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Complexity of anthropogenic influences on coastal ecosystems necessitates use of an integrated assessment strategy for effective interpretation and subsequent management. In this study a multiple lines of evidence (LOE) approach for sediment assessment, that combined use of chemistry, toxicity, and benthic community structure in the sediment quality triad was used to assess spatiotemporal changes and potential risks of persistent toxic substances (PTSs) in sediments of Masan Bay highlighting “long-term changes” between 1998 and 2014. Specific target objectives encompassed sedimentary PTSs (PAHs, alkylphenols (APs), and styrene oligomers), potential aryl hydrocarbon receptor (AhR; H4IIE- luc assay)- and estrogen receptor (ER; MVLN assay)-mediated activities, and finally several ecological quality (EcoQ) indices of benthic community structure. Concentrations of target PTSs in Masan Bay sediments were generally less by half in 2014 compared to those measured in 1998. Second, AhR-mediated potencies in sediments also decreased during this time interval, whereas ER-mediated potencies increased (+3790%), indicating that there has been substantial ongoing, input of ER agonists over the past 16 years. Potency balance analysis revealed that only 3% and 22% of the AhR- and ER-mediated potencies could be explained by identified known chemicals, such as PAHs and APs, respectively. This result indicated that non-targeted AhR and ER agonists had a considerable presence in the sediments over time. Third, EcoQ indices tended to reflect PTSs contamination in the region. Finally, ratio-to-mean values obtained from the aforementioned three LOEs indicated that quality of sediments from the outer region of the bay had recovery more during the period of 16-years than did the inner region. Overall, the results showed that even with the progress supported by recent efforts from the Korean governmental pollution control, PTSs remain a threat to local ecosystem, especially in the inner region of Masan Bay. [ABSTRACT FROM AUTHOR]

In the late 1990s, severe pollution by persistent organic contaminants (POCs) was observed in Lake Sihwa by use of a combination of instrumental analyses and in vitro bioassays. To determine long-term changes (>15-year gaps) in distributions of POCs and their potential toxic potencies in the given region, sediment assessments were reconducted. Target chemicals include polycyclic aromatic hydrocarbons (PAHs), alkylphenols (APs), and recently reported emerging chemicals, styrene oligomers (SOs). We employed in vitro bioassays (such as H4IIE- luc and MVLN) to determine potential sediment toxicities. The reduction rates of mean concentrations of APs and SOs in sediments between the two sampling years (1998 vs. 2015) were estimated to be 99% and 67%, respectively. Although APs and SOs significantly declined over the 15-year period, concentrations of PAHs were consistent. Results of the bioassays were consistent with the instrumental data, with relatively great concentrations of all target compounds being detected, particularly in inland creeks. Compositions of all target compounds exhibited changes in homologue patterns over the 15 years considered. This result indicated varying and/or continuing sources in this region. In particular, PAHs were dominated by higher-molecular-weight PAHs (e.g., benzo[ g,h,i ]perylene and benzo[ b ]fluoranthene) in recent years. This result might indicate consumption of oil-related fuels. Quantitative potency balance analysis revealed that concentrations of instrumentally-derived equivalents accounted for as little as 18.5% of bioassay-derived equivalents, which indicated significant amounts of unknown and/or unmeasured compounds were present. The present study documented the continuing severe pollution by selected POCs in the Lake Sihwa region over the last 15 years, indicating a lack of management in the area studied. [ABSTRACT FROM AUTHOR]

