PCBs and its coupling with eco-environments in Southern Yellow Sea surface sediments

Heavy metal and persistent organic pollutant profile of sediments from marine protected areas: the northern Persian Gulf

Marine protected areas (MPAs) are one of the policy tools to support marine biodiversity conservation and sustainable use of marine resources. The distribution, sources, and ecological risk assessment of persistent organic pollutants (POPs), including polycyclic aromatic hydrocarbon (PAHs), total petroleum hydrocarbons (TPHs), polychlorinated biphenyls (PCBs), and heavy metals (HMs) in sediments of MPAs in the northern Persian Gulf, were evaluated for the first time in this study. The Σ16PAHs ranged from 4.65 to 20.86 μg/kg dry weight (dw). The molecular ratios and ring's pattern of PAHs suggested a mixed origin with a predominance of pyrogenic sources. The TPH concentration varied from 5.21 to 17.90 μg/g dw. Ecological risk assessment suggested that sediment samples in Bushehr Province's MPAs can be categorized as medium risk. The mean concentration of ∑18PCB was 0.345-0.419 ng/g dw, and the main components correspond to PCB-77, PCB-105, PCB-81, PCB-101, and PCB-114. The mean concentration of As, Co, Cr, Ni, V, Mg, Pb, Zn, Cu, Al, and Fe varied from 4.79 to 9.69, 2-12, 39-142, 18-90, 15-58, 184-425, 7-45.9, 6-42.4, 4-20 μg/g dw, 0.75-4.12%, and 0.35-1.62%, respectively. Multivariate analysis, such as principal component analysis (PCA) and cluster analysis (CA), coupled with correlation coefficient analysis, was used to analyze the analytical data and to identify possible pollution sources. The results of this study provided the background information on the extent of POP contamination in the sediment and highlighted the need to further control pollution in MPAs.

Bioaccumulation of PCBs and PBDEs in Fish from a Tropical Lake Chapala, Mexico

Lake Chapala is the largest natural freshwater reservoir in Mexico and the third largest lake in Latin America. Lakes are often considered the final deposit of polluting materials; they can be concentrated in the organisms that inhabit them, the water, and the sediments. The PCBs and PBDEs are environmental pollutants highly studied for their known carcinogenic and mutagenic effects. PCB and PBDE bioaccumulation levels were determined in Chirostoma spp., Cyprinus carpio, and Oreochromis aureus. In addition, we monitored the concentrations of PCBs and PBDEs in sediment and water from Lake Chapala were monitored. Samples were collected during two periods, in October 2018 and May 2019. The samples were analyzed by gas chromatography coupled with mass spectrometry. Two bioaccumulation factors were determined in fish, one in relation to the concentration of PCBs and PBDEs in sediments and the other in relation to the concentration of PCBs and PBDEs in water. The PCB levels were 0.55–3.29 ng/g dry weight (dw) in sediments, 1.43–2.98 ng/mL in water, 0.30–5.31 ng/g dw in Chirostoma spp., 1.06–6.07 ng/g dw in Cyprinus carpio, and 0.55–7.20 ng/g dw in Oreochromis aureus. The levels of PBDEs were 0.17–0.35 ng/g dw in sediments, 0.13–0.32 ng/mL in water, 0.01–0.23 ng/g dw in Chirostoma spp., 0–0.31 ng/g dw in Cyprinus carpio, and 0.1–0.22 ng/g dw in Oreochromis aureus. This study provides information for a better understanding of the movement, global distribution, and bioaccumulation of PCBs and PBDEs. The results show that the fish, water, and sediments of Lake Chapala are potential risks to the biota and the local human population.

Distribution, Source and Potential Risk Assessment of Polychlorinated Biphenyls (PCBs) in Sediments from the Liaohe River Protected Area, China

This study aimed to assess the occurrence, distribution, toxicity equivalency and health risks of dl-PCBs (dioxin-like PCBs) from nine sites collected in surface sediments from Liaohe River Protected Area. ∑dl-PCBs concentrations in sediments range from 79.2 to 365.1 pg/g. Sediment profiles showed that pentachlorobiphenyl is the most abundant congener among all sampling sites. The results of principal component analysis and cluster analysis indicated that PCBs were mainly derived from electronic waste and paint additives in the sediments of Liaohe River Protected Area. Toxic equivalent quantity (TEQ) values of the PCBs in the Liaohe River Protected Area sediments are at comparatively lower levels compared with the previously reported data. Hazardous ratio (HR) for human health risk assessment allied to cancer was found to be lower than the non-carcinogenic risk assessment within an acceptable range.

Biogeochemical characteristics and ecological risk assessment of pharmaceutically active compounds (PhACs) in the surface seawaters of Jiaozhou Bay, North China

