Methods for assessing soil pollution are of great practical importance in economic, agrotechnical and environmental terms. Soil containing toxic elements, heavy or radioactive metals can pose a threat to humans, animals and plants. Therefore, for the purposes of environmental safety and before agricultural use of soil, it is imperative to assess the quality of the soil.
Useful service: Reception of scrap metal in Yekaterinburg.
What methods of soil assessment exist?
For urban areas, the following methods for assessing soil quality are used:
1) MPC methodology (maximum permissible concentration of chemicals).
This is a method to identify the danger of soil contamination. The level of chemicals should not exceed experimentally selected standards, thereby it will not pose any threat to the human body - both direct and indirect. Thanks to its ability to self-purify, the soil has the ability to neutralize a certain amount of harmful elements, and the MAC method allows you to determine whether the concentration of these substances is within acceptable limits or exceeds them.
The MAC method is the main indicator for the sanitary and hygienic assessment of soil contamination with harmful substances.
2) ODC method (approximately permissible concentration of a chemical substance).
Using this calculation method, the level of soil contamination is determined. The research methodology is based on standards designed to assess food safety.
This approach is due to the fact that harmful substances from the soil tend to pass into plants, which can subsequently enter the human body.
Useful service: Waste paper in Nizhny Novgorod.
3) Biotesting technique.
A special feature of the method is that living organisms are used to determine the toxicity level of a soil sample. These can be animals, microorganisms or plants.
How to determine the degree of soil contamination using biotesting? For plants the following assessment is used:
- seed germination level
- length of germinal roots
- shoot length measurement
The obtained indicators are compared with the norm, and based on the obtained comparative data, the degree of soil contamination is determined. This test shows the phytotoxic characteristics of the soil.
Seaweed can also be used. Microorganisms are used to determine the toxic properties of soil.
Another testing option is to use earthworms to assess soil toxicity.
4) Methods of biodiagnostics.
The biological activity of the soil is at a certain level, recorded by numerous studies. Main pollution indicators during the study:
- radioactive elements
The method is based on the study of soil enzymes contained in humus. Their chemical activity changes significantly under the influence of polluting factors. Another factor is the effect on soil microorganisms.
A comprehensive assessment of the degree of soil contamination using the biodiagnostics method is based on the integral indicator of biological state (IPBS).
The disadvantage of the method is the need to use expensive equipment for a full-fledged study.
Useful service: Taking plastic.
What is soil grading?
Soil grading is a method for comparative assessment of fertility. In other words, using this method you can find out which soil has higher fertility indicators compared to another. Among the soil quality indicators, the moisture level, the amount of humus, acidity, fanulometric composition, nutrients, etc. are taken into account.
As a result of the study, such an indicator as a soil quality score is formed. The maximum level on the quality scale is 100 points. The practical significance of the grading method is manifested in the economic assessment of soil if it is intended for agricultural activities.
We invite you to watch a video about soil pollution:
State system of sanitary and epidemiological regulation of the Russian Federation
Federal sanitary rules, norms and hygienic standards
HOUSEHOLD AND INDUSTRIAL WASTE,
SOIL SANITARY PROTECTION
Guidelines
MU 2.1.7.730-99
Ministry of Health of Russia
Moscow-1999
1. Guidelines were developed by: Research Institute of Human Ecology and Environmental Hygiene named after. A. N. Systina RAMS (N. V. Rusakov, N. I. Tonkopiy, N. L. Velikanov), IMPITM named after E. I. Martsinovsky Ministry of Health of the Russian Federation (N. A. Romanenko, G. I. Novosiltsev, L. A. Ganushkina, V. P. Dremova, E. P. Khromenkova, L. V. Grimailo, T. G. Kozyreva, V. I. Evdokimova, O. A. Zemlyansky, V. V. Evdokimov, A. N. Volishchev, V.V. Gorokhov), RADON LLC (V.D. Simonov), All-Russian Research Institute of Nature (Yu.M. Matveev).
2. Approved and put into effect by the Chief State Sanitary Doctor of the Russian Federation on February 5, 1999.
3. Introduced for the first time
4. With the release of these guidelines, the “Guidelines for sanitary-microbiological examination of soil” dated 04.08.76 No. 1446-76 and “Guidelines for assessing the degree of danger of soil pollution by chemicals” lose their force in terms of carrying out a hygienic assessment of the degree of biological and chemical contamination of soils "dated 03/13/87 No. 4266-87, as well as "Estimated indicators of the sanitary condition of the soil in populated areas" dated July 7, 1977 No. 1739-77.
"APPROVED"
Chief State Sanitary Doctor
Russian Federation
G. G. Onishchenko
MU 2.1.7.730-99
Date of introduction: 04/05/99
2.1.7.SOIL, CLEANING PLACES,
HOUSEHOLD AND INDUSTRIAL WASTE,
SOIL SANITARY PROTECTION
Hygienic assessment of soil quality in populated areas
Hygienic evaluation of soil in residential areas
Guidelines
1 area of use
This document is a regulatory and methodological basis for the implementation of state sanitary and epidemiological supervision over the sanitary condition of soils in populated areas, agricultural lands, resort areas and individual institutions. The document is intended for institutions of the State Sanitary and Epidemiological Service of the Russian Federation and special services of federal executive authorities that carry out supervision.
The danger of soil pollution is determined by the level of its possible negative impact on contacting media (water, air), food products and directly or indirectly on humans, as well as on the biological activity of the soil and self-purification processes.
The results of soil examinations are taken into account when determining and forecasting the degree of their danger to health and living conditions of the population in populated areas, developing measures for their reclamation, prevention of infectious and non-infectious diseases, district planning schemes, technical solutions for the rehabilitation and protection of watershed areas, when deciding the priority of remediation activities within the framework of comprehensive environmental programs and assessing the effectiveness of rehabilitation and sanitary-ecological measures and ongoing sanitary control of objects directly or indirectly affecting the environment of the populated area.
The use of unified methodological approaches will help obtain comparable data when assessing soil pollution levels.
The assessment of the danger of contaminated soil in populated areas is determined by: 1) epidemic significance; 2) its role as a source of secondary pollution of the ground layer of atmospheric air and in direct contact with humans.
The sanitary characteristics of soils in populated areas are based on laboratory sanitary-chemical, sanitary-bacteriological, sanitary-helminthological, sanitary-entomological indicators.
2. Normative references
1. Law of the Russian Federation “Fundamentals of the legislation of the Russian Federation on the protection of the health of citizens.”
3. Terms and definitions
Sanitary condition of the soil - a set of physicochemical and biological properties of soil that determine the quality and degree of its safety in epidemic and hygienic terms.
Chemical soil contamination - a change in the chemical composition of the soil that arose under the direct or indirect influence of land use factors (industrial, agricultural, municipal), causing a decrease in its quality and a possible danger to public health.
Biological soil contamination - an integral part of organic pollution caused by the dissemination of pathogens of infectious and invasive diseases, as well as harmful insects and mites, carriers of pathogens of humans, animals and plants.
Indicators of soil sanitary condition - a complex of sanitary-chemical, microbiological, helminthological, entomological characteristics of the soil.
Soil buffering capacity - the ability of the soil to maintain a chemical state at a constant level when the soil is exposed to a flow of a chemical substance.
The priority component of soil pollution is substance or biological agent that is subject to priority control.
