Global pollution monitoring of PCBs and organochlorine pesticides using skipjack tuna as a bioindicator

North-south discrepancy in the contributors to CB153 accumulation in the deep water of the Sea of Japan

The deep-water environment and its ecosystem are becoming the ultimate sinks for Polychlorinated Biphenyls (PCBs). A three-dimensional hydrodynamic-ecosystem-PCB coupled model was applied to the Sea of Japan (SoJ), where deep water is isolated from the surrounding oceans, to elucidate the accumulation processes of CB153 and assess the contributions of physical and biological processes to the accumulation. We suggest that the dissolved CB153 concentration formed a three-layer vertical structure in the SoJ: the highest concentration is in the intermediate layer (100-600 m), followed by those in the deep (600 m to the bottom) and surface layers (0-100 m). Different accumulation mechanisms in the northern and southern SoJ were discovered. The oceanic biological pump enhances the accumulation in the northern SoJ by taking CB153 out of the thermocline in summer and contributes 70 % to the accumulation in the intermediate layer; while the vertical advection contributes 70 % to the accumulation in the intermediate and deep layer in the southern SoJ.

Assessment of metal and organic pollutants in combination with stable isotope analysis in tunas from the Gulf of Cadiz (east Atlantic)

Bioaccumulation patterns of heavy metals (Pb, Cd, Cr, Ni, Fe and Cu) and organic (priority and emerging) pollutants, in combination with stable isotope analysis (SIA), were assessed in muscle and liver of three tuna species from the Gulf of Cadiz (Atlantic bluefin tuna, Thunnus thynnus; Atlantic bonito, Sarda sarda, and skipjack tuna, Katsuwonus pelamis). SIA and contaminant (heavy metal and organic) profiles separately discriminated between species. There was no significant overlap between the trophic niches estimated from isotopic data, suggesting that there are diet differences which may determine differential bioaccumulation patterns. The levels of heavy metals and persistent organic pollutants in muscle of all the individuals analyzed were below the allowable limits established by the current legislation. Concentrations of most contaminants were higher in liver than in muscle, underlining the powerful detoxifying capacity of the liver in tunas. In addition to diet, other factors such as size and age (exposure time to environmental chemicals) explain differences in pollutant accumulation patterns in tissues between species, each with varying degrees of involvement depending on the pollutant class. Our results show that combining contaminant profile data with trophic features based on SIA may help understand pollutant bioaccumulation patterns in upper levels of marine food webs.

Distinct dynamics in mountain watersheds: Exploring mercury and microplastic pollution-Unraveling the influence of atmospheric deposition, human activities, and hydrology

The intensification of human activities all around the globe has led to the spread of micropollutants in high-mountain freshwater environments. We therefore aimed to assess the geospatial distribution and determine the potential sources of (total-) mercury (THg) and microplastics (MPs) in mountain freshwater ecosystems. To do so, we analyzed THg and MP concentrations in brown trout, biofilm, and sediments from lotic and lentic ecosystems in the Pyrenees - all subjected to different types of human pressure. Additionally, we assessed the potential impacts of these pollutants on fish, and explored the bioindication capacity of brown trout (Salmo trutta fario) and biofilm regarding THg and MP pollution. For the first time, we measured concentrations of MPs trapped in the matrix of freshwater biofilm. Our results suggest that THg in the Pyrenees might be explained by both legacy (regional) and distant sources, in combination with environmental characteristics such as the presence of peatlands or streamwater physicochemistry, while MPs in fish are linked to recent local pollution sources such as single-use plastics. In contrast, MPs in biofilm matrix and sediments indicate a combination of distant (i.e., atmospheric deposition) and recent local pollution sources. Moreover, hydrodynamics and plastic density likely control MP distribution in rivers. Based on Fulton's condition factor, we also found that higher THg concentrations caused a negative impact on fish health (K < 1), while no impact of MPs could be seen. Therefore, we suggest that brown trout and biofilm can serve as bioindicators of atmospheric deposition of THg in high-altitude lakes and that biofilm is a reliable bioindicator to assess MP pollution in remote environments. Brown trout may also act as a bioindicator of MP pollution, but only efficiently in more polluted areas.

Ten years after: findings from the medical surveillance program on Health Effects in High-Level Exposure to PCB (HELPcB)

After the detection of high environmental and occupational exposure to polychlorinated biphenyls (PCBs) in a German recycling company for transformers and capacitors in 2010, the multidisciplinary medical surveillance program "HELPcB" (Health Effects in High-Level Exposure to PCB) was established for former PCB-exposed workers of the company, their family members, employees of surrounding companies, and area residents to investigate potential adverse health effects by PCB exposure in a longitudinal study approach with up to seven examination time points between 2010 and 2019. More than 300 individuals were enrolled into the program. Assessments particularly included plasma and urine concentrations of PCB congeners and their metabolites, clinical laboratory parameters, Comet assay, analysis of telomere length, neuropsychological examinations, psychological screening, abdominal and thyroid ultrasound examination. This review summarizes the main results of the studies conducted in the HELPcB program yielding relevant new data on potential adverse effects of PCB exposure in humans and potential mechanisms that underlie these effects. Even larger studies in PCB-exposed individuals are warranted to confirm the results of this program and to further establish causality between PCB exposure and clinical effects in humans.

The Kuroshio Regulates the Air-Sea Exchange of PCBs in the Northwestern Pacific Ocean

Calculating accurate air-sea fluxes for polychlorinated biphenyls (PCBs) is an essential condition for evaluating their transport in the atmosphere. A three-dimensional hydrodynamic-ecosystem-PCB coupled model was developed for the northwestern Pacific Ocean to assess the air-sea fluxes of four PCBs and examine the influences of ocean currents on the fluxes. The model revealed a fine structure in the air-sea flux that is sensitive to the Kuroshio, a western boundary current with a high surface speed. Intense downward and upward fluxes (-23.6 to 44.75 ng m^-2 d^-1 for ∑₄PCBs) can be found in the Kuroshio region south of Japan and the Kuroshio Extension east of Japan, respectively. In strong (weak) current regions, it takes ∼4 and ∼1 days (1-3 and 3-12 days) for dissolved PCBs to reach an equilibrium in scenarios where only air-sea exchange or only ocean advection is considered, respectively. In strong current regions, the ocean advection has a shorter response time than the air-sea exchange, indicating that dissolved PCBs from upstream carried by strong current can easily change the downstream concentration by disrupting the equilibrium with original air-sea exchange and induce new air-sea fluxes there. Therefore, strong western boundary currents should be correctly considered in future atmospheric transport models for PCBs.