Rapid economic growth during the past two decades in the region surrounding the Bohai and Yellow Seas has resulted in severe pollution. Large amounts of monitoring data on persistent organic pollutants (POPs) in various environmental media have been accumulated, which allows us to conduct a fairly comprehensive assessment of the region around the Bohai and Yellow Seas to elucidate spatial patterns of pollution on a regional scale. This review summarized distributions of traditional and new POPs, including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDs), and perfluoroalkyl substances (PFASs), in various environmental media. In general, due to their physico-chemical properties (poor solubility in water), OCPs and PCBs were mainly detected in sediments, PBDEs and HBCDs were mainly detected in sediments and soils. PFASs, which have greater solubility, were mainly detected in the hydrosphere. For conventional POPs, such as OCPs and PCBs, Bohai Bay and Haihe River in China, Gyeonggi Bay and Lake Sihwa in South Korea were found to be most polluted areas. While for new POPs, such as PBDEs, HBCDs and PFASs, some areas were heavily polluted due to local production and applications. Estuarine and coastal areas of the Bohai Sea were more severely contaminated by POPs than coastal regions of the Yellow Sea. Overall, the present review will guide identification of key areas for strengthening risk assessment of POPs and management practices. [ABSTRACT FROM AUTHOR]

The west coast of Korea has experienced environmental deterioration for more than half a century. In the present study, we specifically aimed to: i) evaluate potential toxicities of contaminants in sediments that cause effects mediated through the aryl hydrocarbon receptor (AhR) and estrogen receptor (ER); ii) determine spatio-temporal distributions of polycyclic aromatic hydrocarbons (PAHs) and alkylphenols (APs); and iii) identify causes of greater potencies of samples. From 2010 to 2014, sediments were collected from 12 major estuarine and coastal regions along the west coast of South Korea. In vitro cell bioassays were performed to determine AhR- and ER-mediated potencies using H4IIE- luc and MVLN cells, respectively. Fifteen PAHs and six APs in sediments were identified by GC/MSD. Results of bioassays generally showed a low-to-moderate degree of contamination, however, greater AhR- and ER-mediated potencies were measured at some locations. Concentrations of PAHs and APs varied among locations, which indicated that sources were independently affected by the surrounding environment (e.g., industrial complex and cities). Results of bioassays were generally well correlated with concentrations of putative causative chemicals. Benzo[ k ]fluoranthene, dibenz[ a , h ]anthracene, and benzo[ b ]fluoranthene were the major AhR agonists, explaining approximately 30% of the bioassay-derived benzo[ a ]pyrene equivalent concentration (BaP-EQ). Unknown AhR and ER agonists and potential mixture effects remain in question. Overall, the present study provides baseline information on chemical contaminations and potential toxicity of sediments in a fairly wide geographical region of the west coast of South Korea. [ABSTRACT FROM AUTHOR]

Studies on distribution of microplastics (MPs) in sediments of tidal flats are relatively scarce compared to other coastal areas. In this study, spatial and vertical distributions and compositions of MPs in tidal flat sediments along the west coast of Korea were investigated. The abundance of MPs in surface and core sediments ranged from 20 to 325 and 14 to 483 particles per 50 g dry weight, respectively. Polypropylene (51%) and polyethylene (36%) were the most dominant MPs; the size was <0.3 mm, and the shape was mostly fragments followed by fibers. The abundance of MPs in sediments has increased rapidly since the 1970s, and recently showed a slight decrease. Surface morphology of MPs analyzed using a scanning electron microscope revealed that the MPs in tidal flats were highly weathered mechanically and/or oxidatively. The results of this study provide valid baseline data on distributions of MPs in tidal flats. • MPs in the tidal flats were widely distributed and showed a high level of pollution. • The predominant MPs in tidal flat were PP and PE with <3 mm and fragment shapes. • The abundance of MPs in tidal flat has tended to increase sharply since the 1980s. • MPs in tidal flats were highly weathered mechanically and/or oxidatively. [ABSTRACT FROM AUTHOR]

