Occurrence of polycyclic aromatic hydrocarbons (PAHs) in coral reef fish from the South China Sea

Bioaccumulation and potential human health risks of PAHs in marine food webs: A trophic transfer perspective

Polycyclic aromatic hydrocarbons (PAHs) are persistent pollutants in aquatic environments that can accumulate in marine organisms and pose potential health risks to humans through trophic transfer in the food webs. However, the accumulation and health risks of PAHs in organisms at different trophic levels remain unclear. This study investigated the accumulation and trophic transfer of PAHs in 40 marine organisms from Beibu Gulf (China), and assessed their health risks. Utilizing the trophic level spectrum constructed with stable isotope methods, the organisms were categorized into three trophic levels: Omnivorous (15.00 %), low-level carnivorous (67.50 %), and mid-level carnivorous (17.50 %). The contamination levels of total PAHs in these organisms ranged from "mild pollution" to "moderate pollution", with all organisms exhibiting significant PAH accumulation (Bioconcentration factor value > 2000). Total PAH concentrations increased with higher trophic levels, following the trend of mid-level carnivores > low-level carnivores > omnivores. Notably, only three PAH compounds (Nap, Fla and Phe) showed biomagnification effects, while the others exhibited trophic dilution. Carcinogenic risk assessment indicated an "Unacceptable risk" level for all populations, with the highest risk due to consumption of mid-level carnivorous. These findings offer new insights into the accumulation and health risks of PAHs from a trophic transfer perspective.

Simulating Habitat Suitability Changes of Threadfin Porgy (Evynnis cardinalis) in the Northern South China Sea Using Ensemble Models Under Medium-to-Long-Term Future Climate Scenarios

The impact of global warming on fish distribution is a key factor in fishery management and sustainable development. However, limited knowledge exists regarding the influence of environmental factors on the distribution of Evynnis cardinalis under climate change. This study addresses this gap by predicting the species distribution under current conditions and three future climate scenarios (SSP126, SSP370, and SSP585) using five individual models and four ensemble models. The results demonstrate that the ensemble models outperform the single models, with majority voting (EMca) achieving the highest accuracy (ROC = 0.97, TSS = 0.85). Bathymetry (BM) and the sea surface height (SSH) are the primary factors influencing the distribution. The predictions indicate that the currently suitable habitats of E. cardinalis are primarily located in the Beibu Gulf region of the northern South China Sea. Under future climate scenarios, suitable habitat areas are expected to expand to higher latitudes and deeper waters, though highly suitable habitats in the western Guangdong coastal waters, western Beibu Gulf, and southwestern offshore waters of Hainan Island will significantly decrease.

Toxicity of anthracene on marine organisms and development of seawater quality criteria

The presence of anthracene (ANT) in coastal waters is increasingly being reported and profoundly impacts the marine biota. However, toxicity data for ANT on marine organisms are scarce to develop numerical water quality criteria to protect marine life. Therefore, for the first time, this study derived the seawater quality criteria (SWQC) of ANT are based on the toxicity values of five marine organisms. Acute and chronic toxicity values of ANT were derived on diatoms (Thalassiosira subtilis and Endomoneis paludosa), copepods (Oithona similis and Tisbe furcata), and shrimp (Litopenaeus vannamei). 96 h-EC50 and 96 h-LC50 were ranged between 23.98 ± 2.4 and 1730 ± 330 μg/L. Chronic toxicity values such as no observed effect concentration (NOEC), lowest observed effect concentration (LOEC), and chronic values ranged from 2.1 ± 0.6 to 267 ± 58 µg/L, 2.5 ± 0.8 to 400 ± 7 µg/L, and 2.4 ± 0.8 to 327 ± 71 µg/L, respectively. Seawater quality criteria, viz. predicted no effect concentration (PNEC), criterion continuous concentration (CCC), and criterion maximum concentration (CMC) were derived using NOECs, chronic values, and acute data. The criterion concentrations PNEC, CCC, and CMC can apply to sensitive/protected waters across the coastal waters and accidental spill/outfalls/discharge points in enclosed waters, respectively. The PNEC, CCC, and CMC are derived as 2.7, 8.8, and 17 µg/L, respectively, from the Australian Burrlioz SSD, whereas the USEPA SSD resulted in 3.89 µg/L of PNEC, 10.7 µg/L of CCC, and 26.7 µg/L of CMC. The Australian Burrlioz SSDs delivered sensitive SWQCs, which may ensure the protection of marine life from ANT pollution.

First Record of Malformation in Seahorses Attributed to the Oil Spill off the Brazilian Coast in 2019

In 2019, there was an environmental catastrophe in Brazil, when more than 5000 tons of unknown origin crude oil invaded beaches and mangroves. Two years later, two monitoring areas were selected to study seahorses' offspring: Massangana River estuary (apparently healthy area) and Cocaia Island (affected area). Thirty-six reproductive events of Hippocampus reidi (Syngnathidae) couples from these two areas were monitored to analyze the offspring. At the apparently healthy area, no newborns with malformations were found. However, the offspring from Cocaia Island showed a mean of 19.73% (±5.23) malformations in newborns. It is argued that the toxic/teratogenic effects of polycyclic aromatic hydrocarbons have affected the population in two ways: directly through the induction of mutations in the germ cells of the species and through a drastic reduction of the population (bottleneck effect) whose density observed today recovered through consanguineous couplings, potentiating deleterious genotypes in the offspring. Environ Toxicol Chem 2024;43:1996-2004. © 2024 SETAC.

The emerging and legacy persistent organic contaminants in corals of the South China Sea

Seawater warming, ocean acidification and chemical pollution are the main threats to coral growth and even survival. The legacy persistent organic contaminants (POCs), such as polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), and the emerging contaminants, including polybrominated diphenyl ethers (PBDEs), dechlorane plus (DPs) and novel brominated flame retardants (NBFRs) were studied in corals from Luhuitou fringing reef in Sanya Bay and Yongle atoll in Xisha Islands, the South China Sea (SCS). Total average concentrations of ∑16PAHs, ∑23OCPs, ∑34PCBs, ∑8PBDEs, ∑2DPs and ∑5NBFRs in 20 coral species (43 samples) from the SCS were 40.7 ± 34.6, 5.20 ± 5.10, 0.197 ± 0.159, 3.30 ± 3.70, 0.041 ± 0.042 and 36.4 ± 112 ng g-1 dw, respectively. PAHs and NBFRs were the most abundant compounds and they are likely to be dangerous pollutants for future coral growth. Compared to those found in other coral reef regions, these pollutants concentrations in corals were at low to median levels. Except for PBDEs, POCs in massive Porites were significantly higher than those in branch Acropora and Pocillopora (p < 0.01), as large, closely packed corals may be beneficial for retaining more pollutant. The current study contributes valuable data on POCs, particularly for halogenated flame retardants (HFRs, including PBDEs, DPs and NBFRs), in corals from the SCS, and will improve our knowledge of the occurrence and fate of these pollutants in coral reef ecosystems.

