Groundwater as a Source of Emerging Contaminants in the Chesapeake Bay

Since 2005, high young-of-year natural mortality rates and declines in adult indices of abundance have been observed in some smallmouth bass populations in the Susquehanna River Basin. Endocrine disrupting compounds (EDCs) are hypothesized to be a contributing factor to the observed population dynamics. In order to better understand these compounds in the environment and their effects of fish populations, further research is needed to understand potential exposure pathways. In particular, there is a paucity of information on the role of groundwater as a source of EDCs for aquatic organisms. In fact, current research at river sites throughout the Chesapeake Bay Watershed, including in Pennsylvania – where surface water, stream sediment, and adult/young-of-year smallmouth bass are sampled for contaminants - led to the hypothesis that groundwater could be a potential exposure pathway for EDCs. Therefore, the objective of this research was to investigate the role of groundwater as a source of emerging contaminants in areas of known smallmouth bass spawning and rearing activity. Using thermal cameras to locate areas of groundwater upwelling, we sampled groundwater using drive-point piezometers at three locations, two located in the Susquehanna River Basin and one in West Virginia. Samples of ground and surface water were collected biweekly during smallmouth bass spawning season and monthly through September 2017. As an initial water chemistry screening tool, total estrogenicity was quantified through a bioluminescent yeast estrogen screen to use as an indicator of the presence of estrogenic EDCs. Preliminary analyses suggest that groundwater samples may be an important pathway of exposure, especially given the use of these areas for spawning by smallmouth bass