420 / 2024-09-16 18:07:39

Rubber-derived Chemicals in Urban Water System: Comprehensive Profiling, Influences of Urbanization Factors and Ecological Impacts

target analysis combining suspect screening, annual emission, urbanization, environmental risk assessment, transformation products

The release of rubber-derived chemicals (RDCs), mainly originating from tires, has garnered significant attention. Urban water systems can transport RDCs to urban surrounding water via stormwater, river water, and sewage, stressing aquatic environments due to potential toxic effects. However, RDCs have not been comprehensively studied within urban water systems, and the influences of urbanization on RDCs remain unclear, limiting effective urban water treatment and utilization. To address these issues, we investigated RDCs in stormwater, river water, seawater, and sewage influent and effluent collected in Hong Kong, a metropolis in China, by combining target analysis and suspect screening approach. Among 45 target RDCs, the vulcanizing agents and corrosion inhibitors were predominant in the urban water, accounting for 26.0-66.1% and 29.3-71.7% of total RDCs (∑₄₅RDC), respectively, while antioxidants and their transformation products presented in smaller quantities (0.4-1.7% and 1.2%- 3.3% of ∑₄₅RDC, respectively). Ten RDCs from four classes were additionally identified by suspect screening. An estimated emission of ∑₄₅RDC amounting to 20262 kg/year is discharged into the coastal seawater of Hong Kong via urban water, with sewage effluent being the primary transport pathway. The results of multiple statistical analyses indicated that population and vehicle-related factors were the major drivers shaping the spatial distribution of RDCs in urban surface water. A preliminary risk assessment indicated that two transformation products from antioxidants, 6PPD-quinone and IPPD-quinone, posed high risks to the aquatic ecosystem in most urban water bodies.