoff from livestock farms. A small danger to the aquatic environment from metals is mercury, lead and their compounds.
Tab. 1. The main pollutants of aquatic ecosystems in various industries
IndustryMain types of pollutants
Oil and gas production, oil refining
Petroleum products, synthetic surfactants, phenols, ammonium salts, sulfides
Timber industry, pulp and paper industry
Sulfates, organics, lignins, resinous and fatty substances
Mechanical engineering, metalworking, metallurgy
Heavy metals, fluorides, cyanides, ammonium compounds, petroleum products, phenols, resins
Chemical industry
Phenols, petroleum products, synthetic surfactants, aromatics, inorganics
Mining and coal industry
Flotation reagents, inorganics, phenols
Light, textile and food industry
Synthetic surfactants, petroleum products, organic dyes, other organic substances
A significant amount of hazardous pollutants such as pesticides, ammonium and nitrate nitrogen, phosphorus, potassium, etc., is washed away from agricultural areas. Mostly they enter water bodies and drains without any treatment, and therefore contain a high concentration of organic substances, nutrients and other pollutants.
The main consumer of fresh water is agriculture: 60-80% of all fresh water is used for its needs. Moreover, its irrevocable consumption is great (especially for irrigation).
Expanded production (without treatment facilities) and the use of pesticides in the fields lead to severe pollution of water bodies with harmful compounds. Pollution of the aquatic environment occurs as a result of the direct introduction of pesticides during the treatment of water bodies for pest control, the entry into water bodies of water flowing down from the surface of cultivated agricultural land, when waste from industrial enterprises is discharged into water bodies, as well as as a result of losses during transportation, storage and partially with atmospheric precipitation.
Along with pesticides, agricultural effluents contain a significant amount of fertilizer residues (nitrogen, phosphorus, potassium) applied to the fields. In addition, large amounts of organic compounds of nitrogen and phosphorus enter with runoff from livestock farms, as well as with sewage. An increase in the concentration of nutrients in the soil leads to a violation of the biological balance in the reservoir.
Initially, in such a reservoir, the number of microscopic algae sharply increases. With an increase in the food supply, the number of crustaceans, fish and other aquatic organisms increases. Then there is the death of a huge number of organisms. It leads to the consumption of all the reserves of oxygen contained in the water, and the accumulation of hydrogen sulfide. The situation in the reservoir changes so much that it becomes unsuitable for the existence of any forms of organisms. The reservoir gradually "dies".
Pollutants can also penetrate into groundwater: when industrial and agricultural effluents seep from storage ponds, settling ponds, etc. Groundwater pollution is not limited to the territories of industrial enterprises, waste storage facilities, etc., but spreads downstream to distances up to 20 - 30 km or more from the source of pollution. All this creates a real threat to drinking water supply in these areas.
Moreover, groundwater pollution has a negative impact on the ecological state of surface waters, soils and other components of the natural environment. In particular, contaminants contained in groundwater can be carried by the flow to surface water bodies and pollute them.
Lake Baikal
Almost in the center of the huge continent of Eurasia is a narrow blue crescent - Lake Baikal. In the Baikal mountainous region, surrounded on all sides by high ridges, it stretches for 636 kilometers in length and up to 80 km in width. In terms of area, Baikal is equal to Belgium with its almost 10 million population, many cities and industrial centers, highways and railways. 336 permanent rivers and streams flow into Baikal, while half of the water entering the lake comes from the Selenga. The only river that flows out of Baikal is the Angara. In order to realize the immensity of the Baikal water body, imagine that the Angara, which annually takes out 60.9 km3 of water from the lake, would need 387 years of continuous work to drain its bowl. Provided, of course, that during this time not a liter of water gets into it and not a drop evaporates from its surface.
Pollution of Lake Baikal by the waters of the Selenga River
The largest tributary of Lake Baikal is the Selenga River. The main sources of pollution of the Selenga River are located in Buryatia. There are large industrial cities of Ulan-Ude and Selenginsk. The sewage treatment facilities of the city of Ulan-Ude provide 35% of the total amount of waste dumped into the Selenga.
In 1973, not far from the city of Selenginsk and 60 kilometers from Lake Baikal, the Selenginsky Pulp and Cardboard Plant was opened. Since 1991, a closed water circulation system has been used there.
As the management of the plant assures, the discharge of production waste into the river. Selenga is completely stopped. But at the same time, the enterprise continues to pollute the air, more than 10,000 cubic meters of solid waste are emitted per year, which seep and end up in the waters of the Selenga, and then in Baikal. Chemicals used in agriculture are washed into the Selenga with rain. In addition, the quality of Baikal water pollution in Lake Baikal is adversely affected by the discharge of livestock waste and soil erosion. In the deltas of the Selenga River, according to the results of a study in 2006, the concentration of heavy metals such as zinc, lead and copper exceeded the norm by one and a half to two times.
Severe pollution of the river delta. Selenga is the main cause of death of omul caviar.
Consequences of the construction of the Irkutsk hydroelectric power station for Lake Baikal
In 1950, the construction of the Irkutsk hydroelectric power station, the first hydroelectric power station of the Angarsk cascade, began. The hydroelectric dam raised the water level in Baikal by a meter.
Sharp changes in the water level in Baikal cause great harm to the flora and fauna of Baikal. With a rapid decline in the water level of Lake Baikal, spawning grounds for valuable species of fish dry up, and caviar dies. The dam of the Irkutsk hydroelectric power station, which does not have fish passage devices, blocks the migration paths of fish that go to spawn in the upper reaches of the Angara. Valuable breeds of sturgeon and whitefish are being replaced by horned, perch, and ruff. Buryat scientists came to the conclusion that a sharp change in the water level affects the entire Baikal ecosystem, leads to a mixture of water masses, and a strong destruction of the coast. Spawning grounds, reproduction of fish mass are in danger.
Pollution of water by waste from the settlements of the coastal zone
More than 80 thousand people live in small towns and villages of the Baikal coastal zone.
Together, all these settlements dump about 15 million cubic meters of waste per year. Treatment facilities for domestic and industrial wastewater in settlements near Lake Baikal are either non-existent or of very low quality.
“Laws” of B. Cammoner's ecology are very clear and concise: 1) everything is connected with everything; 2) everything has to go somewhere; 3) nature “knows” better; 4) nothing is given for free.
Causes of pollution of Lake Issyk-Kul.
What measures are already being taken.
What I would like to do.