Spatial Variation in Contaminant Occurrence in Marine Fishes and Prawns from Coastal Tanzania

There are limited data on organic contaminants in marine biota from coastal Tanzania, especially on the occurrence of industrial-use contaminants such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). The present study, performed in 2018-2019 in coastal Tanzania and Zanzibar Island, aimed at assessing spatial variation in the occurrence of PCBs; brominated flame retardants (BFRs), including PBDEs; and organochlorine pesticides, including dichlorodiphenyltrichloroethane (DDT), among three locations that differ in degree of anthropogenic activity. Analyzed samples included edible tissues of marine fishes and prawns representing different trophic levels and habitats. The results indicate a mainland-island difference, with fishes and prawns collected on Zanzibar having significantly lower PCB and DDT concentrations but higher concentrations of hexachlorobenzene compared to the two mainland locations. The highest contaminant concentrations were found in fishes and prawns collected around central Dar es Salaam harbor, with median ΣPCBs ranging from 22.3 to 577 ng/g lipid weight and ΣDDTs from 22.7 to 501 ng/g lipid weight, suggesting local sources. Concentrations of PBDEs were similar among locations, suggesting more diffuse sources. None of the "newer-type" BFRs, including compounds introduced as replacements for PBDEs, were detected in the present study. Stable isotope values of carbon (δ¹³ C) and nitrogen (δ¹⁵ N) varied among locations, and the relationship between contaminants and δ¹⁵ N varied among locations and habitat (pelagic/demersal). Concentrations measured in the present study are below European guidelines for human consumption of fishes and prawns. However, industrial-use contaminants should be monitored in developing countries because they are contaminants of emerging concern as a result of increasing industrialization and global trade of used products and wastes. Environ Toxicol Chem 2022;41:321-333. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Organochlorines and Polycyclic Aromatic Hydrocarbons as fingerprint of exposure pathways from marine sediments to biota

To elucidate the dynamics of a suite of organochlorine contaminants (PCBs, HCB), PAHs and Hg and verify the potential of these pollutants as reliable fingerprints of sources, an ensemble of marine sediments and organisms (finfish, shellfish species and Mytilus galloprovincialis) were analysed from the contaminated Augusta Bay (Southern Italy). The Hg and HCB concentration in the sediments exceeded the EQS of the Directive 2000/60/EU. Similarly, ∑PCB and selected PAHs were above the threshold limit set by regulation. The marine organisms showed Hg concentrations above CE 1881/2006. Contaminants in transplanted mussel evidenced an increased accumulation overtime and different distribution patterns between sampling sites. Analysis of the homolog composition of PCB congeners revealed comparable patterns between sediments and marine organisms and offered the opportunity to define a robust fingerprint for tracing contaminants transfer from the abiotic to the biotic compartments. These results were confirmed by the Fluoranthene/Pyrene, Hg and HCB distribution modes.

Assessment of plastic ingestion by pole-caught pelagic predatory fish from O'ahu, Hawai'i

Although the frequency of occurrence of plastic ingestion in the large-sized dolphinfish and tunas taken by the Hawai'i longline fishery is very low (frequency of occurrence < 5% of sampled individuals), the ingestion of plastic in smaller-sized specimens caught with pole-and-line gear by commercial and recreational fishers has not been investigated.This study examined ingestion of >0.25 mm marine plastic debris (MPD) by four predatory fish species caught by commercial fishers around the Main Hawaiian Islands, and documented ingestion in three species: 85.7% of albacore tuna (n = 7), 40.0% of skipjack tuna (n = 10) and 12.5% of dolphinfish (n = 8).Yellowfin tuna (n = 10) did not contain any MPD, probably owing to the high proportion of empty stomachs (60%).For skipjack tuna, the frequency of occurrence of MPD ingestion was significantly higher for the smaller-sized specimens caught with pole-and-line (40%), compared with the larger-sized specimens caught with longlines (0%).For dolphinfish, the frequency of occurrence of MPD ingestion was similar for the similar-sized specimens caught with pole-and-line and with longlines.The ingested MPD items were micro-meso plastics, between 1 and 25 mm. While most ingested items were fragments, albacore also ingested line and skipjack also ingested sheets.The predatory fishes ingested light MPD items that float in sea water, but there were species-specific differences in their polymer composition: albacore contained more polypropylene and polyethylene, and skipjack contained more elastomers, characterized by a high percentage of ester plasticizers.Altogether, these results suggest that albacore and skipjack tunas ingest plastic of different types and polymers. Yet more research is needed to understand how differences in vertical distribution, foraging ecology and diet influence the MPD sampled by these predatory fish species.

Tissue-specific bioaccumulation of a wide range of legacy and emerging persistent organic contaminants in swordfish (Xiphias gladius) from Seychelles, Western Indian Ocean

Swordfish (Xiphias gladius) is a major marine resource of high economic value to industrial and artisanal fisheries. As a top predator with a long lifespan, it is prone to accumulate high levels of contaminants. The bioaccumulation of a wide range of both legacy and emerging persistent organic contaminants was investigated in the muscle, liver and gonads of swordfish collected from the Seychelles, western Indian Ocean. The detection of all target contaminants, some at frequencies above 80%, highlights their widespread occurrence, albeit at low levels. Mean concentrations in muscle were 5637, 491 and 331 pg g^-1 ww for organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and perfluoroalkyl substances (PFASs), respectively. ∑BFR mean concentrations were far below, i.e. 47 pg g^-1 ww. The data are among the first obtained for such a high diversity of contaminants in an oceanic top predator worldwide and constitute a benchmark of the contamination of Indian Ocean ecosystems.

Legacy and emerging organic contaminants: Levels and profiles in top predator fish from the western Indian Ocean in relation to their trophic ecology

Tuna and billfish are large pelagic fish of ecological importance in open oceans. As top predators with a long lifespan, they are prone to exposure to various contaminants such as persistent organic pollutants (POPs) and contaminants of emerging concern. In this study, three pollutant families were investigated, including polychlorinated biphenyls (PCBs), organochlorinated pesticides (OCPs) and perfluoroalkyl substances (PFASs), including perfluorooctane sulfonate (PFOS) and perfluorocarboxylic acids (PFCAs). Contamination was investigated in individuals from three tropical tuna species, namely bigeye (Thunnus obesus), skipjack (Katsuwonus pelamis) and yellowfin (Thunnusalbacares) tunas and the billfish swordfish (Xiphias gladius), collected from various areas of the western Indian Ocean (WIO) in 2013-2014. Contamination levels and profiles were examined in fish muscle, together with biological parameters (fish length / age, sex, lipid content) and ecological tracers (carbon and nitrogen stable isotopes). POP levels were low in all species in comparison to other locations worldwide, revealing a low impact of anthropogenic organic contaminants in the WIO. A predominance of OCPs (especially DDTs) versus PCBs was highlighted in all species; PFASs were predominant over chlorinated POPs in tunas. Among the studied PFASs, long-chain PFCAs were found to prevail over PFOS in all species. Organic contaminant profiles differed across species according to their foraging habitat; swordfish and bigeye tuna, which both feed in deep oceanic layers, showed similarities in their contaminant profiles. Geographically, the distinct DDT profiles of fish from the Mozambique Channel suggested an exposure to different DDT sources, in line with regional use of this insecticide and coupled with an extended residence time of fish in the Channel. To our knowledge, the data presented here are among the first obtained for legacy and emerging organic contaminants in various species of large pelagic predators from the WIO.

Legacy persistent organic pollutants (POPs) in archive samples of wild Bluefin tuna from the Mediterranean Sea

Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were quantified in archive samples of dorsal white muscle of the wild Bluefin tuna (BFT) (n = 9) collected in the central Adriatic. PCBs were the predominant organochlorine (OC) compounds (60.8-69.4% of the total OC load) found. The contribution of HCB and ΣHCHs was significantly lower, ranging from <LOD (α- and β-HCH) to 1.5% (γ-HCH). p,p'-DDE was the predominant OCP compound (60-89% of the ΣOCPs). PCB and DDT levels were comparable to the values previously found for tuna from the Mediterranean Sea, known as one of the areas most polluted by PCBs.

