Sewage and Pathogen Contamination in Urban Streams in Schenectady in the Lower Mohawk Watershed

Urban streams are becoming increasingly polluted by anthropogenic activity, and in Schenectady (NY) two primary stressors include poor wastewater infrastructure and road salt use. Urban streams in Schenectady include Mill Creek and Cowhorn Creek that empty into the Binnekill (feeder to the Mohawk), and the Hans Groot Kill that empty directly into the Mohawk River. These streams were sampled to evaluate water quality and analyzed for pathogens. This study is primarily focused on fecal indicator bacteria (FIB) <em>Enterococcus, </em>which<em> </em>is an EPA-approved method of determining surface water quality and it is an established indicator of sewage in waterways. The average pathogen values in the Hans Groot Kill and Binnekill exceeded EPA guidance for <em>Enterococcus</em>, often by several orders of magnitude. In the fall of 2021, the majority of samples failed the EPA's criteria for contact with surface waters including those from the Binnekill (74% failure, n=11), the Hans Groot Kill (100% failure, n=32), and the Mohawk River (54% failure, n=43). Geometric means for the Binnekill, Hans Groot Kill, and Mohawk River were 267 MPN/100 mL, 2223 MPN/100 mL, and 223 MPN/100 mL, respectively, all exceeding the EPA's guidance of 33 MPN/100 mL. High pathogen loads occur during rainfall events when contaminants are mobilized. However, <em>Enterococcus levels </em>in the Hans Groot Kill remain high even during dry or low-flow periods, indicating a base-level contamination that occurs in all weather conditions, almost certainly due to impaired infrastructure (broken pipes). During extreme weather events, Union College is impacted by failing sewer systems, as was the case twice in the fall of 2021, when sewer overflows on campus spilled untreated wastewater directly into the Hans Groot Kill. At low base flow, the urban creeks have elevated levels of nitrate, sulfate, chloride, and sodium that may indicate loads from contaminated groundwater. This is especially apparent in elevated levels of sodium and chloride, which probably come from road salt that temporarily resides in groundwater but is released and measurable at base flow. Elevated levels of sodium, chloride, nitrate, and phosphate are particularly problematic. The high dissolved ion loads as well as high pathogen levels in these water bodies indicates the acute leaking of sewer pipes in Schenectady due to aging infrastructure and/or illegally connected pipes. Monitoring of these waters must continue to inform plans for improved sewage handling that need to be implemented to remediate contamination in the Mohawk Watershed.

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