Spatial and temporal distribution and risk assessment of polycyclic aromatic hydrocarbons in surface seawater from the Haikou Bay, China

Risk assessment of trace metals and polycyclic aromatic hydrocarbons in seawater of typical bays in the Bohai Sea

The ecological risks of trace metals (Cu, Zn, As, Cd, Pb, and Hg) and PAHs in seawater from three typical bays of the Bohai Sea (the Liaodong Bay, Bohai Bay, and Laizhou Bay) were comprehensively assessed by recompiling 637 sites. Results highlighted that scrutiny should be given to the ecological risks of Cu (3.80 μg/L) in the Bohai Bay and Hg (0.23 μg/L) in the Laizhou Bay. Conversely, the Liaodong Bay exhibited negligible ecological risks related to trace metals. The risks of ΣPAHs in the Liaodong Bay, Bohai Bay, and Laizhou Bay were moderate, with mean concentrations of 368.16 ng/L, 731.93 ng/L, and 187.58 ng/L, respectively. The source allocation of trace metals and PAHs required consideration of spatial variability and anthropogenic factors, which greatly affected the distribution and composition of these pollutants. The combined ecological risks in the Bohai Bay (6.80 %) and Laizhou Bay (5.43 %) deserved more attention.

Marine Microbiota Responses to Shipping Scrubber Effluent Assessed at Community Structure and Function Endpoints

The use of novel high-throughput sequencing (HTS) technologies to examine the responses of natural multidomain microbial communities to scrubber effluent discharges to the marine environment is still limited. Thus, we applied metabarcoding sequencing targeting the planktonic unicellular eukaryotic and prokaryotic fraction (phytoplankton, bacterioplankton, and protozooplankton) in mesocosm experiments with natural microbial communities from a polluted and an unpolluted site. Furthermore, metagenomic analysis revealed changes in the taxonomic and functional dominance of multidomain marine microbial communities after scrubber effluent additions. The results indicated a clear shift in the microbial communities after such additions, which favored bacterial taxa with known oil and polycyclic aromatic hydrocarbons (PAHs) biodegradation capacities. These bacteria exhibited high connectedness with planktonic unicellular eukaryotes employing variable trophic strategies, suggesting that environmentally relevant bacteria can influence eukaryotic community structure. Furthermore, Clusters of Orthologous Genes associated with pathways of PAHs and monocyclic hydrocarbon degradation increased in numbers at treatments with high scrubber effluent additions acutely. These genes are known to express enzymes acting at various substrates including PAHs. These indications, in combination with the abrupt decrease in the most abundant PAHs in the scrubber effluent below the limit of detection-much faster than their known half-lives-could point toward a bacterioplankton-initiated rapid ultimate biodegradation of the most abundant toxic contaminants of the scrubber effluent. The implementation of HTS could be a valuable tool to develop multilevel biodiversity indicators of the scrubber effluent impacts on the marine environment, which could lead to improved impact assessment. Environ Toxicol Chem 2024;00:1-18. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Spatiotemporal distributions and ecological risk of polycyclic aromatic hydrocarbons in the surface seawater of Laizhou Bay, China

The spatial-temporal distribution, source, and potential ecological risk of polycyclic aromatic hydrocarbons (PAHs) in surface seawater from Laizhou Bay were investigated. The total PAH (ΣPAH) concentrations ranged from 277 to 4393 ng/L with an average of 1178 ng/L, thereby suggesting a relatively moderate to high PAH exposure level in Laizhou Bay in comparison to other bays in the world. The composition patterns and source apportionment results revealed that the coal, biomass burning, diesel emissions, and petroleum combustion as well as the combination of these processes were the dominant sources of PAHs in the surface water, which were closely associated with sail process and sewage effluents. The ecological risk assessment indicated that benzo(a)pyrene (BaP), phenanthrene (Phe), luoranthene (Flua), and naphthalene (Nap) would exist ecological risks in most of surface seawater sites, but the probabilistic risk assessment (PRA) results showed that the current level of risk is not as severe as the risk quotient (RQ) results revealed.

Study on reproductive endocrine disturbance and DNA damage mechanism of female Ruditapes philippinarum under Benzo[a]pyrene stress

The reproductive toxicity of polycyclic aromatic hydrocarbons (PAHs) in aquatic organisms has attracted increasing attention from scholars. Currently, research in this field primarily focuses on vertebrates such as zebrafish and other model species. However, there is still a significant knowledge gap in the toxicity of PAHs to invertebrates and its potential mechanisms. Benzo[a]pyrene (B[a]P) is one of the most representative PAHs. In this study, female Ruditapes philippinarum (R. philippinarum) was treated with B[a]P concentrations of 0, 0.8, 4, and 20 μg/L to investigate reproductive indicators in the proliferative, growth, mature, and spawn stages. Transcriptomics was used to investigate the expression of genes associated with the reproductive endocrine system, DNA repair, autophagy, apoptosis, and ovarian development at different reproductive stages. Our results suggested that B[a]P disrupted the endocrine system by interfering with the production of steroid hormones and the transmission of estrogen signals in female R. philippinarum. The structure of the ovarian DNA duplex is severely damaged under the stress of B[a]P, and a series of cellular responses caused by DNA damage are also interfered. Additionally, we observed a reduction in the gonadosomatic index (GSI) and mature oocytes numbers after B[a]P exposed. Tissue section indicated that severe damage to the ovarian structure at mature and spawn stages. In conclusion, this study combined transcriptomic and toxicological to explore the negative effects on ovarian development induced by B[a]P, focusing on reproductive endocrine disturbance and DNA damage.

