Organic contaminants and trace metals in flounder liver and sediment from the Amsterdam and Rotterdam harbours and off the Dutch coast

Differences on the level of hepatic transcriptome between two flatfish species in response to liver cancer and environmental pollution levels

Environmental factors can cause cancer in both wild animals and humans. In ecological settings, genetic variation and natural selection can sometimes produce resilience to the negative impacts of environmental change. An increase in oncogenic substances in natural habitats has therefore, unintentionally, created opportunities for using polluted habitats to study cancer defence mechanisms. The Baltic and North Sea are among the most contaminated marine areas, with a long history of pollution. Two flatfish species (flounder, Platichthys flesus and dab, Limanda limanda) are used as ecotoxicological indicator species due to pollution-induced liver cancer. Cancer is more prevalent in dab, suggesting species-specific differences in vulnerability and/or defence mechanisms. We conducted gene expression analyses for 30 flatfishes. We characterize between- and within-species patterns in potential cancer-related mechanisms. By comparing cancerous and healthy fishes, and non-cancerous fishes from clean and polluted sites, we suggest also genes and related physiological mechanisms that could contribute to a higher resistance to pollution-induced cancer in flounders. We discovered changes in transcriptome related to elevated pollutant metabolism, alongside greater tumour suppression mechanisms in the liver tissue of flounders compared to dabs. This suggests either hormetic upregulation of tumour suppression or a stronger natural selection pressure for higher cancer resistance for flounders in polluted environment. Based on gene expression patterns seen in cancerous and healthy fish, for liver cancer to develop in flounders, genetic defence mechanisms need to be suppressed, while in dabs, analogous process is weak or absent. We conclude that wild species could offer novel insights and ideas for understanding the nature and evolution of natural cancer defence mechanisms.

Temporal trends, sources, and ecological risk of residual organochlorine pesticides (OCPs) in sediment core from the Dongping Lake, North China

A sedimentary record of the 19 organochlorine pesticides (OCPs) pollutants from Dongping Lake, north China, is presented in this study. According to the dating of core sediment and OCP content analysis in samples, from 1904 to 2016, the total concentration of OCPs varied from undetectable levels (n.d.) to 33.1 ng/g. The OCP concentration was first detected in the samples of 1938, and then gradually increased to a peak level in 2000 thereafter decreased until 2016. Among the detected OCPs, hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) were the predominant and the most frequently detected contaminants in the core sediment, with concentrations ranging from n.d. to 16.9 ng/g and from n.d. to 8.8 ng/g, respectively. The distribution of OCPs in the sediments was affected by organic carbon concentration, showing a significant positive correlation (r = 0.93, p < 0.001), especially for HCHs (r = 0.98, p < 0.001). The source analysis showed that HCH contamination mainly derived from historical use of technical HCHs, while in recent years, it derived from lindane usage. DDT pollution was attributed to historical use of technical DDTs, as well as the microbial degradation of historic DDT residues. Finally, risk analysis was performed for OCPs in sediment cores based on sediment quality guidelines from the Canadian Council of Ministers of the Environment, showing that DDTs presented a high ecological toxicity risk during the period of 1959-2010.

Heavy Metals in Sapropel of Lakes in Suburban Territories of Vilnius (Lithuania): Reflections of Paleoenvironmental Conditions and Anthropogenic Influence

Geochemical and lithological parameters of sapropel in lakes, combined with pollen data and radiocarbon 14C dating, contain a wide spectrum of environmental information. This includes records of fluctuations of water level and changes of conditions of sedimentation, accumulation of organic matter and chemical elements due to climate change, human impacts and other environmental changes. Rising concentrations of hazardous substances in the natural sediments are likely to be a high risk to the natural environment. At the same time, they can greatly reduce opportunities for environmental engineering of lakes. Four lakes with different trophic states and anthropogenic pressures were chosen for this study in Lithuania. Higher concentrations of elements like Cr, Cu and Zn were not only detected in the top most layers of sapropel but also in deeper layers and are attributed to lithogenic association of trace elements in such deep layers. Concentrations of Pb were detected only in upper layers of sapropel which indicates the impact of anthropogenic activity. The main source of heavy metals was multidimensional anthropogenic pollution leading to a biogenic–anthropogenic association of elements. Sapropel with low concentrations of heavy metals exhibits a different inter-association matrix because most of the elements tend to form lithogenic–clastogenic associations.

