Wastewater sources of priority contaminants in four Canadian Arctic communities
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Date
2019-07
Authors
Stroski, Kevin
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Abstract
The main goal of this thesis was the investigate the wastewater sources of pharmaceuticals, microplastics, and per- and poly-fluorinated alkyl substances (PFASs) in Canadian Arctic communities. Current literature on the local sources of these contaminants in this region are lacking. Thus, a novel study into these sources and occurrences was undertook to better understand the impact they may have on the aquatic ecosystem in Arctic communities.
Wastewater treatment plants (WWTPs) have been shown to be sources of all three contaminants studied here in more southern latitudes and in some Arctic cities as well. Given the relatively small populations of Canadian Arctic communities, wastewater systems are typically less sophisticated than those in more urbanized areas. This combined with the harsh Arctic climate can lead to different contaminant profiles and ecological stresses given the reduction of compound degradation prior to wastewater release. The organic diffusive gradients in thin-films (o-DGT) passive sampler was used for pharmaceutical sampling in four communities, a novel usage of this sampler in both a marine and Arctic setting. PFASs were sampled through simple grab sampling while microplastics utilized manta trawls which skim the surface of waters to retrieve floating plastics. Pharmaceutical concentrations (10 – 5000 ng/L) were measured at levels comparable to other studies conducted in the Norwegian and Greenland Arctic. WWTPs varied in both efficiency and detection of compounds leading to varying concentration profiles in communities. No current ecological risk is expected based on concentration in the receiving environment. PFASs were found to be three orders of magnitude higher during wastewater release compared to open ocean concentrations but dilution played a large role in reducing these concentrations over time. Microplastics were unable to be accurately assessed given large field blank contamination.
This thesis demonstrates that for both pharmaceuticals and PFASs, WWTPs can be a significant local source of contamination into aquatic Arctic systems, alongside long-range transport. The results presented here will contribute to both the scientific and regulatory community relating to Arctic contamination.
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Keywords
Pharmaceuticals, Perfluorinated alkyl substances, Wastewater, Passive Sampling, Arctic