Background content (pollution) - the content of chemicals in the soils of areas that are not exposed to technogenic impact or experience it to a minimal extent.
Maximum permissible concentration (MPC) of a chemical substance in the soil is a comprehensive indicator of the content of chemical substances in the soil that is harmless to humans, since the criteria used in its substantiation reflect the possible ways in which pollution affects contacting media, the biological activity of the soil and the processes of its self-purification. Justification of MPC chemicals in soil is based on 4 main indicators of harmfulness, established experimentally: translocation, characterizing the transition of a substance from soil to plant, migratory water characterizes the ability of a substance to transfer from soil to groundwater and water sources, migratory air pollution indicator characterizes the transition of a substance from soil to atmospheric air, and general health indicator of harmfulness characterizes the influence of a pollutant on the self-purifying ability of soil and its biological activity. In this case, each of the exposure routes is assessed quantitatively with justification for the permissible level of substance content for each hazard indicator. The lowest reasonable content level is limiting and is taken for MPC.
4. Notations and abbreviations
MPC- maximum permissible concentration of the pollutant.
ODK - approximately permissible concentration of a substance.
5. General provisions
5.1. The soil survey program is determined by the goals and objectives of the study, taking into account the sanitary and epidemiological condition of the area, the level and nature of load technologies, and land use conditions.
5.2. When selecting objects, first of all, the soils of areas with an increased risk of impact on public health are examined (preschools, schools and medical institutions, residential areas, zones of sanitary protection of water bodies, drinking water supply, lands occupied by agricultural crops, recreational areas, etc.)
Control of soil pollution in populated areas is carried out taking into account the functional zones of the city. Sampling locations are preliminarily marked on a map that reflects the structure of the urban landscape. The test site should be located in a typical location for the study area. If the relief is heterogeneous, sites are selected according to relief elements. A description is drawn up for the territory to be monitored, indicating the address, sampling point, general topography of the microdistrict, location of sampling sites and sources of pollution, vegetation cover, soil type and other data necessary for the correct assessment and interpretation of sample analysis results.
5.3.1. When monitoring soil pollution from industrial sources, sampling sites are located on an area three times the size of the sanitary protection zone along the wind rose vectors at a distance of 100, 200, 300, 500, 1000, 2000, 5000 m or more from the source of pollution (GOST 17.4. 4.02-84).
5.3.2. To monitor the sanitary condition of soils in preschool, school and medical institutions, playgrounds and recreation areas, sampling is carried out at least 2 times a year - in spring and autumn. The size of the test area should be no more than 5
´ 5 m. When monitoring the sanitary condition of soils in the territories of children's institutions and playgrounds, sampling is carried out separately from sandboxes and the general territory from a depth of 0-10 cm.5.3.3. One combined sample, composed of 5 point samples, is taken from each sandbox. If necessary, it is possible to take one combined sample from all sandboxes of each age group, composed of 8-10 point samples.
Soil samples are taken either from the playing areas of each group (one combined of at least five point samples), or one combined sample from a total territory of 10 point points, and the most likely places of soil contamination should be taken into account.
5.3.4. When monitoring soils in the area of point sources of pollution (cesspools, waste bins, etc.), sample plots no larger than 5
´ 5 m are laid at different distances from the source and in a relatively clean place (control).5.3.5. When studying soil contamination by transport highways, test sites are laid on roadside strips, taking into account the terrain, vegetation cover, meteorological and hydrological conditions. Soil samples are taken from narrow strips 200-500 m long at a distance of 0-10, 10-50, 50-100 m from the road surface. One mixed sample is made up of 20-25 point samples taken from a depth of 0-10 cm.
5.3.6. When assessing the soils of agricultural areas, samples are taken 2 times a year (spring, autumn) from a depth of 0-25 cm. For every 0-15 hectares, at least one site measuring 100-200 m2 is laid, depending on the terrain and land use conditions ( ).
5.3.7. Geochemical mapping of the territory of large cities with numerous sources of pollution is carried out using a testing network (,). To identify foci of contamination, geochemists recommend a sampling density of 1-5 samples/km 2 with a distance between sampling points of 400-1000 m. To further identify the territory with the maximum degree of pollution, the testing network is thickened to 25-30 samples/km 2 and the distance between sampling points is about 200 m. It is recommended to take samples from a depth of 0-5 cm. The size of the testing network may vary depending on the scale of mapping, the nature of the use of the territory, requirements for the level of pollution (), as well as the spatial variability of the pollution content in individual areas of the surveyed territories.
Mapping is carried out by specialized organizations.
5.3.8. Spot samples are taken in accordance with GOST (), in compliance with sterility for sanitary-microbiological and helminthological analyses, and filled to the top containers with ground-in lids when determining contamination with volatile substances, at the test site using the envelope method. The combined sample is made up of points of equal volume (at least 5) taken at one site. Pooled samples must be packaged in clean plastic bags, closed, labeled, recorded in a sampling log, and numbered. For each sample, an accompanying coupon is drawn up, along with which the sample is placed in a second outer package, which ensures the integrity and safety of their transportation. The time from sampling to the start of their research should not exceed 1 day.
Sample preparation for analysis is carried out in accordance with the type of analysis (). In the laboratory, the sample is freed from foreign impurities, brought to an air-dry state, thoroughly mixed and divided into parts for analysis. The control part from each analyzed sample (about 200 g) is left separately and stored in the refrigerator for 2 weeks in case of arbitration.
5.4. The list of indicators of chemical and biological soil pollution is determined based on:
· goals and objectives of the study;
· nature of land use ();
· specifics of pollution sources that determine the nature (composition and level) of pollution in the study area (,);
· priority of pollution components in accordance with the list of maximum permissible concentrations and maximum permissible concentrations of chemical substances in the soil and their hazard class according to GOST 17.4.1.02-83. "Protection of Nature. The soil. Classification of chemicals for pollution control" ().
5.5. Determination of the concentrations of chemical substances in the soil is carried out using methods used to substantiate the maximum permissible concentration (MAC) or metrologically certified methods ( , , , ).
Table 1
Methodological principles for soil selection and soil sanitary conditions
|
Nature of analysis |
Sampling frequency |
Placement of trial sites |
Required number of trial sites |
Sample size |
Number of pooled samples from one site |
Sampling depth, cm |
Mass of combined sample |
|
sanitary-chemical |
at least 1 time/year |
at different distances from the source of pollution |
at least one at each control location |
one of at least 5 points of 200 g each |
layer by layer |
||
|
including for heavy metals |
at least 1 time every 3 years |
||||||
|
bacteriological |
at least 1 time/year |
in places where people, animals, and organic waste may be present |
10 of 3 points, 200-250 g each |
layer by layer |
|||
|
helminthological |
2-3 times/year |
the same as for bacteriology |
one platform on an area of 100 m2 |
4-10 each of 10 dots, 20 g each |
layer by layer |
||
|
entomological |
at least 2 times/year |
waste bins of various types, landfills, sludge, sites |
10 sites around one object |
0,2´ 2 m |
1 of 10 sites |
||
|
Assessment of biological activity of soils (dynamics of self-purification) |
within 3 months (growing season) 1st month. weekly, then once a month |
at least 1 experimental and 1 control site |
1 combined of no less than 5 spots of 200 g each |
||||
6.6. In case of multi-element pollution, assessment of the degree of danger of soil pollution is allowed based on the most toxic element with the maximum content in the soil.
