Spatiotemporal distribution of 1,3-diphenylguanidine, benzotriazole, benzothiazole, N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine, and their derivatives in surface and core sediments from Lake Sihwa, Korea

This study presents the first spatiotemporal patterns of 17 tire- and rubber-related chemicals and additives (TRAs) in 43 surface and two core sediments from Lake Sihwa (South Korea), an artificial saltwater lake partitioned by a sea dike into offshore (outside the dike), inshore (inside), and inland creeks (tributaries draining to the inshore). Σ 17 TRAs concentrations in surface sediments ranged from below the method detection limit to 5880 ng/g-dw (median 41.0 ng/g-dw) and were dominated by benzothiazoles (53%), benzotriazoles (23%), guanidine accelerators (19%), and p -phenylenediamines (4%). Σ 17 TRAs concentrations in sediments from downstream creek sites were higher than those found in upstream, and concentrations declined from creeks > inshore > offshore, indicating localized inputs and offshore transport. Screening level ecological risk assessment suggested the need for follow-up studies in inland creeks. Two sediment cores, collected from the lake inshore (medians 52.5 and 41.9 ng/g-dw, respectively), revealed three historical accumulation phases linked to the development of the rubber industry, the 1970s oil crisis, the establishment of national industrial complexes, and subsequent pollution controls. Accumulation of Σ 17 TRAs in one of the sediment cores, at a point influenced by industrial discharges, revealed increasing demand for automobile tires and rubber production. Our study establishes a baseline for tire-derived chemicals in sediments and warrants further studies on aquatic toxicity. • First spatiotemporal record of tire/rubber additives (TRAs) in Lake Sihwa is described. • Land-sea gradient of TRAs indicates localized sources and offshore transport. • Sediment cores reveal decadal TRA shifts linked to industrial and regulatory changes. • Recent TRAs increase reflects expanding synthetic rubber production. • This study provides a baseline for ecological risks and future management of TRAs.