Targeted screening of passive samplers as an “Early Warning” of novel contaminants in the Great Lakes Basin

In a previous study, we identified several novel contaminants of emerging concern (CECs) using non-targeted screening of extracts prepared from passive samplers deployed in wastewater and surface waters in Hamilton Harbour. In the present study, we investigated whether several of these novel compounds are widely distributed in tributaries and coastal waters in other areas of the Great Lakes Basin. Extracts prepared from archived Polar Organic Chemical Integrated Samplers (POCIS) were analyzed for targeted CECs, which included four tire-derived compounds, two prescription pharmaceuticals (i.e., lamotrigine, formycin), a metabolite of a cough suppressant (i.e., dextrorphan) and a component of coal tar (i.e., lepidine). Five of these analytes were widely distributed in the basin. Concentrations in surface waters were estimated using sampling rates (R_s) predicted from physical-chemical properties. The estimated maximum time-weighted average concentrations for three compounds derived from tire-wear, hexamethoxymethylmelamine (HMMM), diphenylguanidine and 6PPD-quinone were 680, 48 and 17 ng/L, respectively. The distribution of these tire-wear compounds and lepidine indicated that they are transported into surface waters from urban runoff. Dextrorphan and lamotrigine were detected at the highest estimated concentrations near discharges of domestic wastewater. This study demonstrates an approach to identify and assess the sources of novel CECs as part of the development of an “Early Warning System” for potential threats to the Laurentian Great Lakes and their tributaries.