Table 3
Critical assessment of the degree of soil contamination with organic matter
6.7. Assessment of the level of chemical contamination of soils as an indicator of adverse effects on public health is carried out according to indicators developed in conjunction with geochemical and geohygienic studies of the environment of cities with active sources of pollution. These indicators are: chemical concentration coefficient (K s). K s is determined by the ratio of the actual content of the analyte in the soil (C
i ) in mg/kg soil to the regional background (C f i):K c = C i C f i;
And total pollution indicator ( Zc) The total pollution indicator is equal to the sum of the concentration coefficients of chemical polluting elements and is expressed by the formula:
Z c = S(K c i +...+K cn) - (n -1), where
n - number of determined summable substances;
K with i - concentration coefficient i th component of pollution.
Analysis of the distribution of geochemical indicators obtained as a result of soil testing using a regular network gives the spatial structure of pollution of residential areas and the air basin, and allows us to identify risk zones for public health (,).
6.8. Assessment of the degree of danger of soil contamination with a complex of metals according to the indicator Zc , reflecting the differentiation of urban air pollution with both metals and other most common ingredients (dust, carbon monoxide, nitrogen oxide, sulfur dioxide), is carried out according to the rating scale given in Table 4.
Determination of chemical substances when assessing the level of soil pollution in populated areas Zc carried out by emission analysis in accordance with methodological instructions (,).
6.9. Assessing the adverse effects of soil pollution through their direct impact on the human body is important for cases of geophagia in children when playing on contaminated soils. This assessment is carried out for the most common pollutant in populated areas - lead, the increased content of which in city soils is usually accompanied by an increase in the content of other elements. If lead is systematically found in the soil of playgrounds within 300 mg/kg, a change in the psychoneurological status of children can be expected (). Lead contamination at the level of maximum permissible concentrations in soil is considered safe.
6.10. The assessment of soils for agricultural use is carried out in accordance with the principle diagram given in.
6.11. To make administrative decisions on the nature of the use of lands contaminated to varying degrees by chemicals, it is recommended to follow the RD “Procedure for determining damage from land pollution by chemicals” (), taking into account the nature of land use.
|
Value Z c |
Changes in population health indicators in pollution hotspots |
|
|
Acceptable |
The lowest incidence of morbidity in children and the minimum incidence of functional abnormalities |
|
|
Moderately dangerous |
Increase in overall morbidity |
|
|
Increase in overall morbidity, number of frequently ill children, children with chronic diseases, disorders of the functional cardiovascular system |
||
|
Extremely dangerous |
Increased morbidity among children, impaired reproductive function of women (increased toxicosis of pregnancy, number of premature births, stillbirths, malnutrition of newborns) |
7. Assessment of the sanitary condition of the soil according to sanitary and chemical indicators
7.1. Sanitary and chemical indicators of the sanitary condition of soils are:
The sanitary number C indirectly characterizes the process of soil humification and allows one to evaluate the self-cleaning ability of the soil from organic contaminants.
Sanitary number C is the ratio of the amount of “soil protein (humic) nitrogen “A” in milligrams per 100 g of absolutely dry soil to the amount of “organic nitrogen “B” in milligrams per 100 g of absolutely dry soil. Thus, the quotient of division: C = A/B. Assessment of the sanitary condition of the soil according to this indicator is carried out in accordance with.
Assessment of soil purity according to the “Sanitary number” (according to N. I. Khlebnikov) ()
7.2. Chemical indicators of the decomposition processes of nitrogen-containing organic matter in the soil are ammonia and nitrate nitrogen. Ammonia nitrogen, nitrate nitrogen and chlorides characterize the level of soil contamination with organic matter. It is advisable to evaluate soils according to these indicators in dynamics or by comparison with uncontaminated soil (control).
8 Assessment of the degree of biological contamination of soils
8.1. Sanitary and bacteriological indicators
8.1.1. In contaminated soil, against the background of a decrease in true representatives of soil microbial cenoses (antagonists of pathogenic intestinal microflora) and a decrease in its biological activity, there is an increase in positive findings of pathogenic enterobacteria and geohelminths, which are more resistant to chemical soil pollution than representatives of natural soil microbial cenoses. This is one of the reasons for the need to take into account the epidemiological safety of soil in populated areas. As the chemical load increases, the epidemic danger of the soil may increase.
8.1.2. Grade soil health carried out based on the results of soil analyzes at high-risk sites (kindergartens, playgrounds, sanitary protection zones, etc.) and in sanitary protection zones according to sanitary and bacteriological indicators:
1) Indirect, characterize the intensity of biological load on the soil. These are sanitary indicator organisms of the Escherichia coli group. (Colibacillus (Coliindex) and fecal streptococci (Enterococcus index)). In large cities with a high population density, the biological load on the soil is very high, and as a result, the indices of sanitary indicator organisms are high, which, along with sanitary and chemical indicators (dynamics of ammonia and nitrates, sanitary number), indicates this high load.
2) Direct sanitary and bacteriological indicators of the epidemic danger of soil - detection of pathogens of intestinal infections (causative agents of intestinal infections, pathogenic enterobacteria, enteroviruses).
8.1.3. The results of the analyzes are evaluated in accordance with.
8.1.4. In the absence of the possibility of direct determination of enterobacteria and enteroviruses in soils, safety assessment can be carried out approximately using indicator microorganisms.
8.1.5. The soil is assessed as “clean” without restrictions on sanitary and bacteriological indicators in the absence of pathogenic bacteria and an index of sanitary indicative microorganisms of up to 10 cells per gram of soil.
The possibility of soil contamination with Salmonella is indicated by an index of sanitary indicative organisms (coliforms and enterococci) of 10 or more cells/g of soil.
The concentration of coliphage in the soil at a level of 10 PFU per g or more indicates the information of the soil by enteviruses.
8.1.6. Sanitary and bacteriological studies are carried out in accordance with the normative and methodological literature given above in (, ,).
Eggs of geohelminths remain viable in the soil from 3 to 10 years, biohelminths - up to 1 year, cysts of intestinal pathogenic protozoa - from several days to 3-6 months.
8.2.3. A direct threat to public health is soil contamination with fertilized and invasive eggs of roundworms, whipworms, tkosocars, hookworms, strongyloid larvae, as well as oncospheres of taeniids, cysts of lamblia, isospores, balantidia, amoebas, and oocysts of cryptosporidium; mediated by viable eggs of opisthorchis, diphylobothriaides.
· type of pathogens;
· their viability and invasiveness;
8.3.1. Sanitary and entomological indicators are the larvae and pupae of synanthropic flies.
Synanthropic flies (house flies, house flies, meat flies, etc.) are of great epidemiological importance as mechanical carriers of pathogens of a number of infectious and invasive human diseases (cysts of intestinal pathogenic protozoa, helminth eggs, etc.).
8.3.2. In populated areas in public and private households, food and trade enterprises, private and public catering establishments, in the zoo, places where service and sporting animals are kept (horses, dogs), meat and dairy plants, etc. The most likely places for flies to breed are accumulations of decaying organic matter (garbage containers of various types, latrines, landfills, sludge areas, etc.) and the soil around them at a distance of up to 1 m.
8.3.3. The criterion for assessing the sanitary and entomological condition of the soil is the absence or presence of preimaginal (larvae and pupae) forms of synanthropic flies in it on an area measuring 20 x 20 cm.