Differential bioaccumulation and tolerances of massive and branching scleractinian corals to polycyclic aromatic hydrocarbons in situ

Scleractinian corals are capable of accumulating polycyclic aromatic hydrocarbons (PAHs) in reef environments; however, the mechanism behind their PAHs tolerance is unknown. This study investigated the occurrence and bioaccumulation of PAHs in coral reef ecosystems and examined the physiological responses induced by PAHs in coral hosts and their algal symbionts, the massive coral Galaxea fascicularis and branching coral Pocillopora damicornis. G. fascicularis had a higher PAHs accumulation capacity than P. damicornis. Both the coral hosts and algal symbionts preferentially accumulated acenaphthene, dibenzo(a,h)anthracene, and benzo(a)pyrene. The accumulated PAHs by G. fascicularis and P. damicornis hosts was accompanied by a reduction in detoxification ability. The accumulated PAHs could induce oxidative stress in P. damicorni hosts, thus G. fascicularis demonstrated a greater tolerance to PAHs compared to P. damicornis. Meanwhile, their algal symbionts had fewer physiological responses to accumulated PAHs than the coral hosts. Negative effects were not observed with benzo(a)pyrene. Taken together, these results suggest massive and branching scleractinian corals have different PAHs bioaccumulation and tolerance mechanisms, and indicate that long-term PAHs pollution could cause significant alterations of community structures in coral reef ecosystems.

Polycyclic Aromatic Hydrocarbons' Impact on Crops and Occurrence, Sources, and Detection Methods in Food: A Review

Polycyclic aromatic hydrocarbons (PAHs) represent a category of persistent organic pollutants that pose a global concern in the realm of food safety due to their recognized carcinogenic properties in humans. Food can be contaminated with PAHs that are present in water, air, or soil, or during food processing and cooking. The wide and varied sources of PAHs contribute to their persistent contamination of food, leading to their accumulation within these products. As a result, monitoring of the levels of PAHs in food is necessary to guarantee the safety of food products as well as the public health. This review paper attempts to give its readers an overview of the impact of PAHs on crops, their occurrence and sources, and the methodologies employed for the sample preparation and detection of PAHs in food. In addition, possible directions for future research are proposed. The objective is to provide references for the monitoring, prevention, and in-depth exploration of PAHs in food.

Occurrence and distribution of polycyclic aromatic hydrocarbons (PAHs) in marine organisms from Shenzhen coastal waters and human health risk assessment

This study investigated the levels and composition of 16 priority polycyclic aromatic hydrocarbons (PAHs) in marine organisms from South China Sea and assessed their potential health risks. The results revealed that the pollution levels of total PAHs ranged from 3.56 to 392.21 ng/g dw. Notably, 4-ring PAHs constituted the predominant fraction (58.02 %) of the total PAHs, with pyrene being the most abundant congener across all species. Intriguingly, our findings suggested that consuming these organisms might pose a low non-cancer hazard. Nonetheless, benzo[a]pyrene was detected in most species, with levels ranging from non-detectable to 11.24 ng/g dw. The individual lifetime cancer risk levels associated with seafood consumption in studied regions ranged from 1.10 × 10-5 to 1.52 × 10-5, highlighting a potential cancer risk that warrants special attention. These findings emphasize the need to prioritize carcinogenic compounds over total PAHs and underscore the importance of continuous monitoring of PAH pollution in seafood.

Preliminary data on the occurrence of PAH and Anisakis spp. in Moroccan anchovies: Environmental parasitology and human health risk

This survey focuses on an environmental parasitology study by investigating Polycyclic Aromatic Hydrocarbons (PAH) bioaccumulation and the occurrence of Anisakis spp. on common anchovies collected from Moroccan coasts over 9 months through chemical (PAH) and Biological (Biometrics and parasitic) analysis. Obtained results were statistically analyzed and human health risks from anchovies consumption were assessed. The results obtained highlighted the good biological and chemical status of this fish in all stations of Morocco's coasts. Anisakis spp. was present in only four stations in the Atlantic fringe (maximum prevalence 22.22 %). Results have shown non-significant differences for tissue nature (Muscle, viscera) or spatial variation and were within a low range of concentrations well below the European Commission standards. Results have shown no serious harmful risk for humans from this fish consumption (ILCR and HI), and statistical analysis had shown positive correlations between prevalence and Chr, prevalence and sex-ratio, and prevalence and weight.

Investigation of the concentration, origin and health effects of PAHs in the Anzali wetland: The most important coastal freshwater wetland of Iran

This study investigated the concentration of PAHs in 19 water samples, 34 sediment samples and 22 fish samples of Anzali Wetland, located in north of Iran. The average concentration of ∑PAHs in the wetland sediment was 89.19 μg/kg (8.28-806.64) and 78.31 ng/L (5.14-253.37) in the wetland water. Also, the average concentration of ∑PAHS in the muscle of the investigated fish in the wetland was 23 μg/kg (56.1 to 7.6). The source apportionment of PAHs in water and sediment considering isomeric ratios and statistical methods reveals the predominance of petrogenic origin of the compounds in water and pyrogenic origin in sediment. Overall, the level of contamination in fish is relatively low to moderate, considering ∑PAHs. The findings present clear evidence of low to moderate level of contamination in the wetland, the PAHs contamination however could cross their ecological thresholds in future unless control measures are taken to protect the wetland.

Identification of Nrf2/Keap1 pathway and its transcriptional regulation of antioxidant genes after exposure to microcystins in freshwater mussel Cristaria plicata

Microcystins (MC) are one of the most abundant and widely distributed cyanotoxins in aquatic systems. MC inhibits the functions of protein phosphatase 1 and 2A (PP1/2A), which can seriously affect ecosystem integrity. The NF-E2-related nuclear factor 2 (Nrf2)/Kelch-like epichlorohydrin-related protein-1 (Keap1) signaling pathway protects against oxidative damage by activating phase II detoxification/antioxidant enzymes. Our previous study revealed that MC upregulates the expression and enhances the activities of the antioxidant enzymes by stimulating the CpNrf2 signaling pathway. In the current study, to further clarify the regulatory role of Keap1 in response to MC-induced oxidative stress in shellfish, we cloned the full-length cDNA of Keap1a and Keap1b from Cristaria plicata (designated CpKeap1a and CpKeap1b), which are 2952 and 3710 bp peptides, respectively. The amino acid sequence of CpKeap1a and CpKeap1b contained Tram-track and Bric-a-brac (BTB), Intervening region (IVR), and Double glycine repeat (DGR) domain. Additionally, CpKeap1a contained two cysteine residues analogous to Cys-273 and -288 in zebrafish, but CpKeap1b did not. Moreover, CpKeap1a and -1b formed a homodimer and heterodimer, respectively, and also formed a heterodimer with CpNrf2. In the hepatopancreas, the expression levels of CpKeap1a and -1b were the highest, but MC treatment down-regulated the expression of these proteins. Moreover, the transcription of antioxidant enzymes with antioxidant response element (ARE-driven enzymes), including CpMnSOD, CpCu/ZnSOD, CpTRX, CpPrx, CpSe-GPx, and Cpsigma-GST was upregulated by CpNrf2 in the hepatopancreas. Compared with the MC-induced group, CpKeap1a-siRNA1117 injection significantly increased the transcription of mRNAs for ARE-driven enzymes and Nrf2. CpKeap1a-siRNA1117 also enhanced the activities of antioxidation enzymes. These findings demonstrated that Keap1a negatively regulated the expression of Nrf2 protein and MC-induced oxidative stress response in C. plicata. Therefore, we speculated that CpKeap1a promoted CpNrf2 by recognizing and binding MC. These events then protected molluscs from MC-induced oxidative damage.