Distribution and sources of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in the glacimarine sediments (35 sites) of Svalbard were investigated. PCBs (32 congeners), traditional PAHs (15 homologs), emerging PAHs (11 homologs), and alkylated PAHs (16 homologs) were widely distributed in the Svalbard sediments (ranges: below method detection limit to 20, 21 to 3600, 1.0 to 1400, and 31 to 15,000 ng g−1 dry weight, respectively). Compositional analysis indicated that PCBs mainly originated from combustion sources, with PAHs being strongly influenced by local sources. Positive matrix factorization analysis showed that PAHs were associated with vehicle and petroleum combustion, coal, and coal combustion. Coal-derived PAHs contributed significantly to the sediments of Van Mijenfjorden. Remnants of coal mining activity trapped in the permafrost appear to enter the coastal environments as ground ice melts. Consequently, PAHs are currently emerging as the most significant contributors to potential risks in the Svalbard ecosystems. [Display omitted] • Distributions of PCBs and PAHs in the sediments of Arctic Svalbard were investigated. • Hornsund and Van Mijenfjorden showed relatively high concentrations of PAHs. • PAHs in Svalbard sediments mainly originated from local coal and petrogenic sources. • PAHs contributed greatly to the potential ecological risks of sediments in Svalbard. [ABSTRACT FROM AUTHOR]

Bioaccessibility of toxic substances in sedimentary residual oil is a crucial factor that needs to be considered for accurate risk assessments posed by oil spills. However, information on oil weathering processes and bioaccessibility of residual oil is often not sufficient and clear. In the present study, bioaccessibility of aryl hydrocarbon receptor (AhR)-active polycyclic aromatic hydrocarbons (PAHs) in coastal sediments near the site of the Hebei Spirit oil spill (Korea, 2007) was assessed by Tenax extraction in effect-directed analysis (EDA). Sediment samples collected 6 years after the oil spill were extracted using Soxhlet or Tenax, and EDA was performed using a battery of H4IIE- luc bioassay and GC/MSD analysis. Concentrations of PAHs and alkyl-PAHs in Soxhlet extracts ranged from 210 to 53,000 μg kg −1 dry mass. However, concentrations of PAHs and alkyl-PAHs in Tenax extracts were approximately 20-fold less compared to those in Soxhlet extracts. In Soxhlet and Tenax extracts, the major AhR-active PAHs were identified as C1-chrysene, C3-chrysene, and C4-phenanthrene. Concentrations of 2,3,7,8-tetrachlorodibenzo- p -dioxin (TCDD) equivalents (TEQ PAHs ) explained 31% and 60% of the bioassay-derived TCDD-EQ concentrations in Soxhlet and Tenax extracts, respectively. Overall, bioaccessibility of PAHs and alkyl-PAHs in sedimentary residual oils depended on hydrophobicity (log K ow ) and degree of weathering of crude oil. The results of the present study provide further evidence in support of the biological and ecological recoveries of oil spill sites. [ABSTRACT FROM AUTHOR]

Novel aryl hydrocarbon receptor (AhR) agonists were identified in coastal sediments in the Yellow and Bohai Seas by use of a combination of effect-directed analysis (EDA) and in silico prediction. A total of 125 sediments were screened for AhR-mediated potencies using H4IIE- luc bioassay. Great potencies were observed in organic extracts, mid-polar fraction (F2), and subfractions of F2 (F2.6–F2.9) of sediments collected from Nantong, Qinhuangdao, and Yancheng. Less than 15% AhR potencies could be explained by detected dioxin-like PAHs. Full-scan screening analysis was conducted for the more potent fractions using GC-QTOFMS to investigate the presence of unmonitored AhR agonists. A five-step prioritization strategy was applied; 92 candidate compounds satisfied all criteria. Among these chemicals, thirteen were evaluated for AhR efficacy. Six compounds; benz[ b ]anthracene, 6-methylchrysene, 2-methylbenz[ a ]anthracene, 1-methylbenz[ a ]anthracene, 1,12-dimethylbenzo[ c ]phenanthrene, and indeno[1,2,3- cd ]fluoranthene, exhibited significant AhR-mediated efficacies. 1,12-dimethylbenzo[ c ]phenanthrene and indeno[1,2,3- cd ]fluoranthene were identified as novel AhR agonists. Potency balance analysis showed that the six newly identified AhR agonists explained 0.4–100% of the total AhR-mediated potencies determined. Overall, combining EDA and in silico prediction applied in this study demonstrated the benefits of assessing the potential toxic effects of previously unidentified AhR agonists in sediments from the coasts of China and Korea. [Display omitted] • AhR potencies in sediments from the Yellow and Bohai Seas at large scale were evaluated. • Unmonitored AhR-active compounds in sediments identified using advanced EDA. • DBcP and IcdF were identified as novel AhR agonists in sediments. • Assay-specific relative potency values were obtained for dominant AhR agonists. [ABSTRACT FROM AUTHOR]