Tracking mercury in the southwestern Atlantic Ocean: the use of tuna and tuna-like species as indicators of bioavailability

Mercury is a trace element that is potentially dangerous due its high toxicity and tendency to bioaccumulate in organisms. Currently, high mercury concentrations are seen in the environment especially due climate changes. Studies regarding mercury bioavailability in the southwestern Atlantic Ocean using tuna and tuna-like species are rare. The aim of the present study was to use tuna and tuna-like species (Thunnus atlanticus, Thunnus albacares, Katsuwonus pelamis, Euthynnus alletteratus, Coryphaena hippurus and Sarda sarda) as indicators of the availability of total mercury (THg) in oceanic food webs of the southwestern Atlantic Ocean. THg concentrations varied significantly among species for both muscle and liver (Kruskal-Wallis test; H_5,130 = 52.7; p < 0.05; H_5,130 = 50.1; p < 0.05, respectively). The lowest concentrations were found in C. hippurus (0.008 mg kg^-1 wet weight in the muscle and 0.003 mg kg^-1 wet weight in the liver), and the highest concentrations were reported in the muscle of T. atlanticus (1.3 mg kg^-1 wet weight) and in the liver of S. sarda (2.5 mg kg^-1 wet weight). The continued monitoring of tuna and tuna-like species is necessary to assist in their conservation since tuna can be sentinels of mercury pollution.

Organochlorine pesticides in marine ecosystems of the Far Eastern Seas of Russia (2000-2017)

The present review provides information on the main organochlorine pesticides (OCPs), widely used in world agriculture in the 1940s-1960s. The patterns of their distribution in the environment, as well as the toxicity, metabolism, and degradation are described. Some data on OCPs distribution in components of aquatic ecosystems in different regions of the World and, particularly, in the Far Eastern Seas of Russia-the Sea of Japan/East Sea, the Sea of Okhotsk, and the Bering Sea-is considered for the period 2000-2017. The obtained results are discussed.

Polychlorinated biphenyls (PCBs) in commonly consumed seafood from the coastal area of Bangladesh: occurrence, distribution, and human health implications

Dietary intake is the most important route of polychlorinated biphenyls (PCBs) exposure and seafood is the major dietary component for the coastal populations. It is, therefore, an urgent need to assess the levels of PCBs in seafood. A comprehensive congener-specific evaluation of PCBs was carried out for the first time in Bangladesh. All 209 congeners of PCBs in 48 seafood samples (5 finfish and 2 shellfish species) collected in winter and summer of 2015 were measured by GC-MS/MS. Regardless of season and site, the ∑PCBs (ng/g wet weight) in finfish and shellfish were in the range of 6.4-86.2 and 3.8-37.7, respectively. The results were comparable to or higher than those observed in other studies worldwide, particularly from Spain, China, Korea, Thailand, and Hong Kong. No significant seasonal variation was observed in the levels of ∑PCBs in the examined seafood (p > 0.05); however, interspecies differences were significant (p < 0.05). Nonetheless, spatial distribution revealed seafood collected from the areas with recent urbanization and industrialization (Chittagong, Cox's Bazar, and Sundarbans) were more contaminated with PCBs than the area unaffected by industries (Meghna Estuary). Moderately chlorinated (4-6 Cl) homologs dominated the PCB profiles. The congener profile and homolog composition revealed that the source origin of PCBs in the Bangladeshi seafood was related to mixtures of technical PCBs formulations. The dietary exposure assessment revealed that the coastal residents are sufficiently exposed to the dietary PCBs through seafood consumption which may cause severe health risk including dioxin-like toxic effects.

Persistent organic pollutants in fish from Charleston Harbor and tributaries, South Carolina, United States: A risk assessment

Fish consumption is an important route of exposure to persistent organic pollutants (POPs) in dolphins as well as humans. In order to assess the potential risks associated with these contaminants, 39 whole fish and 37 fillets from fish representing species consumed by dolphins and humans captured from Charleston Harbor and tributaries, South Carolina, USA, were measured for a suite of POPs. Polychlorinated biphenyls (PCBs) were the predominant contaminant with concentrations ranging from 5.02 to 232.20 ng/g in whole fish and 5.42-131.95 ng/g in fillets (weight weight ww) followed by total organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs). Total POPs levels varied by location and species with general trends indicating significantly higher levels in fish from the Cooper (93.4 ng/g ww) and Ashley Rivers (56.2 ng/g ww) compared to Charleston Harbor (31.6 ng/g ww). Mullet and spot were found to have significantly higher PCBs, OCPs and total POPs, 2-3 times higher than red drum; mullet were also significantly higher in OCPs compared to seatrout. PCB concentrations in whole fish and fillets exceeded EPA human screening values for cancer risk in all fish sampled. For PCBs in fillets, all samples had values of maximum allowable meals per month that were less than the EPA, FDA guidelines for recommended fish meals per month, suggesting lower (more stringent) allowable fish meals per month. All fish exceeded PBDE wildlife values and all fish except two exceeded the level where 95% of the dolphin population would have tissue levels below the health effect threshold. Considering that POP concentrations in fish potentially consumed by humans exceed human health effect thresholds levels, consumption advisories should be considered as a prudent public health measure.

Global Monitoring of Persistent Organic Pollutants (POPs) Using Seabird Preen Gland Oil

Situated at high positions on marine food webs, seabirds accumulate high concentrations of persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs), and hexachlorocyclohexanes (HCHs). Our previous studies proposed the usefulness of seabirds preen gland oil as a nondestructive biomonitoring tool. The present study applied this approach to 154 adult birds of 24 species collected from 11 locations during 2005-2016 to demonstrate the utility of preen gland oil as a tool for global monitoring POPs, i.e., PCBs, DDTs, and HCHs. Concentrations of the POPs were higher in the Northern Hemisphere than in the Southern Hemisphere. In particular, ∑20PCBs and∑DDTs were highly concentrated in European shags (Phalacrocorax aristotelis) and Japanese cormorants (Phalacrocorax capillatus), explainable by a diet of benthic fishes. Higher concentrations of γ-HCH were detected in species from the polar regions, possibly reflecting the recent exposure and global distillation of ∑HCHs. We examined the relationship between age and POP concentrations in preen gland oil from 20 male European shags, aged 3-16 years old. Concentrations and compositions of POPs were not related to age. We also examined sex differences in the POP concentrations from 24 streaked shearwaters (Calonectris leucomelas) and did not detect a sex bias. These results underline the importance of the geographic concentration patterns and the dietary behavior as determinants species-specific POPs concentrations in preen gland oil.

Metabolic enhancement of 2,3',4,4',5-pentachlorobiphenyl (CB118) using cytochrome P450 monooxygenase isolated from soil bacterium under the presence of perfluorocarboxylic acids (PFCAs) and the structural basis of its metabolism

2,3',4,4',5-Pentachlorobiphenyl (CB118) is one of the most abundant polychlorinated biphenyl (PCB) congeners in the environment, and perfluoroalkyl acids, including perfluorocarboxylic acids (PFCAs), are widely distributed in the environment. Although CB118 and perfluoroalkyl acids are present in all humans and biota, effects in the metabolic fate of CB118 leading to toxicity change are unclear. P450BM3, which is isolated from the soil bacterium Bacillus megaterium, metabolized CB118 to three different hydroxylated pentachlorobiphenyls (M1-M3). M2 was identified as 4'-OH-2,3',4,5,5'-pentachlorobiphenyl. These reactions were promoted by the presence of PFCAs, and perfluorooctanoic acid (PFCA-C8) was the most effective for accelerating these reactions among PFCAs with different carbon chain length. The production rate of M2 was accelerated by 25-times using PFCA-C8. Furthermore, the docking models of P450BM3 with CB118 and PFCAs revealed that the conformational changes of the substrate-binding cavity of P450BM3 after binding of PFCAs to P450BM3 were important for selective production of CB118 metabolites. This study leads to the clarification of the different metabolic fates of PCBs under complex contamination with PFCAs.