Metallic nanoparticles affect uptake of polycyclic aromatic hydrocarbons and impacts in the Mediterranean mussels Mytilus galloprovincialis

The impact of metallic nanoparticles (NPs) on the uptake and toxicity of persistent organic pollutants by marine bivalves was assessed through a comparative laboratory study by exposing mussels to polycyclic aromatic hydrocarbon (PAHs), in the presence and absence of ZnO and TiO₂ NPs. PAHs and NPs concentration was analyzed after 14 days of exposure in mussels by GC/MS and ICP/AES. Furthermore, impact on the physiology and neurotoxicity of PAHs and NPs acting alone or in mixtures were also determined. Our results confirmed the bio-uptake of PAHs and NPs by mussels. In addition, the exposure NPs-PAHs resulted in different bio-uptake profile to that of PAHs alone. The NPs and accumulation of PAHs led to disturbance of essential metals concentration and to different impact profiles in the filtration and respiration capacities as well as in the acetylcholinesterase activity. Antagonist interactions between NPs and PAHs could occur after exposure.

Microplastics in water systems: A review of their impacts on the environment and their potential hazards

Microplastics, the microscopic plastics, are fragments of any type of plastic that are being produced today as plastic waste originating from anthropogenic activities. Such microplastics are discharged into the environment, and they enter back into the human body through different means. The microplastics spread in the environment due to environmental factors and the inherent properties of microplastics, such as density, hydrophobicity, and recalcitrance, and then eventually enter the water environment. In this study, to better understand the behavior of microplastics in the water environment, an extensive literature review was conducted on the occurrence of microplastics in aquatic environments categorized by seawater, wastewater, and freshwater. We summarized the abundance and distribution of microplastics in the water environment and studied the environmental factors affecting them in detail. In addition, focusing on the sampling and pretreatment processes that can limit the analysis results of microplastics, we discussed in depth the sampling methods, density separation, and organic matter digestion methods for each water environment. Finally, the potential hazards posed by the behavior of aging microplastics, such as adsorption of pollutants or ingestion by aquatic organisms, due to exposure to the environment were also investigated.

Potential of microplastics participate in selective bioaccumulation of low-ring polycyclic aromatic hydrocarbons depending on the biological habits of fishes

Currently, although the cumulative effects of microplastics (MPs) and organic pollutants (OPs) in the environment and within organisms are being investigated, whether and how MPs participate in bioaccumulation of OPs based on a carrier effect is still unclear. In the present study, water and aquatic organisms were collected from the Pearl River. Polycyclic aromatic hydrocarbons (PAHs) and MPs were separated by solid phase extraction and were measured by gas chromatography mass spectrometry and Fourier transform infrared spectroscopy, respectively. Higher PAH concentrations at the river outlet and higher MPs abundance in the inner river were observed, indicating a mismatched distribution between PAHs and MPs. No correlation between MP abundance and PAH concentration in fishes was detected, implying that MPs exerted limited influence on PAH concentrations. Interestingly, bioconcentration factors of one major low-ring PAH (phenanthrene) in fishes showed a significant correlation with MPs abundance, implying that although MPs did not affect the variation in PAH concentrations, they potentially participated in selective bioaccumulation of PAHs. Moreover, significant correlations between MPs abundance and PAHs in fishes with different feeding and living habits were found, indicating that MPs' participation in PAH bioaccumulation was dependent on fish biology and life history. Furthermore, the health risk posed by PAHs in fishes at the river outlet surpassed the line of potential high risk, while the ecological risk posed by MPs at the inner river was in the danger category, indicating the ecological risks posed by PAHs and MPs are uneven along the Pearl River. These findings deepen our understanding of the underlying mechanism of MPs participating in selective bioaccumulation of low-ring PAHs in fishes based on fish biology and point out the present risks posed by these two pollutants in the Pearl River and its estuary, which contribute to aquatic environmental protection and fishery production in this region.

Comparison of polycyclic aromatic hydrocarbon accumulation in crab tissues with the ambient marine particles from shallow hydrothermal vents, northeast Taiwan

This study investigated and compared polycyclic aromatic hydrocarbons (PAHs) in crab (Xenograpsus testudinatus), suspended particulate matter, and surface sediment sampled from Kuei-shan-tao (KST) shallow water vents just offshore northeast Taiwan. The total concentrations of PAHs (t-PAHs) in suspended particles near the vents (533-685 ng g^-1 dw) were two orders of magnitude higher than the overlying sediment (3.42-6.06 ng g^-1 dw). The t-PAHs in sediment were significantly lower than those found in suspended particulate matter and all crab tissues tested, including hepatopancreas (192-1154 ng g^-1 dw), gill (221-748 ng g^-1 dw), muscle (30-174 ng g^-1 dw), and exoskeleton (22-96 ng g^-1 dw). Principal component analysis (PCA) indicated tissue-specific bioaccumulation of PAHs in crabs. The compositions of PAHs in gill, muscle, and exoskeleton were mainly low molecular weight, while the composition in the hepatopancreas included both high and low molecular weight PAHs. Highly variable but characteristic PAH congeners and concentrations in crab tissues and ambient aquatic particles reflect bioaccumulation.

Pollution of water in Africa: a review of contaminants and fish as biomonitors and analytical methodologies-the case of Senegal

Environmental pollution is one of the major problems facing human health, ecosystems, and biodiversity. This is particularly the case for water quality in Senegal. Fish can be used as a biomonitor of pollution by accumulating pollutants from the environment through their tissues. Fish is an indispensable element in the assessment of the quality of the environment due to the diversity of biological cycles and their position in the food chain. Fish, which is very sensitive to chemical and bacterial pollution, concentrates pollutants and is a good indicator of water quality. This review presents water pollution in Senegal and the possibility of using fish as an ideal monitoring matrix for marine environments, to detect the concentration of heavy metals and organic pollutants. The different extraction and analytical techniques used for fish biomonitoring will be also described.

The scleractinian coral Pocillopora damicornis relies on neuroendocrine regulation to cope with polycyclic aromatic hydrocarbons under heat stress

Polycyclic aromatic hydrocarbons (PAHs) are highly toxic environmental pollutants and are threatening scleractinian corals. In this study, PAHs treatment did not induce significant physiological responses of the coral Pocillopora damicornis and its algal symbionts, but biological processes including response to toxin, drug metabolic, and oxidation reduction were triggered at the mRNA level. These results implied that PAHs could be a group of slow-acting environmental toxicants, whose effects were moderate but persistent. Besides, it was interesting to find that PAHs activated the neuroendocrine system in the coral by triggering the expression of monoaminergic and acetylcholinergic system related genes, indicating that PAHs might function as environmental hormones. Moreover, the combined treatments of PAHs and heat caused a much obvious effect on the coral and its algal symbionts by elevating antioxidant activity and suppressing photosynthesis in the symbionts. Results from the transcriptome data further indicated that corals might perform stress responses upon PAHs and heat challenges through the TNF and apoptosis pathways, which perhaps was modulated by the neuroendocrine system of corals. Collectively, our survey demonstrates that the PAHs can function as environmental hormones and activate the neuroendocrine regulation in scleractinian corals, which may contribute to the stress responses of symbiotic association by modulating photosynthesis, antioxidation, and apoptosis.

