CONTROL OF VARROA DESTRUCTOR USING POWDERED SUGAR AND HEAT

Nicholas Hill, University of Rhode Island

Abstract

Exposure to per- and polyfluoroalkyl substances (PFAS) has been associated with toxicities in wildlife and negative health effects in humans. Decades of fire training activity at Joint Base, Cape Cod, Massachusetts incorporated the use of aqueous film forming foam (AFFF) which resulted in long-term PFAS contamination of sediments, groundwater, and hydrologically connected surface waters. To explore the bioaccumulative potential of PFAS residing in complex environmental mixtures, a mesocosm was established to evaluate bioconcentration of PFAS from AFFF-contaminated groundwater by flow-through design. Fathead minnows (n = 24) were exposed to PFAS in groundwater over a 21-day period and tissue specific PFAS burdens in liver, kidney, and gonad were derived at three different time points. ∑PFAS concentrations in groundwater increased temporally, ranging from approximately 10,000 ng/L at day 1 to 36,000 ng/L at day 21. Relative compositions of PFAS functional groups in liver, kidney, and gonad shifted temporally from majority FASA to PFSA. By day 21, mean ∑PFAS concentrations in tissues displayed predominance in order of: liver > kidney > gonad. Generally, bioconcentration factors (BCFs) for perfluoroalkyl sulfonamides (FASA), perfluoroalkyl carboxylic acids (PFCA), and fluorotelomer sulfonates (FTS) increased with degree of fluorinated chain length, but this was not evident for perfluoroalkyl sulfonic acids (PFSA). Perfluorooctane sulfonamide displayed the highest mean BCF (7,700 L/kg) in day 21 kidney. Generally, mean BCFs for FASA were within or above bioaccumulative thresholds outlined by the U.S. Environmental Protection Agency’s (US EPA) Toxic Substances Control Act (TSCA) criteria, “B”.