Assessing the potential risks, sources and the relationship between the dissolved and particulate polycyclic aromatic hydrocarbons (PAHs) in the typical semi-enclosed bay, Bohai Bay of China

This study aimed to investigate the spatial and temporal distribution as well as the partitioning behavior of dissolved and particulate polycyclic aromatic hydrocarbons (PAHs) during the summer and autumn seasons of 2020. It was found that the average concentration of PAHs in surface seawater was significantly higher in autumn (58.16 ng L-1) than in summer (40.47 ng L-1) due to a large amount of input in autumn and more photodegradation and biodegradation affected by higher temperatures in summer. The spatial distribution indicated that the river had a significant dilution effect on PAHs in summer and became a significant input source in autumn. In addition, a large number of oil and gas development platforms were distributed throughout the Bohai Bay, and the discharge of production and domestic sewage contributed to the PAHs pollution level. As a semi-enclosed bay, the water exchange capacity of Bohai Bay was poor, leading to a greater accumulation of PAHs in the marine environment. The diagnostic ratios and PCA-MLR indicated that petroleum was the most important source of PAHs with a contribution of 45%, followed by fuel combustion (39%) such as coal and oil. Photooxidation in seawater resulted in a reduction of BaP/BeP, indicating that seasonal variations in photooxidation had a significant impact on the composition of PAHs (summer: 1.49, autumn: 2.96). The concentration of particulate PAHs was correlated with the concentration of dissolved PAHs and SPM, and the proportion of 3-rings (43.8%) and 4-rings (49.8%) PAHs was significantly higher on SPM. The distribution coefficients Log Kd and φspm-water showed a trend of increasing and then decreasing as the number of rings increased, with the 4-rings Pyr exhibiting the highest value. According to the ecological risk assessment, the ecological risk of total PAHs was low (RQNCs < 800, RQMECs < 1), but the ecological risk of individual PAHs and the carcinogenicity of high-ring PAHs could not be ignored (＞96.5%). This study is significant for investigating the "sources and sinks" of PAHs in the complex marine environment by analyzing the partitioning behavior of PAHs in different phases.

Impacts of shipyard oil leakage on the PAHs and PCBs occurrence in Xiangshan Bay, China

Here, we studied the shipyard impacts on the distribution of PAHs and PCBs in the semi-enclosed Xiangshan Bay, an important mariculture zone in China. The results showed that the shipyard caused a pollution plume for PAHs but not for PCBs. As characteristic pollutants of oil leakage, the PAHs had concentrations of up to 55.82 ng L-1 in the water, 2235.04 ng g-1 in suspended particulate matter (SPM), and 1489.60 ng g-1 in sediment. The PAHs in water and SPM were dominated by phenanthrene and pyrene that were mostly derived from lubricant and diesel, while those in sediments were dominated by the high-molecular-weight PAHs, such as indeno[1,2,3-c,d]pyrene. In contrast, the PCBs concentrations reached up to 10.17 ng L-1, 79.72 ng g-1, and 124.33 ng g-1 in the seawater, SPM, and sediment samples, respectively, and they did not show spatial patterns affected by the shipyard. Moreover, the health risk assessment indicated that the shipyard discharge caused a substantial PAHs ecological risk to the adjacent and downstream water environment. Therefore, point source discharge in semi-enclosed bays should be paid close attention to due to the strong pollutant transport effect.

Study of DNA methylation of hsd17β, er and reproductive endocrine disrupting effects in female Chlamys farreri under benzo[a]pyrene stress

Benzo[a]pyrene (B[a]P) is one kind of persistent organic pollutants (POPs) in the marine environment which has multiple toxic effects. However, epigenetic studies correlated with reproductive endocrine disruption in invertebrates have not been explored. In our study, Chlamys farreri in the mature stage were exposed to B[a]P (0, 0.4, 2 and 10 μg/L) for 5 and 10 d to explore the effects on reproductive endocrine and DNA methylation. The results proved that B[a]P stress significantly restrained the growth of mature oocytes, reduced the content of sex hormones, and affected the expression of genes related to ovarian development. Histological observation showed that the ovarian microstructure was damaged. The detection of SAM/SAH, dnmts, GNMT in the ovary showed that the level of global DNA methylation fluctuated. Significant hypermethylation of the hsd17β promoter region in the ovary was associated with a significant downregulation of its gene expression. In summary, our results suggested that exposure to B[a]P might affect DNA methylation to regulate key reproductive genes, interfere with the synthesis of sex hormones, and inhibit ovarian development. These findings provide a basis for a better understanding of how epigenetic mechanisms are involved in the response of marine invertebrates to POPs stress, opening up new avenues for incorporating environmental epigenetic approaches into marine invertebrate management and conservation plans.

Elevated nitrate promoted photodegradation of PAHs in aqueous phase: Implications for the increased nutrient discharge

Polycyclic aromatic hydrocarbons (PAHs) are frequently released in aqueous phase by oil spill or from other sources, and photochemical oxidation is one of their major weathering processes. In this study, the photochemical behavior of phenanthrene (PHE, as a representative PAH) were studied and the effects of nitrogenous compounds were evaluated. The results showed that nitrate was an effective photosensitizer for improving the photodegradation of PHE, but the promoting effect was less effective in seawater due to the presence of halogen ions; the ammonia played a negligible role on PHE degradation. The photochemical ionization was a key process for PHE degradation, it can be retarded due to the quenching of triplet excited state by dissolved oxygen, and the inhibition was most prominent in fresh water. The presence of nitrate increased the steady state concentration of •OH from 2.08 × 10^-15 M to 1.04 × 10^-14 M in fresh water, and from 1.5 × 10^-16 M to 2.08 × 10^-15 M in seawater. The secondary-order reaction rate constant between PHE and •OH (k_•OH,PHE) was determined as 5.70 × 10⁹ M^-1 s^-1. Similar trend was observed for ¹O₂. The contribution of •OH to PHE removal was more prominent in fresh water than in seawater due to the quenching effects of halogen, and the increasing of nitrate enlarged the contribution of •OH. Two possible PHE degradation pathways were proposed based on GC-MS analysis and DFT calculation. The Quantitative Structure-activity Relationship (QSAR) evaluation showed that some degradation intermediates were more toxic than PHE, but the total environmental risk was still diminished due to the low percentage of toxic intermediates. This study provided theoretical and experimental insights into the influence of nitrogenous compounds on the photodegradation of PHAs in water environment.