Distribution and risk assessment of hexachlorobutadiene, pentachloroanisole, and chlorobenzenes in sediment and wild fish from a region affected by industrial and agricultural activities in South China

Hexachlorobutadiene, pentachloroanisole, and chlorobenzenes are regulated to control their release into the environment. There is little information regarding the distribution and risks of these pollutants in Chinese rivers. Therefore, we selected a prosperous agricultural and industrial region in South China as our study area and investigated the contamination profiles and risks of these pollutants in sediment and fish tissue samples. The results showed that, when compared with their levels in sediment, these lipophilic pollutants tended to accumulate in fish tissues in the following order: liver > brain > muscle. Some trichlorobenzene was found to be the result of reductive dechlorination of higher chlorinated benzenes. Hexachlorobutadiene and hexachlorobenzene could pose medium risks at certain sampling sites, but in general, almost no risk was found to the ecosystem. When the estimated daily human intakes of analytes through fish consumption were calculated for different age groups, the results suggested the analytes were unlikely to be a serious health concern for human. Our results could be used to update the existing data on the occurrence of these pollutants in the aquatic environment and to provide information for further pollution control by the local government.

Hazardous substances in the sediments and their pathways from potential sources in the eastern Gulf of Finland

Contamination by hazardous substances is one of the main environmental problems in the eastern Gulf of Finland, Baltic Sea. A trilateral effort to sample and analyse heavy metals (HMs), polycyclic aromatic hydrocarbons (PAHs), and organotins from bottom sediments in 2019-2020 were conducted along with harvesting historical data in Russian, Estonian and Finnish waters. We suggest that the input of organotins still occurs along the ship traffic routes. The tributyltin content exceeded the established quality criteria up to more than 300 times. High contamination by PAHs found near the ports, most likely originate from incomplete fuel incineration processes. The Neva River Estuary and Luga Bay might potentially suffer from severe cadmium contamination. The high ecological risk attributed to the HMs was detected at deep offshore areas. The simulated accumulation pattern qualitatively agrees with field observations of HMs in sediments, demonstrating the potential of numerical tools to tackle the hazardous substances problems.

Exposure radius of a local coal mine in an Arctic coastal system; correlation between PAHs and mercury as a marker for a local mercury source

Mercury in the Arctic originates from emissions and releases at lower latitudes and, to a lesser extent, from local and regional sources. The relationship between mercury (Hg) and polycyclic aromatic hydrocarbons (PAHs) in sediment can be applied as an indicator of the mercury source. This research examines the Hg contamination gradient from a land-based coal mine to the surrounding coastal environment to quantify the impact of local sources. Total mercury and PAH (Σ₁₄PAH) were measured in terrestrial and marine sediments as well as in marine biota. Samples were collected at the mine and two reference sites. Mercury and Σ₁₄PAH concentrations in samples collected at the mine site were significantly higher than those at the reference sites. This was also found in the biota samples, although less pronounced. This work addresses the complexities of interpreting data concerning very low contaminant levels in a relatively pristine environment. A clear correlation between PAH and Hg concentration in sediment was found, although a large number of samples had levels below detection limits. PAH profiles, hierarchical clustering, and molecular diagnostic ratios provided further insight into the origin of PAHs and Hg, showing that signatures in sediments from the nearest reference site were more similar to the mine, which was not the case for the other reference site. The observed exposure radius from the mine was small and diluted from land to water to marine biota. Due to low contamination levels and variable PAH profiles, marine biota was less suitable for tracing the exposure radius for this local land-based Hg source. With an expected increase in mobility and availability of contaminants in the warming Arctic, changes in input of PAHs and Hg from land-based sources to the marine system need close monitoring.

