CUERE Seminar Series - Dr. Megan Fork

Wastewater treatment plant effluent is a well-known source of pharmaceutical pollution to stream ecosystems, but less is known about the concentrations, loads, and temporal variation in streams that do not receive treated wastewater effluent. To characterize the amounts and temporal variation of pharmaceuticals in streams, we collected one year of weekly pharmaceutical concentrations in stream water from eight catchments spanning an urbanization gradient in Baltimore, MD. Importantly, the streams in our study do not receive treated wastewater effluent. Instead, the most likely sources of pharmaceuticals are leaks or failures in wastewater infrastructure that transmit untreated wastewater directly to the stream. Over the course of one year and across all sites, we detected 37 of the 92 pharmaceuticals for which we screened. The identity of pharmaceuticals in the mixture and their concentrations are highly variable among weeks, with total pharmaceutical concentrations ranging over 3 orders of magnitude and the total number of detections varying widely among individual compounds. Furthermore, the concentration and detection of pharmaceuticals in any given sample cannot be predicted accurately from routinely-monitored stream parameters, in contrast to “traditional” contaminants like nutrients. Because most wastewater in the world is released to the environment without or with less than adequate treatment, the variability demonstrated here is likely widespread and the toxicological impacts of such a dynamic exposome are worthy of future research.