Stephen Reid, Stuart Cohen, Jim Julian, Shannon Julian, Jan Ferrigan, James Howard
Poster presented at 10th IUPAC International Congress on the Chemistry of Crop Protection, Basel, Switzerland. (2002)
Recently there has been concern raised over the decline of amphibian populations around the world and the increased rate of amphibian deformities. Over the past several years there has been increased research on the cause of these declines and deformities. Pesticides and nitrogen fertilizers have been identified as possible causes, among others. Golf courses, which regularly receive pesticide and fertilizer applications, can be home to a variety of wildlife including amphibians. Golf courses typically make suitable sites for amphibian habitats because of their vast open tracts of land, many water sources, and wooded areas. Amphibian toxicology studies are generally not required by regulatory agencies. Therefore, we developed a three-step methodology to calculate maximum allowable concentrations (MACs) for a variety of pesticides commonly used on golf courses for an amphibian risk assessment. We have also recently developed nitrate-N criteria for two frog species. First, western chorus frog (Pseudacris triseriata) toxicities were estimated based on readily available rainbow trout toxicity data (frequently required as part of pesticide registration). Second, interspecies sensitivities were compared using new toxicity data from Howard (2001) and Julian et al. (2001) to determine if the estimated western chorus frog toxicity could be compared side-by-side with other species of amphibians. Finally, chronic MACs were derived that were protective of all relevant amphibian species, but with a focus on the spotted salamander (Ambystoma maculatum). This was done by analyzing the Howard (2001) and Julian et al. (2001) data for sub-chronic and chronic effects to calculate a conservative factor that was multiplied by the estimated western chorus frog toxicity. A more straightforward approach was used to calculate nitrate MACs for frog species in California and Utah, USA. To our knowledge, this is the first time aquatic amphibian criteria have been calculated for turf pesticides and fertilizers.