Aquatic environmental fates and risks of benzotriazoles, benzothiazoles, and p-phenylenediamines in a catchment providing water to a megacity of China

Wearing of vehicle parts could release many chemical additives into the environment, such as benzotriazoles (BTRs), benzothiazoles (BTHs), and p-phenylenediamines (PPDs), which are potentially toxic to wildlife and humans. This study investigated the occurrence, source, and risks of BTRs, BTHs, and PPDs in a source catchment providing water to Guangzhou, a megacity in South China, covering groundwater, surface water, and storm -water. The results showed that BTRs and BTHs were predominant in surface water and groundwater. Unex-pectedly, the BTR and BTH concentrations were lower in surface water than groundwater in a third of the paired samples. For the first time, 6PPD-quinone, a toxic ozonation product of N-(1,3-dimethylbutyl)-N '-phenyl-1,4-phenylenediamine (6PPD), was extensively detected in source waters. Stormwater decreased the BTR concen-trations but increased the 6PPD-quinone concentrations in surface water owing to their affiliation to suspended particles. From natural to urban segments of Liuxi river, a downstream increasing trend in BTR and BTH con-centrations was observed, confirming that they are indicative of urban anthropogenic activities. Strong corre-lations between industrial activities and BTR or BTH concentrations in surface water indicated that industrial activities were their main sources. Six compounds were prioritized as potentially persistent, mobile, and toxic (PMT) chemicals, combing our monitoring results and REACH criterion. This study improves our understanding of the environmental fates and risks of water-soluble tire-wear chemicals, which provides important information for chemical management, and indicates attention should be paid to the risk posed by 6PPD-quinone in the source water.

Automated summary

Wearing of vehicle parts can release potentially toxic chemicals into the environment, posing risks to wildlife and humans. This study investigated the occurrence, source, and risks of these chemicals in the water supply catchment of Guangzhou. The results showed that certain chemicals were predominant in surface water and groundwater, and unexpected concentrations were found. Additionally, a toxic ozonation product was extensively detected in source waters. This study provides important information for chemical management and highlights the need to address the risks associated with certain chemicals in the water supply.