MPC: what is it, deciphering the concept and types of maximum allowable concentration, measurement

The content of toxic substances in the air, water and soil can adversely affect humans and animals. Sanitary and hygienic standards establish a set level, which is known as MPC or maximum concentration. Consider the classification of MPC, how to determine the value of the content of harmful substances and what precautions to take.

What is MPC

The term stands for "maximum permissible concentration", determines the volume of a substance that is concentrated in the measured object, moreover, does not have a harmful effect on living organisms.This definition refers to the concentration of a chemical compound, which, acting on a person every day and for a long time, will not be able to cause disorders or diseases in him.

Permissible concentration is considered the main indicator of environmental regulation of harmful compounds in the natural environment. Measured in milligrams per volume of medium: air, soil or water.

Classification

The amount of polluting components is measured in different quantities:

• in water - mg per cubic meter. decimeter;
• in atmospheric air - mg per cubic meter. m.
• in soil - mg per kg;
• in the air of the working area - mg per cubic meter. m.

When determining the accumulation of harmful substances, the impact on animals, plants of populated areas, and soil microorganisms is taken into account. That is, in this case, the decoding of MPC is the maximum content of toxic compounds, the excess of which adversely affects the ecosystem and leads to negative consequences.

The condition of animal and plant organisms can be affected by lower concentrations than accepted by the standards. Damage to certain substances, the content of which is an order of magnitude lower than the norm, can cause partial or chronic growth retardation, lower yields.

How to determine the value of PD

The concentration of substances in the working area should not lead to he alth problems, diseases detected by research methods, provided that workers inhale air during the working day, that is, 8 hours. 3 MPC of the working area.

For example, the MPC of ethylbenzene, which is used in the manufacture of plastics and rubbers, in normal air is 0.02 mg/m³, the maximum is 150.0 mg/m³; average daily - 50.0 mg/m³.

In the atmosphere of cities and villages, accepted norms are different. Separately, 2 indicators are determined - average daily and maximum. At the maximum allowable concentration, the smell of the substance should not be felt, it should not irritate the eyes when exposed for 20 minutes. The average daily MPC is determined by exposure to the object of measurement for 1 day, during this time it should not have a general toxic effect.

When determining the MPC in the working area, the impact on adults and he althy people is taken into account, when this indicator is identified for the population, the impact on people of any age and gender, the state of he alth that lives in this area is taken into account. Therefore, for the same compound, these indicators can differ many times.

To determine the maximum content of substances in water, there are different standards for fishery reservoirs, for drinking water and cultural and domestic.

MPC of pollutant compounds in the soil is determined taking into account their chemical origin and toxicity, as well as soil characteristics. Since the properties and composition of the soil are very different, the accumulation of compounds in the ground does not occur quickly, microorganisms modify the incoming substances, there are no exact norms for permissible concentrations.

Precautions

Working at hazardous enterprises should be provided with personal protective equipment for the skin and respiratory organs, overalls and footwear. Enterprises should have: regular laundry, dry cleaning, places for drying overalls and safety shoes, decontamination of clothing and additional PPE.

MAC is considered the main environmental standard for environmental quality indicators. The norms of the main toxic compounds are recommended by the he alth authorities for measurement in air, water and soil, in food, and feed.

It has been established that many toxic substances, at the observed concentrations, harmless to humans, cause great damage to nature, which is why the norms of permissible concentrations are constantly decreasing.

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