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• Transboundary evaluation of HMs in coastal environments of the Yellow Sea was conducted. • Sediments moderately contaminated with HMs significantly contributed to waterborne HMs. • Environmental factors significantly associated to hot spots contaminated by specific HMs. • Integrated management for coastal HMs pollution was highlighted in site-specific manner. The Yellow Sea Large Marine Ecosystem (YSLME) is an important socioeconomic zone in Asia, but has been deteriorated by various environmental pollutants over the last half century. However, comprehensive coastal pollution assessments, particularly for heavy metals (HMs), have been limited from an international perspective. Here, we first evaluate coastal HM pollution in sediment and water from 119 riverine, estuarine, and marine locations along the BS and Yellow Sea to perform a comparative assessment between the two countries of China and South Korea. The occurrence, distribution, sources, multimedia fate, interactions, associated environmental factors, and potential ecological risks relating to the HM pollution are widely addressed. Eight typical HMs (As, Hg, Zn, Cu, Pb, Cd, Cr, and Ni) were targeted in both sediments and water, and in situ water properties (pH, dissolved oxygen, salinity, and temperature) and sediment properties (pH and organic matter (OM) content) were analyzed. The results indicated that As, Cd, Cr, Cu, Ni, and Pb concentrations in water were higher in the estuarine area than those in riverine and marine areas and that particularly severe HM pollution was evidenced in the BS. The dominant elements in pollution hot spots varied greatly among the countries and regions. According to the geo-accumulation index (I geo) and pollution load index (PLI) values, the sediments exhibited high Hg and Pb pollution in the BS; high As, Hg, and Pb pollution in the Yellow Sea of China; and high Cd and Hg pollution in the Yellow Sea of South Korea. In general, the sediments were moderately contaminated by HMs based on the high PLI (>1.0) and risk index (RI) values (>160). Ni and Cr in the sediment mainly originated from geogenic sources, while the other elements (Zn, As, Cd, Cu, Hg, and Pb) were primarily linked to anthropogenic sources. Based on the partial redundancy analysis, we found that environmental factors, especially OM, contributed significantly to the concentrations of HMs in both the sediments and water. The sediment HMs significantly contributed to the waterborne HMs due to their release from the sediments to the water column. An overall assessment of the contamination status, spatial distribution, and potential sources of HMs suggested that the water-sediment interaction of HMs and the influence by environmental factors should be subsequently considered for a better understanding of the multimedia fate of HMs in the given dynamic YSLME system or similar environments elsewhere. [ABSTRACT FROM AUTHOR]

• WWTPs and dams influence distribution of PFASs in Olympic host cities. • PFASs increased greatly during past 8 years due to rising anthropogenic emission. • Riverine flow is still the biggest source of PFASs to the Guanting Reservoir. • PFASs predominantly stored in water compared with sediment or fish in the reservoir. Perfluoroalkyl substances (PFASs) have raised great attention, particularly in regions of rapid urbanization. Zhangjiakou and Beijing will jointly host the Winter Olympic Games in 2022, which will likely increase local PFASs pollution and their associated risks over the coming period. In this study, we identified ecological process of PFASs, including sources, environmental fate, and risks, from the Yongding Watershed to the Guanting Reservoir. The concentrations of total 12 PFASs in water of the Guanting Reservoir were higher than that from the Yongding Watershed, with mean of 48.9 and 33.7 ng/L, respectively. The concentrations of PFASs in sediment of the Yongding Watershed and the Guanting Reservoir were similar, with mean of 1.01 and 0.827 ng/g dry weight, respectively. Detected levels of PFASs in the Guanting Reservoir significantly increased during the past eight years, possibly due to an improving economy and a rapidly developed service industry. Moderate PFASs levels in fish of the Guanting Reservoir were detected relative to other lakes and reservoirs. The daily intake of PFASs via fish and water ranged from 4.96 to 15.0 ng/kg bw/day, with higher levels found in children relative to adults. In total, approximately 9.06 kg of PFASs from riverine flow and atmospheric deposition annually entered the Guanting Reservoir. PFASs from the Yongding River significantly contributed to the pollution of Guanting Reservoir, with predominance of perfluorobutanoic acid (PFBA) in water, and long-chain perfluorinated carboxylic acids (PFCAs) and perfluorooctane sulfonate (PFOS) in sediment in both the Yongding Watershed and the Guanting Reservoir. Most of the PFASs (23.5 kg) were stored in water of the Guanting Reservoir, while the annual storage of PFASs in sediment and fish was only 4.68 × 10−2 kg and 4.36 × 10−2 kg via deposition and accumulation, respectively. The results suggest that water quality management of the Yongding Watershed is necessary for effective control on PFASs pollution in the Guanting Reservoir. [ABSTRACT FROM AUTHOR]