Heavy Metals in Estuarine Food Webs
Gillen Curren, Environmental Science 2022, was selected as a Beckman Scholar for 2019-2020. She is working in the laboratory of Dr. Nathaniel Weston at Villanova University to compare the heavy metal concentrations found in various plants, insects, fish, benthic infauna, and filter feeders from coastal tidal marsh systems in the Delaware Estuary (New Jersey and Delaware), the Plum Island Estuary (Massachusetts), and the York Estuary (Virginia). Heavy metals in estuarine soils are a result of natural rock weathering augmented by anthropogenic sources that are delivered from the watershed to the coastal zone. Anthropogenic sources of heavy metals to coastal systems have become a concern with the increase in development in many coastal watersheds. Research in Dr. Weston’s lab has previously found that these three coastal ecosystems represent a gradient of heavy metal contamination. Gillen’s project will focus on the movement of these heavy metals into the food web in these estuarine ecosystems. Gillen began sampling plants, insects, fish, benthic infauna, and filter feeders in summer 2019, and collections are complete for the Plum Island system and underway in the Delaware River. Gillen will continue sampling during summer 2020. Samples from each organism will be digested using a hot acid microwave digestion system and analyzed on an inductively coupled plasma mass spectrometer (ICP-MS), which will yield the concentrations of a suite of heavy metals in each sample. Gillen will compare the heavy metal concentrations between organisms of the same species across the three estuaries to determine the relationships between heavy metal delivery to the coastal zone and heavy metals in the estuarine food web. In addition, she will compare the concentrations of heavy metals between different organisms within the same estuary to elucidate how the trophic level and location in the estuarine food web influences the heavy metal load of estuarine organisms. Estuarine food webs support the production of fish and shellfish that humans consume, and so understanding levels of potentially toxic heavy metals in estuarine organisms has implications for human health, along with ecosystem health. Should Gillen discover that any of these organisms contain a level of heavy metals that rise to a level of concern for human health, she will contact regional stakeholders and managers for appropriate public notice.