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 (Igeo) 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.

Although wastewater treatment plants (WWTPs) can purify wastewater, they also discharge numerous contaminants into the environment through effluent discharge and sludge disposal. The occurrence, emission flux, and risk assessment of traditional pollutants (e.g., heavy metals [HMs]), and emerging pollutants (e.g., perfluoroalkyl substances [PFASs] and pharmaceutical and personal care products [PPCPs]) in WWTP emissions are of important concern. The present study analyzed 17 PFASs, 25 PPCPs, and 8 HMs in influent, effluent, and excess sludge from six WWTPs along the Yanghe River, North China. Samples were collected during four sampling campaigns from November 2016 to July 2017. The mean concentrations of PFASs and PPCPs in influent were 46.4 ng L-1 and 6.57 μg L-1, respectively; while those in effluent were 38.5 ng L-1 and 2.14 μg L-1, respectively. The highest concentrations of HMs was detected of Zn in influent (2,866 μg L-1) and effluent (3,960 μg L-1). According to the concentration composition, short-chain PFASs, fluoroquinolones (FQs), and Zn were the predominant components in both influents and effluents. The mean PFAS and PPCP concentrations in excess sludge were 5.95 ng g-1 and 3.74 μg g-1 dry weight (dw). Zn was the most abundant HMs in excess sludge with the concentration range of 156-14,271 μg g-1 dw. The compositions of PFASs, PPCPs and HMs differed between wastewater and excess sludge. The estimated emission flux of these pollutants was ordered as HMs > PPCPs > PFASs through effluent discharge and sludge disposal. Sludge disposal discharged more PPCPs and HMs into the environment than effluent discharge, which was contrary for PFASs. Relative risk of each pollutant is calculated by comparing the mean effluent concentration with the median effective concentration. Algae and fish were selected as recipient organisms to calculate the relative risk of 23 selected pollutants towards aquatic organisms. The highest-risk pollutant was Zn on both algae and fish, while perfluorobutane sulfonate (PFBS) and atenolol (ATE) posed the lowest risk. In general, HMs (regarded as traditional pollutants) presented higher risks in effluent, followed by the emerging pollutants (PPCPs and PFASs). Therefore, control of traditional pollutants should be prioritized in WWTPs in this region. This study presents an overall assessment of the current status of traditional and emerging pollutants in WWTPs and provides useful information for upgrading wastewater treatment processes.

Significant quantities of perfluoroalkyl acids (PFAAs) are released to the environment from fluorochemical manufacturing processes through wastewater discharge and air emission in China, which may lead to human exposure and health risks through crop bioaccumulation from PFAAs-contaminated soil and irrigation water. This paper systematically studied the distribution and transport of PFAAs in agricultural soil, irrigation water and precipitation, followed by crop bioaccumulation and finally human exposure of PFAAs within a 10km radius around a mega-fluorochemical industrial park (FIP). Hotspots of contamination by PFAAs were found near the FIP and downstream of the effluent discharge point with the maximum concentrations of 641ng/g in agricultural soil, 480ng/g in wheat grain, 58.8ng/g in maize grain and 4,862ng/L in precipitation. As the distance increased from the FIP, PFAAs concentrations in all media showed a sharp initial decrease followed by a moderate decline. Elevated PFAA concentrations in soil and grains were still present within a radius of 10 km of the FIP. The soil contamination was associated with the presence of PFAAs in irrigation water and precipitation, and perfluorooctanoic acid (PFOA) was the dominant PFAA component in soil. However, due to bioaccumulation preference, short-chain perfluoroalkyl carboxylic acids (PFCAs), especially perfluorobutanoic acid (PFBA), became the major PFAA contaminants in grains of wheat and maize. The bioaccumulation factors (BAFs) for both grains showed a decrease with increasing chain length of PFAAs (approximately 0.5 log decrease per CF2 group). Compared to maize grain, wheat grain showed higher BAFs, possibly related to its higher protein content. The PFCA (C4-C8) concentrations (on a log10 basis) in agricultural soil and grain were found to show a linear positive correlation. Local human exposure of PFOA via the consumption of contaminated grains represents a health risk for local residents, especially for toddlers and children.