Geographic Differences in Persistent Organic Pollutant Levels of Yellowfin Tuna

BACKGROUND

Fish are a source of persistent organic pollutants (POPs) in the human diet. Although species, trophic level, and means of production are typically considered in predicting fish pollutant load, and thus recommendations of consumption, capture location is usually not accounted for.

OBJECTIVES

Yellowfin tuna (Thunnus albacares) are harvested from across the world's oceans and are widely consumed. Here, we determined geographic variation in the overall mass, concentration, and composition of POPs in yellowfin and examined the differences in levels of several POP congeners of potential relevance to human health.

METHODS

We sampled dorsal muscle of 117 yellowfin tuna from 12 locations worldwide, and measured POP levels using combined liquid or gas chromatography and mass spectrometry according to U.S. Environmental Protection Agency standard procedures.

RESULTS

POP levels varied significantly among sites, more than 36-fold on a mass basis. Individual fish levels ranged from 0.16 to 138.29 ng/g wet weight and lipid-normalized concentrations from 0.1 to 12.7 μM. Levels of 10 congeners that interfere with the cellular defense protein P-glycoprotein, termed transporter interfering compounds (TICs), ranged from 0.05 to 35.03 ng/g wet weight and from 0.03 to 3.32 μM in tuna lipid. Levels of TICs, and their individual congeners, were strongly associated with the overall POP load. Risk-based analysis of several carcinogenic POPs indicated that the fish with the highest levels of these potentially harmful compounds were clustered at specific geographic locations.

CONCLUSIONS

Capture location is an important consideration when assessing the level and risk of human exposure to POPs through ingestion of wild fish. https://doi.org/10.1289/EHP518.

Accelerated telomere shortening in peripheral blood lymphocytes after occupational polychlorinated biphenyls exposure

Polychlorinated biphenyls (PCBs) are organochlorine pollutants with a worldwide dissemination. We examined telomere length (TL) in peripheral blood cells of 207 individuals with a high body burden of PCBs due to occupational exposure in a transformer recycling company. Whereas TL in granulocytes was not affected, the age-adjusted TL in lymphocytes (∆TLLymph) of exposed individuals was significantly shorter than expected [-0.77 kb; 95 % confidence interval (CI) -0.9316; -0.6052; p = 0.0001]. PCB exposure did not affect lymphocyte numbers or T cell receptor excision circle (TREC) levels in T cells, suggesting that PCBs cause loss of telomeric DNA in T cells due to their metabolic activation and antigen-stimulated proliferation. In support of this hypothesis, blood plasma levels of PCB-exposed individuals inhibited expression of telomerase, the telomere elongating enzyme in vitro in antigen-specific T cell proliferation assays. 3-OH-CB28, a downstream metabolite of the lower chlorinated PCB-28 in PCB-exposed individuals (mean blood plasma concentration: 0.185 ± 0.68 ng/mL), inhibited telomerase gene expression within 48 h of incubation in lymphoproliferative assays starting at a concentration of 0.27-6.75 µg/mL and accelerated telomere shortening in long-term cell culture experiments. Accelerated telomere shortening due to PCB exposure may lead to limitations of cell renewal and clonal expansion of lymphocyte populations. As PCB-related immune dysfunctions have been linked to increased susceptibility to infectious diseases and increased risk of cancer, our data provide a possible explanation, for how PCBs could promote infections and cancer through limiting immune surveillance.

Persistent Organic Pollutants in albacore tuna (Thunnus alalunga) from Reunion Island (Southwest Indian Ocean) and South Africa in relation to biological and trophic characteristics

The contamination of albacore tuna (Thunnus alalunga) by Persistent Organic Pollutants (POPs), namely polychlorinated biphenyls (PCBs) and dichlorodiphenyl-trichloroethane (DDT), was investigated in individuals collected from Reunion Island (RI) and South Africa's (SA) southern coastlines in 2013, in relation to biological parameters and feeding ecology. The results showed lower PCB and DDT concentrations than those previously reported in various tuna species worldwide. A predominance of DDTs over PCBs was revealed, reflecting continuing inputs of DDT. Tuna collected from SA exhibited higher contamination levels than those from RI, related to higher dietary inputs and higher total lipid content. Greater variability in contamination levels and profiles was identified in tuna from RI, explained by a higher diversity of prey and more individualistic foraging behaviour. PCB and DDT contamination levels and profiles varied significantly in tuna from the two investigated areas, probably reflecting exposure to different sources of contamination.

Distribution of persistent organic pollutants (POPS) IN wild Bluefin tuna (Thunnus thynnus) from different FAO capture zones

Residues of environmental contaminants in food represent a concern in food safety programs. In this study, the distribution of persistent organic pollutants (POPs) were evaluated in 79 tuna samples from FAO areas 51 (Indian Ocean), 71 (Pacific Ocean), 34 (Atlantic Ocean), and 37 (Mediterranean Sea). 6 polychlorinated biphenyls (PCBs), 16 organochlorines (OCs) and 7 polybrominated biphenyl ethers (PBDEs) were selected as representative compounds according to EFSA POPs monitoring guidelines. An analytical method, based on Accelerated Solvent Extraction (ASE), with an "in-line" clean-up step and GC-MS/MS detection, was developed, validated and applied. PCBs were detected in all FAO areas, with a prevalence of 100% for most of them. In the FAO area 37, only, all PBDEs were detected. Only 5 OCs were detected. The results showed that POPs contamination of tuna reflects FAO area contamination; in particular FAO area 37 was the most polluted. Moreover, tuna muscle was an appropriate matrix for monitoring contamination and for obtaining information about food safety.

Review on the occurrence and profiles of polybrominated diphenyl ethers in the Philippines

The environmental occurrence of polybrominated diphenyl ethers (PBDEs) has been a subject of concern for the past decade because they are persistent, bioaccumulative, and toxic. These compounds have been listed as persistent organic pollutants (POPs) by the Stockholm Convention and are expected to disperse in the global environment even after their use and production. While the occurrence of PBDEs has been well characterized in environmental and biological samples from North America, Europe, and some Asian countries (i.e. China, Japan, and Korea), there is a scarcity of available data in developing Asian countries, such as the Philippines. Examination of PBDE contamination in the Philippine environment is particularly important because regulations have only recently been implemented on the production and use of PBDEs in this country. Additionally, the Philippines receives e-waste from Western countries, which is becoming a major source of organic contaminants in the tropical Asian regions. Ultimately, the Philippines may be a hot spot for contributing to on-going global PBDE pollution due to long-range atmospheric transport. This paper presents a review of the available literature on PBDEs in both environmental and biological samples collected from the Philippines. It is also intended to provide an overview on the levels and congener profiles of PBDEs in samples from the Philippines and to compare these data with other Asian countries. New data are presented on PBDE occurrence and congener profiles in fish commonly consumed by Filipinos and in particulate matter samples collected in Metro Manila, the capital of the Philippines. Both studies contribute to the available knowledge of PBDEs in the Philippines. We aim to stress the importance of future studies in countries receiving e-wastes, such as the Philippines, and suggest what future directions might be taken to enhance the available data on the presence of PBDEs in the Philippine environment.