Characterization of SDGs towards Coastal Management: Sustainability Performance and Cross-Linking Consequences

The Sustainable Development Goals (SDGs) and associated targets focus on a wide range of global issues and can be useful in coastal challenges such as climate change and green economic growth. The aim of this study is to tailor the SDGs, as a universally recognized policy framework, to assess the sustainability performance for coastal flood protection management to enhance climate-resilient and adaptable coastal development. To operationalize this aim, the SDG Sustainability Impact Score (SDG-SIS) framework was developed. Based on system functionalities for the land–sea interface, 38 SDGs were identified in the SDG-SIS framework. Given the availability of public numeric data, only 12 SDG targets are connected with Key Performance Indicators (KPIs). The SDG-SIS framework was applied to two different sets of cases, including five coastline and five sand nourishment cases. This study shows that the geographical and socioeconomic characteristics of the two sets of cases should be considered in the selection of system functionalities as well as the consideration of SDG targets. Moreover, cross-linking cumulative consequences of SIS do not directly indicate the level of sustainability, but the individual SDG target data are essential to reveal the underlying details. This stresses the importance of prioritizing SDGs to serve as leverage for policymakers to optimize the climate resilience and adaptation of coastal management. The SDG-SIS framework enables the support of coastal policy by addressing long-term measures and providing a sustainable vision for future implementation.

The occurrence and distribution of nonylphenols and nonylphenol ethoxylates in different species of fish

The aim of this study was to analyze the accumulation of nonylphenols (NPs) and nonylphenol ethoxylates (NPEOs) in the muscles, liver, and bile of flounder (Platichthys flesus), cod (Gadus morhua), and eels (Anguilla anguilla). The flounder and cod were caught in the Gulf of Gdańsk (the Baltic Sea), while the eels were sampled in the Vistula and Szczecin lagoons (the Baltic Sea) and in the inland waters of the Masurian Lake District. NP concentrations in muscles were low in all the samples analyzed and ranged from 14.2 to 28.2 μg-1 kg ww. In contrast, a wide range of NP concentrations were observed in livers, which seemed to depend on both the species and the feeding status of the fishes. NP levels in flounder and eel livers were from three to twenty times higher than those in the muscles, but they were below the limit of quantitation (LOQ) in all the cod liver samples. The mean concentration of NPs in the liver of flounder caught in the Gulf of Gdańsk was 222 μg kg-1 ww, while in that of the eel ranged from 57 μg kg-1 ww in fish caught in the Masurian Lake District to 519 μg kg-1 ww in eels caught in the Vistula Lagoon. NPs were detected in bile in only a few eel samples, which indicated that bile analysis has limited applications for estimating NP contamination in marine fish. The NPEOs in all the samples analyzed were below the LOQ.

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.

Organochlorine pesticides and polychlorinated biphenyls in the Bering flounder (Hippoglossoides robustus) from the Sea of Okhotsk

The purpose of this study is to establish the presence of POPs in the Bering flounder (Hippoglossoides robustus) from the Sea of Okhotsk (North-West Pacific). Concentration of OCPs (α-HCH, β-HCH, γ-HCH, o,p'-DDT, p,p'-DDT, o,p'-DDD, p,p'-DDD, o,p'-DDE and p,p'-DDE) and PCBs (28, 52, 155, 101, 118, 143, 153, 138, 180, 207) in samples were measured by GC-MS and GC-ECD. The mean OCP concentrations in flounder from East and South areas of the Sea of Okhotsk were 99.8 ± 125.4 and 53.6 ± 40.5 ng/g lipid, respectively; PCB congeners - 112 ± 94.2 and 88.8 ± 50.8 ng/g lipid, respectively. POPs in fish tissue decreased in the order: PCBs > HCHs > DDTs. Our results indicate that consumers will have no health risk due to fish consumption from Sea of Okhotsk. OCP and PCB levels in the Sea of Okhotsk may be considered as background level for the North Pacific.

Endosulfan, Short-Chain Chlorinated Paraffins (SCCPs) and Octachlorostyrene in Wildlife from Greenland: Levels, Trends and Methodological Challenges

