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Understanding spatial and temporal patterns of contaminants in the Maumee River to assess biological hazards
Citation:
Rearick, D., G. Ankley, J. Berninger, B. Blackwell, J. Cavallin, K. Fay, K. Jensen, M. Kahl, S. Poole, E. Randolph, A. Schroeder, J. Swintek, AND D. Villeneuve. Understanding spatial and temporal patterns of contaminants in the Maumee River to assess biological hazards. SETAC North America, Toronto, ON, CANADA, November 03 - 07, 2019.
Impact/Purpose:
To understand the potential biological impacts of environmental contaminants, it is necessary to understand the temporal and spatial patterns that influence contaminant profiles. To better characterize the spatial and temporal variability of contaminants in an agricultural to urban watershed, we collected data from 8 locations in the Maumee River watershed (OH) during 2012 and across two seasons in 2016. Statistical techniques identified distinct site separations associated with divergent contaminant mixtures. To put chemical concentrations into a biological context, exposure-activity ratios (EARs) for detected chemicals were assessed using the ToxCast database. The EAR analysis identified sites and biological pathways to prioritize, providing resource managers with information to better understand the potential for contaminant mixtures to impact biota.
Description:
Assessing the potential for adverse biological effects of complex contaminant mixtures in aquatic environments is an ongoing challenge. The interplay of environmental complexity, seasonal variation, and human activities leads to dynamic mixtures varying through space and time. To evaluate potential hazards influenced by system complexity, an understanding of how chemical mixtures vary across anthropogenic gradients interannually and seasonally is necessary. To better characterize the spatial and temporal variability of contaminants in an agricultural to urban watershed, we collected data from 8 locations in the Maumee River watershed (OH) during 2012 and across two seasons in 2016. Sites were selected to capture a range of human activity gradients including wastewater treatment, urban drainage, and agricultural sources. Analysis of organic contaminants targeted pharmaceuticals and wastewater indicators to evaluate interannual patterns among sites between 2012 and 2016. In 2016, a detailed assessment of pesticides was conducted to observe seasonal variability. Chemicals varied greatly across sampling sites, ranging from 27 to 64 chemicals detected in 2012. Sites downstream and nearby WWTPs generally had the highest chemical detections for pharmaceuticals and wastewater indicators. In 2016, pesticide concentrations increased significantly in June with pronounced changes in more agricultural, upstream locations. Highest concentrations were detected for atrazine and metolachlor in 2016. Hierarchical cluster analysis revealed distinct site separations associated with diverse chemical mixtures across the landscape for both years indicating such approaches may be effective to predict chemical occurrence for future prioritization. To put chemical concentrations into a biological context, exposure-activity ratios (EARs) for detected chemicals were assessed using the ToxCast database. EAR analysis identified multiple sites, biological pathways, and chemicals that warrant future prioritization for assessment in the complex system.