EFFECT OF INGESTION OF 20 PESTICIDES IN COMBINATION AT ACCEPTABLE DAILY INTAKE LEVELS ON RAT-LIVER CARCINOGENESIS

Exposure of agricultural workers and the general population to pestici des is a major concern, and possible summation or synergistic effects deserves particular attention. In this study, however, combined dietar y administration of 19 organophosphorus compounds and one organochlori ne pesticide, each at acceptable daily intake (ADI) levels, did not en hance rat liver preneoplastic lesion development initiated by diethyln itrosamine. In contrast, a mixture of 100 times ADI significantly incr eased the number and area of lesions. The results thus provide direct support for the present safety factor approach to the quantitative haz ard evaluation of pesticides.