The occurrence and distribution of 168 pharmaceutically active compounds (PhACs) in the surface seawater of Jiaozhou Bay (JZB) were investigated using ultra-high-performance liquid chromatography in tandem with a triple-quadrupole mass spectrometer equipped with an electrospray ionization source (UHPLC-ESI-MS-MS). Thirty-six compounds were detected, and 17 of these compounds were first detected in seawater, including sulfabenzamide, sulphacetamide, cephalonium, desacetyl-cefotaxime, cefminox, cefotaxime, cephradine, cefazolin, carprofen, nabumetone, glibenclamide, glimepiride, glipizide, prednisone, fluoromethalone, diazepam and amantadine. The total concentration of PhACs in the surface seawater ranged from 23.6 ng/L to 217 ng/L. The compounds found at the highest mean concentrations included amantadine (24.7 ng/L), lincomycin (8.55 ng/L), carprofen (8.30 ng/L), and tetracycline (7.48 ng/L). The PhAC concentration was higher in the inner bay than in the outside of the bay. In the inner bay, the eastern district showed higher concentrations of PhACs than the western district. Input from the Licun River may be the primary source of pollution. A statistically significant positive correlation was observed between nutrients and PhACs in seawater. Phosphate can be used to indicate the distribution of PhACs in JZB. Based on the individual risk quotient (RQ) values, lincomycin and ofloxacin posed high risks to the relevant aquatic organisms in JZB, especially in the eastern parts. Regular monitoring is required to evaluate the levels of PhACs as they are constantly released into JZB.

First polychlorinated biphenyls (PCBs) monitoring in seawater, surface sediments and marine fish communities of the Persian Gulf: Distribution, levels, congener profile and health risk assessment

Polychlorinated biphenyls (PCBs) are persistent organic pollutants that, due to their high toxicity, lipophilic property and widespread dispersal in the global environment, present a danger for human health and ecological systems. Although the inventory and use of PCBs are extensively reported worldwide, the status of PCBs in Iran is still unknown. In this study, the concentrations of PCBs were determined in the environmental matrices and in five commercially important fish species from Larak coral Island, Persian Gulf, Iran, in winter and summer 2015. A positive correlation was found among PCBs levels and congeners profiles in seawater (0.97-3.10 ng L^-1), surface sediments (2.95-7.95 ng g^-1dw) and fish samples (7.20-90.19 ng g^-1dw), indicating fish as suitable bioindicator of environmental PCBs contamination. In all matrices, a high contribution of light and medium chlorinated congeners was detected in both seasons. In fish, the higher PCBs levels were found for both sexes in both seasons in liver and kidney than other tissues (skin, gonad, muscle) due to their high lipid content and PCBs lipophilicity. More importantly, the risks for human health associated with fish consumption were also evaluated, and it was found that all the toxicity indices measured for PCBs were within the World Health Organization (WHO) permissible limit of food consumption. However, it is highly recommended to inform the local population about potential risks attributable to dietary incorporation of locally caught fish, and establish a surveillance monitoring programme on PCBs in this region.

Redox characteristics of humins and their coupling with potential PCB dechlorinators in southern Yellow Sea sediments

Natural attenuation of polychlorinated biphenyls (PCBs) by indigenous bacteria is an effective remediation strategy for polluted marine sediments. This study investigated the relationships between PCB concentrations in sediment pore water, humin electron transfer capacity, and potential PCB dechlorinators at eight sediment sampling sites in the southern Yellow Sea, China, with differential PCB contamination. Station A2 showed the highest PCB concentration (453.16 ng L^-1 for seven indicator PCBs), especially of less chlorinated PCB congeners (≤5 Cl atoms), humin redox activity, and Dehalococcoides abundance (p < 0.05). Statistical analyses revealed a highly positive correlation between Dehalococcoides abundance and PCB concentration (r = 0.836, p < 0.05) and the electron shuttling ability of humins (r = 0.952, p < 0.01), whereas this was not observed for total bacteria and other potential PCB dechlorinators, e.g., Dehalobacter and Dehalogenimonas. Based on these results, Dehalococcoides might play an important role in the in situ reductive dechlorination of PCBs involving humins in marine sediments, and the natural microbial PCB attenuation capacity at station A2 was high. Chemical characterizations, electrochemical properties, and Fourier transform infrared analysis suggested that humins at station A2 had the highest electron transfer capacity. Furthermore, quinones are likely to be the functional groups that shuttle electrons during PCB dechlorination. Overall, this study provides a useful foundation for evaluating the natural microbial attenuation potential and fates of PCBs in marine sediments and for determining the role of humins as redox mediators in in situ PCB dechlorination by putative indigenous dechlorinators.

Quantitative analyses of selected polychlorinated biphenyl (PCB) congeners in water, soil, and sediment during winter and spring seasons from Msunduzi River, South Africa

The lack of information and the need for knowledge on the organic pollutants within the area of KwaZulu-Natal together with the global problem of water supply have prompted our investigation into the analyses of eight polychlorinated biphenyl (PCB) congeners in the Msunduzi River of KwaZulu-Natal, South Africa. Soil, sediment, and water samples were collected at ten different sites along the river during winter and spring seasons. Soil and sediment samples were extracted using ultra sonication with dichloromethane while water samples were liquid-liquid extracted using dichloromethane. All sample extracts were cleaned-up using a multi-layer silica gel column and analyzed with gas chromatography-mass spectrometry. Quality assurance measures were also determined. The percentage recoveries for water were 53-128 for all the PCBs analyzed, while sediment recoveries ranged between 69 and 105%. The highest total concentrations of the PCBs in sediment were 214.21-610.45 ng/g dw at the Du Toit sampling site and 30.86-444.43 ng/g dw basis at the wastewater treatment inlet for winter and spring, respectively. Soil PCB concentrations were 76.53-397.75 ng/g dw at the Msunduzi Town sampling site and 20.84-443.49 ng/g (dry weight) at the Du Toit sampling site for winter and spring, respectively. In addition, high PCB concentrations were found in effluent of the wastewater treatment inlet compared to other sampling sites, which ranged between 0.68-22.37 and 2.53-35.69 ng/mL for winter and spring seasons, respectively. In all the sampling sites selected for this study, Du Toit afforded the highest PCB concentration levels and the lowest was after chlorination at the Darvill wastewater treatment plant. The results presented are new and it is the first study of organic pollutants such as PCBs that has been carried out on this river.