Environmental processes and fate of PAHs at a shallow and enclosed bay: West Nanao Bay, Noto Peninsula, Japan

From August 2019 to August 2020, particulate and dissolved polycyclic aromatic hydrocarbons concentrations (PAHs) were analyzed in the water body of West Nanao Bay, Japan, to determinate their levels, environmental pathways, and ecological risks at this remote but shallow and semi-enclosed bay. The 14 targeted PAHs were analyzed by high performance liquid chromatography-fluorescence detector. Even when water column stratifies, the summatory of 14 targeted dissolved PAHs did not follow significantly change with depth. Results agreed with our previous findings in the surface distribution at the bay and can be attributed to long retention time of the water mass of the semi-enclosed bay. Suspended solids start precipitating according to their size; with biggest particles rapidly settling in the proximities of river mouths. Partition coefficients (Kp) varied from 10³ to 10⁷, according to molecular weights. In general, highest Kp were found in the nepheloid layer. The risk quotients, RQ_{∑14 PAHs (NCs)} (1.04-174.08), indicated that PAHs represented a very low to low environmental risks.

Characterizing spatiotemporal variations of polycyclic aromatic hydrocarbons in Taihu Lake, China

In this study, we analyzed the concentration distributions of 20 polycyclic aromatic hydrocarbons (PAHs) in 41 water samples which were collected from the northern part of Taihu Lake during 4 field campaigns (201511, 201606, 201702 and 201709). The concentrations were determined with GC-MS, and their spatial and seasonal distribution characteristics were interpreted. The results show that 2-ring PAHs present considerably higher concentrations in warm seasons than cold seasons, but the concentrations of the other higher-ring PAHs are rather stable in warm and cold seasons. The distribution patterns of these PAHs might be mainly attributed to ambient temperature effects on the PAH solubility in the water body. Meanwhile, the spatial distributions of the PAH concentrations in cold seasons were rather various in the sampling area, while the distributions in the warm seasons were homogeneous. The different distributions could result from the water recharge from the Yangtze River during cold seasons, which diluted PAH concentrations in the northeastern part of the lake. Furthermore, via literature review on PAH concentrations in water body, PAHs are in a wide range of levels and their patterns are different among the studies, which should be more effected by local factors instead of general PAH properties. The results from this study also present special characteristics of PAHs in Taihu Lake, which exhibit more insight on PAHs existence in water bodies.

Spatial distribution and ecological risks of polycyclic aromatic hydrocarbons in sea ice and seawater from northern Liaodong Bay, China

To better understand the spatial distribution and ecological risks of polycyclic aromatic hydrocarbons especially in low latitude coastal productive areas, PAHs in sea ice were examined for the first time in northern Liaodong bay of China in December 2020. Results showed ΣPAHs were dominated by 2- and 3-ring, with the mean concentration of 241.9 ng L^-1 and 202.8 ng L^-1 in sea ice and seawater, respectively, suggesting a moderate ecological risk based on Risk Quotients assessment. Ice enrichment factors were greater than 1 at 82% of the sampling sites, reflecting enrichment of PAHs in sea ice. The characteristic compounds ratios demonstrated PAHs mainly derived from petrogenic sources, while combustion was another crucial source for PAHs in sea ice via atmospheric deposition. This helps to better elucidate pollution status, potential sources and risk assessment of PAHs in productive coastal oceans especially during ice-covered period for contamination control and environmental management.

Spatial distribution of polycyclic aromatic hydrocarbons in the Philippine Sea, Western Pacific and the impact factors analysis

Knowing the polycyclic aromatic hydrocarbons (PAHs) pollution properties in ocean is highly needed to protect the open sea. In July to August of 2020, twenty surface water samples were obtained from the East China Sea to the Philippine Sea. The ranges of Σ₁₅PAHs concentrations were 3.188-5.29 ng L^-1 in dissolved phase, 0.455-1.305 ng L^-1 in particulate phase in the Philippine Sea. 3, 4-Ring PAHs were the most abundant PAHs. Their spatial differences in dissolved phase were mainly caused by human activities, the summer monsoon from the Philippine Islands and the Northern Equatorial Current, and the Kuroshio Current and Subtropical Countercurrent. The source analysis showed that PAHs in surface water in the Philippine Sea may come from coal combustion. It is the first time to analyze the occurrence and distribution of PAHs in the Philippine Sea.

Geochemical Control of PAHs by Inflowing River Water to West Nanao Bay, Japan, and Its Influences on Ecological Risk: Small-Scale Changes Observed under Near-Background Conditions at an Enclosed Bay

Polycyclic aromatic hydrocarbons (PAHs), even at low concentrations, have been shown to trigger changes in life cycles and provoke abnormal behaviors in numerous marine organisms. From May 2019 to September 2020, particulate and dissolved PAH concentrations were analyzed on the surface water of West Nanao Bay, Japan, to determinate their levels, emission sources, environmental pathways, and ecological risks at this remote but semi-enclosed bay. The 14 targeted PAHs were analyzed by HPLC-fluorescence detector. Mean total PAH concentrations were lower than 20.0 ng L⁻¹ for most samples. Based on fluoranthene (Flu) to pyrene (Pyr) ([Flu]/[Flu + Pyr]) and benzo[a]anthracene (BaA) to chrysene (Chr) ([BaA]/[BaA + Chr]) isomeric ratios and a varimax rotated PCA, it was established that biomass combustion was the principal source in the particulate phase and that liquid fossil fuel combustion was the principal source in the dissolved phase. From salinity and turbidity distribution, riverine discharges were determined to be the major and continuous transportation pathway of particulate PAHs. It was observed that rain events had a role in the transport of dissolved PAHs. The risk quotients (RQ_{∑14 PAHs (NCs)}: 0–84.53) indicated that PAHs represented a very low to low acute environmental risk. The results of this study will contribute to filling the paradigm gap of ecotoxicological studies in remote areas, working as a booster for future in-lab studies of non-lethal implications of endocrine disruptors such as PAHs.