Soils in coastal areas of the land-sea interface are vulnerable to heavy metal (HM) accumulation and subsequently to human health risk. However, few studies have investigated the HM pollution and risk in soils along the coastal areas of the Yellow Sea Large Marine Ecosystem (YSLME), in an international perspective. This study is the first comprehensive work in the YSLME encompassing 122 coastal locations along the Bohai Sea (BS), Yellow Sea of China (YSC), and Yellow Sea of South Korea (YSK). Soil HM pollution showed great spatial variations cross the regions and countries. Accumulations of As, Cu, Pb, and Zn in the YSK were significantly higher than those in the BS and YSC (p < 0.05). Whilst the elevated Cd, Hg, and Ni in soils were found in the BS and YSC compared to those in the YSK (p < 0.05). Meantime, the assessment of ecological risk posed by HMs indicated higher potential risk in the BS than other coastal areas. In specific, Cd and Hg posed a higher risk in the BS and YSC, while As showed relatively high risk in the YSK, indicating site-dependent accumulation of HMs in soils. Soil pH and organic matter were found to be important factors affecting the HM accumulation in the study areas. Industrial activities are the major driving factors influencing spatial distributions of HMs, and such activities exhibited different degrees of influence across the sampling sites. Altogether, the results of present study first identified the bilateral characteristics of soil HM pollution along the entire coasts of the YSLME in a comprehensive manner in several aspects: (1) sources, (2) hot spots, (3) priority chemicals of concern, and (4) site-specific potential risk of the soil HMs. Overall, this study provides references and backgrounds for future environmental management strategies and aids in developing a bilateral government policy towards coastal pollution management of HMs from an international scale and perspective.

Pharmaceuticals and personal care products (PPCPs) are recognized as one emerging group of environmental contaminants, capturing worldwide attention. These chemicals, closely connected to anthropogenic activities, are mainly transported through aquatic environments and reach coastal areas, eventually entering ocean offshore. Thus, this study concentrated on the 30 PPCPs in coastal waters of the Yellow and Bohai seas (77 sites), a fast-growing area with intensive anthropogenic activities. In general, the total concentrations of PPCPs in Chinese coastal waters (0.880-1194 ng L^-1) greatly varied and were relatively greater than those (9.91-442 ng L^-1) in Korean coastal waters. Sulfamethoxazole, sulfamethazine, oxytetracycline, ofloxacin, roxithromycin, anhydro-erythromycin, and caffeine were the seven predominant PPCPs in the coastal waters of study area. Further, we established the Predicted PPCPs Contamination Indicator (PPCI) to address potential anthropogenic activities being associated with site-specific PPCPs contamination. Three anthropogenic factors to PPCPs contamination were proven as the most influential, including (1) quantity of wastewater discharge, (2) gross product of meat, poultry, eggs and milk, and (3) gross aquatic product. The relatively high PPCI values appeared in Tianjin, Dalian, Tangshan, Yantai, and Qingdao in China and Gyeonggi and Jeonbuk in South Korea, which exhibited fairly good consistency with the corresponding PPCPs concentrations. A mini-review of the global PPCPs distributions revealed that seven priority PPCPs found in this study distributed widely in Asia rather than Europe, North America, and Australia. In general, global PPCPs contamination also reflected site- and region-specific distributions, suggesting varying usages and sources cross the region and/or country. Finally, the risk assessment suggested that ofloxacin and anhydro-erythromycin, with 36.4% and 23.4% sites higher than medium risks respectively, posed relatively high risks to sensitive algal species, Microcystis aeruginosa and Selenastrum capricornutum. Overall, the ecological risks of exposure of PPCPs in the Yellow and Bohai seas were higher compared to other regions of the world, thus the bilateral management of PPCPs between China and South Korea needs an immediate attention.