Deep-ocean foraging northern elephant seals bioaccumulate persistent organic pollutants

As top predators in the northeast Pacific Ocean, northern elephant seals (Mirounga angustirostris) are vulnerable to bioaccumulation of persistent organic pollutants (POPs). Our study examined a suite of POPs in blubber (inner and outer) and blood (serum) of free-ranging northern elephant seals. For adult females (N=24), we satellite tracked and sampled the same seals before and after their approximately seven month long foraging trip. For males, we sampled different adults and sub-adults before (N=14) and after (N=15) the same foraging trip. For females, we calculated blubber burdens for all compounds. The highest POP concentrations in males and females were found for ∑DDTs and ∑PCBs. In blubber and serum, males had significantly greater concentrations than females for almost all compounds. For males and females, ∑DDT and ∑PBDEs were highly correlated in blubber and serum. While ∑PCBs were highly correlated with ∑DDTs and ∑PBDEs in blubber and serum for males, ∑PCBs showed weaker correlations with both compounds in females. As females gained mass while foraging, concentrations of nearly all POPs in inner and outer blubber significantly decreased; however, the absolute burden in blubber significantly increased, indicating ingestion of contaminants while foraging. Additionally, we identified three clusters of seal foraging behavior, based on geography, diving behavior, and stable carbon and nitrogen isotopes, which corresponded with differences in ∑DDTs, ∑PBDEs, MeO-BDE 47, as well as the ratio of ∑DDTs to ∑PCBs, indicating the potential for behavior to heighten or mitigate contaminant exposure. The greatest concentrations of ∑DDTs and ∑PBDEs were observed in the cluster that foraged closer to the coast and had blood samples more enriched in (13)C. Bioaccumulation of POPs by elephant seals supports mesopelagic food webs as a sink for POPs and highlights elephant seals as a potential sentinel of contamination in deep ocean food webs.

Measuring pesticide ecological and health risks in West African agriculture to establish an enabling environment for sustainable intensification

We outline an approach to pesticide risk assessment that is based upon surveys of pesticide use throughout West Africa. We have developed and used new risk assessment models to provide, to our knowledge, the first detailed, geographically extensive, scientifically based analysis of pesticide risks for this region. Human health risks from dermal exposure to adults and children are severe enough in many crops to require long periods of up to three weeks when entry to fields should be restricted. This is impractical in terms of crop management, and regulatory action is needed to remove these pesticides from the marketplace. We also found widespread risks to terrestrial and aquatic wildlife throughout the region, and if these results were extrapolated to all similar irrigated perimeters in the Senegal and Niger River Basins, they suggest that pesticides could pose a significant threat to regional biodiversity. Our analyses are presented at the regional, national and village levels to promote regulatory advances but also local risk communication and management. Without progress in pesticide risk management, supported by participatory farmer education, West African agriculture provides a weak context for the sustainable intensification of agricultural production or for the adoption of new crop technologies.

Polychlorinated biphenyls (PCBs) in marine fishes from China: levels, distribution and risk assessment

Muscle tissues of large yellow croakers (Pseudosciaena crocea) and sliver pomfret (Pampus argenteus) from nine coastal cities of East China including Dalian, Tianjin, Qingdao, Shanghai, Zhoushan, Wenzhou, Fuzhou, Quanzhou and Xiamen were analyzed for polychlorinated biphenyl (PCB) concentrations. Thirty-six PCB congeners were quantified in the fishes, of which 11 congeners were dioxin-like PCBs. The total PCB concentrations of the present study were at the low end of the global range, which may be related to the smaller usage and shorter consumption history of PCBs in China. PCBs 18, 29, 52, 66, 101, 104, 138, 153, 180 and 194 were the major constituents found in the fish samples. Regression analysis showed a strong positive correlation (R(2)=0.800; p<0.001) between total dioxin-like PCBs and total PCB concentrations, and that total PCB concentrations explain 80% of the variability in total dioxin-like PCB concentrations. Among the species investigated, significantly higher concentrations of total PCBs were found in croakers than in pomfrets, which may be attributed to their different feeding and living habits. No significant difference in total PCB concentrations among the cities was observed; principal component analysis (PCA) of PCB profiles indicated that PCB pollution came from similar sources in the sampling areas and that there may be other PCB sources in Dalian and Wenzhou. The calculated carcinogenic risks (CRs) from the two species based on a low consumption group and high consumption group were all greater than 10(-6), suggesting that daily exposure to dioxin-like PCBs via fish consumption results in a lifetime cancer risk of greater than one in one million. In contrast, the hazard quotients (HQs) of noncancer risks were all less than unity.

Organochlorine pesticides in seawater and the surrounding atmosphere of the marginal seas of China: spatial distribution, sources and air-water exchange

Shipboard air and surface seawater samples collected over the Yellow Sea, East China Sea and South China Sea were analyzed for organochlorine pesticides (OCPs). In air, γ-hexachlorocyclohexane (HCH), trans-chlordane (TC) and cis-chlordane (CC) had significantly (p<0.001) higher concentrations than α-HCH, o,p'-Dichlorodiphenyltrichloroethane (DDT), p,p'-DDE, p,p'-DDT and α-endosulfan. Generally, α-HCH concentrations in the atmosphere were quite uniform over the Chinese marginal seas. However, the highest concentrations of γ-HCH, TC, CC and DDT compounds were found in the southern parts of the marginal seas, and higher concentrations of α-endosulfan were observed in the northern part of the marginal seas. In water, the OCP concentrations varied over a narrow range, with hundreds picogram per liter levels. Air-water exchange gradients suggested net deposition or equilibrium for γ-HCH and o,p'-DDT and net volatilization for α-HCH, CC, TC, p,p'-DDE and p,p'-DDT. Due to the potential source of those compounds from coastal water runoff, the ocean water played an important role of OCP sources for the atmosphere after a long period of OCP prohibition.

A numerical study on the seasonal variability of polychlorinated biphenyls from the atmosphere in the East China Sea

A three-dimensional/high-resolution transport model for persistent organic pollutants (POPs) has been developed for the East China Sea (ECS). The POPs model has four compartments (gaseous, dissolved, phytoplankton-bound, and detritus-bound phases) and includes processes for diffusive air-water exchange, phytoplankton uptake/depuration to POPs, decomposition of dissolved phase, vertical sinking of phytoplankton, detritus production by phytoplankton mortality, and vertical sinking and decomposition of detritus. The POPs model is coupled with an ocean circulation model that can reproduce the seasonal variation in physical variables to represent the advection and diffusion of POPs. We applied the POPs model to the polychlorinated biphenyl congener 153 (PCB 153) from the atmosphere and examined the behavior of PCB 153 in the ocean. The model showed a remarkable seasonal variability of PCB 153. Concentrations in the dissolved and particulate phases are high in winter (January-March) and low in summer (July-September). In coastal regions, where chlorophyll a concentration is high, horizontal and vertical distributions in the dissolved and particulate PCB 153 concentrations are strongly affected by phytoplankton uptake. The sensitivity experiments on the dynamics of PCB 153 suggested that a change of Henry's law constant associated with water temperature is the major factor controlling the seasonal variability of PCB 153. The model-based yearly mass balance of PCB 153 in the ECS indicated that most of the atmospheric input (35.5 kg year(-1)) is removed by the horizontal advection outside the ECS (19.0 kg year(-1)) and accumulates to the sea bottom by vertical sinking (15.7 kg year(-1)). For comparison with PCB 153, we also conducted simulations for PCB 52, 101, and 180. The seasonal variations are similar to that of PCB 153. The mass balance of PCB 52 that has short half-life time and less hydrophobic property shows the different results compared with PCB 101, 153, and 180.

