BIOLOGICAL MONITORING OF OCCUPATIONAL PESTICIDES EXPOSURE

Two kinds of measurement: (1) enzyme activities in blood, and (2) unch anged pesticides and their metabolites in urine or blood have been use d in biological monitoring for assessing exposure to pesticides. The a ssays of acetylcholinesterase (AChE) activity in whole blood and eryth rocytes are mainly applied to estimate inhibition by organophosphates (OPs) and carbamates. A level at 70% of an individual's baseline or of a mean population AChE activity has been recommended as a reference v alue for exposure control. The measurement of lymphocyte ''neuropathy target esterase (NTE)'' activity in subjects handling axonopathic OPs is mainly for research application. Analytical methods are available f or detecting alkylphosphates, carbamates, pyrethroids, chlorinated hyd rocarbons, some herbicides and fungicides, chlordimeform, chlorobenzil ate, dichloropropene, dinitrocresol and pentochlorophenol or their met abolites in urine or blood. However, due to lack of significant dose-r esponse or dose-effect relationship, the majority of these determinata nts can only be used as biological exposure indicators to confirm expo sure or to estimate internal dose. Further research in developing adeq uate indicators and methods for biological monitoring of occupational pesticides exposure is needed. Pre-exposure value and/or reference val ue of relevant indicators are necessary for assessing the degree of ex posure and absorption.