Assessment of the Potential Neuropathic Risk to Banana Workers from Dermal Exposure to Chlorpyrifos. L. M. Plunkett, ENVIRON Int. Corp., Houston, TX 77056; S. L. Brown, R2C2, Oakland, CA 94605; and N. J. Rachman, P.O. Box 6426, Thousand Oaks, CA 91359
Concerns about the potential neurotoxicity of chlorpyrifos have been raised recently in the popular and chemical trade press. Review of the available literature revealed a lack of discussion of the neuropathic risk to either worker or nonworker populations following exposure to chlorpyrifos. An integrated pest management (IPM) program for insect control widely used by the banana industry involves sheathing developing fruit in a very thin, perforated polyethylene bag that has been impregnated with < 1% chlorpyrifos by weight. Workers are potentially exposed through inhalation and dermal contact. Using available published toxicological data (Richardson et al. 1993a, 1993b) that examined the risk of organophosphate-induced delayed neurotoxicity (OPIDN), published data on the disposition of chlorpyrifos following dermal exposures (Nolan et al. 1984), and a reasonable exposure scenario for banana workers, a risk assessment for occupational exposure to chlorpyrifos was performed. The assessment demonstrated that chlorpyrifos exposure is devoid of OPIDN risk at doses below those associated with clinical signs of cholinergic toxicity. In fact, doses would have to approach lethal levels before signs of OPIDN are apparent. As a result, cholinesterase testing programs would be expected to provide adequate early warning of problem exposures. Using a plausible exposure scenario for banana plantation workers, it is unlikely that workers would be at risk of OPIDN.