Distribution and controls of heavy metals and organic matter in the surface sediments of the Southern Yellow Sea, China

Accurate and effective determination of the source of heavy metals is essential for the treatment of marine ecological environments. This article attempts to combine geochemical composition data and hydrocarbon composition data to achieve this purpose. The concentrations of six heavy metals (Cu, Pb, Zn, Cr, Ni, and Co), grain size, total organic carbon (TOC) content, Al₂O₃ content, and aliphatic hydrocarbons (AHs) in 501 surface samples from the Southern Yellow Sea (SYS) were analyzed. The results showed that most sample sites ranged from not polluted to moderately polluted. However, Cu, Pb, Cr, and Ni may represent potential hazards, and the toxic probability for the combination of five metals (Cr, Cu, Ni, Zn, and Pb) was 21% for all sampling sites. The highest heavy metal concentrations were associated with the fine-grained sediments in the eastern area, especially in the northeastern muddy area. However, high concentrations of Pb and Cu were also found in some sites with coarse sediment in the western region. The lipid biomarkers showed that the n-alkanes were dominated by large odd-numbered carbon molecules, indicating that the organic matter in the sediments originated mainly from terrestrial plants. Principal component analysis (PCA) results, AH data, and the sediment distributions indicated that the organic matter and heavy metals in the SYS were mainly sourced from the Old Yellow River Delta, transported by ocean currents and deposited in the central SYS. In addition, a small proportion of the heavy metals originated from airborne dust. The spatial distribution pattern of the heavy metals in the surface sediments provides a basis for the protection of the marine ecological environments.

The mechanism for enhanced oxidation degradation of dioxin-like PCBs (PCB-77) in the atmosphere by the solvation effect

The reaction pathways of PCB-77 in the atmosphere with ·OH, O₂, NO_x, and ¹O₂ were inferred based on density functional theory calculations with the 6-31G* basis set. The structures the reactants, transition states, intermediates, and products were optimized. The energy barriers and reaction heats were obtained to determine the energetically favorable reaction pathways. To study the solvation effect, the energy barriers and reaction rates for PCB-77 with different polar and nonpolar solvents (cyclohexane, benzene, carbon tetrachloride, chloroform, acetone, dichloromethane, ethanol, methanol, acetonitrile, dimethylsulfoxide, and water) were calculated. The results showed that ·OH preferentially added to the C5 atom of PCB-77, which has no Cl atom substituent, to generate the intermediate IM5. This intermediate subsequently reacted with O₂ via pathway A to generate IM5a, with an energy barrier of 7.27 kcal/mol and total reaction rate of 8.45 × 10⁻⁸ cm³/molecule s. Pathway B involved direct dehydrogenation of IM5 to produce the OH-PCBs intermediate IM5b, with an energy barrier of 28.49 kcal/mol and total reaction rate of 1.15 × 10⁻⁵ cm³/molecule s. The most likely degradation pathway of PCB-77 in the atmosphere is pathway A to produce IM5a. The solvation effect results showed that cyclohexane, carbon tetrachloride, and benzene could reduce the reaction energy barrier of pathway A. Among these solvents, the solvation effect of benzene was the largest, and could reduce the total reaction energy barrier by 25%. Cyclohexane, carbon tetrachloride, benzene, dichloromethane, acetone, and ethanol could increase the total reaction rate of pathway A. The increase in the reaction rate of pathway A with benzene was 8%. The effect of solvents on oxidative degradation of PCB-77 in the atmosphere is important.Graphical abstract

Congener profiles, distribution, sources and ecological risk of parent and alkyl-PAHs in surface sediments of Southern Yellow Sea, China

Congener profiles, distribution and sources of parent and alkyl-polycyclic aromatic hydrocarbons (PAHs) in surface sediments of Southern Yellow Sea (SYS), China were investigated. The ecological risk of parent-PAHs to aquatic organisms were evaluated based on sediment quality guidelines (SQGs), risk quotient (RQ), organic carbon (OC)-normalized analysis and mean effects range-median quotient (M-ERM-Q). The concentrations of 33 PAHs were analyzed, including 14 parent PAHs (without naphthalene and acenaphthylene), 16 alkyl-PAHs (7 methylphenanthrenes, 3 methylanthracenes, 3 methylfluoranthenes, and 3 methylpyrenes), dibenzothiophene, retene and perylene. Total concentrations of PAHs (TPAHs) ranged from 200.8 to 3629.0ng/g dry weight (d.w.), with a mean value of 1035.4ng/g d.w., and mainly contributed by fluorene, phenanthrene, methylphenanthrene, retene, fluoranthene and pyrene. Analysis of a broad variety of diagnostic ratios suggested that combustion was the key source of PAHs. Principal component analysis-multiple linear regression (PCA-MLR) indicated that combustion of coal, softwood and nature gas, coke oven, petroleum and vehicle emission were the main sources of PAHs in sediments of SYS, contributing 41.5%, 30.6%, 18.8%, and 9.0% to TPAHs, respectively. Ecological risk assessment of individual parent-PAHs suggested that fluorene, phenanthrene and fluoranthene may cause some risk to aquatic organisms in some stations. OC-normalized analysis and M-ERM-Q indicated that risk of multiple parent-PAHs was quite low in the studied area.