Horizontal and vertical segregation of polycyclic aromatic hydrocarbons in the Egyptian Mediterranean coast

Egyptian Mediterranean coast receives significant amounts of polycyclic aromatic hydrocarbons (PAHs) from industrial exhausts, riverine inputs, maritime shipping and fishers, and oil and natural gas production and exploration. The present study considers the first exhaustive assessment for the dissolved PAHs along the Egyptian Mediterranean coast (Alexandria to Manzallah) to monitor their spatial distribution and investigate the effect of the marine currents and the role of microorganisms in their distribution. Surface water levels ranged between 124.97 and 301.02 ng L^-1 with an average 223.68 ± 41.11 ng L^-1. The distribution increases from west to east based on the water circulation in the Mediterranean Sea. The levels in near shore stations were lower than those of middle and onshore stations. The intensive existence of micro-organisms near shore stations consumes great part of PAHs, while this bio-remediation process decreases gradually away from the shoreline leaving relative high concentrations of dissolved PAHs in the middle and onshore stations. Middle and deep-water levels ranged between 312.75 and 1042.95 ng L^-1 with an average 633.47 ± 225.53 ng L^-1. Deeper waters showed higher PAHs concentrations where the average concentrations of 50 m stations (868.12 ± 138.35 ng L^-1) ˃ 30 m stations (629.49 ± 143.85 ng L^-1) ˃ 10 m stations (402.79 ± 59.46 ng L^-1). The wind-induced waves re-suspend rich PAHs sediment particles to increase its concentration in the water column. Carcinogenic toxic equivalent quotient (TEQ) for total detected PAHs in the middle and deep water represented more than double (75.46 ng TEQ L^-1) the value in the surface water (34.76 ng TEQ L^-1). The diagnostic ratios and principal component analysis indicated mainly pyrogenic origin in surface, middle, and deep waters.

Bioaccumulation and trophic transfer of PAHs in tropical marine food webs from coral reef ecosystems, the South China Sea: Compositional pattern, driving factors, ecological aspects, and risk assessment

Multiple environmental pressures caused by global warming and human activities have aroused widespread concern about PAHs pollution in tropical marine coral reef regions (CRRs). However, the trophodynamics of PAHs in the food webs of the CRRs and the related influence factors have not been reported. This study investigated the occurrence, trophic amplification, and transmission of PAHs in various organisms selecting between at least representative species for each level in CRRs of the South China Sea (SCS); revealed their driving mechanisms; and explored the trophodynamics of PAHs in the food web of the coral reef ecosystem. Results showed that more PAHs can be accumulated in the mantle tissue of Tridacnidae, and the proportion of mantle tissue of Tridacnidae increases with the increase of latitude (y = 0.01x + 0.17, R² = 0.49, p < 0.05). Latitude drives the differential occurrence level and bioaccumulation of PAHs in tropical marine organisms, and also affects the trophodynamics of PAHs in aquatic ecosystem food webs. PAHs undergo trophic amplification in the food webs of tropical marine ecosystems represented by coral reefs, thus further aggravating the negative environmental impact on coral reef ecosystems. The cancer risk caused by accidental ingestion of PAHs by humans through consumption of seafood in CRRs is very low, but we should be alert to the biomagnification effect of PAHs.

Pollution level and health risk assessment of the total petroleum hydrocarbon in marine environment and aquatic products: a case of China

To evaluate the pollution level and health risk of total petroleum hydrocarbon (TPH), seawater, sediments, and aquatic organisms were sampled from the southern sea area of Zhejiang Province (Yangtze River Delta, China) between 2017 and 2019. TPH was widely present in the aquatic environment and products, and its concentration was highly variable. The average value of pollution index (PI) exceeded 1 from 2017 to 2018, and 45.46-69.19% of seawater samples and 56.87-50.00% of sediment samples were polluted. The results showed significant differences in the TPH concentration in various species of aquatic organisms. The average TPH value in aquatic organisms could be ranked in the order as follows: bivalve > shrimp > crab > fish, further reflecting that the ability to accumulate and metabolize TPH existed differently among aquatic organisms within the same pond aquaculture environment. It was relatively safe to eat aquatic products since the exposure risk index was found to be far below the threshold value in this study. Therefore, it would be prudent to undertake regular monitoring of TPH to ensure effective ecosystem functioning and seafood safety in the southern Zhejiang ocean.

Polycyclic aromatic hydrocarbons (PAHs) in the Bohai Sea: A review of their distribution, sources, and risks

The distribution, risks, and sources of polycyclic aromatic hydrocarbons (PAHs) observed in seawater and sediments in the Bohai Sea were reviewed. The ecological risk of total PAHs in seawater was low, but the ecological risks of several individual PAHs (Pyr, BbF, and IcdP) were high. Detected PAHs in sediments rarely had adverse biological effects. High PAH concentrations were identified in Bohai Bay, in the sea area near Qinhuangdao, in Jinzhou Bay, and in Bohai Strait. Low PAH concentrations were found in the central Bohai, in Laizhou Bay, and in the sea area with more intensive ocean currents near Caofeidian. PAH concentrations in the Bohai Sea present a seaward-decreasing trend. Their spatial distribution could be attributed to the influence of human activities (population, industrial activities, and shipping activities), which determined PAH emissions. The PAHs were characterized by local sources, indicating that coal consumption and vehicle emissions were important sources of PAHs. Integr Environ Assess Manag 2022;18:1705-1721. © 2022 SETAC.

Polycyclic aromatic hydrocarbons (PAHs) in surface soils of tropical reef islands in China under external plant and soil introduction: Occurrence, sources, risks, and relationships with soil properties, vegetation cover, and soil source

This study explored the levels, sources, and risks of PAHs in soils from Yongle Atoll (YLA) and Xuande Atoll (XDA) of the Xisha Islands (XSIs) in the South China Sea, China, under different vegetation cover types and soil sources. The results clearly showed that the levels of 16 US EPA priority PAHs (Σ₁₆PAHs) are relatively low in XDA and YLA, with concentrations ranging from not detected (ND) to 151 ng/g (average 15.7 ng/g) and ND to 5.8 ng/g (average 2.1 ng/g), respectively. Three- and four-ring PAHs (62.3% and 53.8%) were widely distributed in YLA and XDA. The average concentration of Σ₁₆PAHs in soils with shrub cover was 1.4, 1.8, 4.8, and 5.0 times higher than that in soils with herbaceous cover, vegetable cover, arbor cover, and no plant cover, respectively. Source analysis using binary diagnostic ratios and the positive matrix factorization (PMF) model suggested that PAHs have similar sources (gasoline/coal combustion, coke production, and biomass combustion), but different contributions in native soil and introduced soil. Moreover, diesel-related vehicular emission was identified to be an additional source of PAHs in native soil. Pearson's correlations revealed strong relationships between PAHs and organic matter or total organic carbon. The cancer risk of PAHs varied among different vegetation cover types and soil sources, following the orders herbaceous cover > vegetable cover > shrub cover > arbor cover > no plant cover and introduced soil > mixed soil > native soil. Nevertheless, the risk remained lower than the risk threshold (10^-6), suggesting low carcinogenesis risk in the two atolls. Our findings provide new evidence for the introduction of external vegetation/soil acting as a driver of changes in the characteristics of PAHs in islands, and also underline the negligibility of the PAH increase in soils in the South China Sea, China, from the perspective of health hazards.