Besides globally banned "legacy" persistent organic pollutants, other compounds might be present in Arctic wildlife, for which regulation was introduced recently (the insecticide endosulfan), is considered (short-chain chlorinated paraffins, SCCPs) or does not exist (octachlorostyrene, OCS, a byproduct of manufacturing and combustion processes involving chlorine). The purpose of this study was to analyze the time trend of endosulfan (1986-2012) in ringed seals and to address the levels of SCCPs and OCS in wildlife species from Greenland (black guillemot, glaucous gull, ringed seal, polar bear), while taking a critical standpoint to analytical methods typically applied. The metabolite endosulfan sulfate was the only endosulfan compound consistently above detection limits, with a median concentration of 0.23 ng/g lipid weight (lw) and a significant annual decrease of -5.6%. The low-resolution mass spectrometry (LRMS) method appeared accurate and sufficiently precise; however, the gel permeation chromatography had to balance lipid removal and analyte loss. SCCPs and OCS were present in all samples. OCS median concentrations were between 2.8 (ringed seal blubber) and 29 (glaucous gull liver) ng/g lw, determined by a straightforward dual column electron capture detection method. SCCPs were analyzed by LRMS, following removal of potential interferences, and had median concentrations of several 100 ng/g wet weight. While the method showed good precision and recovery rates as well as acceptable accuracy in control samples, the Greenland samples had high concentrations in an Arctic context, possibly indicating limited selectivity of the LRMS method.

Metals in the Scheldt estuary: From environmental concentrations to bioaccumulation

To investigate the relationship between metal concentrations in abiotic compartments and in aquatic species, sediment, suspended matter and several aquatic species (Polychaeta, Oligochaeta, four crustacean species, three mollusc species and eight fish species) were collected during three seasons at six locations along the Scheldt estuary (the Netherlands-Belgium) and analysed on their metal content (Ag, Cd, Co, Cr, Cu, Ni, Pb, Zn and the metalloid As). Sediment and biota tissue concentrations were significantly influenced by sampling location, but not by season. Measurements of Acid Volatile Sulphides (AVS) concentrations in relation to Simultaneously Extracted Metals (SEM) in the sediment suggested that not all metals in the sediment will be bound to sulphides and some metals might be bioavailable. For all metals but zinc, highest concentrations were measured in invertebrate species; Ag and Ni in periwinkle, Cr, Co and Pb in Oligochaete worms and As, Cd and Cu in crabs and shrimp. Highest concentrations of Zn were measured in the kidney of European smelt. In fish, for most of the metals, the concentrations were highest in liver or kidney and lowest in muscle. For Zn however, highest concentrations were measured in the kidney of European smelt. For less than half of the metals significant correlations between sediment metal concentrations and bioaccumulated concentrations were found (liver/hepatopancreas or whole organism). To calculate the possible human health risk by consumption, average and maximum metal concentrations in the muscle tissues were compared to the minimum risk levels (MRLs). Concentrations of As led to the highest risk potential for all consumable species. Cadmium and Cu posed only a risk when consuming the highest contaminated shrimp and shore crabs. Consuming blue mussel could result in a risk for the metals As, Cd and Cr.

Integrated hazard, risk and impact assessment of tropical marine sediments from Tema Harbour (Ghana)

The potential ecological hazard, risk and impact of tropical marine sediments from the Tema Harbour (Greater Accra, Ghana) was investigated by integrating Corophium volutator and Hediste diversicolor whole-sediment toxicity bioassays with data on the metals (Cd, Pb, Cr, Ni, Cu, Zn and As) concentrations of the sediments. The whole-sediment toxicity bioassay results showed that sediments of the Tema Harbour are potentially hazardous to marine benthic invertebrates. C. volutator exhibited a higher vulnerability to the sediment toxicity than H. diversicolor, although the latter showed higher biota-sediment accumulation factors for the investigated metals. Statistically significant correlations were observed between C. volutator mortality and sediment Cd concentration (r = 0.84, p < 0.05; n = 6) and between H. diversicolor mortality and sediment Cu concentration (r = 0.94, p < 0.05; n = 5). Comparison of metal concentrations with international action levels for contaminated sediment disposal indicates that the Tema Harbour sediments contain potentially hazardous concentrations of Cu and Zn. This study shows that sediments from the Tema Harbour are not suitable for disposal at sea without remediation. There is, therefore, a need to improve environmental management and regulate the disposal of dredged material originating from the Tema Harbour.

