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Main principles of the hygienic reglamentation harmful factors in environment
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MAIN PRINCIPLES OF THE HYGIENIC REGLAMENTATION HARMFUL FACTORS IN ENVIRONMENT
There are general scientific principles of estimation MPC of harmful factors in environment.
1. Priority medical indications at establishment the specification.
At definition size of the specification only levels of its safe action at organism are taken into account, instead of technical and economic reasons for observance this specification.
2. Differentiation degree of biological answer of organism at action harmful factor.
Depending from level of harmful factor, which influence on organism, and resistibility of organism to harmful influence we can allocate the following levels of biological answers:
1 - destruction of organism,
2 - illness,
3 - prepathology (violations functions of organism without clinical signs of desease), 4 - pressure adaptive and compensatory processes (functional violations unknown aethyology),
5 - accumulation substance in bodies and fabrics without functional and clinical changes.
Specifications must be established not above 4 level.
3. Division objects of environment for sanitary protection.
As each object of environment (air, water, ground, food) has the physical and chemical features and different conditions of contact to organism of the person, specifications are established separately for each object of environment.
4. Principle accountation all probable adverse influences of the normalized factor on concrete object of an environment.
There are the most important parameters reflecting harmful action investigated factors at quality concrete object of environment. Such parameters named attributes or criteria of harmful action: Organoleptic, Common sanitary, Phitoaccumulative, Water migration, Air migration, Reflex, Toxicological, etc. (see tab. )
Attributes of harmful activity at normalization harmful
factors in objects of environment
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Sign of harm Kind of unfavorable activity
Organoleptic change of odour, taste, colouring etc.
Common sanitary influence on saprophytic microflora,
processes of self-cleaning
Phytoaccumulative accumulation pollutant in vegetative
products not higher MPC
Water-migration accumulation pollutant in ground waters
not higher MPC
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Air-migration evaporation pollutant in air not higher MPC
Reflective irritating activity on mucous cowers of organism
Toxicological toxical effects on organism of animal
Specific allergenic, gonadotrophic, embryotropic effects
The remote effects oncogen, mutagen effect
At learning each attribute of harm in laboratory determine threshold (limit) concentration (LC) of pollutant to each attribute of harm, the parameter of harm from the least LC is termed, named limiting attribute of harm and on it is proved MPC.
5. Principle presence the threshold (limit) of harmful action - the central principle of normalization. For each harmful factor there is a threshold of harmful action - a level at which the harmful effect are registrated (LOAEL) and a low level (NOAEL) - when such effect is absent.
6. Principle dependence harmful effect from concentration (doze) of the investigated factor and time of its influence. It is based on mathematical dependences " concentration (doze) - effect" or " time - effect". Last dependence is observed at chronic influence at presence cumulation (chronoconcentration poisons).
7. Principle laboratory experiment. Researches influence of the normalized factor on attributes of harm must be carried out in laboratory conditions at unification and standardization techniques for comparability the results received by different researchers.
8. Principle aggravation. In laboratory researches are modelled the most adverse conditions promoting the maximal display of harmful effects of the investigated factor. The same principle - to carry the toxicological data received on laboratory animals, on an organism of the person.
9. Principle relativity of specifications. The established specifications are not constant and final. At occurrence new experimental data or results negative influence of the normalized factor at the health of the population at levels, which is lower than maximal permissible concentration, specifications must be decreased.
Scheme of research toxicological attribute of harmful action at hygienic normalization chemical substances in environment.
One of the most difficult and expensive for research attributes of harm at normalization is toxicological. It is investigated under the following scheme:
1 Stage. Learning physic - chemical properties standartised substance with the purpose to search similar materials, for which there are specifications, for approximate evaluation levels of toxicity and mechanisms of activity new toxicant.
2 Stage. Studying acute toxicity of substance (at one time influence - letal doses and concentrations, threshold of acute harmfull action, etc. ).
3 Stage. Studying half-acute toxicity of substance at influence on experimental animals during 30-45 days (ability to cumulation, etc. ).
4 Stage. Studying chronic toxicity of substance (during some months or years- theshold of the chronic harmfull action).
5 Stage. Definition limit concentration or dozes by the toxicological attribute of harm. Limit (LOAEL) and underlimit concentration (NOAEL) for the person are determined on the basis of the received data on laboratory animals.
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