Traditional and new POPs in environments along the Bohai and Yellow Seas: An overview of China and South Korea

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.

Analysis of the Enantioselective Effects of PCB95 in Zebrafish (Danio rerio) Embryos through Targeted Metabolomics by UPLC-MS/MS

As persistent organic pollutants, polychlorinated biphenyls (PCBs) accumulate in the bodies of animals and humans, resulting in toxic effects on the reproductive, immune, nervous, and endocrine systems. The biological and toxicological characteristics of enantiomers of chiral PCBs may differ, but these enantioselective effects of PCBs have not been fully characterized. In this study, we performed metabolomics analysis, using ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) to investigate the enantioselective toxic effects of PCB95 in zebrafish (Danio rerio) embryos after exposure to three dose levels of 0.1, 1, and 10 μg/L for 72 h. Multivariate analysis directly reflected the metabolic perturbations caused by PCB95. The effects of (-)-PCB95 and (+)-PCB95 were more prominent than those of the racemate in zebrafish embryos. A total of 26 endogenous metabolites were selected as potential marker metabolites with variable importance at projection values larger than 1 and significant differences (p<0.05). These metabolites included amino acids, organic acids, nucleosides, betaine, and choline. The changes in these biomarkers were dependent on the enantiomer-specific structures of PCB95. Fifteen metabolic pathways were significantly affected, and several nervous and immune system-related metabolites were significantly validated after exposure. These metabolic changes indicated that the toxic effects of PCB95 may be associated with the interaction of PCB95 with the nervous and immune systems, thus resulting in disruption of energy metabolism and liver function.

Prediction of octanol-air partition coefficients for polychlorinated biphenyls (PCBs) using 3D-QSAR models

Based on the experimental data of octanol-air partition coefficients (KOA) for 19 polychlorinated biphenyl (PCB) congeners, two types of QSAR methods, comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA), are used to establish 3D-QSAR models using the structural parameters as independent variables and using logKOA values as the dependent variable with the Sybyl software to predict the KOA values of the remaining 190 PCB congeners. The whole data set (19 compounds) was divided into a training set (15 compounds) for model generation and a test set (4 compounds) for model validation. As a result, the cross-validation correlation coefficient (q(2)) obtained by the CoMFA and CoMSIA models (shuffled 12 times) was in the range of 0.825-0.969 (>0.5), the correlation coefficient (r(2)) obtained was in the range of 0.957-1.000 (>0.9), and the SEP (standard error of prediction) of test set was within the range of 0.070-0.617, indicating that the models were robust and predictive. Randomly selected from a set of models, CoMFA analysis revealed that the corresponding percentages of the variance explained by steric and electrostatic fields were 23.9% and 76.1%, respectively, while CoMSIA analysis by steric, electrostatic and hydrophobic fields were 0.6%, 92.6%, and 6.8%, respectively. The electrostatic field was determined as a primary factor governing the logKOA. The correlation analysis of the relationship between the number of Cl atoms and the average logKOA values of PCBs indicated that logKOA values gradually increased as the number of Cl atoms increased. Simultaneously, related studies on PCB detection in the Arctic and Antarctic areas revealed that higher logKOA values indicate a stronger PCB migration ability. From CoMFA and CoMSIA contour maps, logKOA decreased when substituents possessed electropositive groups at the 2-, 3-, 3'-, 5- and 6- positions, which could reduce the PCB migration ability. These results are expected to be beneficial in predicting logKOA values of PCB homologues and derivatives and in providing a theoretical foundation for further elucidation of the global migration behaviour of PCBs.

Polybrominated diphenyl ethers in sediments from the Southern Yellow Sea: Concentration, composition profile, source identification and mass inventory

The Southern Yellow Sea (SYS) is believed to be influenced by the contaminants from mainland China and the Korean peninsula. Here we report the first record about concentrations of polybrominated diphenyl ethers (PBDEs) in the sediments of the SYS. The concentrations of ∑(7)PBDEs (BDE-28, 47, 99, 100, 153, 154, 183) and BDE-209 were 0.064-0.807 ng g(-1) (dry weight) and 0.067-1.961 ng g(-1) with a mean value of 0.245 ng g(-1) and 0.652 ng g(-1), respectively. These are distinctively low compared with the PBDE levels previously reported in other regions of the world. PBDE concentrations gradually increased from the coastal areas to the central mud area. BDE-209 was the dominant congener, accounting for 70.2-91.6% of the total PBDEs. Congener profiles of PBDEs were similar to those in sediments from the Bohai Sea (BS), Laizhou Bay and modern Yellow River, which might be a tentative indication that they shared similar sources. Principal component analysis (PCA) revealed that PBDEs in the SYS were mainly from continental runoff (69.0%) and atmospheric deposition (31.0%). Depth profile of PBDEs in a sediment core collected from the edge of the central mud area showed that concentration of BDE-209 rapidly increased in recent years, which is in accordance with the replacement in demand and consumption of Penta- and Octa-BDEs by the Deca-BDE. Compared with BS, East China Sea, Erie and Ontario, the SYS was a relatively weak sink of PBDEs (0.102-1.288 t yr(-1) for ∑(7)PBDEs and 0.107-3.129 t yr(-1) for BDE-209) in the world.