8.3.4. Assessment of the sanitary condition of soils based on the presence of fly larvae and pupae in it is carried out in accordance with.
The presence of larvae and pupae in the soil of populated areas is an indicator of dissatisfaction with the sanitary condition of the soil and indicates poor cleaning of the territory, improper sanitary and hygienic collection and storage of household waste and their untimely disposal.
8.3.5. Sanitary and entomological studies are carried out in accordance with methodological instructions ().
9. Indicators of soil biological activity
9.1. Research on the biological activity of soil is carried out when it is necessary to in-depth assess its sanitary condition and ability to self-purify.
9.2. The main integral indicators of soil biological activity are: total microbial number (TMC), number of main groups of soil microorganisms (soil saprophytic bacteria, actinomycetes, soil micromycetes), indicators of the intensity of transformation of carbon and nitrogen compounds in the soil (“soil respiration”, “sanitary number” , dynamics of ammonia nitrogen and nitrates in the soil, nitrogen fixation, ammonification, nitrification and denitrification), dynamics of acidity and redox potential in the soil, activity of enzymatic systems and other indicators.
9.3. The list of indicators is determined by the objectives of the study, the nature and intensity of pollution, and the nature of land use.
At the first stage of research, it is advisable to use the simplest and most quickly determined informative integral indicators: soil “respiration”, total microbial numbers, redox potential and soil acidity, dynamics of ammonia nitrogen and nitrates.
Further in-depth research is carried out in accordance with the results obtained and the general objectives of the study.
9.4. Methods for measuring and assessing the biological activity of soil are given in the “Methodological guidelines for the hygienic justification of maximum permissible concentrations of chemicals in soil” dated 05.08.82 No. 2609 82. Thus, the soil can be considered “uncontaminated” in terms of biological activity if changes in microbiological indicators do not exceed 50% and biochemical no more than 25% compared to the same for control soils, taken as clean, unpolluted soils.
10 Conclusion on the sanitary condition of soils
A conclusion on the sanitary condition of the surveyed territory is given based on the results of comprehensive studies ( , , , , ) taking into account:
· sanitary and epidemiological situation in the survey area;
· requirements for soil pollution levels depending on their economic use;
· general patterns, given in, that determine the behavior of chemical elements and pollutant compounds in the soil.
Annex 1
Classification of sections of the surveyed territory according to economic use and requirements for the level of soil contamination ()
|
Usage |
Requirements |
Mapping |
|
|
Household farms, vegetable gardens, coastal areas, children's and medical institutions |
1: 200-1: 10000 |
||
|
Farmland, recreation areas |
Elevated |
1: 10000-1: 50000 |
|
|
Forests, waste lands, large industrial facilities, urban industrial zones |
Moderate |
1: 50000-1: 100000 |
Oil and petroleum products, mg/kg
Volatile phenols, mg/kg
Arsenic, mg/kg
Polychlorinated biphenyls, µg/kg
Lactose-positive Escherichia coli (Coli form), index
Enterococci (fecal streptococci), index
Pathogenic microorganisms (according to epidemiological indications), index
Eggs and larvae of helminths (viable), ind./kg
Cysts of intestinal pathogenic protozoa, specimens/100 g
Larvae and pupae of synanthropic flies, specimens/in soil area 20 ´ 20 cm
Notes: * the choice of a specific indicator depends on the nature of the agricultural chemicals used ; ); *** determination of fecal forms is allowed
The “+” sign means that it is mandatory to determine the indicator when determining the sanitary condition of soils, the “-” sign means the indicator is optional, the “ ± » is a mandatory indicator if there is a source of pollution..
Appendix 3
List of sources of pollution and chemical elements,
accumulation of which is possible in the soil in areas influenced by these sources
|
Type of industry |
Production facilities |
Chemical elements |
|
|
Priority |
Related |
||
|
Non-ferrous metallurgy |
Production of non-ferrous metals directly from ores and concentrates |
Lead, zinc, copper, silver |
Tin, bismuth, arsenic, cadmium, antimony, mercury, selenium |
|
Recycling of non-ferrous metals |
Lead, zinc, tin, copper |
||
|
Production of hard and refractory metals |
Tungsten |
Molybdenum |
|
|
Titanium production |
Silver, zinc, lead, boron, copper |
Titanium, manganese, molybdenum, tin, vanadium |
|
|
Ferrous metallurgy |
Production of alloy steels |
Cobalt, molybdenum, bismuth, tungsten, zinc |
Lead, cadmium, chromium, zinc |
|
Iron ore production |
Lead, silver, arsenic, thallium |
Zinc, tungsten, cobalt, vanadium |
|
|
Mechanical engineering and metalworking industry |
Enterprises with heat treatment of metals (without foundries) |
Lead, zinc |
Nickel, chromium, mercury, tin, copper |
|
Production of batteries, production of devices for the electrical and electronics industry |
Lead, nickel, cadmium |
Antimony, lead, zinc, bismuth |
|
|
Chemical industry |
Production of superphosphate fertilizers |
Strontium, zinc, fluorine, barium |
Rare earths, copper, chromium, arsenic, yttrium |
|
Plastics production |
Sulfur compounds |
Copper, zinc, silver |
|
|
Construction materials industry |
Cement production (when using waste from metallurgical production, accumulation of relevant elements is possible) |
Mercury, zinc, strontium |
|
|
Printing industry |
Type foundries and printing houses |
Lead, zinc, tin |
|
|
Municipal solid waste from large cities used as fertilizers |
Lead, cadmium, tin, copper, silver, antimony, zinc |
||
|
Sewage sludge |
Lead, cadmium, vanadium, nickel, tin, chromium, copper, zinc |
Mercury, silver |
|
|
Contaminated irrigation water |
Lead, zinc |
||
|
Source of pollution |
Ferrous and non-ferrous metallurgy |
Instrumentation |
Mechanical engineering |
Chemical industry |
Motor transport |
|||||||||
|
Molybdenum |
||||||||||||||
Note.“O” - mandatory control, “ W» - optional control.