Occurrence of polycyclic aromatic hydrocarbons (PAHs) in the seafood from an important fishing area in the East China Sea and a comparison between seafood from different origins

Polycyclic aromatic hydrocarbons (PAHs) were analyzed in a variety of coastal marine seafood from the Wentai fishing area, which is in proximity to highly urbanized areas and provides a significant portion of the marine aquatic products in Eastern China. Specifically, total PAHs ranged from 320 to 2500 ng/g d.w., whereas carcinogenic PAHs ranged from 21 to 92 ng/g d.w. According to the source diagnosis, the PAHs in the seafood were generally from sources highly related to fossil fuel. Thus, it is necessary to control the unintentional use of fossil fuels and optimize the energy structure in the terrestrial area nearby. Moreover, the food chain structure and the environmental behavior of PAHs through the food chain, which are relevant to dietary risk, were assessed. The δ¹⁵N values fell in a narrow range, which indicates a relatively short food chain, which is due to overfishing in this area. Furthermore, in this shortened food chain, the trophic magnification factors (TMFs) ranged from 0.23 to 6.6, which were generally higher than those in more complex food chains. The cancer risk (ILCR) ranged from 2.2 × 10^-8 to 2.2 × 10^-6. It is noted that the carcinogenic risk of consuming yellow croaker, which is one of the most popular seafood among people on the east coast of China, was the highest. In conclusion, trophic magnification implied a possible elevated risk through this marine food chain, and overfishing may have increased the uncertainty associated with TMF estimations.

Assessment of Total Petroleum Hydrocarbon Contamination of the Red Sea with Endemic Fish from Jeddah (Saudi Arabia) as Bioindicator of Aquatic Environmental Pollution

The aim of this study was to determine whether endemic coral fish commonly consumed by Jeddah residents could serve as bioindicators of oil contamination. In addition, we planned to investigate the relationship between amino acid changes and hydrocarbon concentrations in fish tissue. The composition of amino acids was analyzed using high-pressure liquid chromatography with precolumn derivatization. An analytical study of the polycyclic aromatic hydrocarbons and total petroleum hydrocarbons was conducted by combining gas chromatography with gas chromatography/mass spectrometry. Multivariate statistical analysis was applied using Statgraphics software to determine the impact of the polycyclic aromatic hydrocarbons and total petroleum hydrocarbons on the amino acid profile of three species of fish. In addition, the bioconcentration factor was estimated in the studied species and was used to validate the results obtained from the multivariate analysis. Based on the results of the study, the sum of polycyclic aromatic hydrocarbons with two cycles, and with five to six cycles, is in reverse order in Plectropomus pessuliferus with respect to Epinephelus tauvina and Cephalopholis argus. The factor analysis showed high factor scores for aspartic acid, glutamic acid, tyrosine, chrysene, and total petroleum hydrocarbons, and for lipids and benzo(g,h,i)perylene, which could be explained by bioaccumulation. It was concluded that the high proportions of glutamic acid (8.32–11.10%) and aspartic acid (6.06–8.27%) in the muscles of the studied species are a sign of contamination with petroleum hydrocarbons. The incremental lifetime cancer risk values for the three endemic fish exceeded the limit value (>10−5), indicating a high potential cancer risk for the Saudi population.

Occurrences, Sources, and Human Health Risk Assessments of Polycyclic Aromatic Hydrocarbons in Marine Organisms From Temperate Coastal Area

The pollution characteristics of 16 polycyclic aromatic hydrocarbons (PAHs) in marine organism species (6 species of fishes and 2 species of crustaceans) from the coastal area of the East China Sea were determined. The concentrations of 16 PAHs in the studied organisms ranged from 29.73 to 87.02 ng/g dw and 2- and 3-ring PAHs were the most abundant compounds in the aquatic organisms. The habitat, diet and predator-prey relationship have posed potential effects on the PAH accumulation in marine organisms. The source identification of PAHs was performed by using the molecular diagnostic ratios and principal component analysis (PCA). The results showed that the main sources of PAHs in the marine organisms were coal combustion, followed by mixture of gasoline combustion, oil combustion, crude oil spill and vehicle emissions. The incremental lifetime cancer risk of human via ingestion process of marine organisms in this sea area was also estimated and the assessment showed that it posed an acceptable but non-negligible risk to human health.

Thyroid disruption and growth inhibition of zebrafish embryos/larvae by phenanthrene treatment at environmentally relevant concentrations

Phenanthrene induces reproductive and developmental toxicity in fish, but whether it can disrupt the thyroid hormone balance and inhibit growth had not been determined to date. In this study, zebrafish embryos were exposed to phenanthrene (0, 0.1, 1, 10 and 100 μg/L) for 7 days. The results of this experiment demonstrated that phenanthrene induced thyroid disruption and growth inhibition in zebrafish larvae. Phenanthrene significantly decreased the concentration of l-thyroxine (T4) but increased that of 3,5,3'-l-triiodothyronine (T3). The expression of genes related to the hypothalamic-pituitary-thyroid (HPT) axis was altered in zebrafish larvae exposed to phenanthrene. Moreover, phenanthrene exposure significantly increased the malformation rate and significantly reduced the survival rate and the body length of zebrafish larvae. Furthermore, phenanthrene significantly decreased the concentrations of growth hormone (GH) and insulin-like growth factor-1 (IGF-1). Changes observed in gene expression patterns further support the hypothesis that these effects may be related to alterations along the GH/IGF-1 axis. In conclusion, our study indicated that exposure to phenanthrene at concentrations as low as 0.1 μg/L resulted in thyroid disruption and growth inhibition in zebrafish larvae. Therefore, the estimation of phenanthrene levels in the aquatic environment needs to be revisited.

Polycyclic aromatic hydrocarbons in seawater, surface sediment, and marine organisms of Haizhou Bay in Yellow Sea, China: Distribution, source apportionment, and health risk assessment

The pollution status of polycyclic aromatic hydrocarbons (PAHs) in seawater, surface sediment, and marine organisms was investigated in Haizhou Bay, which is a traditional marine fish farming region in China. The total concentrations of PAHs in seawater, surface sediment, and marine organisms were 12.4-40.3 ng/L (average 24.8 ng/L), 183.2-496.6 ng/g (average 293.5 ng/g), and 228.1-679.9 ng/g (average 392.6 ng/g), respectively. Source analysis results showed that the PAH sources for seawater and marine organisms were coal and biomass combustion (66.53%), petroleum (28.94%), and traffic (4.52%), while those for the surface sediment were traffic (48.14%), coal and biomass combustion (40.56%). The lifetime cancer risk increment (ILCR) values of marine organisms in the Haizhou Bay were less than 10^-6, indicating no carcinogenic risk. In the future, this study can be used as a reference to understand the distribution and interrelation of PAHs in other semi-enclosed bays in the world.