Selected current-use pesticides (CUPs) in coastal and offshore sediments of Bohai and Yellow seas

China is one of the largest producers, consumers, and traders for pesticides in the world. Currently, there are more than 600 pesticide-active substances registered in China, whereas few studies were conducted to improve our understanding of the occurrence and environmental impact of current-use pesticides (CUPs) in China's environment. In this work, 72 surface sediment samples were taken from the coastal and offshore of Bohai and Yellow seas and were analyzed for six CUPs (trifluralin, dacthal, quintozene, endosulfan, chlorpyrifos, and dicofol) and two metabolites (pentachloroanisole and endosulfan sulfate). Sediment samples were categorized as estuarine or near-shore sediments (Laizhou Bay, Taozi Bay, Sishili Bay, and Jiaozhou Bay) and offshore sediments. Trifluralin, α-endosulfan, endosulfan sulfate, chlorpyrifos, dicofol, and pentachloroanisole were detected in more than 60 % of the samples. Dicofol was the predominant compound with concentrations mostly higher than 100 pg/g dry weight (dw) with the highest concentration of 18,000 pg/g dw. Concentrations of other compounds were mainly below 100 pg/g dw. CUP levels were much lower than the sediment screening benchmark calculated. The highest levels of α-endosulfan, endosulfan sulfate, trifluralin, and chlorpyrifos existed at Laizhou Bay, whereas pentachloroanisole and dicofol had highest mean concentrations at Jiaozhou Bay. Generally, no correlation between pesticide concentrations and total organic carbon was observed either for offshore samples or for near-shore samples.

Historical sediment record and distribution of polychlorinated biphenyls (PCBs) in sediments from tidal flats of Haizhou Bay, China

The spatial and temporal variations and sources of polychlorinated biphenyls (PCBs) in sediment of tidal flat from Haizhou Bay, China were investigated. PCBs concentrations in surface sediments ranged from 1.33 to 6.27ngg(-1) dry weight. Low-chlorinated PCBs, dominated by the tri-PCB homologs, were identified as the prevalent contaminate of surface sediments. These results were in agreement with the fact that tri-PCB homologs are the dominant contaminants in China. In surface sediment, the highest level appeared in the estuary, and it decreased with distance from the Linhong River estuary. PCBs concentrations started to rise from the mid-1950s, and reached a maximum in 2005. PCBs in sediment might originate from surface runoff and discharges of local source as well as slight atmospheric deposition, based on PCA. Additionally, the PCBs levels in the sediments were considered to rarely pose hazard to the aquatic and human health, based on Sediment Quality Guidelines (SQGs).

Use of lipid biomarkers for identification of regional sources and dechlorination characteristics of polychlorinated biphenyls in the East China Sea

Terrestrial organic matter (TOM) indicators could serve as proxies in studying the environmental behavior of organic pollutants because they are transported into the shelf seas along with the TOM. In this study, comparisons between polychlorinated biphenyls (PCBs) and TOM indicators of ∑C27+C29+C31n-alkanes, as well as branched and isoprenoid tetraether (BIT) index, were performed to examine the regional sources of PCBs in the East China Sea. The results indicated that sedimentary PCBs in the mud area southwest of the Cheju Island, coastal area north of the 29°N, and coastal area south of the 29°N were mainly from atmospheric deposition, riverine input of the Yangtze River, and local coastal sources via atmospheric deposition, respectively. The broad resemblance of the spatial patterns of non-definitive indicators of PCB dechlorination, hypoxia, and ∑ladderane lipids suggested that deep dechlorination mainly occurred at the coastal areas and center shelf southwest of Cheju Island.

Sedimentary records of hydroxylated and methoxylated polybrominated diphenyl ethers in the southern Yellow Sea

Although hydroxylated (OH-) and methoxylated (MeO-) polybrominated diphenyl ethers (PBDEs) have caused much concern in recent years, few reports had discussed on their input history. In this study, we measured the contents of nine MeO-BDEs, ten OH-BDEs, and total organic carbon (TOC) of two sediment cores from the southern Yellow Sea. 6-MeO-BDE-47, 2'-MeO-BDE-68, 6-OH-BDE-47, and 2'-OH-BDE-68 were the predominant congeners in HH12, while only 2'-OH-BDE-68 and 6-OH-BDE-47 were frequently detected in core HH11. The records showed that OH-/MeO-BDEs in both cores had increased rapidly since the 1950s. Their existence was detected at the bottom layers (∼1800 s) prior to the production of PBDEs (1960s), thus OH-/MeO-BDEs originate from natural origins rather than artificial PBDEs. Comparisons between TOC and OH-/MeO-BDEs indicated that TOC is a potential factor affecting the accumulation of OH-/MeO-BDEs in marine environments. Similar trends and significant correlations between OH-BDEs and MeO-BDEs suggest their common origins or interconversion.