Industry: A - alloy steel plant; B - non-ferrous metal plant; C- alloy plant;D- processing of secondary color metal; E - battery production; F- radiator production; G- electrical production; N - precision engineering; I- production of household products; J- heavy engineering; K - light engineering; L- production of plastics; M- production of paints and varnishes; N- road network of gas stations. Appendix 6
Schematic diagram for assessing agricultural soils contaminated with chemicals ()
|
Characteristics of contamination |
Possible uses |
Suggested activities |
|
|
1. Acceptable |
Use without restrictions for any crops |
Reducing exposure to pollution sources. Implementation of measures to reduce the availability of toxicants for plants (liming, application of organic fertilizers, etc.) |
|
|
2. Moderately dangerous |
Use for any crops subject to quality control of agricultural products |
Activities similar to category 1. If there are substances with a limiting water or air migration indicator, the content of these substances in the breathing zone of agricultural workers and in the water of local water sources is monitored |
|
|
3. Highly dangerous |
Use for industrial crops. Use for agricultural crops is limited, taking into account hub plants |
1. In addition to the measures specified for category 1, mandatory control over the content of toxicants in plants - food and feed 2. If it is necessary to grow plants - food - it is recommended to mix them with food grown in clean soil 3. Limitation of the use of green mass for livestock feed, taking into account the plants - concentrators |
|
|
4. Extremely dangerous |
Use for industrial crops or exclude from agricultural use. Forest shelterbelts |
Measures to reduce the level of pollution and bind toxicants in the soil. Monitoring the content of toxicants in the breathing zone of agricultural workers and water from local water sources |
Appendix 7
Maximum permissible concentrations (MAC) of inorganic chemicals in soil and permissible levels of their content according to hazard indicators
|
Name of substance |
MPC mg/kg soil taking into account background |
Levels of hazard indicators (K1 - K4) and the maximum of them - (K max) in mg/kg |
Hazard Class |
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|
Translocation (K1) |
Migration |
General sanitary |
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Air (K3) |
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Mobile forms extracted from soil with ammonium acetate buffer with pH 4.8 |
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Mobile forms extracted from soil with ammonium acetate buffer with pH 4.8 |
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|
Mobile forms extracted from soil with ammonium acetate buffer with pH 4.8 |
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|
Manganese chernozem |
Mobile forms extracted from soil with ammonium acetate buffer with pH 4.8 |
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Manganese soddy-podzolic soil with pH 1.4-5.6 |
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Manganese soddy-podzolic soil with pH > 6 |
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|
Manganese chernozems |
Extractable 0.1 and H 2 SO 4 |
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Manganese soddy-podzolic soil with pH 4 |
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|
pH > 6 |
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|
Ammonium-sodium buffer pH 3.5 for gray soils and 4.7 soddy-podzolic soil |
> 1000 |
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|
Water soluble |
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|
Manganese |
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Manganese + vanadium |
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Lead + mercury |
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|
Potassium chloride (K 2 O) |
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Sulfur compounds (S): Elemental sulfur |
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Hydrogen sulfide (H 2 S) |
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|
Sulfuric acid |
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|
Coal flotation waste (CFW)1 Complex granular fertilizers (KGU) 2 NPK(64:0:15) |
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|
Liquid complex fertilizers (LCF) 3 NPK (10:4:0) |
> 800 |
> 8000 |
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|
Benz(a)pyrene |
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NotesMPCs must be adjusted in accordance with newly developed documents.
1) MPCs of OFU are controlled by the content of benzo(a)pyrene in the soil, which should not exceed the MPC of benzo(a)pyrene.
2) MPC of KGU composition NPK(64:0:15) are controlled by the nitrate content in the soil, which should not exceed 76.8 mg/kg abs. dry soil.
3) Maximum permissible concentration of liquid and gas fluid composition NPK(10:4:0) TU 6-08-290-74 with manganese additives no more than 0.6% of the total mass are controlled by the content of mobile phosphates in the soil, which should not exceed 27.2 mg/kg abs. dry soil. 5 . GOST 17.4.4.02 -84 “Nature conservation. The soil. Methods for collecting and preparing soil samples for chemical, bacteriological and helminthological analysis.”
6 . GOST 17.4.3.06 -86 (ST SEV 5101-85) “Nature conservation. Soils. General requirements for the classification of soils according to the influence of chemical pollutants on them.”
7. Guidelines for assessing the degree of danger of soil contamination by chemicals No. 4266-87. Approved USSR Ministry of Health 03.13.87.
8. Estimated indicators of the sanitary condition of soils in populated areas No. 1739-77 Approved. Ministry of Health of the USSR 7.07.77.
9. Guidelines for sanitary and microbiological soil testing No. 1446-76. Approved USSR Ministry of Health 08/04/76.
10. Guidelines for sanitary and microbiological soil testing No. 2293-81. Approved Ministry of Health of the USSR 02.19.81.
11. Guidelines for helminthological examination of environmental objects and sanitary measures to protect against contamination by helminth eggs and neutralize sewage, soil, berries, vegetables, and household items from them No. 1440-76. Approved USSR Ministry of Health.
12. Methodological recommendations for geochemical assessment of contamination of urban areas with chemical elements. - M.: IMGRE, 1982.
13. List of maximum permissible concentrations (MAC) of chemicals in soil No. 6229-91. Approved USSR Ministry of Health 11/19/91.
14 . Approximate permissible concentrations (APC) of heavy metals and arsenic in soils: GN 2.1.7.020-94 (Addition No. 1 to the list of MPC and APC No. 6229-92). Approved GKSEN RF 12/27/94.
15. Methodological recommendations for assessing the degree of atmospheric air pollution in populated areas by metals based on their content in snow cover and soil No. 5174-90. Approved Ministry of Health of the USSR 05.15.90.
16 . Guidelines for controlling flies No. 28-6.3. Approved USSR Ministry of Health 01/27/84.
18 . Maximum permissible concentrations of chemicals in soil (MPC): USSR Ministry of Health. - M., 1979, 1980, 1982, 1985, 1987.
19. Methodology for measuring the mass fraction of acid-soluble forms of metals (copper, lead, zinc, nickel, cadmium) in soil samples by atomic absorption analysis: Guidelines: RD 52.18.191-89. Approved GKGM USSR. - M., 1989.
20. Dmitriev M.T., Kaznina N.I., Pinigina I.A.: Handbook: Sanitary-chemical analysis of pollutants in the environment. - M.: Chemistry, 1989.
21. Methods of soil microbiology and biochemistry./ Ed. prof. D.G. Zvyagintseva. - M.: MSU, 1980.
22 . GOST 26204-84, 26213-84 “Soils. Methods of analysis".
23. GOST 26207-91 “Soils. Determination of mobile forms of phosphorus and potassium using the Kirsanov method as modified by TsINAO."
24 . The procedure for determining the parameters of damage from land pollution with chemicals. Approved Chairman of the Federation Committee on Land Resources and Land Management 11/10/93 Ministry of Environment Protection and Natural Resources 11/18/93. Agreed by: 1st Deputy Minister of Agriculture of the Russian Federation on September 6, 1993, Chairman of the State Committee for Social Security of the Russian Federation on September 14, 1993 and President of the Russian Academy of Agricultural Sciences on September 8, 1993.
2.6. Assessment of soil contamination levels
There are different approaches to assessing the level of soil contamination.
For inorganic pollutants, the division of soils into categories (classes) of pollution is carried out taking into account the hazard class of the pollution component, its maximum permissible concentration and the maximum value of the permissible level of element content (Kmax) according to one of four hazard indicators. For organic pollutants, the division of soils into categories (classes) of pollution is carried out taking into account the hazard class of the substance and the multiplicity of excess of its MPC in the soil.
According to the sanitary and hygienic condition of agricultural soils, the content of chemicals in the soil is divided into acceptable; moderately dangerous; highly dangerous and extremely dangerous, and the MPC for the translocation sign of harmfulness is very important.
The grouping of soils contaminated with heavy metals is based on the methodology of the Soil Institute named after. V.V. Dokuchaev, the clarke content of the element lies. According to this method, the level of soil contamination is determined using the arithmetic or geometric progression of the clarke of the element.
To assess technogenic anomalies with a polyelement composition, total pollution indicators Z C are used, characterizing the degree of pollution by an association of elements relative to the background and reflecting the effect of exposure to a group of elements:
Where TO ci– concentration coefficient i-th element in the sample;
n– number of elements taken into account.
The concentration coefficient is defined as the ratio of the actual content of an element in the soil to the background content, and it must be greater than unity (otherwise the element is not concentrated, but dispersed). If there are no background values for comparing landscape pollution, the element clarke or MPC is taken instead.