Fate and Occurrence of Polycyclic Aromatic Hydrocarbons and Their Derivatives in Water and Sediment from Songhua River, Northeast China

The Songhua River is one of the most populated and oldest industrial areas in Northeast China. To understand the sources and distribution of polycyclic aromatic hydrocarbons and their derivatives, such as 16 priority (PAHs), 33 methylated (Me-PAHs), and 12 nitrated (NPAHs) in river water and sediment, were noticed. The concentrations of ∑PAHs, ∑Me-PAHs, and ∑NPAHs in river water scaled from 135 to 563, 9.36 to 711, and 1.26 to 64.7 ng L−1, with mean values of 286, 310, and 17.9 ng L−1, and those in sediments were from 35.8 to 2000 ng g−1, 0.62 to 394 ng g−1, and 0.28 to 176 ng g−1 (dry weight) with mean values of 283, 103, and 21.7 ng g−1. The compositions proved that two-ring and three-ring compounds of PAHs, NPAHs, and four-ring, six-ring of Me-PAHs were prevalent in water samples; in contrast, four-ring dominated in sediments. Principal components analysis (PCA) and diagnostic ratios confirmed that pollutant source was mixed petrogenic and pyrogenic origin. The fugacity fraction (ƒƒ) was also calculated to explain the trend of sediment–water exchange, high ƒƒ values found in summer, for most HMW PAHs and Me-PAHs that these substances acted as a secondary source of emissions from sediment to water. The risk assessment for water was categorized as high.

Health and ecotoxicological risk assessment for human and aquatic organism exposure to polycyclic aromatic hydrocarbons in the Baiyangdian Lake

Seasonal and regional distributions of 17 polycyclic aromatic hydrocarbons (PAHs) in surface waters from four different main water functional regions of the Baiyangdian Lake were analyzed through GC/MS/MS during spring and summer season. The aim was to identify their possible pollution sources and evaluate their health risk for human and ecotoxicological risk for aquatic organisms. Results showed that the range of total PAH concentration is 35.38-88.06 ng/L (average 46.57 ng/L) in spring and 25.64-301.41 ng/L (average 76.23 ng/L) in summer. PAH contamination was observed slightly lower in the summer season from the pollution characteristics of water bodies in most areas of the Baiyangdian Lake, and the levels of PAH pollution in the water body of urban residential regions and rural residential regions were relatively higher than those in tourist regions and low human disturbance regions. Source analysis based on diagnostic ratios confirmed that combustion sources and petroleum sources were two main sources for PAHs entering into the waters of the Baiyangdian Lake. Human health risk assessment showed that PAHs in surface waters from the Baiyangdian Lake will not cause a potential non-carcinogenic risk to local residents and the carcinogenic risk could mostly be accepted, but the potential lifetime carcinogenic risk for infants in rural residential regions should be concerned about. Urban residential regions and rural residential regions were subject to higher cumulative non-carcinogenic and carcinogenic risk when compared to the other functional regions. Ecotoxicological risk assessment found a moderate risk to aquatic organisms presented by individual PAH and a low risk by total PAHs, and PAHs in the water body of urban residential regions and rural residential regions also have relatively higher harm effects to aquatic organisms compared with the other two functional regions. This study revealed the pollution characteristics of PAHs and their possible sources in waters of the Baiyangdian Lake, clarified its correlation to regional anthropogenic activities, and provided corresponding risk management strategies for human and aquatic organisms.

Comparative study of polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs) in corals, sediments and seawater from coral reefs of Hainan, China

This work investigated levels of PAHs and HMs in fourteen species from seven genera of scleractinian corals, adjacent sediments, and surface seawater in Hainan, China. The sources of contaminations were analyzed as well. The results showed that scleractinian corals had a relatively higher bioaccumulation capacity for PAHs from sediments than for HMs. There were inter-species differences for these contaminants enriched in corals. Pavona varians and Porites lutea could accumulate PAHs more readily. While higher concentrations of Cr, Mn and Pb occurred in Favites flexuosa, other metal levels, such as for Ni, Cu, Zn and As, were found to be elevated in Pocillopora damicornis, as well as for Cd in Acropora echinata. It was found that PAHs originated from petrogenic and pyrolytic sources, and were mainly linked to onshore and on-sea activities, such as motorboats. Mn, Ni, As and Cd were from crustal materials or natural weathering, while Cr, Cu, Zn and Pb were non-crustal origin connecting with the use of anti-fouling boat paint and agricultural and/or aquacultural chemicals. This study suggested that corals could serve as good bioindicators for two types of chemical pollution in the reef system, especially for the two species P. varians and P. lutea for PAHs contaminants.

Benzo[a]pyrene exposure induced reproductive endocrine-disrupting effects via the steroidogenic pathway and estrogen signaling pathway in female scallop Chlamys farreri

Benzo[a]pyrene (B[a]P), as one of the typical polycyclic aromatic hydrocarbons and environmental contaminants, may cause endocrine disrupting effects and reproductive impairments in bivalves. However, the molecular mechanisms are still not fully understood. In this study, three reproductive stages (proliferative stage, growing stage and mature stage) of female scallops Chlamys farreri were exposed to B[a]P at 0, 0.38 and 3.8 μg/L. The present study determined the adverse effects of B[a]P on gonadosomatic index, circulating hormone concentrations, endocrine-associated gene expression and ovarian histology. Significant decrease in sex hormones including progesterone (P), testosterone (T) and 17β-estradiol (E2), was observed in B[a]P-treated C. farreri at growing stage and mature stage. These effects were associated with down-regulated expression of steroidogenic enzymes, including 3β-HSD, CYP17 and 17β-HSD, which were regulated by the upstream adenylate cyclase (Adcy) - protein kinase (PKA) signaling pathway. Ovarian transcript levels of estrogen receptor (ER) and caveolin-1 (cav-1) were decreased in B[a]P-treated C. farreri. Vitellogenin (Vtg), an estrogen-mediated gene involved in ovarian development, was down-regulated by B[a]P. Furthermore, ovarian histology was investigated to clarify the impairment of B[a]P on ovaries at growing stage and mature stage. Overall, the present results elucidated the anti-estrogenic mechanisms along the steroidogenic pathway and estrogen signaling pathway for the stage-dependent endocrine-disrupting effects of B[a]P. This finding provides important information regarding to the underlying molecular mechanisms of B[a]P-induced endocrine disruption in different reproductive stages of bivalves. In addition, the adverse effects should be taken into concertation during protection of bivalves germplasm resources and comprehensive evaluation of ecological risks.