Distribution and pollution assessment of heavy metals in surface sediments in the Yellow Sea

Heavy metal concentrations in surface sediments at 56 stations during two cruises in the Yellow Sea in summer and winter, 2011 were analyzed by inductively coupled plasma-mass spectrometry. The pollution status was assessed via the Geoaccumulation index and Hankanson potential ecological risk index. Higher concentrations of heavy metals (except for Mn) were found in the central Southern Yellow Sea and the western Northern Yellow Sea. The higher contents of Mn were much closer to Shandong Peninsula. Correlation analyses indicated that Pb, Cu, Fe, Ni, Zn and Co probably had the same origin and were controlled by grain size and total organic carbon. Pollution assessment showed that most areas of the Yellow Sea were not or lowly contaminated with the exception of the northwest and south parts of the Southern Yellow Sea showing Cd-contamination. The pollution status of the Yellow Sea in summer was worse than that in winter.

Distribution and ecological risk of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in surface sediments from the Bizerte lagoon, Tunisia

Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were determined in 18 surface sediment samples collected from Bizerte lagoon, Tunisia. The total concentrations of ten PCBs (∑PCBs) and of four OCPs (∑OCPs) in the sediments from this area ranged from 0.8 to 14.6 ng g(-1) dw (average value, 3.9 ng g(-1) dw) and from 1.1 to 14.0 ng g(-1) dw (average value, 3.3 ng g(-1) dw), respectively. Among the OCPs, the range of concentrations of dichlorodiphenyltrichloroethane and its metabolites (DDTs) and hexachlorobenzene (HCB) were 0.3-11.5 ng g(-1) dw (1.9 ng g(-1) dw) and 0.6-2.5 ng g(-1) dw (1.4 ng g(-1) dw), respectively. Compositional analyses of the POPs indicated that PCB 153, 138 and 180 were the predominant congeners accounting for 60 % of the total PCBs. In addition, p,p'-DDT was found to be the dominant DDTs, demonstrating recent inputs in the environment. Compared with some other regions of the world, the Bizerte lagoon exhibited low levels of PCBs and moderate levels of HCB and DDTs. The high ratios ΣPCBs/ΣDDTs indicated predominant industrial versus agricultural activities in this area. According to the established guidelines for sediment quality, the risk of adverse biological effects from such levels of OCPs and PCBs, as recorded at most of the study sites, was insignificant. However, the higher concentrations in stations S1 and S3 could cause biological damage.

Organochlorine pesticide content and distribution in coastal seafoods in Zhoushan, Zhejiang Province

Thirteen types of seafoods were collected from four counties (districts) of Zhoushan, Zhejiang Province, China and analyzed for organochlorine pesticides (OCPs). The average concentrations of OCPs in seafoods ranged from 258.3 ng g⁻¹ (lw) to 3459.6 ng g⁻¹ (lw). Hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) were the most abundant compounds in these environments and in total accounted for 8.2-62.2% and 32.1-89.0% of the total OCPs in seafoods, respectively. The total OCP contents were higher in seafoods from Shengsi and Putuo and lower in those from Dinghai and Daishan. The ratios of (DDE+DDD)/DDTs reflected a mixed input of accumulated and fresh DDTs in Shengsi, Putuo. The ratios of o,p'-DDT/p,p'-DDT in seafoods of Shengsi ranged 0.10-0.60 (mean 0.33), indicating that DDTs in seafoods of Shengsi may partly contain dicofol products and other pollutants accumulated in Yangtze Estuary. DDTs are a greater concern for ecotoxicological risk in the study area.

Polychlorinated biphenyls in sediments of the Yellow Sea: distribution, source identification and flux estimation

Although there is no direct major riverine input, a large quantity of waste produced in mainland China and Korea is transported continuously to the Yellow Sea (YS) through atmospheric deposition, currents and tides; therefore, the environment is distinctly influenced by man-made pollution. This study focuses on the associated pollutant transport mechanisms and fluxes by sampling polychlorinated biphenyls (PCBs). PCBs (Σ24PCB) in YS sediments ranged between 99 pg/g and 3.13 ng/g of dry sediment (with a mean value of 715 pg/g). PCBs produced unintentionally by industrial and other processes appeared to be the major source of PCBs in the sediments, accounting for 60.5%. Industrially synthesized PCBs with 3Cl and 5Cl accounted for 15.5% and 24.0%, respectively. PCBs were mainly from atmospheric deposition (84.5%), followed by continental runoff (15.5%). The average atmospheric deposition flux of technical PCBs was 789 ng/(m(2)a) and flux of surface runoff was 2.27 ng/L.

Distributions and sources of polychlorinated biphenyls in the coastal East China Sea sediments

The Yangtze River estuary (YRE) and the adjacent East China Sea (ECS) inner shelf is an important sink of pollutants originated from mainland China. In this work, we studied the spatial and temporal variations and sources of polychlorinated biphenyls (PCBs) in sediments from the YRE and the ECS inner shelf. Total concentration of 23 PCBs (Σ23PCB) ranged between 24.3 and 343.3 pg/g (with a mean value of 126.7 pg/g), and higher values occurred in the estuarine region. The homolog profile was dominated by 3-5Cl CBs, accounting for 76.1% of Σ23PCB. The Cl proportion ranged from 45.1% to 58.8% (with a mean value of 49.9%); the lowest level appeared in the estuarine region, and it increased with distance from the YRE. Lower chlorinated congeners were carried mainly by the YR into the ocean, to be finally buried in sediments of the estuary region and vicinity. However, higher chlorinated ones were imported mainly via direct emission from local sources, to be finally buried in sediments farther away from the estuary. Of the PCBs in surface sediments, 40.1% came from the YR, 37.9% from the local sources and the rest 22.0% from atmospheric deposition. In a sediment core, we found that 81% of PCBs were technically produced and 19% unintentionally produced in the last century. Before the 1970s, PCB levels were influenced predominantly by the production and consumption of technical PCBs. While in recent decades, the effect of human activities on PCB levels has been increasing continuously.