A review of new and current-use contaminants in the Arctic environment: evidence of long-range transport and indications of bioaccumulation

Systematic monitoring of persistent organic pollutants (POPs) in the Arctic has been conducted for several years, in combination with assessments of POP levels in the Arctic, POP exposure and biological effects. Meanwhile, environmental research continues to detect new contaminants some of which could be potential new Arctic pollutants. This study summarizes the empirical evidence that is currently available of those compounds in the Arctic that are not commonly included in chemical monitoring programmes. The study has focused on novel flame retardants, e.g. alternatives to the banned polybrominated diphenyl ethers (PBDEs), current-use pesticides and various other compounds, i.e. synthetic musk compounds, siloxanes, phthalic acid esters and halogenated compounds like hexachlorobutadiene, octachlorostyrene, pentachlorobenzene and polychlorinated naphthalenes. For a number of novel brominated flame retardants, e.g. 2,3-bibromopropyl-2,4,6-tribromophenyl ether (DPTE), bis(2-ethylhexyl)tetrabromophthalate (TBPH), 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (TBB), 1,2-bis(2,4,6-tribromophenoxy)-ethane (BTBPE), decabromodiphenyl ethane (DBDPE), pentabromoethylbenzene (PBEB) and hexabromobenzene (HBBz), transport to the Arctic has been documented, but evidence of bioaccumulation is sparse and ambiguous. For short-chain chlorinated paraffins and dechlorane plus, however, increasing evidence shows both long-range transport and bioaccumulation. Ice cores have documented increasing concentrations of some current-use pesticides, e.g. chlorpyrifos, endosulfan and trifluralin, and bioaccumulation has been observed for pentachloroanisole, chorpyrifos, endosulfan and metoxychlor, however, the question of biomagnification remains unanswered.

Distributions and sources of persistent organic pollutants (aliphatic hydrocarbons, PAHs, PCBs and pesticides) in surface sediments of an industrialized urban river (Huveaune), France

Surface sediments from the Huveaune River were analyzed for n-alkanes, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine and organophosphorous pesticides (OCs and OPs) by using gas chromatography-mass spectrometry (GC-MS). Concentrations of total alkanes ranged from 184 to 26,780 μg·kg(-1) sediment dry weight (dw) with a mean concentration of 6,126 ± 8,006 μg·kg(-1)dw, concentrations of total PAHs ranged from 572 to 4,235 μg·kg(-1)dw with a mean concentration of 1966 ± 1,104 μg·kg(-1) dw, concentrations of total PCB ranged from 2.8 to 435 μg·kg(-1)dw with a mean concentration of 148 ± 164 μg·kg(-1)dw and concentrations of total pesticides ranged from 0.07 to 1.25 μg·kg(-1)dw with a mean concentration of 1.23 ± 1.29 μg·kg(-1)dw. The spatial distribution of POPs reveals that pollutant concentration is relatively higher at the mouth of the river. The molecular indices of specific n-alkanes (CPI, NAR and TAR) and molecular indices of PAHs (Ant/(Ant+Phe), Fl/(Fl+Pyr), BaA/(BaA+Chry), IPyr/(Ipyr+BghiP)) were calculated to evaluate the possible sources of hydrocarbons. These molecular indices suggest mainly pyrolytic inputs which are markedly biogenic. All contaminant levels were also compared with Sediments Quality Guidelines (SQG) showing that the contamination levels in all stations were most of the time lower than their respective SQG. While, for PCBs, five stations (H5, H6, H7, H8 and H9) were higher than their effect range median (ERM) values which may indicate high potential toxicity of the sediment with probable adverse effects to the living biota.

Analysis of HCHs and DDTs in a sediment core from the Old Yellow River Estuary, China

The present study analyzed the distribution of HCHs and DDTs in a sediment core from the Old Yellow River Estuary, China. The OCP levels were detected by Soxhlet extraction followed by gas chromatography (GC) using a mass-selective detector. Sediment age was analyzed for (210)Pb using an Ortec GWL HPGe gamma spectrometer. The results indicated that the concentrations of ∑DDT in the sediment core were much lower than those of ∑HCH. Compared with the other estuarine and coastal regions in Chinese rivers, HCHs levels in this area were higher or similar, while DDTs levels were lower. The compositional analysis indicated that β-HCH and p, p'-DDD were the predominant species. The temporal trends indicated that levels of HCHs and DDTs were related with their historical usage, emission and soil residues. According to the analysis of the ratio, HCHs in this area was mainly due to the technical historical residue and recent lindane. DDTs was mainly due to historical residue. The biodegradation conditions for DDTs were anaerobic. The dicofol-type DDTs application occurred in this area.

