Pesticides, delayed adverse effects

Formulas for safety factors are calculated according to cumulative properties, species sensitivity coefficient, and occurrence of delayed adverse effects (Sidorov 1980). It should be noted that the safety factor is designed mainly to allow for the potentially higher sensitivity of humans to specific pesticides than laboratory animals. This factor should also ensure the safety of a selected dose or concentration if new, unexpected adverse properties are identified for the substance in question. The final adjustment of health standards is based on clinical and epidemiological examinations of people exposed to that substance. 

All organophosphates recommended as pesticides are subjected to screening for delayed neurotoxicity through research into their influence on neurotoxic esterase, as well as in direct experiments on hens. Enough data have been collected to show pesticides as potential producers of various delayed adverse effects, which may be irreversible or somewhat reversible (atherosclerosis, hepatocirrhosis, pulmonary fibrosis, demyelinization of nerve trunks). These effects should be projected and considered in human health assessments of pesticides. 

Accepted criteria for toxicological and hygienic pesticide assessments in the USSR are also systematically reviewed, with respect to the evaluation of physical and chemical properties, toxicity as defined through acute and subacute experiments, cumulative properties, and effects on skin and mucous membranes. The methodology for establishing threshold and noneffective (harmless) levels is also described, along with the prediction of delayed adverse effects. 

Neurotoxicity is the result of improper (careless) use, handling, and negligence in the management of chemical substances such as metals, food additives, pesticides, industrial solvents, cosmetics, radiation treatment, and drug therapies. Depending upon route and dose of exposure, the symptoms of neurotoxicity appear immediately after exposure or are delayed. The symptoms include limb weakness or numbness loss of memory, vision, and/or intellect headache cognitive and behavioral problems and sexual dysfunction. Children and workers with certain existing health disorders are more vulnerable to the adverse effects of neurotoxic chemicals. 

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