A copepod bioassay with Tigriopus japonicus was applied to evaluate the relative ecotoxicity of sediments in the Yellow and Bohai seas, and contributions of individual PAHs to copepod toxicity were evaluated. Mean toxicity was greatest in the Yellow Sea of China, followed by the Bohai Sea and Yellow Sea of Korea. Elevated concentrations of sedimentary PAHs, alkylphenols, and styrene oligomers back-supported the significant toxicities observed in bioassay. Copepod toxicity in relation to PAHs indicated the greatest contribution by indeno[1,2,3 -c,d ]pyrene. However, lacked contribution by PAHs, viz., 2.4 and 3.0 % for the total immobilization and mortality, respectively, indicated a large proportion of unknown toxicants being widely distributed along the Yellow Sea Large Marine Ecosystem (YSLME) coastline. Overall, the present study provides useful baseline information for evaluating the potential sedimentary toxicants, with emphasizing further investigation to identify the unknown toxicants at an LME scale, and elsewhere. [Display omitted] • Copepod bioassay was applied to assess sediment toxicity in Yellow and Bohai seas. • Great ecotoxicity was found in Huludao and Nantong in China and Lake Sihwa in Korea. • Copepod toxicity to HMW PAHs was greater than those of LMW PAHs. • The contribution of PAHs to the total copepod toxicity in sediments of all sites was low. • IcdP, BghiP, BbF, and BkF were identified as major copepod toxicants in sediments. [ABSTRACT FROM AUTHOR]

Abstract: Pohang is a mid-sized city in which Korea's largest manufacturer of steel is located. The Hyeongsan River, which runs through Pohang and empties into Yeongil Bay, is therefore expected to be affected by various municipal and industrial inputs. In order to characterize aryl hydrocarbon receptor (AhR)-mediated activities in sediments from the Pohang area, a total of eight locations along the Hyeongsan River were chosen and 16 sediment samples were collected during two sampling campaigns in 2010. Organic extracts of sediments were characterized by both quantitative chemical analyses of dioxin-like chemicals and the in vitro H4IIE-luc bioassay. Significant dioxin-like activities were observed in sediments from industrial and municipal areas, which indicates that most of the dioxin-like chemicals were associated with surrounding anthropogenic sources. In general, responses of the H4IIE-luc assay were significantly correlated with concentrations of target compounds including dioxins, furans, co-planar PCBs, and dioxin-like PAHs. A potency balance analysis indicated that instrumentally derived TCDD equivalents (TEQs) explained about 77% of the bioassay-derived TCDD equivalents (TCDD-EQs). Among the target chemicals measured, certain penta-chlorinated dioxin and furan compounds accounted for the majority of dioxin-like activities associated with sediments. Compositional analysis of target chemicals the sources of such dioxin-like activities were mainly derived from the local activities such as the iron and steel industries. Concentrations and activities of AhR agonists were similar to what was measured approximately 10years ago. Thus, while AhR agonists seem to be persistent in sediments there seem to have been no large increases in these chemicals in the Pohang area. [Copyright &y& Elsevier]