Metabolic activation of nonpolar sediment extracts results in enhanced thyroid hormone disrupting potency

Traditional sediment risk assessment predominantly considers the hazard derived from legacy contaminants that are present in nonpolar sediment extracts, such as polychlorinated biphenyls (PCBs), dioxins, furans (PCDD/Fs), and polyaromatic hydrocarbons (PAHs). Although in vivo experiments with these compounds have shown to be thyroid hormone disrupting (THD), in vitro their THD potency is not observed in nonpolar sediment extracts. This is hypothesized to be due to the absence of in vitro biotransformation which will result in bioactivation of the lipophilic compounds into THD hydroxyl metabolites. This study reveals that indeed metabolically activated nonpolar contaminants in sediments can competitively bind to thyroid hormone transport proteins. Sediment fractions were incubated with S9 rat microsomes, and the metabolites were extracted with a newly developed method that excludes most of the lipids to avoid interference in the applied nonradioactive 96-well plate TTR competitive binding assay. Metabolic activation increased the TTR binding potency of nonpolar fractions of POP-polluted sediments up to 100 times, resulting in potencies up to 240 nmol T4 equivalents/g sediment equivalent (nmol T4-Eq/g SEQ). This demonstrates that a more realistic in vitro sediment THD risk characterization should also include testing of both polar and medium polar sediment extracts for THD, as well as bioactivated nonpolar sediment fractions to prevent underestimation of its toxic potency.

Historical contamination and ecological risk of organochlorine pesticides in sediment core in northeastern Chinese river

Twenty-eight surface sediment samples and one sediment core were analyzed for 21 organochlorine pesticides (OCPs), in order to provide extensive information of distribution, sources, pollution history and ecological risk of these OCP compounds in Daling River area, China. The results showed that hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) were the most frequently detected contaminants in the surface sediment samples with concentrations (in ngg(-1) dry weight (dw)) from 1.1 to 30 and from 2.2 to 45, respectively. Analysis of variance showed significant (P<0.05) differences between HCHs and DDTs residues in surface sediment sampled from the various locations. Residues of HCHs and DDTs in sediment core (in ngg(-1)dw) ranged from 2.1 to 18 and 9.1 to 53, respectively. The temporal trends of HCHs and DDTs concentrations in the sediment core were affected by application history, emission and soil residues. Compositional analysis of HCHs and DDTs indicated that new sources were lindane and dicofol mainly due to agricultural activities. Additionally, based on the available sediment quality guidelines, slight potential health risks of DDTs may exist to benthic organisms in Daling River and Bohai Sea.

Persistent organochlorine pollutants and metals residues in sediment and freshwater fish species cultured in a shallow lagoon, Egypt

Six freshwater fish species cultured in Lake Edku fish farm, one of the northern Nile Delta lakes in Egypt that receives input from numerous anthropogenic activities in addition to agriculture wastes through several huge drains, were collected for the detection and evaluation of residues of the persistent organochlorine (OC) pollutants polychlorinated biphenyls (PCBs), 1,1,1 -trichloro-2,2-di(4-chlorophenyl)ethane (DDT), total cyclodienes (TC), hexachlorocyclohexanes (HCHs) and heavy metals (Cu, Cd and Pb) in their edible parts. In all fish and sediment samples, PCBs were found in higher concentrations than pesticides; the edible parts of Mugil capito, Tilapia galilaeus, Tilapia zilli and Clarias lazera had the highest PCBs (3.49, 0.83, 1.06 and 4.29 ng/g wet weight respectively), PCB 28 being most prevalent in Mugilcapito and Clarias lazera with ratios 86 and 62%, respectively, of the total PCBs. PCB 180 was most prevalent in Tilapia zilli (about 56% of the total PCBs). In these four fish species OCs were found in the order: PCBs > DDTs > HCHs > TC. The other two species (Tilapia nilotica and Tilapia aureus) had the highest concentrations of pesticides (7.58 and 1.13 ng/g wet weight, respectively) with HCHs being most prevalent (96% and 74% of the total pesticides, respectively). OCs were found in the order: HCHs >> PCBs > DDTs > TC in the edible Tilapia nilotica, and in the order: PCBs > HCHs > DDTs > TC in the other species. The mean concentrations of PCBs and pesticides in sediments are 539.66 +/- 48.8 and 259.17 +/- 81.2 ng/g dry weight, respectively. Among the studied metals in the edible parts of the fish samples, about 67% of the samples contained marginally higher Pb content in the edible parts, above the European Community's legal limit. About 50% of the samples contained marginally higher Cd content (N.D to 0.88 microg/g) above the permissible level of Cd in fish edible parts; the Cu content ranged from 0.37-2.36 microg/g, with a marginally higher content in the fish but below the maximum permissible limits. As for the concentration of the studied metals in sediments of Edku lagoon, results showed that copper had the highest concentration (2.2 +/- 0.37 microg/g) in the lake sediment.

