Organophosphate Esters in the Canadian Arctic Ocean

Eleven organophosphate esters (OPEs) were detected in surface water and sediment samples from yearly sampling (2013-2018) in the Canadian Arctic. In water samples, Sigma chlorinated-OPEs (Cl-OPEs) concentrations exceeded Sigma non-chlorinated-OPEs (non-Cl-OPEs) with median concentrations of 10 ng L-1 and 1.3 ng L-1, respectively. In sediment samples, Sigma Cl-OPEs and Sigma nonchlorinated-OPEs had median concentrations of 4.5 and 2.5 ng g(-1), respectively. High concentrations of OPEs in samples from the Mackenzie River plume suggest riverine discharge as an OPE source to the Canadian Arctic. The prevalence of OPEs at other sites is consistent with long-range transport. The OPE inventory of the Canadian Arctic Ocean representative of years 2013-2018 was estimated at 450-16,000 tonnes with a median Sigma 11OPE mass of 4100 tonnes with >99% of the OPE inventory estimated to be in the water column. These results highlight the importance of OPEs as water-based Arctic contaminants subject to long-range transport and local sources. The high OPE inventory in the water column of the Canadian Arctic Ocean points to the need for international regulatory mechanisms for persistent and mobile organic contaminants (PMOCs) that are not covered by the risk assessment criteria of the Stockholm Convention.

Automated summary

Eleven organophosphate esters (OPEs) were detected in surface water and sediment samples from yearly sampling in the Canadian Arctic. Chlorinated OPEs (Cl-OPEs) had higher concentrations in water samples compared to non-chlorinated OPEs, while concentrations in sediment samples were relatively similar. Samples from the Mackenzie River plume indicated riverine discharge as a source of OPEs in the Canadian Arctic.