Trends in the impact of socioeconomic developments on polycyclic aromatic hydrocarbon concentrations in Dianchi Lake

An analysis of the correlation between polycyclic aromatic hydrocarbons (PAHs) and economic parameters demonstrates that the total population, gross domestic product, coal consumption, petroleum, temperature, and day consumption significantly affect PAH concentrations in Dianchi Lake, Yunnan province, China. An artificial neural network (ANN) model was developed to predict the trend in PAH concentrations in the sediments of Dianchi Lake over the next 10 years based on current indicators of economic development. The ANN model estimated the concentration of PAHs from 1980 to 2014. The model was evaluated using available observations for the historical trends; concentrations of PAHs in the sediments of Dianchi Lake are calculated to be at 2128.1 ng/g in 2025 and are expected to decline up to 1044.3 ng/g by 2030. These concentrations are considered relatively high because of their impacts on the health of people and aquatic organisms and the development of surrounding industries. We show the importance of the socioeconomic and climate factors in increasing the pollution levels. Our results could support the local government to formulate effective measures to reduce the pollution levels in the lake.

Bioaccumulation and potential risk of organophosphate flame retardants in coral reef fish from the Nansha Islands, South China Sea

Organophosphate flame retardant (OPFR) pollution in marine environment has attracted increasing attention in recent years. Coral reefs are regarded as significant marine ecosystems, however, research on OPFR contamination in coral reefs is limited. In the present work, 9 OPFR compounds were analyzed in fish samples collected from the Zhubi Reef and Yongshu Reef of the Nansha Islands, South China Sea, to evaluate the biomagnification and potential threats of OPFRs in the coral reef ecosystems. ∑OPFR concentrations in the coral reef fish ranged from 38.7 to 2090 ng/g lipid weight (lw), with an average of 420 ± 491 ng/g lw. Alkyl OPFRs were more abundant than chlorinated OPFRs and aryl OPFRs. Individually, TBEP and TCPP were the two most abundant OPFR compounds. Biomagnification potential was indicated for TCPP, TCEP, TBP, TBEP and TEHP along the marine food web, with trophic magnification factors being greater than one. The estimated dietary intakes of OPFRs via coral fish consumption were 0-1.11 ng/kg bw/d and 0.01-2.06 ng/kg bw/d, respectively, for rural and urban residents. Additionally, the hazard quotients of OPFR compounds ranged from 2 × 10^-7 to 7.41 × 10^-5 for rural residents and from 4 × 10^-7 to 1.37 × 10^-4 for urban residents. Although the risk to human health from exposure to OPFRs via consuming coral reef fish from the South China Sea was low, further investigation of these chemicals is still recommended.

Source analysis and influencing factors of historical changes in PAHs in the sediment core of Fuxian Lake, China

In this study, the influencing factors and sources of historical changes in polycyclic aromatic hydrocarbons (PAHs) in the sediment core of Fuxian Lake were analyzed. Before 1970, the Σ₁₆PAH concentration fluctuated widely, with one or more maximum values. During 1971-2004, the Σ₁₆PAH concentration showed a slow growth trend, while during 2005-2017, the concentration increased sharply, reaching a peak value of 821 ng g^-1. dw in 2017. The results of a positive matrix factorization (PMF) model demonstrated that before 1970, PAHs were mainly derived from biomass burning in the Fuxian Lake sediment core, with an overall contribution of 40 %. During 1971-2004, the source of PAHs was mainly coal combustion, with an overall contribution of 34 %. During 2005-2017, PAHs primarily originated from traffic, with an overall contribution of 33 %. Population, coal, GDP, motor, and petroleum had a significant influence on low molecular weight (LMW) PAHs in 1980-2004 and 2005-2017. Motor, coal, population, and GDP had a greater impact on high molecular weight (HMW) PAHs. Before 1970 and in 1971-2004, meteorological factors had little effect on PAHs in the sediment core in Fuxian Lake. During 2005-2017, day and rainfall were significantly negatively correlated with HMW PAHs, while temperature and wind were not correlated with PAH concentrations. During 2005-2017, total organic carbon (TOC) and total nitrogen (TN) had greater adsorption effects on HMW PAHs than on LMW PAHs. Before 1970 and in 1971-2004, the adsorption effects of TOC and TN on 3-4-ring PAHs were greater than those of 2-ring and 5-6-ring PAHs. Total phosphorus (TP) had no adsorption effect on PAHs in the entire sedimentary column.

The impact of national energy structure on the concentrations, environmental behavior, and sources of polycyclic aromatic hydrocarbons in riverine and coastal sediments of the Beibu Gulf, China

In this study, polycyclic aromatic hydrocarbons (PAHs) were measured in sediments of the Beibu Gulf in 2017 to investigate sources and a risk assessment. The results showed the total PAH concentration (∑₁₆PAHs) in sediments of the Beibu Gulf in 2017 (17.6 ± 16.7 ng g^-1) was significantly lower than that in 2010 (47.8 ± 27.4 ng g^-1). The ∑₁₆PAHs concentrations varied spatially within the Beibu Gulf, impacted by point source pollution. The results of adsorption/desorption and water-air partitioning suggest that the environmental behavior of PAHs in the Beibu Gulf is affected by atmospheric deposition and sediment-water partitioning. A risk assessment showed that the PAHs in sediments were within a safety threshold. Three source apportionment methods show that oil spills and oil and biomass burning were the most important (>83.8%) sources of PAHs in sediments of the Beibu Gulf.

Baseline distributions and sources of polycyclic aromatic hydrocarbons (PAHs) in reef-associated sediments of Vembar group of Islands, Gulf of Mannar, India

The study aims to investigate the source and concentration of PAH fractions in the reef sediments of the Vembar group of Islands, Gulf of Mannar, India. The concentration of PAHs ranged from 0.36 to 15.98 ng/g. The reef environment was less contaminated with low-molecular-weight PAH fractions. The accumulation of the LMW-PAH fraction was very less, whereas the HMW fraction was derived from pyrolytic sources. The level of low and high molecular weight PAHs was lower than the level of Effective Range Median (ERM) and Effective Range Low (ERL).The calculated total TEQ value ranged from ND to 10.24 ng/g in the reef sediments.

Pollution level and health risk assessment of polycyclic aromatic hydrocarbons in marine fish from two coastal regions, the South China Sea

Marine fishes are consumed in large quantities by humans as nutritious food. However, the intake of fish polluted by chemicals may pose a severe threat to human health. This study measured the concentrations of 16 priority polycyclic aromatic hydrocarbons (PAHs) in the muscles of 22 species of marine fish from two coastal regions, i.e., Tanmen and Zhuhai, identified the source of PAHs, and assessed the human health risk by dietary exposure. Total PAH (Σ₁₆PAHs) levels in Tanmen and Zhuhai fish were in the range of 24.29-684.83 ng g^-1 dry weight (dw) and 13.74-42.59 ng g^-1 dw, averaging 161.46 ng g^-1 dw and 31.21 ng g^-1 dw, respectively. Compared with other regions in the world, PAH concentrations in Tanmen fish were at median levels, and Zhuhai fish were at low levels. Low molecular weight PAHs (with 2- and 3-rings) were the predominant compounds detected. Molecular diagnostic ratios suggested that PAHs in Tanmen mainly originated from petrogenic sources such as vessel operations or tanker accidents, while Zhuhai fish were mainly polluted by pyrolytic sources such as combustion of coal and wood. The human health risk assessment results indicated that the risk of PAH intake via fish consumption from Zhuhai was negligible, while five species from Tanmen may pose potential health risks to local residents.