Persistent organic pollutants in the Scheldt estuary: environmental distribution and bioaccumulation

Levels of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and organochlorine pesticides (OCPs) were determined in the sediment and several species (European flounder, Platichthys flesus; common sole, Solea solea; Chinese mitten crab, Eriocheir sinensis; shore crab, Carcinus maenas; brown shrimp, Crangon crangon; blue mussel, Mytilus edulis and bristle worms, Polychaeta) from 7 locations in the Scheldt estuary (SE, the Netherlands-Belgium). Overall POP levels in the sediment were low. The average PCB and PBDE concentrations were respectively 31.5 and 115 ng/g dry weight (dw). Highest sediment loads were measured in the vicinity of Antwerp (368 ng PCBs/g dw), a location with intense harbor and industrial activities. Pollution concentrations in the tissues of biota were species-specific. Blue mussels contained the highest lipid concentrations (2.74±0.55%) and reached the highest contamination levels (from 287 to 1688 ng PCBs/g ww, from 2.09 to 12.4 ng PBDEs/g ww). Lowest tissue loads were measured in brown shrimp (from 3.27 to 39.9 ng PCBs/g ww, from 0.05 to 0.47 ng PBDEs/g ww). The PCB congener profile in most of the species was similar with the pattern found in the sediment. PCB 153 was the most abundant congener (16.5-25.7% in biota, 10.4% in sediment). In the sediment, the total amount of PBDEs consisted for more than 99% of BDE 209. Congener BDE 47 had the highest concentrations in all sampled species (38.5-70.1%). Sediment POP loadings and tissue concentrations were poorly correlated, indicating that a simple linear or non-linear relationship is insufficient to describe this relationship, possible caused by the complexity of the bioaccumulation processes and the variability in exposure. Because of the high PCB levels, regular consumption of fish and seafood, especially mussels, from the Scheldt estuary should be avoided.

Bioaccumulation of mercury in the trophic chain of flatfish from the Baltic Sea

Mercury concentrations in three flatfish species - flounder (Platichtys flesus), plaice (Pleuronectes platessa), and Baltic turbot (Scophthalmus maximus), netted in the southern Baltic Sea were assessed and compared to concentrations of this metal in sediments, sea water, and flatfish food - bivalve Macoma balthica, isopod Saduria entomon, and sprat (Sprattus sprattus). Collected simultaneously with flatfish in 2009 and 2010. Different concentrations of mercury depending on species, tissue or organ, sex, individual length, kind of food, and region were determined. The muscle tissues of turbot had the highest concentrations of the metal. The bioaccumulation (BF) and biomagnification (BMF) factors has been counted showing that the muscle tissues of turbot have maximum affinity for mercury, and thus best reflected the metal contamination of the Baltic Sea environment. The data suggest that the common Baltic turbot (S. maximus) is an important model species, suitable and cost-effective to biomonitor environmental mercury pollution for ecological research.

Relationships between body burdens of trace metals (As, Cu, Fe, Hg, Mn, Se, and Zn) and the relative body size of small tooth flounder (Pseudorhombus jenynsii)

