First evidence of benzothiazoles in arctic aerosols: Seasonal trend and sources attribution

Benzothiazoles are a class of compounds with wide-ranging applications, particularly in industrial chemistry. They are used as accelerators in the vulcanization process in the rubber industry, and have applications in pharmaceuticals, due to their antimicrobial, antifungal, and anticancer properties. This class of compounds can be considered emerging contaminants due to their persistence in the environment, and some of them may pose toxicological risks to aquatic life and potentially to human health. The transport mechanisms and environmental fate of these compounds are poorly investigated, particularly in aquatic compartments such as wastewater, and research has been limited to urban areas. For the first time, eight benzothiazoles were found in Arctic atmospheric aerosol over an entire sampling year, from February 2022 to March 2023. A comparison of the seasonal trends of benzothiazoles with specific markers (i.e., major ions, methanesulfonic acid (MSA), levoglucosan, and arabitol) and the employment of a chemometric approach allowed us to identify three key findings: i) two benzothiazoles (BTH-OH and BTH-NH₂) can be linked to a local natural source; ii) soil resuspension is another possible source of two other species (BTH-SH and BTH-MeS); and iii) long-range atmospheric transport sources are associated with BTH and BTH-SO₃H. The species present in the Arctic aerosol have different abundances compared to urban areas, confirming the necessity to improve research in different environments to better understand their transport mechanisms and environmental fate.