Significance of Pesticide Residues to Human Health

The use of chemical pesticides provides a number of health benefits, including control of insect-vector-borne diseases and increased food production. However, the use of these toxic materials on man or in his immediate environment has created potential hazards that are of great public health significance. Use experience data for pesticide manufacturing plant workers, formulators and spraymen under study by the Food and Drug Administration shows subtle biochemical differences related to high-level pesticide exposure. The significance of these differences is not known. The sen-sitivity of currently available chemical techniques has made possible the measurement of very small amounts of the chlorinated hydrocarbon pesticides in the environment and in human tissues, including blood. DDT levels in adipose tissue of the United States general population have not increased since they were first measured in 1950. However, current studies have shown that race, geographic location, and age are all important factors in determining the DDT storage level for an individual. Recent tests in experimental animals suggest that teratology from 2,4,5,-T formulations, potential carcinogenicity of DDT, and induction of drug metabolizing enzymes by various chlorinated hydrocarbon pesticides are problems whose significance for human health must be evaluated. In two-year human volunteer studies, daily doses of DDT up to 200 times the ordinary dietary level did not produce detectable adverse effects. The Single most important factor in determining toxicity, including cancer and teratogenicity, is dosage.