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Risks from occupational and dietary exposure to mevinphos
R C Cochran1, T A Formoli, M H Silva
1Department of Pesticide Regulation, California Environmental Protection Agency, Sacramento 95814-5624, USA.
Reviews of Environmental Contamination and Toxicology
|January 1, 1996
Summary
Mevinphos, an organophosphate insecticide, poses risks due to its high acute toxicity, primarily from cholinesterase inhibition. Occupational exposures, especially for ground applicators and harvesters, exceeded safety margins, leading to production cancellation.
Area of Science:
- Environmental toxicology
- Pesticide risk assessment
Background:
- Mevinphos (Phosdrin) is a category 1 organophosphorus insecticide used on vegetable crops.
- High acute toxicity necessitates risk assessment for occupational and dietary exposure.
- Primary toxic effects stem from cholinesterase inhibition.
Purpose of the Study:
- To conduct a risk assessment for occupational and dietary exposure to mevinphos.
- To evaluate the safety margins (MOSs) for various exposure scenarios.
- To determine the adequacy of existing tolerances for protecting public health.
Main Methods:
- Calculated margins of safety (MOSs) using a human no-observed-effect level (NOEL) for cholinergic signs.
- Estimated occupational exposure via passive dosimetry and surrogate data.
- Assessed dietary exposure based on dislodgeable foliar residues and transfer factors.
Main Results:
- MOSs for mean acute occupational exposure of ground applicators and harvesters were inadequate.
- MOSs for the 95th percentile of short-term worker exposure were also inadequate.
- MOSs for potential acute dietary exposure were adequate, but some USEPA tolerances were insufficient.
Conclusions:
- Mevinphos poses significant risks from short-term occupational exposures.
- Inadequate MOSs for certain worker groups and theoretical dietary exposures prompted regulatory action.
- Production was ended for domestic use, with existing stocks allowed limited use.