2.7. Standardization of the quality of agricultural products
When standardizing quality food They use such an indicator as the maximum permissible concentration of a harmful substance in food, otherwise called the permissible residual amount (ARK).
Maximum permissible concentration (permissible residual amount) of a harmful substance in food (MPC, DOC)- This is the maximum concentration of a harmful substance in food products, which for an unlimited period of time (with daily exposure) does not cause diseases or deviations in human health.
For each type of product, the maximum permissible concentration for certain pollutants that can accumulate in it when receiving agricultural products, during their processing and storage is standardized. Sometimes the maximum permissible concentration also depends on the conditions and time of receipt of the product. For example, the nitrate content in vegetable products is standardized taking into account the type of crop, growing conditions (open or protected ground) and harvest time (early or late production). The content of some heavy metals in canned food is standardized taking into account their possible entry from metal containers.
Standardization of product quality is carried out on the basis of the permissible daily dose of pollutants or the limit of its annual intake, taking into account the diet of the population.
Permissible daily dose (ADI) – This is the maximum amount of a pollutant that can enter the human body with all food and water on average per day throughout life and at the same time not affect the health of a person and his offspring. The ADI is established in units of mass of pollutant per kg of body weight (mg/kg, ng/kg) or simply in units of mass of pollutant (mg, ng), with the mass of an average person being taken to be 70 kg. The World Health Organization (WHO) has developed DDIs for heavy metals, nitrates, etc.
Annual Income Limit (AGL) - this is the maximum amount of a pollutant that can enter the human body with all food and water on average per year throughout life and at the same time not affect the health of a person and his offspring. The GWP is established, for example, for anthropogenic radionuclides.
Certain limiting indicators (signs) of harmful substances have been developed that have to be taken into account when regulating the quality of agricultural products:
– organoleptic, characterizing the influence of a substance on changes in the properties of a product determined by human senses (taste, smack, smell, color, turbidity, the presence of foam and films, etc.);
– toxicological, characterizing the toxicity of a substance to humans;
– technological, characterizing the ability of a substance to degrade the quality of a product as a result of certain reactions during its production;
– hygienic, characterizing the ability of a substance to impair the beneficial properties of a product as a result of certain reactions with beneficial substances contained in the product.
Control questions.
1. What is the principle of separate rationing? How is it used in assessing air and water quality?
2. What indicators (signs) of harmfulness are used when regulating the quality of air, water, soil, and products? What is a limiting indicator (sign) of harmfulness (LPH)?
3.What is the summation effect? How is it used in assessing air and water quality?
4. What is IZA, IZV? How are they calculated?
5 What is the total indicator of soil contamination with heavy metals? How is it calculated?
6. What is DSD? GWP? How do they affect the maximum permissible concentrations of contaminants in food in different countries?
State educational institution
higher professional education
Ulyanovsk State Technical
university
Essay
on the topic of: “Analysis of methods for assessing soil pollution”
Performed:
2nd year student
day department
Ulyanovsk
Introduction
1. Assessment of the hazard of soil pollution
2. Biotesting as the most appropriate method for determining the integral toxicity of soil
3. Biodiagnostics of technogenic soil pollution
Conclusion
Introduction
The Earth's soil cover is the most important component of the biosphere. It is the soil shell that determines many of the processes occurring in the biosphere. The most important importance of soils is the accumulation of organic matter, various chemical elements, and energy. The soil cover performs the functions of a biological absorber, destroyer and neutralizer of various contaminants, and soil also plays a vital role in the life of society, since it is a source of food, providing 95-97% of food resources for the planet's population. If this link of the biosphere is destroyed, then the existing functioning of the biosphere will be irreversibly disrupted. It is extremely important to study the global biochemical significance of the soil cover, its current state and changes under the influence of anthropogenic activities, since effective protection of the environment from hazardous chemicals is impossible without reliable information on the degree of soil contamination.
An assessment of the soil’s ability to perform functions that ensure the stability of individual biocenoses and the biosphere as a whole is obtained using special methods for studying contaminated soils. Let's look at some of them.
Methods for assessing soil pollution
1. Assessment of the hazard of soil pollution
Before considering methods for assessing soil pollution, it is necessary to become familiar with some indicators and provisions that determine the degree of danger of pollutants, as well as assessing the danger of soil pollution.
The principle of rationing chemicals in soil differs significantly from the principles underlying their rationing in water bodies, atmospheric air, and food products. Chemicals entering the soil enter the human body mainly through media in contact with the soil: water, air and plants (in the latter case, along the soil-human biological chain). Therefore, when rationing chemicals in the soil, not only the danger posed by the soil in direct contact with it is taken into account, but also the consequences of secondary pollution of media in contact with the soil.
The establishment of maximum permissible concentrations for pollutants in soil is in the initial stage, therefore, to date, maximum permissible concentrations have been established for only 30 harmful substances, mainly pesticides.
Due to the fact that harmful substances enter the human body for food purposes, permissible residual quantities (MRC) of pesticides in soil, food and feed products have been established (Table 1).
Table 1“MPC and DOC of some substances in soil”
The results of hygienic studies of contaminated soils make it possible to assess the degree of danger of pollution by harmful substances according to the level of their possible impact on the systems “soil - plant”, “soil - microorganisms, biological activity”, “soil - groundwater”, “soil - atmospheric air” and indirectly - on human health. From a hygienic point of view, the danger of soil pollution is determined by the level of its possible negative impact on contacting media, food products and directly on humans, as well as on the biological activity of the soil and its self-purification processes.
And it is the maximum permissible concentration of chemical substances in the soil that is the main criterion for hygienic assessment of the danger of soil pollution with harmful substances.
To assess the risk of soil pollution, the choice of chemicals - pollution indicators - is carried out taking into account:
- specifics of pollution sources that determine the complex of chemical elements involved in soil pollution in the studied region (Table 1);
- priority of pollutants in accordance with the list of maximum permissible concentrations of chemicals in soil and their hazard classes;
- nature of land use.
If it is not possible to take into account the entire complex of chemical substances that pollute the soil, the assessment is carried out based on the most toxic substances, that is, those belonging to the highest hazard class.
If the documentation does not contain the hazard class of chemicals that are priority for the soils of the study area, their hazard class J can be determined using the following formula:
where A is the atomic weight of the corresponding element; S - solubility of a chemical compound in water, mg/l; M is the molecular weight of the chemical compound that contains this element; a is the arithmetic average of six maximum permissible concentrations of chemicals in different food products (meat, fish, fruits, bread, vegetables).
When assessing the risk of soil contamination from chemicals, the following should be considered:
- the higher the actual levels of controlled substances in the soil compared to the MPC, the greater the danger of contamination;
- the higher the hazard class of controlled substances, the greater the risk of contamination;
- soil buffering, which affects the mobility of chemical elements, which determines their effect on contacting media.
The assessment of the danger of soil pollution in populated areas is, in turn, determined by:
- the epidemiological significance of chemically contaminated soil;
- the role of contaminated soil as a source of secondary pollution of the ground layer of atmospheric air and in its direct contact with humans;
- The significance of the degree of soil pollution as an indicator of air pollution.
Assessment of the level of soil pollution as indicators of adverse effects on public health is carried out using indicators developed in conjunction with geochemical and geohygienic studies of the urban environment. Such indicators are the concentration coefficient of the chemical substance K c and the total pollution indicator Z c, equal to the sum of the concentration coefficients of chemical elements:
where n is the number of elements to be summed.
