Distribution of benzotriazole ultraviolet absorbers in the nearshore marine environments of the East China Sea

Benzotriazole ultraviolet absorbers (BUAs) are regarded as emerging contaminants due to their persistent, bioaccumulative, and toxic (PBT) or very persistent and very bioaccumulative (vPvB) properties, raising concerns about their presence in aquatic environments. This study explored BUAs in the northwest nearshore of the East China Sea, revealing their prevalent occurrence in both seawater and sediments. The total concentrations of eight BUAs ranged from 4.96 to 620 ng/L in seawater and from 7.41 to 131 ng/g dry weight in sediments. Their distribution between sediments and seawater was basically dependent on log K ow, though UV-P presented an unusual preference for sediment due to its lower steric hindrance. Environmental factors had limited effects on BUAs distribution, and their decreasing concentrations from nearshore to offshore indicate terrestrial inputs and coastal anthropogenic activities are the primary sources of marine BUAs. Results of the initial ecological risk assessment suggested the occurrence of BUAs may pose potential ecological risks to the local marine environments. This study provides an overview of BUAs spatial distribution in the northwest nearshore of the East China Sea, emphasizing the urgent need for toxicological studies to fully understand their potential risks and establish regulatory measures for mitigating coastal pollution.