Monitoring temporal and spatial trends of legacy and emerging contaminants in marine environment: results from the environmental specimen bank (es-BANK) of Ehime University, Japan

The Environmental Specimen Bank (es-BANK) for Global Monitoring at the Center for Marine Environmental Studies, Ehime University, Japan has more than four decades of practical experience in specimen banking. Over the years, es-BANK has archived specimens representing a wide range of environmental matrices, i.e. fishes, reptiles, birds, aquatic mammals, terrestrial mammals, human, soils, and sediments. The samples have been collected as part of the various monitoring programs conducted worldwide. The current review is a summary of selected studies conducted at the Center for Marine Environmental Studies, on temporal and spatial trends of legacy and emerging contaminants in the marine environment. One of the major conclusions drawn from the studies is that environmental problems are no more regional issues and, thus, environmental specimen banking should not be limited to national boundaries, but should have a global outlook.

Levels of mercury and organohalogen compounds in Pacific bluefin tuna (Thunnus orientalis) cultured in different regions of Japan

Contamination levels of total mercury (T-Hg), p,p'-DDE, and polychlorinated biphenyls (PCBs) in akami (leaner meat) and toro (fatty meat) samples from Pacific bluefin tuna cultured in the southern (four locations) and central (three locations) regions of Japan were analyzed. The contamination level of T-Hg in the akami and toro samples from the southern region tended to decrease with an increase in latitude, whereas those of p,p'-DDE and PCBs tended to increase. These spatial trends in contaminants were similar to those reported previously in wild tuna caught off the coast of Japan (Hisamichi et al., in Environ Sci Technol 44:5971-5978, 2010). However, the contamination level of T-Hg in akami and toro samples from one location in the central region was the highest among all seven locations, whereas the contamination level of p,p'-DDE was lower than that from any location studied in the southern region. Thus, contamination levels of T-Hg, p,p'-DDE, and PCBs in the cultured tuna may reflect contamination levels not only in the marine environment but also in prey fish used as bait.

Exposure to toxic chemicals in the diet: is the Brazilian population at risk?

In Brazil, in the last 20 years, dietary risk assessments have been conducted on pesticides, mycotoxins, food additives, heavy metals (mainly mercury), environmental contaminants (mainly DDT) and acrylamide, a compound formed during food processing. The objectives of this paper were to review these studies, discuss their limitations and uncertainties and identify the most critical chemicals that may pose a health risk to Brazilian consumers. The studies have shown that the cumulative intake of organophosphorus and carbamate pesticides by high consumers of fruits and vegetables may represent a health concern (up to 169% of the ARfD), although the benefits of consuming large portions of those foods most probably overcome the risks. High consumers of maize products may also be at risk due to the presence of fumonisin (355% of the PMTDI), a mycotoxin present at high levels in Brazilian maize. The studies conducted in the Brazilian Amazon have shown that riparian fish consumers are exposed to unsafe levels of mercury. However, this is a more complex issue, as mercury levels in the region are naturally high and the health benefits of a fish-based diet are well known. Studies conducted both in Brazil and internationally on acrylamide have shown that the exposure to this genotoxic compound, mainly from the consumption of French fries and potato chips, is of health concern. Reducing the population dietary exposure to toxic chemicals is a challenge for government authorities and food producers in all countries. Management strategies aimed at decreasing exposure to the critical chemicals identified in this review involve limiting the use or eliminating highly toxic pesticides, implementing good agricultural practices to decrease maize contamination by fumonisins, educating local fish-eating communities toward a fish diet less contaminated by mercury, and changing dietary habits concerning the consumption of fried potatoes, the main processed food containing acrylamide.

Levels and distribution of polybrominated diphenyl ethers and organochlorine compounds in sea turtles from Japan

Three species of sea turtles (green, hawksbill and loggerhead turtles) stranded along the coasts or caught (by-catch) around Ishigaki Island and Kochi, Japan were collected between 1998 and 2006 and analyzed for six organohalogen compounds viz., PBDEs, PCBs, DDTs, CHLs, HCHs and HCB. The present study is the first and foremost to report the occurrence of organohalogen compounds in the sea turtles from Japan. Among the compounds analyzed, concentrations of PCBs, DDTs and CHLs were the highest in all the turtle samples. PBDEs were ubiquitously present in all the turtle species. Comparing with the other two species, concentrations of organohalogens in green turtle were relatively low and decreasing trend in the concentrations were noted with increasing carapace length. Concentrations of OCs in sea turtles from the coasts of Ishigaki Island and Kochi were relatively low as compared to those from other locations in the world.

Contamination status and spatial distribution of organochlorine compounds in fishes from Nansei Islands, Japan

Two species of fishes (n=52; tilapia and mullet) from industrialized and urbanized areas of Okinawa Island (Manko-Noha river, Hija river and Shikaza river) and from a remote area of Ishigaki Island (Anparu mudflat), Japan were collected between August 2005 and July 2006, and analyzed for five organochlorine compounds (OCs), viz., DDTs, PCBs, CHLs, HCHs and HCB. Concentrations and the contamination patterns of OCs in fishes varied between locations. Considerable residue levels of OCs, especially CHLs and DDTs were found in both fishes from the main Okinawa Island. These levels were relatively higher than the reported values for seafood from Japanese coasts, indicating that even now pollution sources of these contaminants still exist in this region. On the other hand, lower concentrations of OCs were detected in fishes from Ishigaki Island waters than those of other Japanese coastal waters, suggesting that this region is less contaminated by OC contaminants.

Effects of polychlorinated biphenyls on liver function and sexual characteristics in Japanese medaka (Oryzias latipes)

The effects of polychlorinated biphenyls (PCBs) on liver function and their differences between sexes were analyzed in Japanese medaka (Oryzias latipes) exposed to PCB126 or Kanechlor-400 (KC-400) using microarray. PCB exposure induced vitellogenin 1 expression in female medaka while suppressing choriogenin genes, which suggests that the effects of PCBs on estrogen-responsive genes do not occur directly through an estrogen receptor-mediated pathway. Reduction of androgen receptor alpha expression was also observed, and the gene expression pattern in PCB-exposed males changed to become more similar to that of females. Furthermore, changes in glycolysis-related genes indicate that PCB exposure might enhance glucose production via gluconeogenesis in the liver of medaka. Taken together, our results suggest that PCBs disrupt the endocrine system, especially androgen function, and may have the potential to cause demasculinizing effects. Additionally, induction of gluconeogenesis might be a response to maintain glucose levels consumed as a result of PCB exposures.

Specific profiles of polybrominated diphenylethers (PBDEs) and polychlorinated biphenyls (PCBs) in fish and tucuxi dolphins from the estuary of Paraíba do Sul River, Southeastern Brazil

Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) are ubiquitous pollutants in the environment and subject of several studies due to their adverse effects as endocrine disruptors. Despite the concern over widespread distribution of PBDEs even in sparsely populated regions of the world, few studies have reported their occurrence in Brazil. In this study, PBDEs and PCBs levels were measured in selected fish species and dolphins from Paraiba do Sul River, Brazil. BDE 47 and 85 were the predominant congeners. Low chlorinated congeners showed the highest concentrations in fish; however dolphins presented the highest proportion of PCBs 153, followed by 138 and 180. The daily intake of PBDEs and PCBs was estimated for the population of this region. PCB daily intake through consumption of croaker was above the limits set by the Brazilian Ministry of Agriculture, raising great concern over the existence of a source of PCB contamination in Brazil.