Assessment of the danger of soil pollution by a complex of metals according to the Z c indicator, reflecting the differentiation of urban air pollution, both with metals and other most common ingredients (dust, carbon monoxide, nitrogen oxides), is carried out according to the rating scale given in Table 2. Gradations of the rating scale developed based on the study of health indicators of the population living in areas with different levels of soil contamination.
Table 2. Approximate rating scale of the danger of soil pollution based on the total pollution indicator Z with
|
MeaningZWith |
Changes in population health indicators in pollution hotspots |
|
|
Acceptable |
The lowest level of illness in children and the minimum incidence of functional abnormalities |
|
|
Moderately dangerous |
Increase in the level of general morbidity |
|
|
Increase in the level of general morbidity, the number of frequently ill children, children with chronic diseases, disorders of the functional state of the cardiovascular system |
||
|
Extremely dangerous |
Increase in the level of general morbidity among children and women with reproductive disorders (increase in the number of premature births, etc.). |
2. Biotesting as the most appropriate method for determining the integral toxicity of soil
The maximum permissible concentration of toxic substances (MAC) in water, soil, and food is currently the basis for monitoring harmful substances in the environment. However, it should be noted that exceeding the maximum permissible concentration of chemical substances in the studied substructures serves only as an indirect indicator of their toxicity. It is not always possible to establish a direct relationship between the content of a pollutant in the environment and its suitability for living organisms. The soil can be highly contaminated, but non-toxic or slightly toxic, and, conversely, slightly contaminated, but highly toxic. The toxic effect of some components can be neutralized or enhanced by the presence of others, so the toxicity of soil is not determined by the toxicity of individual compounds contained in it. It is necessary to evaluate the integral toxicity of soil, reflecting the influence of the entire complex.
The most appropriate method for determining the integral toxicity of soil is biotesting. An indicator of the degree of toxicity during biotesting is the change in the selected test function of the bioindicator organism during its interaction with the environmental sample. The successful use of biotesting to diagnose the state of an ecosystem largely depends on the correct selection of the test object.
Animals, plants, and microorganisms can be used as bioindicators. The level of organization of the biological system being tested can vary from precellular (macromolecules) to supraorganismal (communities). Most researchers believe that the use of a single biological parameter for biotesting purposes is unreliable due to the various mechanisms of response of the test organism to various anthropogenic pollutants. The most complete analysis of integral toxicity is achieved by using a set of biotests using various test organisms while monitoring their biological parameters.
The most obvious criteria for selecting test organisms are ease of operation and accuracy of the data obtained as a result of testing. Simplicity means the ease of isolating a test organism from natural sources, storing it, propagating it, testing it for toxicity, processing it, and interpreting the results obtained. Accuracy in this case is the presence of unambiguous, pronounced changes in the test function of the indicator organism as a result of exposure to the pollutant of interest.
In some cases, to assess soil toxicity, it is necessary to take microorganisms as test objects. The advantages of microbiological tests are due to the following reasons. Due to their small size, microbial cells have a relatively large surface of contact with the surrounding environment, which determines their high sensitivity to changes occurring in it. High rates of growth and reproduction of microorganisms make it possible, in a relatively short period of time, to monitor the impact of any unfavorable factor over tens and even hundreds of generations. In addition, they are compact and in most cases do not require significant material costs to maintain life. The use of microorganisms to assess the integral toxicity of soil and the creation on their basis of a comprehensive system of sensitive, reliable and economical biotests is a promising area of research.
The disadvantages of microbiological tests include the rather high ability of microorganisms to form resistant mutant strains, which can in some cases lead to unreliable results.
One of the simplest and most informative ways to assess the microbotoxicity of contaminated soils is to take into account the number of microorganisms, which, as a rule, quite easily reflects the microbiological activity of the soil, the rate of decomposition of organic matter and the cycle of mineral elements. So, for example, in the case of soil contamination with oil, based on this indicator, one can not only judge the degree of contamination, but also the potential for restoration of the soil. But determining the total number of bacteria in this case as an indicator of toxicity can be recommended for heavily contaminated soils, since, depending on its concentration, oil can both stimulate and inhibit the development of microorganisms.
In natural ecosystems, microarthropods, which are soil invertebrates, are widely used for monitoring at the species assemblage level. In areas with intense anthropogenic load, they often remain the only group by which the degree of impact on the soil can be judged. Soil springtails (collembolas) are very sensitive to the effects of organic substances, so they can be successfully used in determining the integral toxicity of contaminated soils; in particular, the percentage of surviving springtails, their life expectancy, and behavioral reactions can serve as a test indicator.
The tests described above are accessible and easy to perform, do not require complex laboratory equipment and can be recommended to researchers of different levels of training. Their advantage is also the fact that the work is carried out with objects typical of the soil habitat in natural conditions. A set of test objects from plant seeds, microorganisms, soil invertebrates and enzymes can be used either in full or partially, depending on the purpose of the research. If samples with soil springtails and enzyme activity provide a good quantitative characteristic of soil toxicity at low and medium degrees of contamination, then microbiological tests are convenient for describing the state of heavily polluted, highly toxic soils.
3. Biodiagnostics of technogenic soil pollution
The high sensitivity of soil to any negative and positive influences allows the use of biological indicators as biomonitoring parameters.
Biological activity is a derivative of a combination of abiotic, biotic and anthropogenic factors of soil formation. In the soil, zoo- and microbiocenoses are combined into a single system with the products of their vital activity—extracellular and intracellular enzymes, as well as with abiotic components of the soil.
The main provisions of the proposed methodology are as follows:
- simultaneous study of soil biological activity indicators;
- identification of the most informative ecological and biological indicators and a possible integral indicator of the ecological state of the soil;
- taking into account the spatial and temporal variability of the biological properties of the soil;
- use of comparative geographical and profile genetic approaches to assess soil condition.
The study of the state of degraded soils will be most complete if the following are determined:
- direct indicators of pollution with heavy metals and petroleum products (gross content of heavy metals, content of their mobile forms, content of petroleum products, thickness of the contaminated layer);
- indicators of resistance to pollution by heavy metals and petroleum products (cation exchange capacity, degree of saturation with bases, humus content, environmental reaction);
- Biological indicators of changes in soil properties under the influence of metal pollutants and petroleum products (activity of soil enzymes, for example invertase, catalase, intensity of carbon dioxide release, cellulose decomposition ability, total number of soil microorganisms, structure of microbial cenosis, etc.).
For practical purposes, determining the entire set of indicators is very labor-intensive and requires expensive equipment. It is more appropriate to determine indicators that objectively reflect the level and consequences of pollution.
General patterns of changes in soil properties as the content of pollutants increases can only be formulated on the basis of experimental materials. As a result of many years of research, the most informative indicators of soil biological activity for biodiagnostics and biomonitoring have been established. These include, first of all, biochemical indicators, since they better correlate with the level of pollution and have less variation in space and time compared to microbiological ones. Of those studied, it is recommended to use enzymatic activity—catalase activity, which is one of the indicators of stabilizing soil conditions. Its change is associated with contamination and buffer capacity of the soil (Fig. 1).
With mild contamination, redox processes are stimulated.