Distribution, fate and sources of polycyclic aromatic hydrocarbons (PAHs) in atmosphere and surface water of multiple coral reef regions from the South China Sea: A case study in spring-summer

Our previous study revealed PAHs' wide occurrence in corals from multiple coral reef regions (CRRs) in the South China Sea. However, little is known about their occurrence, distribution, fate, and sources in the ambient environment of these CRRs. This study aimed to resolve these research gaps. The results showed ∑₁₅PAHs (total concentrations of 15 US EPA priority controlled PAHs exclude naphthalene) in the atmosphere (gas-phase: 0.31-49.6 ng m^-3; particle-phase: 2.6-649 pg m^-3) were mainly influenced by air mass origins. Southwesterly wind caused higher ∑₁₅PAHs than the southeasterly wind. The ∑₁₅PAHs in seawater from the nearshore (462 ± 244 ng L^-1) was higher than that from offshore Zhongsha Islands (80.5 ± 72.1 ng L^-1) because of the effect of terrigenous pollution and ocean current. Source apportionment indicated that the mixed sources of spilled oil and combustion from neighboring countries were the main contributors to PAHs in these CRRs. The total deposition fluxes showed that PAHs tended to migrate from the atmosphere to seawater. Global warming may inhibit this process, but PAHs still have a migration pattern of atmosphere-ocean-corals, which will further increase the environmental pressure on coral reef ecology.

Polycyclic aromatic hydrocarbons in sediments and fish species from the White Nile, East Africa: Bioaccumulation potential, source apportionment, ecological and health risk assessment

The impact of oil exploration and production activities on the environment of sub-saharan African countries is not well studied. This study aimed at determining concentrations, sources, and bioaccumulation of 13 polycyclic aromatic hydrocarbons (PAHs) in sediments and fish from the White Nile near Melut oil fields, South Sudan. The study also assessed the ecological and human health risk associated with PAHs in this aquatic system. Total (∑₁₃) PAH concentrations ranged from 566 to 674 ng g^-1dry weight (dw) in sediments, while those in fish were 191-1143 ng g^-1 wet weight (ww). ∑₁₃PAH concentrations were significantly higher in C. gariepinus than in other fish species. Low molecular weight PAHs (LPAHs) dominated the profile of PAHs in sediments (constituted 95% of ∑₁₃PAHs) and fish (97% of ∑₁₃PAHs). Compared to Sediment Quality Guidelines of the United States Oceanic and Atmospheric Administration, the levels of LPAHs in this study were all above the threshold effect limits, but below the probable effect level, while those of high molecular weight PAHs (HPAHs) were all below the lowest effect levels. The carcinogenic potency equivalent concentrations of PAHs in L. niloticus and C. gariepinus were above the US EPA screening level; suggesting consumption of these species could adversely affect human health. Biota-sediment accumulation factor values (range: 0.006-3.816 g OC g^-1 lipid) for PAHs showed high bioaccumulation of LPAHs in fish muscle, and that bioaccumulation decreased with increase in hydrophobicity of the compounds. This is possibly because LPAHs have higher aqueous solubilities which increases their bioavailability through water-gill transfers compared to HPAHs. Profiles of PAHs in the White Nile environment indicate predominant contribution from petrogenic sources, which could be attributed to presence of crude oil reservoirs and oil production operations. More research into the levels of other environmental pollutants in the oil-rich area is recommended.

Halogenated polycyclic aromatic hydrocarbons in edible aquatic species of two Asian countries: Congener profiles, biomagnification, and human risk assessment

Seventy-five contaminants including chlorinated/brominated/parent polycyclic aromatic hydrocarbons (Cl/Br/PAHs) were investigated in 29 edible aquatic species from the Indian Ocean near Sri Lanka and 10 species from the Pacific Ocean near Japan. Concentrations of total ClPAHs and BrPAHs in the samples were 2.6-57 and 0.30-9.5 ng/g-dry weight from the Indian Ocean, and 0.35-18 and 0.03-3.3 ng/g-dry weight from the Pacific Ocean, respectively. Comparing the profiles of Cl/BrPAHs among the samples, congeners of chlorinated and brominated pyrene were predominant components and enhanced the potential for biomagnification in the sample from the off-shore pelagic environment in the Indian Ocean. The incremental lifetime cancer risks estimated by intake of the targets in consuming aquatic organisms showed that approximately one-third of studied organisms exceeded the acceptable risk level for Sri Lankans.

Effects of Nrf2-Keap1 signaling pathway on antioxidant defense system and oxidative damage in the clams Ruditapes philippinarum exposure to PAHs

NF-E2-related factor 2 (Nrf2) is a master regulator of antioxidant defense system which can maintain the oxidation balance in the cell. In our previous study, we first cloned the Nrf2 gene in clams and preliminarily explored the role of the Nrf2 at the transcription level. In this study, RNA interference (RNAi) technology was used to interfere with the expression of Nrf2 after being exposed to benzo(a)pyrene (BaP) for 5 days to verify the role of Nrf2 in the antioxidant defense system. Besides, we examined the mRNA expression and enzyme activities of antioxidases and the oxidative damage. The positive correlations between the Nrf2 with the mRNA expression and the enzyme activities of antioxidases indicated that Nrf2 was required for the induction of these antioxidant genes. Additionally, the mRNA expression and the enzyme activities of the glutathione peroxidase (GPx) in the Nrf2-dsRNA group were significantly higher than those in the control groups on the fifth day, indicating that the GPx is more sensitive to oxidative stress. Moreover, the oxidative damage in the RpNrf2-dsRNA group was markedly increased than control groups, indicating that Nrf2 transcriptional regulation may play an essential role in defending against oxidative damage. This study provides a foundation for further research on the mechanism of detoxification and antioxidation of polycyclic aromatic hydrocarbons (PAHs) in the clams at the transcription level and the protein level.

Accumulation of PAHs in the tissues and algal symbionts of a common Mediterranean coral: Skeletal storage relates to population age structure

Polycyclic aromatic hydrocarbons (PAHs) are widespread and harmful environmental pollutants that threaten marine ecosystems. Assessing their level and source is crucial to estimate the potential risks for marine organisms, as PAHs represent an additional threat to organism resilience under ongoing climatic change. Here we applied the QuEChERS extraction method to quantify four PAHs (i.e. acenaphthene, fluorene, fluoranthene, and pyrene) in three biological compartments (i.e. skeleton, tissue, and zooxanthellae symbiotic algae) of adult and old specimens of a scleractinian coral species (Balanophyllia europaea) that is widespread throughout the Mediterranean Sea. A higher concentration of all four investigated PAHs was observed in the zooxanthellae, followed by the coral tissue, with lowest concentration in the skeleton, consistently with previous studies on tropical species. In all the three biological compartments, the concentration of low molecular weight PAHs was higher with respect to high-molecular weight PAHs, in agreement with their bioaccumulation capabilities. PAH concentration was unrelated to skeletal age. Observed PAHs were of petrogenic origin, reflecting the pollution sources of the sampling area. By coupling PAH data with population age structure data measured in the field, the amount of PAHs stored in the long term (i.e. up to 20 years) in coral skeletons was quantified and resulted in 53.6 ng m^-2 of acenaphthene, 69.4 ng m^-2 of fluorene, 2.7 ng m^-2 of fluoranthene, and 11.7 ng m^-2 of pyrene. This estimate provides the basis for further assessments of long-term sequestration of PAHs from the marine environment in the whole Mediterranean, given the widespread distribution of the investigated coral species.

