An in vitro evaluation of the potential toxicities and interactions of carbamate pesticides.
The inhibition of rat plasma cholinesterase was used to screen the toxicity of carbamate pesticides in vitro. All three carbamates studied-aldicarb, carbofuran and oxamyl-inhibited the rat cholinesterase in a dose-dependent manner, as determined by the Ellman technique. The concentrations that produced 25 and 50% inhibition of cholinesterase (IC(25) and IC(50)) were, respectively, 1 x 10(-8) and 5 x 10(-7)m for aldicarb, 1 x 10(-9) and 1.5 x 10(-7)m for carbofuran, 5 x 10(-11) and 5 x 10(-8)m for oxamyl and 4 x 10(-11) and 6.5 x 10(-8)m for a mixture consisting of equal proportions of all three carbamates. In the interaction study, based on the data for the mixture of all three carbamates, and for the individual carbamates, cholinesterase inhibition by aldicarb was found to be potentiated by carbofuran and oxamyl. The effects of carbofuran were also potentiated by aldicarb and oxamyl but the presence of carbofuran and aldicarb was found to reduce cholinesterase inhibition by oxamyl.
Iyaniwura
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Laboratory for General Toxicology, National Institute of Public Health and Environmental Hygiene, Bilthoven, The Netherlands.