Biomagnification of persistent chlorinated and brominated contaminants in food web components of the Yellow Sea

Concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs) were measured in 32 species inhabiting the Yellow Sea to assess their bioaccumulation potentials. The concentrations in these samples were lower than those reported for other countries or locations. Relatively high levels of BDE 209 in biota suggest an ongoing source of deca-BDE technical mixing within the Yellow Sea. The accumulation profiles of PCBs were uniform between species, but the concentrations of OCPs and PBDEs varied widely. Pelagic and benthic food-chain components were separated by their δ(13)C values. Significant positive correlations between δ(15)N and PCB 153, PCB 138, p,p'-DDE, oxy-chlordane, and trans-nonachlordane were found only for pelagic consumers, indicating that the pelagic food chain is an important bioaccumulation pathway for selected PCB and OCP compounds. The other compounds did not show any biomagnification through benthic and pelagic food chains, suggesting the lower bioaccumulation potentials of these contaminants.

Distribution of organochlorine pesticides (OCs) and polychlorinated biphenyls (PCBs) in marine sediments directly exposed to wastewater from Cortiou, Marseille

INTRODUCTION

The future 'Calanque National Park' coastlines of the Bouches-du-Rhône and Var departments in France, constitute one of the ten biodiversity hot spots identified in the Mediterranean basin that receives industrial and urban wastewaters discharged from Marseille and its suburbs.

MATERIALS AND METHODS

Organochlorine pesticides (OCs) and polychlorinated biphenyls (PCBs) were measured in sediments collected from 12 sampling sites (C1-C12) of sewage discharge to the sea from the wastewater treatment plant of Cortiou-Marseille. This study aims to determine the extent of these compounds in the sediments and to establish the possible sources of these contaminants.

RESULTS AND DISCUSSION

Total pesticides in the sediments ranged from 1.2 to 190.6 ng g(-1) dry weight of sediment. The highest value was found at station C1, with a decreasing trend in total OC concentrations seaward. Among these compounds, the concentrations of the sum of dichlorodiphenyltrichloroethane (ΣDDT) were the highest, ranging from 0.7 to 114.3 ng g(-1). PCB concentrations, expressed as equivalent to Arochlor 1260, varied from 9.1 to 226.9 ng g(-1). Individually, the dominant coplanar PCB congeners CB-153, CB-138 and CB-101. Generally, PCB concentrations at stations C2, C3, C5 and C7 were higher than those at stations C10, C11 and C12. Through some pollution indices, we showed the long-term contamination input of these OCs (DDT, endosulfan, HCH and heptachlor cases) rather than a recent release resulting from degradation and long-term weathering (dieldrin, aldrin and methoxychlor cases). Occurrence of PCBs might be due to their resistance to degradation processes or/and chronic inputs.

CONCLUSIONS

By comparison with available sediment quality guideline (SQG) values, the environmental significance and toxicological implications of PCBs and OCs (i) reveal the probable adverse effects for the sediments from C1, C5, C6, C9 and (ii) confirm the adverse effect for marine biota and more particularly for benthic communities at C2-C4, C7 and C8.

Assessment of polychlorinated biphenyls contamination in sediment and organism from Xiamen offshore area, China

In Xiamen offshore area, sediment polychlorinated biphenyls (PCBs) concentrations ranged from 2.33 to 30.94 ng/g, with an average value of 8.94 ng/g. The in situ organic carbon normalized partition coefficients (log K'(oc)) of the 12 co-polar congeners PCBs between sediments and porewater were from 1.50 to 2.64, and the log K'(oc) decreased with increasing chlorine number. PCB congeners pattern of marine organism were characterized by 5-6 CB chlorinated compounds, and the world health organization total dioxin equivalents of PCBs in organism ranged from 1.45 to 88.26 pg/g lipid.

Polycyclic aromatic hydrocarbons in surface sediments of the East China Sea and their relationship with carbonaceous materials

This study measured concentrations of polycyclic aromatic hydrocarbons (PAHs) in surface sediments in the East China Sea (ECS) to investigate possible sources and fate of PAHs. Total concentration of PAHs in the sediments of the ECS ranged from 22 to 244 ng g(-1), with the highest levels in the coastal area and outer shelf. The observed PAH results showed elevated levels in both inner and outer shelf areas, a finding that is different from predictions by an ocean circulation model, suggesting that terrestrial sources are important for PAH contaminations in the ECS, while sediment resuspension, tidal changes and lateral transport may be important in affecting the distribution of PAHs in the outer shelf. The distribution of PAHs in the surface sediments of the ECS is similar to the distribution of carbonaceous materials (e.g., particulate organic carbon and black carbon), suggesting that carbonaceous materials may strongly affect the distribution of PAHs.

