Passive sampling with targeted and non-targeted analysis as an “Early Warning” of water-soluble contaminants in the Great Lakes

Abstract

The objective of this study was to integrate passive sampling with targeted analysis to quantify known contaminants of emerging concern (CECs) and, with non-targeted analysis. to identify previously unknown water-soluble compounds. Polar Organic Chemical Integrative Samplers (POCIS) were deployed in the treated effluent of a wastewater treatment plant serving the City of Hamilton, ON, Canada, as well as at three stations in Hamilton Harbour and at nearshore locations in Lake Ontario. Targeted analysis indicated that there was a gradient of pharmaceuticals, caffeine, and artificial sweeteners from highest levels in wastewater to lowest levels in the harbour furthest from the wastewater discharge. The estimated concentrations of current use pesticides were highest in the central part of the harbour. Pooled POCIS extracts were also analyzed using high-resolution quadrupole-time-of-flight mass spectrometry and the exact mass data generated were screened using a pattern recognition application. The greatest number of features were detected in positive ion mode from POCIS deployed in the central part of the harbour, and so exact mass data from this station were further evaluated using the Global Natural Products Social Molecular Networking data base. Novel CECs tentatively identified included pharmaceuticals from the angiotensin receptor blocker class. Follow-up targeted analysis confirmed that a tire wear compound, hexamethoxymethylmelamine (HMMM), the coal-tar derived compound, lepidine, the anticonvulsant, lamotrigine and a metabolite of a cough suppressant, dextrorphan, were present in POCIS. We propose that this approach be part of a Great Lakes Early Warning System to identify emerging threats from chemical contaminants.