The mechanism of Mitogen-Activated Protein Kinases to mediate apoptosis and immunotoxicity induced by Benzo[a]pyrene on hemocytes of scallop Chlamys farreri in vitro

Benzo [a]pyrene (B [a]P) has received widespread attention for serious pollution in the sea, which may reduce immunity and lead to the outbreak of disease in bivalves. However, the mechanism of immunotoxicity induced by B [a]P in bivalves was still unclear. Previous studies have found that Mitogen-Activated Protein Kinases (MAPKs) including three classic pathways (ERK, p38 and JNK) play an important role in mediating this process. Thus, in order to explore the mechanism of immunotoxicity induced by B [a]P in scallop Chlamys farreri, hemocytes were treated with PD98059 (ERK inhibitor), SB203580 (p38 inhibitor) and SP600125 (JNK inhibitor) for 1 h and then incubation with B [a]P for 24 h at 1 μg/mL. Indexes including oxidative damage, apoptotic rate, and immune indicators were detected in the present study. The results showed that the increase of Reactive Oxygen Species (ROS) and DNA damage induced by B [a]P was inhibited with PD98059 and SB203580. Besides, lysosomal membrane stability (LMS) damage was promoted by PD98059, while it was opposite when treated with SB203580. Moreover, the ascended apoptosis rate induced by B [a]P was increased significantly after treatment with PD98059, but it was remarkably attenuated by SB203580 and SP600125. However, the opposite pattern was showed in phagocytosis compared with apoptosis rate in all of three inhibitors. In addition, antibacterial activity and bacteriolytic activity were enhanced by SB203580 while inhibited by PD98059. Therefore, these results showed that MAPKs directly or indirectly mediate the decrease of oxidative damage, apoptosis and immune defense ability of C. farreri hemocytes, which suggesting ERK/p38/JNK pathways have different functions in the apoptosis and immunity of C. farreri hemocytes after B [a]P exposure. In conclusion, this study intended to enrich the theoretical basis for immunotoxicology of bivalves exposed to pollutants.

Interannual Survey on Polycyclic Aromatic Hydrocarbons (PAHs) in Seawater of North Nanao Bay, Ishikawa, Japan, from 2015 to 2018: Sources, Pathways and Ecological Risk Assessment

To improve the understanding of the emission sources and pathways of polycyclic aromatic hydrocarbons (PAHs) in the coastal environments of remote areas, their particulate and dissolved concentrations were analyzed on a monthly basis from 2015 to 2018 in surface waters of Nanao Bay, Japan. The concentration of the targeted 13 species of PAHs on the United States Environmental Protection Agency (USEPA) priority pollutant list in dissolved and particle phases were separately analyzed by high-performance liquid chromatography (HPLC) coupled to a fluorescence detector. Particulate and dissolved PAHs had average concentrations of 0.72 ng∙L^-1 and 0.95 ng∙L^-1, respectively. While most of the samples were lower than 1 ng∙L^-1, abnormally high levels up to 10 ng∙L^-1 were observed in the winter of 2017-2018 for particulate PAHs. Based on the isomer ratios of Flu to Flu plus Pyr, it was possible to determine that the pyrogenic loads were greater than the petrogenic loads in all but four out of 86 samples. The predominant environmental pathway for PAHs in winter was determined to be long-range atmospheric transportation fed by the East Asian winter monsoon, while for the summer, local sources were more relevant. By the risk quotients method, it was determined that PAHs in surface seawater presented a very low risk to marine life during the interannual survey.

Distribution, sources and ecological risk assessment of PAHs in surface seawater from coastal Bohai Bay, China

The distribution, composition, potential sources and ecological risk of 16 US EPA priority polycyclic aromatic hydrocarbons (PAHs) were investigated in surface water from coastal Bohai Bay. The PAH concentrations ranged from 48.0 to 607 ng L^-1 with the mean value of 267 ng L^-1 in dissolved phase and 198 to 935 ng L^-1 with the mean value of 424 ng L^-1 in particle-associated phase, and decreased following the order: Qinhuangdao (QHD) > Caofeidian (CFD) > Huanghuagang (HHG). The 2-3 ring PAHs accounted for 79.9% to 86.2% in particle-associated phase and 65.6% to 73.2% in dissolved phase of total 16 PAHs, in which naphthalene (Nap) was the most dominant compound. The PAHs in surface seawater mainly originated from petrogenic sources according to the molecular ratios of benzo[a]anthracene/228 and fluoranthene/202. Risk quotients indicated that there was potential ecological risk for PAHs in surface seawater, especially for pyrene and fluorene.

Using multi-integrated biomarker indexes approach to assess marine quality and health status of marine organism: a case study of Ruditapes philippinarum in Laizhou Bay, China

With the progress of technology and the deepening of understanding of biological monitoring, much more attention has been paid to the multiple evaluation of marine pollution monitoring. In view of this, our study aimed at establishing a multi-integrated biomarker indexes approach to evaluate marine condition systematically and comprehensively. In the current study, sampling was conducted in Laizhou Bay, China (S1, S2, and S3) in May, August, and October of 2015. And then, multi-integrated biomarker indexes approach was applied to assess marine PAHs pollution, select appropriate biomarkers, and evaluate marine environmental quality and health status of the clams of Ruditapes philippinarum. As the results showed, S2 was the most PAHs-polluted site while S1 was the least polluted site, and the levels of tPAHs in seawater and sediments ranged from 69.78 to 315.30 ng/L and 163.19 to 565.17 ng/g d.w., respectively. And all three sampling sites had different sources of PAHs. IBR represented DNA damage (F value), the expression of SOD, EROD activity, GST activity, and LPO could be served as biomarkers to monitor the PAHs pollution in Laizhou Bay. And MPI suggested the quality of all three sites: S1 was generally favorable, S2 was moderately polluted, and S3 was lightly polluted. BRI values showed that the order of health status of R. philippinarum was S1 > S3 > S2.