Organohalogen compounds in deep-sea fishes from the western North Pacific, off-Tohoku, Japan: Contamination status and bioaccumulation profiles

Twelve species of deep-sea fishes collected in 2005 from the western North Pacific, off-Tohoku, Japan were analyzed for organohalogen compounds. Among the compounds analyzed, concentrations of DDTs and PCBs (up to 23,000 and 12,400 ng/g lipid wt, respectively) were the highest. The present study is the foremost to report the occurrence of brominated flame retardants such as PBDEs and HBCDs in deep-sea organisms from the North Pacific region. Significant positive correlations found between delta(15)N ( per thousand) and PCBs, DDTs and PBDEs suggest the high biomagnification potential of these contaminants in food web. The large variation in delta(13)C (per thousand) values observed between the species indicate multiple sources of carbon in the food web and specific accumulation of hydrophobic organohalogen compounds in benthic dwelling carnivore species like snubnosed eel. The results obtained in this study highlight the usefulness of deep-sea fishes as sentinel species to monitor the deep-sea environment.

Hexachlorobenzene sources, levels and human exposure in the environment of China

This article summarizes the published scientific data on sources, levels and human exposure of hexachlorobenzene (HCB) in China. Potential sources of unintended HCB emission were assessed by production information, emission factors and environmental policies. HCB was observed in various environmental compartments in China. HCB levels increased from South China to North China in most of environmental compartments (air, soil and mussel). Some hotspots were identified near the factories producing and using HCB. In terms of spatial distribution, HCB concentrations in air and shellfish showed much variation, which indicated some primary emission sources in China. HCB levels in air and human milk in China were relatively higher than those in other countries, but HCB levels in other compartments were similar to those in Europe and other countries in Eastern Asia. In the limited studies on temporal trends of HCB levels in China, HCB concentrations in air, sediment, fish and human milk did not show a consistent downward trend. Although HCB levels in food and human milk does not pose a health risk in China at present, long-term exposure to HCB should not be overlooked.

Persistent organochlorine pollutants in Korean offshore waters: squid (Todarodes pacificus) as a biomonitor

Persistent organochlorine pollutants (POPs) such as polychlorinated biphenyls (PCBs), dichlorodiphenyl trichloroethane and its metabolites (DDTs), chlordane compounds (CHLs), and hexachlorocyclohexanes (HCHs) were determined in Japanese common squid collected from the offshore waters of Korea. Liver accumulated higher levels of contaminants than mantle. The sums of DDTs, PCBs, CHLs and HCHs in liver were in the ranges of 164-4430 ng g(-1), 95-1030 ng g(-1), 15-121 ng g(-1), and 13-98 ng g(-1) on a lipid weight basis, respectively. Among the POPs, DDTs showed distinct regional difference in concentration levels and composition between the western and eastern offshore of Korea. One of the highest concentrations of DDTs so far recorded in the western offshore of Korea, that is Yellow Sea. This implies ongoing fresh input of technical DDT to this regional sea. HCHs were relatively high in the Yellow Sea as well, with an enhanced signal of gamma-HCH indicating recent input of lindane. In contrast, CHLs showed higher level in the eastern offshore of Korea, that is East Sea, but PCBs showed an even distribution in both regions. Squid could be a useful bio-indicator for monitoring offshore water contamination by POPs.

Skipjack tuna as a bioindicator of contamination by perfluorinated compounds in the oceans

Perfluorinated chemicals (PFCs) have emerged as global environmental contaminants. Studies have reported the widespread occurrence of PFCs in biota from marine coastal waters and in remote polar regions. However, few studies have reported the distribution of PFCs in biota from offshore waters and open oceans. In this study, concentrations of nine PFCs were determined in the livers of 60 skipjack tuna (Katsuwonus pelamis) collected from offshore waters and the open ocean along the Pacific Rim, including the Sea of Japan, the East China Sea, the Indian Ocean, and the Western North Pacific Ocean, during 1997-1999. At least one of the nine PFCs was found in every tuna sample analyzed. Overall, perfluorooctanesulfonate (PFOS) and perfluoroundecanoic acid (PFUnDA) were the predominant compounds found in livers of tuna at concentrations of <1-58.9 and <1-31.6 ng/g, wet wt, respectively. Long-chain perfluorocarboxylates such as perfluorodecanoic acid (PFDA) and perfluorododecanoic acid (PFDoDA) were common in the tuna livers. In livers of tuna from several offshore and open-ocean locations, concentrations of PFUnDA were greater than the concentrations of PFOS. The profiles and concentrations of PFCs in tuna livers suggest that the sources in East Asia are dominated by long-chain perfluorocarboxylates, especially PFUnDA. High concentrations of PFUnDA in tuna may indicate a shift in sources of PFCs in East Asia. The spatial distribution of PFOS in skipjack tuna reflected the concentrations previously reported in seawater samples from the Pacific and Indian Oceans, suggesting that tuna are good bioindicators of pollution by PFOS. Despite its predominance in ocean waters, PFOA was rarely found in tuna livers, indicative of the low bioaccumulation potential of this compound. Our study establishes baseline concentrations of PFCs in skipjack tuna from the oceans of the Asia-Pacific region, enabling future temporal trend studies of PFCs in oceans.

Global contamination of coplanar polybrominated/chlorinated biphenyls (Co-PXBs) in the market fishes from Japan

Polybrominated chlorinated biphenyls (PXBs, X=Br, Cl) are a group of environmental contaminants that have not been studied previously. The introduction of the second halogen to the biphenyl backbone increases the number of possible congeners to more than 9000. Only a limited number of PXBs are commercially available. In order to determine the occurrence of these compounds in environmental matrices, an isotope dilution HRGC/HRMS method for determination of five co-planar polybrominated/chlorinated biphenyls (Co-PXBs) in biota was developed. The method detection limit for these compounds ranged between 0.05 and 0.5 pg/g for 4'-monobromo-3,3',4,5-tetrachlorobiphenyl and 3',4',5'-tribromo-3,4-dichlorobiphenyl, respectively. Concentrations of five co-planar polybrominated and chlorinated biphenyls in eighteen different fish fillets from Japanese markets ranged between 4 and 46 pg/g wet weight for mink whale and young yellow-tail fish. These values are substantially lower than those reported for Co-PCBs; however, it should be noted that due to the unavailability of standards, identification and quantification of all the isomers was not possible.

Historical distribution of PCDDs, PCDFs, and coplanar PCBs in sediment core of Ariake Bay, Japan

Persistent organic pollutants, particularly polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), coplanar polychlorinated biphenyls (co-PCBs) and toxic equivalent quantity (pg TEQ g(-1)) were determined in sediment samples collected from Ariake Bay, Japan. The total concentration of PCDDs/DFs in surface sediment of the Yabe River (17,000 pg g(-1) dry wt) was approximately 2.5-fold higher than that of the Chikugo River (7,000 pg g(-1) dry wt) which has the highest flow amount of about 40% inputting to the northern Bay. The congener profile suggested that dioxin sources could be close to the study area. The PCDDs concentration (12,000 pg g(-1) dry wt) in the sediment layer, which was corresponding to the 1960s, was reflected on the pentachlorophenol (PCP) contamination occurring at that time in Ariake Bay. The reflecting of PCP in the sediment core was significantly considered by hierarchical cluster analysis. Based on isomer-specific analysis, the tetrachlorodibenzo-p-dioxin composition showed a gradual increase from 1978-1982 toward the surface, indicating that the pollution source at that period might be more influenced by chloronitrofen than PCP. This fact was supported, based on the ratio of Sigma PCDD to Sigma PCDF concentration. The PCDDs/DFs-derived TEQ contributed more than 90% of the SigmaTEQ (PCDDs/DFs and co-PCBs) in all the detected sediment layers. The contribution of PCBs to the total TEQ was low; however, an increasing historical trend of concentration was clearly observed.

