Tasks and legislative regulation
The main goals of soil protection are to maintain its natural fertility and the required level of biomicronutrients. The most important task is to prevent radioactive and chemical contamination (from fertilizers, pesticides, and industrial emissions), as well as biological contamination (by pathogenic microbes, helminth eggs, and organic waste from sewage).
The legislative framework is based on Federal Law No. 52-FZ "On the Sanitary and Epidemiological Welfare of the Population." Article 21 sets requirements for soil quality in cities and industrial facilities, while Article 22 regulates waste management processes (collection, transportation, treatment, and disposal).
Additionally, the following sanitary rules are in effect:
- SanPiN 2.1.7.1287-03 establishes soil quality standards in populated areas and methods for their control.
- SanPiN 2.1.7.728-99 regulates the disposal of healthcare facility waste, dividing it into hazard classes (A–D).
Waste collection and disposal
Municipal solid waste is usually collected by the house-to-house method: residents dispose of it via garbage chutes or outdoor containers. Special vehicles then haul the garbage away for subsequent treatment.
Available methods for treating solid waste:
- Disposal at specialized landfills.
- Biothermal processing, or composting (waste is placed on a clay base and layered with peat or soil).
- Destruction in incineration plants.
- Pyrolysis (thermal decomposition without oxygen).
- Autoclave processing.
- Disinfection using microwave radiation.
Hygienic standardization
Establishing standards for soil is difficult because it is a multi-factor system whose properties vary even in neighboring areas. The basic principle of standardization states that not every introduction of chemical compounds into the soil is automatically hazardous. A threat arises when the soil's self-cleaning capacity is exceeded or the adaptive reserves of the most vulnerable population groups are depleted.
Standards are developed based on studies in extreme climatic and soil conditions under which harmful substances migrate most actively into other media. The pollutant's effect on soil microflora is also taken into account.
The main standard is the Maximum Permissible Concentration (MPC). This is the maximum amount of a chemical substance in the arable layer (in mg per kg of absolutely dry soil) at which it does not harm human health or offspring and does not disrupt soil self-cleaning processes.
Safety must be maintained both during direct contact with the soil and through indirect exposure when a toxin migrates through ecological chains (e.g., soil — plant — human or soil — water — human).
Hazard indicators and derivative standards
Standards are determined by limiting hazard indicators (LHIs). These include:
- General sanitary (effect on the soil's self-cleaning capacity).
- Toxicological.
- Water migration and air migration (transfer of toxins into water and air).
- Phytoaccumulation (accumulation in plants).
- Organoleptic (effect on the taste and odor of water or crops).
For agrochemicals and pesticides, two indicators are calculated based on the MPC:
- MPAR (maximum permissible application rate) — a safe dose of the preparation for treatment (kg/ha).
- SRR (safe residual residue) — the permissible residue of the chemical in the soil (mg/kg), measured before people enter the fields and at the end of the season.
Classification of chemical pollutants
Harmful chemical substances in the soil are divided into three hazard classes:
- 1st class (highly hazardous): mercury, lead, arsenic, zinc, cadmium, fluorine, 3,4-benzopyrene.
- 2nd class (moderately hazardous): copper, cobalt, boron, nickel, molybdenum, chromium, antimony.
- 3rd class (low-hazard): strontium, barium, tungsten, vanadium, manganese, acetophenone.
Briefly: answers to topical questions
What hazard classes are healthcare facility waste divided into, and what do they include?
Waste from healthcare and prophylactic institutions is classified by degree of hazard into classes A, B, C, D, and E. This division and the rules for its safe handling are regulated by sanitary and epidemiological rules. Detailed information on which specific types of waste are included in each of the listed classes is not provided in the available materials.
What sanitary and microbiological indicators are used to assess the epidemic hazard of soil?
To assess epidemic hazard and detect fecal soil contamination, the following sanitary-microbiological indicator parameters are used:
- Coliform bacteria index (coli-form index) — the number of bacteria in 1 g of soil.
- Perfringens titer (Clostridium perfringens) — the smallest mass of soil in which the bacterium is detected (an indicator of long-standing contamination).
- Enterococcus titer (enterococcus index) — an auxiliary indicator of recent fecal contamination.
- Soil microbial count — the total number of microorganisms.
- Thermophile titer — bacteria growing at 60 °C (an indicator of manure and compost contamination).
The assessment of epidemic hazard also takes into account the presence of pathogenic bacteria, including Salmonella.
What sanitary-helminthological indicators are investigated during the hygienic assessment of soil?
General sanitary-parasitological indicators are investigated during the hygienic assessment of soil quality. The specific list of sanitary-helminthological indicators is not provided, but the presence of eggs of the following helminths in the soil is of epidemiological significance:
- Geohelminths — develop in the soil without an intermediate host (Ascaris, whipworm, pinworm, hookworm). Ascaris eggs can remain viable for up to one year, undergoing a soil developmental cycle up to the infectious larva stage.
- Biohelminths — require an intermediate host (beef and pork tapeworms, echinococcus, cat liver fluke).
Sewage and excreta play a key role in the spread of geohelminthiases, and helminth eggs can be carried by synanthropic flies.
Class and exam questions
What is the maximum permissible concentration (MPC) of an exogenous substance in soil?
This is the maximum permissible amount of a substance in the arable layer of absolutely dry soil (in mg/kg) that does not exert a negative impact on health and does not interfere with self-cleaning.
What are the limiting criteria of harmfulness for soil?
General sanitary, toxicological, phytoaccumulation, organoleptic, as well as water and air migration indicators are distinguished.
How are safe levels for pesticides calculated?
Based on the MPC, the maximum permissible application rate (MPAR, kg/ha) and safe residual residue (SRR, mg/kg) are determined.
What else to study on this topic
- Mechanisms and processes of soil self-purification
- Migration ecological chains of toxins
- Classification of medical waste (classes A–D) according to SanPiN 2.1.7.728-99
- Impact of pollutants on soil microbiocenoses
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Other topics in "Chapter 3. Ecological and Hygienic Problems of Soil and Sanitation of Populated Areas"
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