MPC in soil: sanitary standards for the content of harmful chemicals

MAC of chemical elements in the soil is the maximum allowable concentration, which does not produce a negative impact on the human body. It is not easy to identify these parameters, since they are based not only on the chemical nature or toxicity assessment, but also on the basic properties of the soil itself. Soils differ in composition and structure, therefore MPC parameters depend on a whole range of factors.

What is it and how is it measured?

Under the maximum allowable concentration of pollutants understand the level of their content in the soil, below which the elements do not pose a danger to humans, animals and the ecosystem as a whole.This indicator is very important, since the soil is far from always able to cope with man-made pollutants on its own.

The MPC value is determined experimentally for each chemical element. It is set in milligrams per 1 kilogram of dry land and unified for all types of soil and territories.

Besides this, another parameter matters - UEC. This term stands for "approximately permissible concentrations". They are installed taking into account different types of soil. In official documents, the level of MPC or AEC is several times higher than the actual dangerous one.

Specific MPC values are fixed in GOST. They are also included in the sanitary and hygienic regulations. Such indicators are of great importance for the correct assessment of the state of the environment.

When determining MPC, it is important to take into account many features:

1. Harmful substances enter the body indirectly. They can be taken up by plants or seep into the air or water. There is also a public he alth impact. At the same time, harmful substances provoke the deterioration of the state of the land and affect the biocenosis. Therefore, MPC, first of all, is set for substances that are able to leave the ground.
2. The maximum danger is not the content of a harmful substance, but its mobile form. However, in practice, it is quite difficult to establish this indicator. Therefore, when carrying out measurements, gross parameters are usually determined.
3. The content of hazardous substances varies significantly depending on the type of soil. There are also differences in the ability of lands to self-purify. In addition, the composition and properties of the soil depend on the use of top dressings.
4. The soil is capable of accumulating hazardous substances for a long time before a negative effect is visible. Therefore, single measurements are few. Long-term research is required to get the real picture.

MAC of various chemicals in soil

The main document that regulates MPC for soil is GN 2.1.7.2041-06. Now the sanitary standards provide values for 49 substances - mainly heavy metals.

The movable form is given for 8 elements that belong to hazard classes 1 and 2. There are the following MPC parameters for 1 kilogram of soil:

• cob alt - 5 milligrams;
• manganese - 60-700 milligrams depending on soil type and pH;
• copper - 3 milligrams;
• nickel - 4 milligrams;
• lead - 6 milligrams;
• fluorine - 2.8 milligrams;
• zinc - 23 milligrams;
• trivalent chromium - 6 milligrams.

For other inorganic elements gross MPC values are given. The following parameters are set for 1 kilogram of soil:

• arsenic - 2 milligrams;
• antimony - 4.5 milligrams;
• mercury - 2.1 milligrams;
• sulfur - 160 milligrams;
• vanadium - 150 milligrams;
• sulfuric acid - 160 milligrams;
• hexavalent chromium - 0.05 milligrams.

Soil-specific parameters are designed for manganese only. For another 6 substances there are standards for different types of soil. They are presented in the form of the DEC in the document GN 2.1.7.2511-09. Such indicators are available for lead, copper, nickel, zinc, arsenic, cadmium.

If a standardized document cannot be created, industry and local regulations apply. Permissible concentrations of various substances can be indicated there - for example, iron, potassium, phosphorus, cesium, strontium. There may also be regulations regarding phenols, chlorides, cyanide, formaldehyde, hydrocarbons and other substances. The assessment of exchangeable cations and anions is of great importance.

An important issue is the development of MPCs for fertilizers and chemicals that can cause great damage to the soil. The following values are set in the GN 2.1.7.2041-06 standard:

1. When using complex granular fertilizers, the level of nitrates in the soil should not exceed 76.8 milligrams per 1 kilogram.
2. For liquid combined fertilizers, the content of mobile phosphates should not exceed 27.2 milligrams per 1 kilogram.

How to assess soil pollution

The standard research package includes:

• determination of the level of heavy metals - in total, you need to establish the gross content of at least 7 harmful components;
• assessment of the content of oil products in the soil structure.

Extended analysis can be done if necessary. In this case, it is recommended to take into account the characteristics of the source of pollution. Sometimes it is acceptable to evaluate only one substance. It is required in case of accidents or the release of a specific element.

Soil sampling is recommended in accordance with established standards. They are defined by state standards. To assess the content of heavy metals, it is recommended to study the soil at intervals of at least 3 years.At the same time, it is required to take it from a depth of 0-5 and 5-20 centimeters. To assess the content of easily migrating elements, the entire depth of the soil profile is affected.

When taking soil samples, it is important to consider the type of land:

1. For agricultural land, samples are taken from every 0.5-20 hectares.
2. When examining a personal plot, it is worth doing 10 sampling from different parts of the territory.
3. Industrial facilities are required to take measurements in an area that is equal to three times the size of the sanitary zone along the direction of air flow.

MACs for hazardous elements are important for assessing the state of the environment. To obtain reliable values, it is recommended to perform research according to the rules.

Recommended