Alteration of gene expression profiles in the brain of Japanese medaka (Oryzias latipes) exposed to KC-400 or PCB126

Polychlorinated biphenyls (PCBs) are known as neurotoxic chemicals and possibly alter animal behavior. We previously reported that PCB-exposure induced abnormal schooling behavior in Japanese medaka (Oryzias latipes). This abnormal behavior might be caused by the functional alteration of central or terminal nervous system. To understand the mechanism(s) of behavioral change by PCB-exposure, we analyzed the gene expression profiles in the brain of medaka exposed to 3,3',4,4',5-pentachlorobiphenyl (PCB126) or a PCB mixture (Kanechlor-400: KC-400) using a cDNA microarray that we constructed. Twelve FLF-II strain medaka (six individuals per treatment) were dietary exposed to PCB126 (0.01 microg/g b.w./day) or KC-400 (1 microg/g b.w./day) for three weeks. For the control, six fish were fed a control diet. After the exposure period, fish were dissected, and the brain samples were collected. The samples from control fish were pooled and used as a common reference in the microarray experiment. Microarray data were normalized by the LOWESS method, and we screened the genes whose expression levels were altered more than 1.5-fold. Gene expression profiling showed 97 down-regulated and 379 up-regulated genes in the brain of medaka exposed to PCB126. KC-400 exposure suppressed 15 genes and induced 266 genes in medaka brain. Among these genes, the expression levels of 7 and 188 genes were commonly down- or up-regulated, respectively in both treatment groups. On the other hand, 31 gene expressions were significantly different between PCB126 and KC-400 treatment groups, and three out of 31 genes were received opposite effects. In addition, the microarray data showed that thyroid hormone-responsive genes were up-regulated by PCB-exposure, which may imply that PCBs or their metabolites mimic thyroid hormone effects in the brain of PCB-exposed medaka.

Brominated flame retardants in the environment of Asia-Pacific: an overview of spatial and temporal trends

In this paper, we summarize spatial and temporal trends of polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) in coastal and marine biota, and further assess human exposure to these brominated flame retardants (BFRs) in Asia-Pacific. The review is based mainly on the studies that were conducted in our laboratory and utilized samples archived in the environmental specimen bank (es-BANK) of Ehime University, Japan. The studies suggest that the target BFRs are ubiquitous in the environment of Asia-Pacific. Examination of spatial trends reveals that concentrations of these contaminants are relatively high in samples from Korea, South China and Japan. In general, the magnitude of environmental contamination by PBDEs in Asia-Pacific, as well as human exposure to these contaminants, seem to be comparable to or slightly higher than in Europe, but lower than in North America. Evaluation of temporal trends in concentrations of BFRs in marine mammals from the coastal waters of Japan and China showed drastic increase during the last 30 years. These changes in BFR levels in samples from Japan were in line with trends in production/use of the commercial formulations. Since the withdrawal of some PBDE products from the Japanese market in the 1990s, concentrations of HBCDs appear to exceed those of PBDEs, reflecting increasing usage of HBCDs over PBDEs. The increasing environmental contamination by BFRs in Chinese coastal waters indicates that contamination by BFRs has already become evident, even in developing countries. In view of the rising environmental levels and the high consumption volume of BFRs in Asia, further efforts should be made to monitor environmental contamination by these chemicals in order to identify sources and reduce emissions.

Levels and distribution of organochlorines in fish from Indonesia

Organochlorines such as PCBs, DDTs, HCHs, CHLs and HCB were determined in pooled whole body homogenized of fish samples collected from five locations during 1998 and 2003 in order to understand their contamination status, temporal and spatial variation in Indonesian waters. PCBs and DDTs were the predominant contaminants with concentrations from 9.7 to 2700 ng/g lipid wt. and 12 to 1100 ng/g lipid wt., respectively, while HCHs (nd-24 ng/g lipid wt.), CHL compounds (nd-81 ng/g lipid wt.) and HCB (0.22-28 ng/g lipid wt.) were one to two orders of magnitude lower. Among the locations, PCBs and CHLs were higher in the samples from highly industrialized and thickly populated-locations, whereas OC pesticides such as DDTs and HCHs were particularly more prominent in suburban and rural areas. Levels of OCs observed in the waters surrounding Java Island were higher than those in Sumatra Island, implying significant use of OCs in highly populated Java Island. Concentrations of PCBs and DDTs in fish from Jakarta Bay were significantly lower in the samples collected in 2003 as compared to fish in 1998, indicating decreasing trend of these compounds in the Indonesian environment. Recent estimated average daily intakes of PCBs (0.81 microg/person/day), DDTs (1.1 microg/person/day), HCHs (0.018 microg/person/day), CHLs (0.010 microg/person/day) were much lower than the threshold values recommended by various agencies, suggesting minimal risk of this compound via fish ingestion to Indonesians.

Asian Mussel Watch Program: contamination status of polybrominated diphenyl ethers and organochlorines in coastal waters of Asian countries

Mussel samples were used in this study to measure the levels of polybrominated diphenyl ethers (PBDEs) and organochlorines (OCs) in the coastal waters of Asian countries like Cambodia, China, Hong Kong, India, Indonesia, Japan, Korea, Malaysia, the Philippines, and Vietnam. PBDEs were detected in all the samples analyzed, and the concentrations ranged from 0.66 to 440 ng/g lipid wt. Apparently higher concentrations of PBDEs were found in mussels from the coastal waters of Korea, Hong Kong, China, and the Philippines, which suggests that significant sources of these chemicals exist in and around this region. With regard to the composition of PBDE congeners, BDE-47, BDE-99, and BDE-100 were the dominant congeners in most of the samples. Among the OCs analyzed, concentrations of DDTs were the highest followed by PCBs > CHLs > HCHs > HCB. Total concentrations of DDTs, PCBs, CHLs, and HCHs in mussel samples ranged from 21 to 58 000, 3.8 to 2000, 0.93 to 900, and 0.90 to 230 ng/g lipid wt., respectively. High levels of DDTs were found in mussels from Hong Kong, Vietnam, and China; PCBs were found in Japan, Hong Kong, and industrialized/urbanized locations in Korea, Indonesia, the Philippines, and India; CHLs were found in Japan and Hong Kong; HCHs were found in India and China. These countries seem to play a role as probable emission sources of corresponding contaminants in Asia and, in turn, may influence their global distribution.

Distribution of organochlorine pesticides in the northern South China Sea: implications for land outflow and air-sea exchange

The South China Sea (SCS) is surrounded by developing countries in Southeast Asia, where persistent organic pollutants (POPs), such as organochlorine pesticides (OCPs), are still used legally or illegally, and are of concern. Yet little is known about the distribution of OCPs in the water and atmosphere over SCS, as well as their air-sea equilibrium status and time trends. In this study, ship-board air samples and surface seawater collected in the northern SCS between September 6 and 22, 2005 were analyzed for selected OCPs. The measured OCP concentrations in the atmosphere over the northern SCS were influenced by proximity to source regions and air mass origins. The highest atmospheric OCP concentrations were found at sampling sites adjacent to continental South China. OCPs in surface seawater showed significant spatial variations, with the highest concentration observed in a water sample from off Vietnam. The coastal currents were suggested to play a key role in the delivery of waterborne OCPs in the northern SCS. Time trend, land outflow, and air-sea exchange of selected OCPs in the SCS were investigated, by comparison of this dataset with historical data.