Progress in Pesticide Toxicology in the Ussr

In the USSR the study of pesticide toxicity and toxicodynamics began in 1932. All the compounds used are assessed; hygienic standards of acceptable concentrations in foods, working area air, atmospheric air, and water are calculated. The maximum acceptable daily intake of chemicals from all the media is tabulated and these data are examined for hygienic standardization. In the past toxicologists were engaged in the problem of prevention of acute and chronic poisoning, but for more than ten years already particular scientific attention has been paid to delayed effects (carcinogenicity, mutagenicity, embryotoxicity, etc.) Search is also made for alternative organotoxicity of pesticides and their allergenic properties. As pesticide circulation in the biosphere is unavoidable, in contrast to industrial effluents, pesticide selection assumes ever greater importance. Thus the hygienic classification of pesticides has been worked out. Highly toxic persistent and stable substances with adverse delayed effects are strictly forbidden. Hence, cyclodienes and other stable organochiorine substances, highly toxic systox, parathion, etc. are prohibited. Studies are carried out on the whole body, on isolated organs, and at cellular and subcellular levels. The correlation of pesticide effect with chemical structure is established. Some molecular sttuctural peculiarities of organophosphate chemicals resulting in their hepatotropy (chlorine presence), embryotoxicity and teratogenicity (phthalimide group), and the morphological blood content effect (nitrophenol groups) are revealed. Distribution variations of organochlorine compounds in lipids are determined. The highest levels of DDT and its metabolites are found in cholesterin ethers, lindane in glycerylates, and polychlorocamphene in phospholipids of the central nervous system. Prolonged exposure to small doses of DDT can change liver function and structure, increase susceptibility of the cardiovascular system to coronarospastic agents, and accelerate development of atherosclerosis and autoaggressive antihepatic and antierythrocytic antibodies. The adverse effect of DDT ingestion on pregnancy, delivery and posterity has been established. All these disturbances are based upon the disorder of mitochondria function, changes of cellular and intracellular membrane permeability, their bioelectric properties and intracellular regulatory mechanisms, and the alteration of catecholamine, serotonin and histamine metabolism. Studies of the physiological and biochemical modes of the action of pesticides facilitates elucidation of significant regularities. Now and in the foreseeable future the leading role in the system for protecting plants from pests, diseases and weeds is played by chemical substances. The assortment and the amounts of pesticides are increasing, and new