Identifying potential trace metal contamination impacts of a coal ash landfill on the largest Chesapeake Bay tributary (Chester, VA, USA).

Abstract

Coal fly ash is a highly heterogeneous waste product that becomes concentrated with metals after combustion that have been shown to act as neurotoxins and/or carcinogens in both wildlife and humans. As such, increased understanding of the presence, concentrations, and potential ecosystem impacts is needed. The Chesterfield power station contains more than 15 million tons of ash and is located adjacent to the James River, which serves as a tributary to the Chesapeake Bay. Our study investigated (1) the presence and concentrations of aluminum (Al), aresnic (As), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), lead (Pb), selenium (Se), and zinc (Zn) in surface water, deep water, and sediment samples obtained from the surrounding area and (2) the presence of various teleost species, using environmental DNA (eDNA) sampling. Universal cokriging was used to estimate the spatial variability of metals in sediments and the extent of pollution interpreted using enrichment factors (EF). Little contamination was observed in water samples compared to sediment samples. Elevated concentrations of Al, As, Cd, Cr, Fe, Pb, and Zn were observed in areas immediately adjacent to the coal ash landfills. Arsenic, Cd, and Pb showed increased EF in sites adjacent to the landfills, suggesting that the contamination observed is due to anthropogenic factors. Environmental DNA analyses revealed the presence of 22 teleost species, several of which have been identified as threatened, endangered, diadromous, and/or consumed by anglers who use the James River. Collectively, our results provide novel insight regarding the impacts of coal ash on an important Chesapeake Bay watershed and guidance for future risk assessment.