The legacy of organochlorinated pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in Chinese coastal seawater monitored by semi-permeable membrane devices (SPMDs)

Semi-permeable membrane devices (SPMDs) were applied to sample some Organochlorinated Pesticides (OCPs), Polycyclic Aromatic Hydrocarbons (PAHs) and Polychlorinated Biphenyls (PCBs) from the seawater of 14 Chinese coastal areas. The total concentrations of OCPs (∑₁₆OCPs), PAHs (∑₁₅PAHs) and PCBs (∑₃₅PCBs) were in the ranges of 489.2-2174, 589.4-53,160, and 133.2-3658 ng/g lipid, respectively. The ∑₁₅PAHs varied significantly with the sampling locations, which were far higher in north Chinese coastal areas than in south areas, whereas ∑₁₆OCPs and ∑₃₅PCBs only slightly fluctuated along the entire coast line. Comparing SPMD to grab sampler, it was found that the distribution patterns of the PCBs and OCPs in seawater were generally similar. However, the compositional profiles of the PAHs, PCBs, DDTs and HCHs in SPMDs were slightly different to grab samplers and organisms. The SPMDs accumulated less lipotropic compounds, which are inclined to dissolve in water rather than in organisms.

From headwaters to estuary: distribution, sources, and ecological risk of polycyclic aromatic hydrocarbons in an intensively human-impacted river, China

Located in the Shandong Province, North China, the Xiaoqing River is heavily contaminated by industrial wastewater and domestic sewage. However, it plays a significant role with regard to irrigation for agriculture in the river basin. In this study, spatial distribution, sources, and the ecological risk of aqueous polycyclic aromatic hydrocarbons (PAHs) in the Xiaoqing River Basin were investigated from the headwaters to the estuary. Fifteen USEPA priority PAHs (except naphthalene) were quantified in water particulate and soluble phases and in sediment samples. Σ₁₅PAHs concentrations in the sediment varied from 17.15 to 3808.01 ng/g dry weight (dw), with an average of 988.72 ng/g dw, suggesting severe pollution of the Xiaoqing River in comparison with other rivers worldwide. The composition of PAHs was characterized by the high abundance of 4-ring and 5-ring PAHs in sediments and 2-ring and 3-ring PAHs in water. Industrial wastewater is a significant source of PAHs. In the river section, point source was the main factor affecting the distribution of PAHs, while in the estuary region, estuarine turbidity maximum zone (ETM), riverine flow and discharge, and its hydrodynamic parameters play more key roles on PAH levels. Molecular diagnostic ratios have proved that PAHs in sediments were derived from mixed sources, primarily a combination of several combustion processes. Toxicity equivalency concentrations (TEQs) and Ecological risk assessment by Sediment Quality Guidelines indicated that PAHs in sediments might have certain unfavorable effects on ecosystems in certain sites.

Seasonal occurrence, source evaluation and ecological risk assessment of polycyclic aromatic hydrocarbons in industrial and agricultural effluents discharged in Wadi El Bey (Tunisia)

Polycyclic aromatic hydrocarbons are of great concern due to their persistence, bioaccumulation and toxic properties. The occurrence, source and ecological risk assessment of 26 polycyclic aromatic hydrocarbons in industrial and agricultural effluents affecting the Wadi El Bey watershed were investigated by means of gas chromatographic/mass spectrometric analysis (GC/MS). Total PAHs (∑ 26 PAH) ranged from 1.21 to 91.7 µg/L. The 4- and 5-ring compounds were the principal PAHs detected in most of 5 sites examined. Diagnostic concentration ratios and molecular indices were performed to identify the PAH sources. Results show that PAHs could originate from petrogenic, pyrolytic and mixed sources. According to the ecotoxicological assessment, the potential risk associated with PAHs affecting agricultural and industrial effluents ranged from moderate to high for both aquatic ecosystem and human health. The toxic equivalency factor (TEF) approach indicated that benzo[a]pyrene and benz[a]anthracene were the principal responsible for carcinogenic power of samples.

Polycyclic aromatic hydrocarbons and organochlorine pesticides in surface water from the Yongding River basin, China: Seasonal distribution, source apportionment, and potential risk assessment

The presence of 17 polycyclic aromatic hydrocarbons (PAHs) and 15 persistent organochlorine pesticides (OCPs) in surface water of the Yongding River Basin was analyzed through GC/MS/MS during the spring and summer at 46 sampling sites. The goal was to investigate their seasonal distribution, possible sources, and potential risk. Our results showed that the total PAH concentration in surface water of Yongding River Basin ranged from 41.60 to 1482.60ng/L with a mean value of 137.85ng/L in the spring, and from 53.53 to 506.53ng/L with a mean value of 124.43ng/L in the summer. The total OCP concentration ranged from <0.08 to 197.71ng/L with a mean value of 7.69ng/L in the spring, and from <0.08 to 93.58ng/L with a mean value of 7.92ng/L in the summer. Moreover, the total PAH concentration was slightly lower in the spring than in the summer, whereas the total OCP concentration was similar between seasons. Source analysis indicated that combustion sources and petroleum sources both contributed to the presence of PAHs. Historical environmental residues and long range atmospheric transport were the major sources of HCH and DDT contamination. The concentrations of total PAHs and single PAHs including benz(a)anthracene, benzo(a)pyrene, benz(b)fluoranthene, and benz(k)fluoranthene in surface water at some sampling sites exceeded the water environmental quality standards of China and several other countries or organizations. This indicated a potential threat to human health from the consumption of aquatic organisms due to PAH bioaccumulation. The concentrations of α-HCH, p,p'-DDE, and p,p'-DDD at several sampling sites exceeded the limit for human health specified in the ambient water quality criteria developed by the US Environmental Protection Agency, which indicated that these pollutants provide potential hazards to the residents around the sampling sites.

