Exposure limits for occupational and environmental chemical pollutants in various media

Exposure limits for occupational and environmental chemical contaminants are based on animal experimentation and observation in humans. Usually, the final recommendations are "predictions" which can hardly guarantee the absolute safety for all. Late effects were discovered to lately in the past. The impact of the biotransformation of pollutants on their biological activity is demonstrated with trichloroethylene, styrene and N,N-dimethylformamide, which are suspected of having carcinogenic potential. In addition, trichloroethylene and N,N-dimethylformamide cause intolerance of alcohol with hyperacetaldehydemia; acetaldehyde is claimed to be carcinogenic as well. The biotransformation of these three widely used substances differs among various species. Different fate of chemicals in human and animal organisms results in the necessity to consider kinetic and metabolic studies in setting limits; in microorganisms also metabolites supposed to be formed in humans should be tested. Limits for some pollutants in various media are given.