Contamination by benzothiazoles in the Arctic: First evidence in the seawater of the Greenland Sea

Abstract

Benzothiazoles (BTHs), used in industrial chemistry, consumer products, and pharmaceuticals, are emerging contaminants due to their environmental presence and toxicological risks to aquatic life and human health. However, their environmental fate in seawater remains poorly investigated. This study reports for the first time the occurrence and distribution of six BTHs in the sub-Arctic seawater of the Greenland Sea. Using solid-phase extraction combined with ultrahigh performance liquid chromatography tandem mass spectrometry, total BTHs were detected at concentrations ranging from 0.2 to 1043 ng L⁻¹. Benzothiazole, 2-hydroxy-benzothiazole, 2-methylthio-benzothiazole, and 2-methyl-benzothiazole exhibited higher mean concentrations (355 ± 335, 114 ± 80, 34 ± 7, 15 ± 8 ng L⁻¹, respectively) compared to 2-thiocyanomethylthio-benzothiazole (0.5 ± 0.9 ng L⁻¹) and 2-amino-benzothiazole (0.3 ± 0.2 ng L⁻¹). Local emissions and both short- and long-range transport may account for BTHs presence in the Greenland Sea. The spatial distribution of BTHs along the 75° N transect and in the water column appears influenced by the Greenland Sea Gyre circulation and deep convection processes. Total BTHs distribution showed no significant differences between superficial and water column concentrations or between the outermost and innermost transect zones, as determined by the Mann-Whitney test, although concentrations were generally higher in the zone influenced by the Norwegian Atlantic Current. The ecological risks of BTHs, assessed using the risk quotient methodology, indicate a low threat to aquatic life. This research underscores the need for monitoring BTHs in the Arctic to understand their sources, transport, and environmental fate, providing a foundation for future studies.