by Thanh-Binh Duong
Faculty Mentor: Dr. Ben Kisila
The Chesapeake Bay is a large estuary located along the east coast of the United States, with numerous wastewater treatment plants (WWTP) located throughout its basin. This area supports a vast diversity of aquatic biota and provides for numerous communities throughout the eastern United States. While effluent from WWTPs has been identified as a major contributor to microplastic pollution, little research has been conducted to examine microplastic contamination in the Chesapeake Bay watershed areas surrounding these effluent streams. Microplastics are unique in that their size (<5mm) enables ease of ingestion by aquatic organisms, causing adverse health effects such as energy depletion and digestive tract obstructions. MPs may also biomagnify throughout trophic levels, ultimately posing a threat to human health due to unintended consumption. In this study, the presence of microplastics in major rivers in the lower basin of the Chesapeake Bay, USA was examined. Water samples and sediment samples were collected in the Potomac and Rappahannock river upstream, midstream, and downstream of WWTP outfall sites via dip sampling and grab sampling, respectively. Sediment samples were treated with a wet peroxide oxidation using Fenton’s reagent to digest natural organic matter and sodium chloride to separate MPs from the sample. Surface water samples were filtered by vacuum filtration to separate suspended particles from water. Presence, type, and quantity of MPs were assessed using light microscopy. While this project is currently ongoing, we expect to find that MPs are more abundant in samples collected at WWTP outfall locations rather than locations upstream or downstream from those sites. The results of this study will provide novel information regarding the presence, distribution, and concentrations of MPs in water and sediment samples from several areas of the Chesapeake Bay watershed due to inputs from WWTP effluent.
I think this was a very interesting study as I find discussions about microplastics to be relatively new, and not quite talked about much. I like the approach in this study that narrows down the search from “are microplastics present” to ” what form are they present in and a point source of origin”. The results being that there were more microplastics present close to the wastewater treatment plants illuminate that they are coming from the wastewater effluent, and that a major source is from textile fibers from washing and microbeads from facial scrub. It further makes me think about how we can change our consumerist patterns to negate impacts on the environment.
Thank you for sharing this fascinating study. Have you considered in vitro weathering studies for see the impact of weathering on different micro plastics.
Bihn,
This is such an interesting study. We hear about microplastics, but it is nice to see someone gathering data on the types and concentrations in waterways. This combined with the study you also did on possible effects on aquatic life was intriguing and I look forward to seeing results of next steps, particularly information about how the distribution may have changed over time. Thanks for this work.