Research Product

This study compared in situ, field and laboratory toxicity testing results for several insecticides (azinphosmethyl - an organophosphate; endosulfan - an organochlorine, and fenvalerate - a synthetic pyrethroid) with ecotoxicological biomonitoring results from the macropelagic, estuarine tidal creek community in pristine habitats and in areas receiving significant insecticide runoff from agriculture. Field studies were conducted over a four-year period (1985-88) at several coastal field sites on Wadmalaw (Leadenwah Creek) and Johns (unnamed tidal creek near Kiawah Island) Island, coastal sea islands located just south of Charleston, South Carolina. Results indicated that laboratory and field toxicity testing and biomonitoring methodologies should be integrated to provide holistic environmental risk assessments for pesticides. Laboratory toxicity tests provide the initial bench mark for estimating toxic effects. In situ, field toxicity tests provide a mechanism to validate initial laboratory tests and expand their design to test differences in formulations, life history stages, pulsed versus continuous dose, salinity interactions, and pesticide mixtures for more realistic estimations of effects of field exposures. Application of this method in the environmental risk assessment for three classes of pesticides (organochlorines-endosulfan, pyrethroids-fenvalerate, and organophosphates-azinphosmethyl) has been demonstrated in assessing the effects of nonpoint source agricultural runoff on sensitive estuarine tidal creek fauna in South Carolina. Over a three year period of study, the integration of this approach has provided significant data to assist environmental regulators trying to control recurrent problems of agricultural runoff effects in Leadenwah Creek and other areas of the state. Future studies should be expanded to broaden our understanding of the usefulness of this integrated approach in better assessing pesticide runoff in other aquatic ecosystems throughout the U.S.