Occurrence, trophic magnification and potential risk of short-chain chlorinated paraffins in coral reef fish from the Nansha Islands, South China Sea

As emerging persistent organic pollutants in marine environment, short-chain chlorinated paraffins (SCCPs) have attracted increasing attentions recently. Coral reefs are important ocean ecosystems. However, data on SCCP pollution in the coral reef regions is still unavailable. In the present work, bioaccumulation of SCCPs in the coral reef ecosystems was reported for the first time. SCCP concentrations in coral reef fish from the Nansha Islands of the South China Sea were in the range of 37.9-25,400 ng/g lipid weight (lw) (average: 4400 ± 6590 ng/g lw; median: 1020 ng/g lw). C₁₀ SCCPs were the dominating SCCP homologues, accounting for 59% to 80% of the total SCCPs (average: 70 ± 5.0%), followed by C₁₁ SCCPs (average: 23 ± 4.5%). Regarding chlorine substitution, SCCPs were dominated by Cl₇ SCCPs (average: 45 ± 2.5%) and Cl₈ SCCPs (average: 30 ± 5.4%). Trophic magnification factor (TMF) of total SCCPs was 8.5, indicating trophic magnification potential of SCCPs in the coral reef ecosystems. In addition, a parabolic relationship was established between TMFs and log K_ow of specific SCCP homologues. SCCP residues in the coral reef fish from the Nansha Islands of the South China Sea did not pose significant risk to human health.

Air-water exchange and distribution pattern of organochlorine pesticides in the atmosphere and surface water of the open Pacific ocean

Surface seawater and lower atmosphere gas samples were collected simultaneously between 18°N and 40°S in the open Pacific Ocean in 2006-2007. Samples were analyzed for organochlorine pesticides (OCPs) to assess their distribution patterns, the role of ocean in the long-range transport (LRT), and the air-water exchange directions in the open Pacific Ocean. Such open ocean studies can yield useful information such as establishing temporal and spatial trends and assessing primary vs secondary emissions of legacy OCPs. Target compounds included hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs) and its derivatives, and chlordane compounds. Concentrations for α-HCH, γ-HCH, trans-chlordane (TC), and cis-chlordane (CC) were higher in the Northern Hemisphere (NH) than the Southern Hemisphere (SH) in both gaseous and dissolved phases, while the distribution patterns of DDTs and heptachlor exo-epoxide (HEPX) showed a reversed pattern. In the N Pacific, concentrations of α-HCH and γ-HCH in the present work were lower by 63 and 16 times than those observed in 1989-1990. The distribution patterns of DDT suggested there was usage in the SH around 2006. Calculated fugacity ratios suggested that γ-HCH was volatilizing from surface water to the atmosphere, and the air-water exchange fluxes were 0.3-11.1 ng m^-2 day^-1. This is the first field study that reported the open Pacific Ocean has become the secondary source for γ-HCH and implied that ocean could affect LRT of OCPs by supplying these compounds via air-sea exchange.

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.

Microplastic pollution around remote uninhabited coral reefs of Nansha Islands, South China Sea

Microplastic (MP) pollution is a growing environmental problem in the global oceans. However, there is relatively little evidence of the extent of MP pollution around remote islands, such as coral reefs, in the open ocean. In this study, we conducted a large-scale investigation of MP pollution in the surface waters around the remote uninhabited coral reefs of Nansha Islands in South China Sea. Microplastics were widespread in the surface waters with an average abundance of 0.0556 ± 0.0355 items/m³, although this varied among the coral reefs. The MPs were predominantly composed of polypropylene (PP) and polyethylene (PE), and > 70% of them were <3 mm in size. Fragments and fibers comprised the most common MP types. The similarity between macro plastic and MP compositions provided evidence for the tracing of MP sources in the study area. The main pollutants (transparent PP fibers and PE fibers) around these remote coral reefs may originate from fishing gear abrasions. The plastic waste released from nearby residential islands and high-intensity fishing activities around Nansha Islands likely represented important local sources. Overall, the abundance of MPs found in the surface waters surrounding these remote coral reefs in the South China Sea was relatively low; however, these levels of MP pollution should not be disregarded given the importance of coral reef ecosystems.

Polycyclic aromatic hydrocarbons (PAHs) in marine organisms from two fishing grounds, South Yellow Sea, China: Bioaccumulation and human health risk assessment

Sediment and marine organism samples collected from Haizhou Bay and Lusi fishing ground in South Yellow Sea, China were analysed for polycyclic aromatic hydrocarbons (PAHs). The concentrations of 16 PAHs in marine organisms ranged from 127.43 to 350.53 ng/g dry weight (dw, Haizhou Bay fishing ground) and from 86.37 to 213.02 ng/g dw (Lusi fishing ground). The dominant compounds were 2- and 3-ring PAHs in marine organism tissues. The main PAH sources were found to be coal combustion. Specific habitat, feeding habit, trophic level and environmental differences may affect the PAH levels in marine organisms in our study area. The biota-sediment accumulation factor (BSAF) decreased with increasing PAH log K_ow and BSAF values might differ in response to various environmental conditions and species. The excess cancer risk from PAH-contaminated seafood consumption was slightly higher than the guideline value (10^-6), but much lower than the priority risk level (10^-4).

Microplastic pollution in water and fish samples around Nanxun Reef in Nansha Islands, South China Sea

Nanxun Reef is one of the typical reefs in Nansha Islands, South China Sea. As the Nansha Islands are surrounded by certain developing countries, the economic and population growth have resulted in increased surface runoff of persistent organic pollutants in offshore areas. Microplastic has been found in many freshwaters and sea areas in recent years. However, the levels of microplastics contamination in Nansha Islands are still uncharted. In this study, 15 water and 35 fish samples were collected around the Nanxun Reef. The average concentration of microplastics was 1733 items/m³ for surface water samples and 3.1 items per individual for fish samples. The majority of ingested microplastics by fish were fibers, mostly transparent or blue. In surface water samples, blue microbeads were the main types of microplastics, accounting for 76.5% of all the detected particles. The main size of microplastics was <0.5 mm both in water and fish samples. Our results demonstrated that fishery activities and human domestic sewage might be the dominant sources of microplastic pollution in the Nansha Island, South China Sea.

Distribution characteristics of microplastics in Zhubi Reef from South China Sea

As a new type of emerging pollutant in the ocean, microplastics have received global attention in recent years. Considering the increasing amount of human activities around the South China Sea, it is important to determine the current status of microplastic pollution in this region. In this study, we analyzed the abundance and distribution of microplastics at Zhubi Reef in the South China Sea. Microplastic abundance ranged from 1400 to 8100 items/m³ of surface water, which was much higher than the values reported from other ocean areas. About 80% of the microplastics were smaller than 0.5 mm in size. Fibers and pellets comprised the most common microplastic types. The dominant microplastics were transparent or blue in color. The main polymer types were polypropylene (25%) and polyamide (18%). In general, our results revealed Zhubi Reef was contaminated with microplastics, which were likely derived from the intensive fisheries in the area and emissions from coastal cities. This study also provides baseline data that are useful for additional studies of microplastics in the South China Sea.