Solvent bar micro-extraction (SBME) based determination of PAHs in seawater samples

Measuring the impact of PAHs in seawater samples is often difficult due to the low concentrations in which they appear and the complexity of the sample matrix. Traditional methods for sample preparation such as liquid-liquid extraction and solid phase extraction require the use of excessive amounts of solvents and reagents, and sample handling. In this work, hollow fiber liquid phase micro-extraction (HFLPME), in the configuration of solvent bar micro-extraction (SBME), was proposed as an environmentally friendly and more effective tool, for the extraction of the 16 priority PAHs from seawater samples. Extraction was conducted using hexane as a solvent. Enrichment factors from 45 to 163 were obtained after 60min at a stirring rate of 500rpm in the sample. Moreover, a negative linear relationship was observed between the enrichment factor and the molecular weight of the PAHs. Under optimized conditions, the limits of detection were in the range from 0.21 to 0.82ngL^-1, the method showed a linear response up to 500μgL^-1, and the average relative standard deviation for seawater samples spiked with 5ngL^-1 was 11.6%. After calibration, the SBME was applied to extract PAHs in seawater samples from the Bay of Cadiz (SW Spain), showing an average recovery of 99%. In conclusion, the SBME is an environmentally friendly, one-step alternative for sample preparation in the determination of PAHs in seawater samples.

Assessing PAHs pollution in Shandong coastal area (China) by combination of chemical analysis and responses of reproductive toxicity in crab Portunus trituberculatus

The concentrations of PAHs in seawater and sediments were measured at three selected sites (S1, S2, and S3) along the coastal area of Shandong (China) in April, May, and June, 2015, which ranged from 29.72 to 123.88 ng/L and 82.62 to 232.63 ng/g, respectively. Meanwhile, the reproductive toxicity responses in crab Portunus trituberculatus were also evaluated to assess the pollution of PAHs during the sampling period. Chemical analysis showed that S3 was the most PAH-contaminated area while S1 was the least, and the biochemical parameters concerned with reproduction were efficiently responded to the three sites, especially in S3 (p < 0.05). Moreover, the principal component analyses (PCA) showed that parameters for DNA alkaline unwinding, protein carbonyl content, and lipid peroxidation levels in two genders, 17β-estradiol in female, testosterone and TESK2 gene expression in male crabs, were closely correlated with the concentrations of PAHs (2 + 3 rings, 4 rings, and 5 + 6 rings), which were considered to be good candidate indicators to assess the environmental pollutions resulting from PAHs in the coastal area of Shandong, China.

Spatial distribution and composition of aliphatic hydrocarbons, polycyclic aromatic hydrocarbons and hopanes in superficial sediments of the coral reefs of the Persian Gulf, Iran

This study is the first quantitative report on petroleum biomarkers from the coral reefs systems of the Persian Gulf. 120 reef surface sediment samples from ten fragile coral reef ecosystems were collected and analyzed for grain size, biogenic elements, elemental ratios, and petroleum biomarkers (n-alkanes, PAHs¹ and Hopanes) to assess the sources and early diagenesis of sedimentary organic matter. The mean grain size of the reef sediments ranged from 13.56 to 37.11% (Clay), 26.92 to 51.73% (Sand) and 35.97 to 43.85% (Silt). TOC² (3.35-9.72 mg.g^-1) and TON³ (0.4-1.10 mg.g^-1) were identified as influencing factors on the accumulation of petroleum hydrocarbons, whilst BC⁴ (1.08-3.28 mg.g^-1) and TIN⁵ (0.13-0.86) did not exhibit any determining effect. Although BC and TIN demonstrated heterogeneous spatial distribution, TOC and TON indicated homogenous distribution with continually upward trend in concentration from the east to west ward of the Gulf. The mean calculated TOC/TN ratios vacillated according to the stations (p < 0.05) from 2.96 at Shidvar Island to 8.64 at Hengam Island. The high TOC/TN ratios were observed in the Hengam (8.64), Kharg (8.04) and Siri (6.29), respectively, suggesting a predominant marine origin. The mean concentrations of ∑C_11-35n-alkanes, ∑30 PAHs and ∑9Hopanes were found in the ranges of 385-937 μg.g^-1dw, (overall mean:590 μg.g^-1dw), 326-793 ng.g^-1dw (499 ng.g^-1dw), 88 to 568 ng.g^-1 d (258 ng.g^-1dw), respectively. Higher concentrations of detected petroleum biomarkers in reef sediments were chiefly distributed near main industrial areas, Kharg, Lavan and Siri, whilst the lower concentrations were in Hormoz and Qeshm. In addition, one-way ANOVA⁶ analysis demonstrated considerably significant differences (p < 0.05) among concentration of detected total petroleum hydrocarbons between most sampling locations. Some sampling sites especially Kharg, Lavan, Siri and Lark indicated higher concentration of n-alkanes due to the higher maintenance of organic matter by high clay content in the sediments. Furthermore, most sediment samples, except for Hormoz, Qeshm and Hengam showed an even carbon preference for n-alkanes which could be correlated to bacterial input. NPMDS⁷ analysis also demonstrated that among the congeners of petroleum biomarkers, n-C₁₂,n-C₁₄, n-C₁₆,n-C₁₈ and n-C₂₀ for n-alkanes, Phe⁸ and Naph⁹ along with their Alkyl homologues for PAHs (2-3 rings accounted for 60%) and C₃₀αβ and C₂₉αβ for Hopanes were discriminated from their other congeners in the whole study area. Our results based on the PCA¹⁰ analysis and diagnostic indices of AHs¹¹ and PAHs along with ring classification of PAHs, in addition, the ubiquitous presence of UCM,¹² and Hopanes revealed that the main sources of the pollution were petroleum and petroleum combustion mainly from offshore oil exploration and extraction, discharge of pollutants from shipping activities.