Potential toxicants in sediments collected from an industrialized bay of Korea were identified by use of effect-directed analysis (EDA). Three marine microalgal bioassays (Dunaliella tertiolecta , Isochrysis galbana , and Phaeodactylum tricornutum) with diverse endpoints were employed. Initial screening of raw organic extracts of sediments indicated large variations among locations and species in a traditional endpoint "inhibition of growth". After fractionation, inhibition of growths increased significantly, particularly in some fractions containing aromatics with log K OW 5−6 (F2.6). While viabilities of cells were adversely affected in more fractions, including F2.6−F2.7 (log K OW 5−7) and F3.5−F3.6 (log K OW 4–6). Among the several endpoints of viability, esterase activity seemed to be more sensitive, followed by integrity of cell membranes, chlorophyll a , cell size, and intracellular complexity. Instrumental analyses indicated that toxicities to microalgae observed in F2.7 could not be fully explained by target PAHs. Full-scan screening analysis using GC-QTOFMS identified 58 compounds in F2.7 with matching scores ≥90%. Based on toxic potencies for these compounds predicted by ECOSAR, several causative agents, including 1-phenylpyrene, dibenz[ a , c ]anthracene, and picene were suggested. Overall, viability of microalgae provided sensitive and high-resolution toxicity screening of samples into integrative assessment of sediment. ga1 • Potential microalgal toxicants in sediments were identified by effects-directed analysis. • Three marine microalgal bioassays were utilized with a sensitive cell viability analysis. • Inhibitions of microalgal growth were observed for fractions of aromatics with log K OW 5–6. • Esterase activity was more sensitive, followed by cell membrane integrity and Chl. a. • 1-Phenylpyrene, dibenz[ a , c ]anthracene, and picene were found to be causative agents. [ABSTRACT FROM AUTHOR]

Contamination status of traditional and emerging persistent toxic substances (PTSs) in sediments and their major sources were investigated in Ulsan Bay, Korea. A total of 47 PTSs, including 15 traditional PAHs, ten styrene oligomers (SOs), six alkylphenols (APs), and 16 emerging PAHs (E-PAHs) were analyzed. Concentrations of traditional PAHs, SOs, and APs ranged from 35 to 1300 ng g−1 dry weight (dw), 30 to 3800 ng g−1 dw, and 30 to 430 ng g−1 dw, respectively. For the last 20 years, PTSs contamination in the bay area has been improved. However, 12 E-PAHs were widely detected in sediments, with a maximum of 240 ng g−1 dw (for benzo[ e ]pyrene) at the creek site. These E-PAHs seemed to originate from surrounding activities, such as biomass combustion, mobile sources, and diesel combustion. Due to environmental concerns for E-PAHs, further research on the potential toxicity, distribution, and behavior of these compounds should be implemented. Unlabelled Image • Contamination levels of PTSs in sediments have decreased during the last decades. • The major source of PAHs has changed from petroleum sources to combustion origins. • E-PAHs were widely distributed in the sediments, originating from surrounding activity. • E-PAHs have some potential toxicity; thus, further research should be implemented. [ABSTRACT FROM AUTHOR]

Oil is a complex mixture of numerous compounds. Therefore, oil spills near shore can cause various adverse effects on coastal ecosystems. However, most toxicological assessments conducted on oil spill sites have focused on limited modes of toxic actions. In the present study, we utilized the Escherichia coli ( E. coli ) live cell array system (LCA) to identify novel modes of toxicities of the oil spill-affected sediments. For this purpose, sediment samples were collected from an area heavily polluted by Hebei Spirit oil spill (HSOS) incident of 2007. A total of 93 E. coli reporter genes were used to study responses to the chemicals in the mixture. E. coli K12 strains were exposed to extracts of oil or the sediment, and changes in gene expression were measured. Exposure to extracts of crude and weathered oil resulted in decreased expression in ∼30% of tested genes. However, changes in expression observed after exposure to sediment extracts varied. Sediment extracts containing large concentrations of polycyclic aromatic hydrocarbons (PAH) caused down-regulation of >70% of the genes, while extracts containing lesser total concentrations of PAHs exhibited different trends: genes involved in drug resistance were generally up-regulated, while genes responsive to DNA damage were up-regulated in only two extracts. Results suggest that oil pollution can modulate several toxic response pathways related to DNA repair and antibiotic responses. Results from LCA obtained from the sediment and oil samples were different from those observed in the H4IIE- luc assay. Toxicological implications of such observations deserve further examination. Overall, LCA is a promising tool for screening samples and identifying potential modes of toxicities of environmental samples associated with oil spills. [ABSTRACT FROM AUTHOR]