The distribution, enrichment and source of potential harmful elements in surface sediments of Bohai Bay, North China

A geochemical study of Bohai Bay surface sediments was carried out to analyze the potential harmful element (PHE: Ge, Mo, In, Sn, Sb, Te, Tl, Bi and V) concentrations, transportation and deposition, enrichment factors and sources. Germanium, Mo, In, Sn, Sb, Te, Tl, Bi and V concentrations in the surface sediments were: 1.43-1.71, 0.52-1.43, 0.04-0.12, 2.77-4.14, 1.14-2.29, 0.027-0.085, 0.506-0.770, 0.27-0.63 and 70.35-115.90 μg/g, respectively. The distributions of total PHE concentrations, together with sequential extraction analyses, showed that the PHEs were mainly due to natural inputs from the continental weathering delivered to the bay by rivers and atmospheric transportation and deposition. However, high Mo, Sb, Te, Bi and V occurred in non-residual fractions, suggesting some anthropogenic inputs in addition to the natural inputs. Besides sources, the distributions of PHEs were influenced by the coupling of physical, chemical and biological processes. Enrichment factor (EF) was computed for each site for each element in order to assess the polluting elements and the degree of pollution at each site. Results revealed that the EFs were generally lower than 1.0, particularly for Ge, Mo, In, Sn, Tl and V; however, the EFs were higher (>1.5), particularly for Sb, Te and Bi, revealing moderate contamination.

Relationships between persistent organic pollutants and carbonaceous materials in aquatic sediments of Taiwan

Recent studies have shown that many persistent organic pollutants (POPs, e.g., polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and various pesticides), are strongly associated with carbonaceous materials (including organic carbon (OC) and black carbon (BC)). We hypothesize that carbonaceous materials can be used as a first-order pollution index, to indicate areas where POP pollution may require further investigation. We tested our hypothesis and found that strong, positive correlations between BC and OC contents versus the concentrations of PCBs (and PAHs) existed in estuarine sediments of the Danshui River in 2005 and 2008. Thus, our preliminary results demonstrate that POC and BC are potential indicators of the POP pollution potential in fluvial sediments of the Danshui River in Taiwan. This innovative approach can provide a simple, relatively inexpensive and expedient means to monitor concentrations of POPs in polluted aquatic sediments of Taiwan, and/or those having a legacy of POP inputs.

One century record of contamination by polycyclic aromatic hydrocarbons and polychlorinated biphenyls in core sediments from the southern Yellow Sea

Sixteen polycyclic aromatic hydrocarbons (PAHs) and 28 polychlorinated biphenyls (PCBs) were measured at a 2-cm interval in a core sample from the middle of the southern Yellow Sea for elucidating their historical variations in inflow and sources. The chronology was obtained using the 210pb method. PAHs concentrations decreased generally with depth and two climax values occurred in 14-16 cm and 20-22 cm layers, demonstrating that the production and usage of PAHs might reach peaks in the periods of 1956-1962 and 1938-1944. The booming economy and the navy battles of the Second World War might explain why the higher levels were detected in the two layers. The result of principal component analysis (PCA) revealed that PAHs were primarily owing to the combustion product. Down-cored variation of PCB concentrations was complex. Higher concentrations besides the two peaks being the same as PAHs were detected from 4 to 8 cm, depositing from 1980 to 1992, which probably resulted from the disposal of the out-dated PCB-containing equipment. The average Cl percentage of PCBs detected was similar to that of the mixture of Aroclor 1254 and 1242, suggesting they might origin from the dielectrical and heat-transfer fluid. The total organic carbon (TOC) content played a prevalent role in the adsorption of high molecular weight PAHs (> or = 4-ring), while no obvious relationship among total PCBs, the concentration of congeners, and TOC was found.

Persistent organochlorine residues in estuarine and marine sediments from Ha Long Bay, Hai Phong Bay, and Ba Lat Estuary, Vietnam

To assess the organochlorine contamination in the northeast coastal environment of Vietnam, a total of 41 surface sediments were collected from Ha Long Bay, Hai Phong Bay, and Ba Lat estuary, and analyzed for their organochlorine content. Organochlorine compounds (OCs) were widely distributed in the Vietnamese coastal environment. Among the OCs measured, DDT compounds predominated with concentrations ranging from 0.31 to 274 ng g(-1). The overall contamination level of DDTs in coastal sediments from northern Vietnam is comparable with those from other Asian countries. However, concentrations exceeding 100 ng g(-1) are comparable with high concentrations reported from India and China, the largest DDT consumers in the world. The overall concentrations of PCBs, HCHs, and chlordanes in surface sediments were in the ranges of 0.04-18.71 ng g(-1), not detected (n.d.) - 1.00 ng g(-1), and n.d. - 0.75 ng g(-1), respectively. Ha Long Bay and Hai Phong Bay were relatively more contaminated with DDTs and PCBs than other regions, respectively. In contrast, the distribution of HCHs was relatively homogeneous. OCs contamination in the coastal environment of Vietnam is closely related to shipping and industrial activities. The levels of DDT compounds in harbors and industrial areas exceeded their sediment quality guideline values suggested by Environment Canada [CCME (Canadian Council of Ministers of the Environment), 2002. Canadian sediment quality guidelines for the protection of aquatic life. In: Canadian Environmental Quality Guidelines. Canadian Council of Ministers of the Environment, Winnipeg, MB] and Australian and New Zealand [ANZECC and ARMCANZ, 2000. National water quality management strategy. Paper No. 4, Australian and New Zealand Guidelines for Fresh and Marine Water Quality, vol. 1, The Guidelines. Australia. Document: http://www.deh.gov.au/water/quality/nwqms/volume1.html], indicating that adverse effects may occur to marine species in that areas.