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Investigating the Influence of Environmental Factors on Pesticide Exposure in Amphibians
Citation:
Glinski, D., Matt Henderson, R. VanMeter, AND Tom Purucker. Investigating the Influence of Environmental Factors on Pesticide Exposure in Amphibians. Presented at 2015 Society of Toxicology Meeting, San Diego, CA, March 22 - 26, 2015.
Impact/Purpose:
Presented at the 2015 Society of Toxicology Meeting.
Description:
Environmental factors such as temporal weather patterns and soil characterization coupled with pesticide application rates are known to influence exposure and subsequent absorption of these compounds in amphibians. Amphibians are a unique class of vertebrates due to their varied life histories and thus can be considered indicators of the health of an ecosystem. Absorption of pesticides in amphibians occurs primarily through a highly vascularized seat patch; however, they can also transit the superficial dermis via aquaporins or other mechanisms. Previous work in our laboratory has determined the influence of organic carbon content on pesticide body burden following exposure. The objective of this study was to investigate the influence of hydration status on the absorption of pesticides in leopard frogs (Rana pipiens) and American toads (Bufo americanus). Amphibians were dehydrated for 0,2, 4, 6, 8, and 10 hrs before being introduced to pesticide contaminated soils for 8 hrs. Following exposure, whole body homogenates and soil aliquots were extracted for LC-MS2 analysis to quantify each pesticide and its corresponding metabolites. A simple uptake model was developed that integrated application rates and soil partition coefficients with the absorption of pesticides into a compartmentalized amphibian model. The data show that increased time of dehydration results in lower pesticide body burden in both species as well as increased hepatic metabolism of pesticides. Modeling efforts demonstrate that coupling soil characterization with hydration status of the dermis are key factors in predicting dermal uptake in amphibians. Understanding these key parameters and how they govern pesticide uptake in amphibians will ultimately lead more accurate exposure estimates and less uncertainty in pesticide risk assessments for these non-target species.