Polycyclic aromatic hydrocarbons (PAHs) in seawater and sediments from the northern Liaodong Bay, China

Levels, sources, and potential ecological risks of polycyclic aromatic hydrocarbons (PAHs) in surface seawater and sediments from the northern Liaodong Bay of China were seasonally investigated. Total concentrations of 16 PAHs varied from 145.96ng/L to 896.58ng/L in seawater, and from 191.99ng/g to 624.44ng/g in sediments. PAH concentrations in seawater differed significantly, whereas those in sediments exhibited a relatively stable pattern across seasons. PAHs with low molecular weight were predominant in seawater, but PAHs with high molecular weight were abundant in sediments. Crop straw and coal combustion were the main PAH pollution sources. The current levels of PAHs in the northern Liaodong Bay are relatively moderate compared with those in other bays and estuaries. Sediment from all sampling sites is characterized by low to medium ecotoxicological risk. No highly negative toxic effect could occur on the organisms and ecosystems in the northern Liaodong Bay.

Aliphatic and polycyclic aromatic hydrocarbons risk assessment in coastal water and sediments of Khark Island, SW Iran

The potential sources and ecotoxicological risks of 26 aliphatic hydrocarbons (AHs), 16 polycyclic aromatic hydrocarbons (PAHs) and total petroleum hydrocarbons (TPHs) were investigated in coastal water and sediments of Khark Island, SW Iran. The major sources of the contamination were petroleum and petroleum combustion based on the PCA analysis and diagnostic indices of AHs and PAHs, and also ring classification of PAHs. The ecological risk of both individual and multiple PAHs was quite low in sediments compared with screening benchmarks. Likewise, the low concentration of TEQ, MEQ and TEQ(carc) of sediments suggest low toxicity of PAHs in the study area. However, environmental control is recommended to reduce the pollution burden of PAHs in seawater. The human health risk assessment for PAHs through dermal adsorption indicated that the possibility of negative adverse effects of PAHs in sediments is rare but swimming in the vicinity of industrial facilities should be done cautiously.

Organic pollutants in the central and coastal Beibu Gulf, South China Sea

Surface sediments from the central and coastal Beibu Gulf, southern China, were analyzed for persistent organic pollutants. The absence of polychlorinated biphenyls (PCB; generally below detection limit), low concentrations of polycyclic aromatic hydrocarbons (PAH; 24-647 ng g(-1)), and locally high contamination with organo-chloro pesticides (DDT; 0.03-92 ng g(-1)) reflect the early stages of development in southwest China, with human activities dominated by agriculture and low impact of industry. Concentrations of PCB and PAH indicate no ecological risk, while DDT accumulation poses a probable toxic risk in coastal but not in shelf sediments. Diagnostic ratios suggest PAH originating mainly from combustion of biomass and diesel fuels, and recent DDT use in agriculture and antifouling paint. Distribution patterns along the coastal-shelf-gradient indicate mainly airborne transport of PAH and waterborne transport of DDT. In the central Gulf, also water column samples reveal low concentrations of PAH (1.7-7.8 ng L(-1)) and DDT (0.006-0.053 ng L(-1)).

Environmental risk assessments and spatial variations of polycyclic aromatic hydrocarbons in surface sediments in Yangtze River Estuary, China

In this study, based on sampling data from 30 sites in August 2010, the environmental risks associated with 16 priority PAHs were estimated in surface sediments from the Yangtze River Estuary (YRE). The results indicated that the toxic equivalent quantities of the benzo[a]pyrene (TEQBap) from 30 sites were in the range of 1.93-75.88ngg(-1), and the low-molecular-weight PAHs were the dominated species with higher potential toxicity. The results of the Incremental Lifetime Cancer Risk (ILCR) model indicated that the ILCR values of dermal contact were higher than 10(-6) in the northeast region, suggesting that there were significant potential carcinogenic health risks for fishermen exposure to sedimentary PAHs via dermal contact in these areas. RQ values of PAHs indicated the various distributions of ecological risk levels in the study area. These variations might be caused by the natural and anthropogenic inputs and currents in the YRE.

Concentration distribution and potential health risk of heavy metals in Mactra veneriformis from Bohai Bay, China

To investigate the pollution level and evaluate the potential health risks of heavy metals, the concentrations of chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), molybdenum (Mo), cadmium (Cd), antimony (Sb), and lead (Pb) were determined by inductively coupled plasma-mass spectrometry (ICP-MS) in 198 clams (Mactra veneriformis) collected from 11 sites of the Bohai Bay. The results showed that heavy metal concentrations in the clams were different at different sites (p<0.05). Mn was dominant with a percentage of 22.08-77.03% in heavy metals, followed by Zn with 12.66-57.11%, and the concentration of Pb was the lowest with 0.45-1.04%. The potential health risk to consumers was evaluated by the target hazard quotient (THQ) and the maximum daily consumption rate (CRmax). The results indicated that the THQs of Co were the highest with the values of 1.125, 1.665, and 1.144 at three sections; the values of other individual metals were <1, which indicated that consumption of clams from the study areas caused health risks due to Co. Moreover, the CRmax values also indicated the potential health risk caused by Co in clams consumed in this area. Pearson correlation analysis and principal component analysis (PCA) indicated that there were significantly positive or negative correlations between the heavy metals (p<0.05), and the studied metals were divided into four groups. The results indicated that the concentrations of heavy metals in clams were affected not only by pollution sources but also by the characteristics of clams that could absorb selectively and accumulate special metals. This study offers important information on the pollution levels of heavy metals in clams and warns consumers of the health risks associated with the consumption of clams in the area.