Hazard assessment and justification of the medical and sanitary regulation of clopyralid in the air of the working area

Goal. Establishment of toxicity parameters and substantiation of the maximum permissible concentration of the herbicide clopyralid in the air of the working area. Object and research methods. Clopyralid (3,6-dichloropyridine-2-carboxylic acid) manufactured by SUPERUS Co. Ltd (China). The research methods are toxicological-hygienic, biochemical, immunological, physico-chemical, statistical. Research results and their discussion. The results of toxicological and hygienic studies of the herbicide clopyralid on laboratory animals (white mice, white rats, ants, rabbits) are presented. It was established that clopyralid according to the parameters of acute toxicity with a single intragastric injection and a single application to the skin belongs to low-hazard substances (hazard class 4), with a single inhalation effect - to moderately hazardous substances (hazard class 3), does not have a skin resorptive effect, exhibits moderately pronounced irritant effect upon repeated contact with the skin and strongly pronounced irritant effect upon contact with mucous membranes, causes sensitization of the body. With subchronic oral exposure and application to the skin, it exhibits weak cumulative properties. Gonadotoxic, embryotoxic and teratogenic effects are caused by the general toxic effect of clopyralid. Genotoxic and carcinogenic properties were not detected. Based on the established parameters of toxicity, the stock factor was calculated, the maximum permissible concentration of clopyralid in the air of the working area was proposed and the method of measuring the mass concentration of the herbicide was developed. Conclusions. The maximum permissible concentration of clopyralid in the air of the working area is recommended at the level of 1.0 mg/m3, aerosol, 2nd hazard class, + - mark requires special eye protection. A gas chromatographic technique for measuring the mass concentration of clopyralid in air has been developed. Keywords. Clopyralid, toxicity parameters, maximum permissible concentration, air of the working area.