In the studies carried out, catalase activity was maximum at a Zc coefficient of pollutant concentration equal to 2 - 8; at Zc = 32 or more, it practically did not manifest itself.
With a Zc coefficient of 2 - 8, the level of pollution is acceptable, with 8 - 32 - medium, with 32 - 64 - high, with Zc > 64 - very high.
Of all the enzymes studied, catalase is the most sensitive, so its activity can be used as a criterion for assessing the restoration of soil functions.
It was found that the most informative indicator of the ecological state of technogenically contaminated soils is the integral indicator of biological state (IBS). When calculating the IPBS, the maximum value of each indicator in the sample is taken as 100% and in relation to it the value of the same indicator in other samples is expressed as a percentage, that is, a relative indicator
B 1 = B / B max ´ 100%,
where B is the value of the indicator in the sample; B max - maximum value of the indicator.
Then the average value of the indicator is determined
B av = (B 1 + B 2 + B 3 + ... + B n) / n,
where n is the number of indicators.
The integral indicator of biological activity is calculated using the formula
IPBS = (B avg / B av max) ´ 100%,
During diagnostics, the value of each indicator in uncontaminated soil is taken as 100%.
The integral indicator of the biological state of the soil for all levels of pollution is directly dependent on the content of heavy metals in it (Fig. 2).
It is advisable to determine the influence of the degree of pollution on biological processes in the soil by the deviation of the activity of extracellular biological processes from control according to ecotoxicological standards: 50% is a very dangerous level of influence.
Different types of soils with the same nature and degree of pollution exhibit different stability. For gray forest soil, the average level of pollution is already very dangerous; in this case, restoration of biocenotic functions is difficult or almost impossible. In leached chernozem, a 50% reduction in IPBS occurs only at a high level of pollution.
The results of biomonitoring of technogenically contaminated soils can be widely used in assessing the impact on the environment, environmental regulation of soil pollution, forecasting the environmental consequences of any economic activity in a given territory, conducting environmental assessments, auditing and certification of enterprises.
Conclusion
Soils are polluted by various harmful chemicals, pesticides, waste from agriculture, industrial production and municipal enterprises. Chemical compounds entering the soil accumulate and lead to a gradual change in the chemical and physical properties of the soil, reduce the number of living organisms, and worsen its fertility. Due to the fact that soil is an integral part of the biosphere and plays a vital role in the life of society throughout the planet, it is extremely important to study its current state and changes under the influence of anthropogenic activities.
Thus, at present it is necessary to have methods for assessing soil pollution that could give an objective idea of the condition of the soil, that is, how capable it is of performing its assigned functions. The considered methods, such as biotesting and biodiagnostics of contaminated soils, meet the modern requirements for the study of contaminated soils.
Biotesting is the most appropriate method for determining the integral toxicity of soils. It is accessible and easy to use, does not require complex laboratory equipment, and can be recommended to researchers of different levels of training. In turn, biodiagnostics of technogenic soil pollution is a fairly simple method that can give a real assessment of the condition of soils. This became possible after many years of research, when the most informative indicators were discovered that objectively reflect the level and consequences of pollution and do not require expensive equipment for their determination. At the present time, when the contradiction between economics and ecology has become acute, it is important that methods for assessing soil pollution can not only provide an objective picture of the state of soils, but also be accessible in material terms.
List of used literature
- Butorina M.V., Drozdova L.F., Ivanov N.I. Engineering ecology and environmental management: Textbook. - M.: Logos, 2004. - 520 pp.: ill.
- Demina T. A. Ecology, environmental management, environmental protection. - M.: publishing house Aspect-press, 1995.
- Dobrovolsky G.V., Nikitin E.D. Conservation of soils as an irreplaceable component of the biosphere. - M.: Nauka, 2001.
- Ismailov N. M. Oil pollution and biological activity of soils. - M.: Nauka, 1991.
- Korobkin V.I., Peredelsky L.V. Ecology. - Rostov n/d: publishing house "Phoenix", 2003. - 576 p.
- Burlaka V. A., Kazarin V. F. Restoration of soil fertility contaminated with highly mineralized formation waters // Ecology and industry of Russia. 2005. February. - P. 21 - 25.
- Devyatova T. A. Biodiagnostics of technogenic soil pollution // Ecology and industry of Russia. 2006. January. - P. 36 - 37.
- Kireeva N.A., Novoselova E.I., Yamaletdinova G.F. Diagnostic criteria for self-purification of soil from oil // Ecology and industry of Russia. 2001. December.
- Kireeva N. A., Tarasenko E. M. Biotesting as a method for assessing soil pollution with oil // Ecology and industry of Russia. 2004. February. - P. 26 - 29.
- Smirnova N.V., Shvedova A.V. The influence of lead and cadmium on soil phytotoxicity // Ecology and industry of Russia. 2005. April. - P. 32 - 35.
The use of unified methodological approaches will help obtain comparable data when assessing the level of soil pollution and the possible consequences of pollution, and will also make it possible to predict the quality of food products of plant origin. The accumulation of factual material on soil pollution and its indirect impact on humans will make it possible to subsequently improve the proposed guidelines.
These guidelines do not apply to the assessment of pesticide contamination.
1. General Provisions
1.1. From a hygienic point of view, the danger of soil contamination with chemicals is determined by the level of its possible negative impact on contacting media (water, air), food products and indirectly on humans, as well as on the biological activity of the soil and its self-purification processes.
1.2. The main criterion for hygienic assessment of the danger of soil pollution by harmful substances is the maximum permissible concentration (MPC) of chemicals in the soil. MPC is a comprehensive indicator of the content of chemical substances in the soil that is harmless to humans, since the criteria used in their scientific substantiation reflect all possible ways of indirect exposure of the pollutant to contact media, the biological activity of the soil and its self-purification processes. In this case, each of the exposure routes is assessed quantitatively with justification for the permissible level of substance content for each hazard indicator. The lowest reasonable level of content is limiting and is taken as the maximum permissible concentration of the substance, since it reflects the most vulnerable route of exposure to this toxicant.
1.3. To assess the danger of soil pollution, the choice of chemical substances - pollution indicators - is carried out taking into account:
Specifics of pollution sources that determine the complex of chemical elements involved in soil pollution in the studied region (Appendix 1);
Priority of pollutants in accordance with the list of maximum permissible concentrations of chemicals in soil (Table 2) and their hazard class (Appendix 2) (“Maximum permissible concentrations of chemicals in soil”, 1979, 1980, 1982, 1985, 1987);
The nature of land use (Appendix 3).
1.3.1. If it is not possible to take into account the entire complex of chemical substances that pollute the soil, the assessment is carried out based on the most toxic substances, i.e. belonging to a higher hazard class (Appendix 2).
1.3.2. If the given documents (Appendix 2) do not contain the hazard class of chemicals that are priority for the soils of the surveyed area, their hazard class can be determined by the hazard index (Appendix 4).
1.4. Soil sampling, storage, transportation and preparation for analysis are carried out in accordance with GOST 17.4.4.02-84 "Nature conservation. Soils. Methods for collecting and preparing soil samples for chemical, bacteriological and helminthological analysis."
1.5. The determination of chemical substances in soil is carried out by methods developed to justify their MPCs in soil and approved by the USSR Ministry of Health, which are published in the appendices to the “Maximum Permissible Concentrations of Chemicals in Soil (MPC)” (1979, 1980, 1982, 1985).