Occurrence and aquatic toxicity of contaminants of emerging concern (CECs) in tributaries of an urbanized section of the Delaware River Watershed

The presence of contaminants of emerging concern (CECs) in environmental matrices is an ongoing issue. This research project was carried out to increase our understanding of the loading, distribution and potential risk of CECs by sampling large and small tributaries in a specific area of the Delaware River watershed (in northeast USA) that is highly urbanized and significantly impacted by wastewater treatment plant effluents. Fifteen target compounds were selected for analysis based on their high frequency of detection in a previous multiyear study conducted on the Delaware River mainstem. Ten sampling sites were chosen on tributaries receiving numerous municipal and industrial discharges. Sampling locations were above and below potential source discharges. Sampling was designed to assess seasonal differences in CECs loadings. The measured environmental concentrations of the target compounds present a detailed picture of urban and industrial impacts on subwatershed receiving waters. An index of concern ranking system was applied to the sample locations by comparing measured environmental concentrations, existing target compound water quality criteria or predicted no effects levels and developing a concern summary variable. Triclocarban and diphenhydramine demonstrated to be compounds of high relative risk (RR) to the aquatic life of the Pennsylvania tributaries to the Delaware River.