Oil spills near the coastlines may damage marine and intertidal ecosystem. Constituents of the oil have been reported to cause toxic consequences mediated by aryl hydrocarbon receptor (AhR), and estrogen receptor (ER). In the present study, AhR– and ER–mediated toxicities of coastal sediments of Taean were investigated seven years after Hebei Spirit oil spill (HSOS). Sediment samples were collected on June and October 2014 from seven locations along the Taean coastline, where signs of oil spill were detected. Sediment samples were extracted in Soxhlet extractors and further processed through activated silica gels to separate into four fractions; F1 (saturate hydrocarbons), F2 (aromatic hydrocarbons), F3 (resins and polar compounds), and F4 (residues). ER–mediated and AhR–mediated potencies (% E2 max and % TCDD max ) of each fraction were determined using MVLN cells and H4IIE- luc cells, respectively. F2 and F3 fractions of Sinduri 1, Sinduri 2, and Sogeunri 1 samples showed greater AhR–mediated potencies (up to 107% TCDD max ). Chemical analysis revealed that PAH components are correlated with AhR–binding activities. The % E2 max results varied by sample: While there was no noticeable induction of ER–dependent responses (<45%), some aromatics fractions (F2) exhibited the highest ER–mediated responses. Compared with previous reports from the same sites, both AhR–mediated and ER–mediated potencies have decreased over time. Nevertheless, AhR–mediated potencies could be identified in the environmental samples even after 7 years of the incident. Therefore, possible ecosystem implications of these findings should be further investigated. [ABSTRACT FROM AUTHOR]

Abstract: The influence of industrial and/or municipal contaminant inputs on the aquatic environment of Pohang, Korea was investigated, with a focus on bioassay combined with instrumental analysis. Pohang is the most heavily populated city in Gyeongsangbuk-do province of Korea, with more than half a million residents, and also hosts the nation's biggest steel manufacturer and related industries. Sediment (n=15) and surface water samples (n=17) were collected from Hyeongsan River which runs across the Pohang city, in two separate events, i.e., June 2010 and February 2011. Sediment samples were first Soxhlet-extracted (raw extract) and were measured for estrogenicity using H295R cell line, and also analyzed for alkylphenols (APs), bisphenol A (BPA), PAHs, and PCBs. For sediment samples which exhibited greatest effects in the cell line, further fractionation was performed into non-polar, mid-polar, and polar portions. In surface water samples, heavy metals were also analyzed. Among 15 sediment samples, station S2 near the steel industry complex and station M3 near the municipal area showed the greatest sex hormone changes, and these changes were generally explained by the fractions which contained APs and BPA. Principal component analysis (PCA) however suggests that chemicals that were not analyzed in the present study would better explain endocrine disruption capacity of sediments. In water samples, adverse effects on hatchability and growth of Japanese medaka fish, and on Daphnia reproduction were noted following exposure to six water samples collected from stations near industrial and municipal areas. Several heavy metals and nonylphenol (NP) concentrations exceeded surface water quality guidelines, suggesting adverse effects of contamination inputs from both industrial and municipal activities. Observed estrogenicities in stations such as S2 and M3 warrant further investigations on longer term ecosystem impacts near industrial and municipal areas. The levels of major organic chemicals in sediments are quite comparable to those reported in ~10years ago, emphasizing a need for source control. [Copyright &y& Elsevier]