Several studies have described strong relationships between body size and the accumulation of trace metals in animal tissues. However, few of these studies have utilized aging techniques to control for age related effects. We utilized relative body size (gy(-1)) of a model flounder species, Pseudorhombus jenynsii, in order to control for age related effects on growth and size measurements. We investigated links between relative body size, concentrations of trace metals in flounder muscle tissue, physico-chemical variables (temperature, salinity, pH, and turbidity), and levels of trace metals in the sediment. Flounder were sampled using an otter trawl net in the inner areas of eight estuaries that were either heavily modified or relatively unmodified by urbanization and industrial activity. Our results indicate that this commonly eaten fish is accumulating significant levels of some trace metals in their muscle tissue, both in relatively unmodified and heavily modified estuaries. Concentrations of Cu, Zn and Fe in muscle tissue, as well as temperature, showed a negative relationship to the relative body size of flounder. In contrast, Se and Hg in muscle showed a positive relationship to relative body size. Observed growth patterns indicate that these effects are not driven by age related differences in metabolic activity. Instead, our results suggest that differences in food supply or toxicological effects may be responsible for the observed relationships between relative body size and concentrations of Cu, Zn, and Se in muscle tissues. The use of otolith aging and growth measurement techniques represents a novel method for assessing the relationships between trace metal accumulation and the relative body size of fish in a field environment.

Risk posed by chlorinated organic compounds in Abu Qir Bay, East Alexandria, Egypt

INTRODUCTION

In Egypt, the picture of threats to humans and the environment from the exposure to organic pollutants is still incomplete. Thus the objectives of this study were to assess the occurrence and distribution of polychlorinated biphenyls (PCBs), organochlorine pesticides, and chlorpyrifos in sediments and mussels of Abu Qir Bay and their risks for environment and human health.

MATERIALS AND METHODS

Twenty-three different compounds organochlorines were determined in 20 surfacial sediment and 10 mussel samples by gas chromatography-electron capture detector. A Screening Level Ecological Risk Assessment (SLERA) and a Human Health Risk Assessment (HHRA) were performed with the data.

RESULTS AND DISCUSSION

ΣDDT (DDT, DDE, DDD) (average concentration 27 µg/kg dw) dominated the detected organic pollutants in the sediments, followed by CHLs (chlordane, heptachlor, heptachloro epoxide), hexachlorocyclohexane, chlorpyrifos, endosulfane, dieldrine, Σ6 PCBs, aldrine, hexachlorobenzene, pentachlorobenzene, methoxychlor, and mirex. In general, concentrations of Σ6 PCBs in mussels were higher than their corresponding sediment concentrations reflecting their relatively high bioavailability and bioaccumulative potential. However, concentrations of the organochlorine pesticides in mussels were lower than their corresponding sediment samples. Nevertheless, the SLERA on the bay sediments revealed that adverse ecological effects to benthic species are expected to occur whereas the HHRA showed that adverse health effects are not expected to occur from the consumption of the mussels.

CONCLUSIONS

With the help of a SLERA, it was possible to indicate which class of chlorinated organic compounds is of highest concern to assess and to improve the environmental quality of the bay. Monitoring of organochlorines and chlorpyrifos would be needed to control the future trend of pollution.

Effects of cumulative stress on fish health near freshwater outlet sluices into the sea: a case study (1988-2005) with evidence for a contributing role of chemical contaminants

Epizootic skin diseases in euryhaline flounder (Platichthys flesus) in the Dutch Wadden Sea were first reported in 1988. Particularly high prevalences of skin ulcers (up to one-third of individual fish being affected) were encountered in the vicinity of sluices draining freshwater from IJsselmeer Lake, in contrast with much lower levels in the freshwater bodies behind the sluices and open sea areas (<2%). It was proposed that salinity stress, high bacterial loads, nutritional deficiencies, and obstruction to fish migration by the sluices could all be involved in disease causation. Results of follow-up surveys at these outlet sluices from 1994 to 2005 further substantiate our preliminary findings. The follow-up data also show a general reduction in disease and improved condition factor during this period, which can be explained by improved habitat conditions for the flounder, partly due to effective sluice gate management. Furthermore, statistical correlations (p<0.05) were demonstrated between flounder ulcer occurrence and chemical contaminant concentrations in liver (Hg, Cd, Cu, Zn) and bile (the metabolite 1-OH pyrene as an indicator of chronic polycyclic aromatic hydrocarbon exposure), and histological liver lesions generally indicative of contaminant exposure (hydropic vacuolization of biliary duct epithelial cells). The findings suggest that a combination of osmotic and contaminant-induced stress also contributed to the observed disease patterns.

Polybrominated diphenyl ethers in three commercially important fish from the northwestern Arabian Gulf: occurrence, concentration, and profiles

Polybrominated diphenyl ethers (PBDEs) were measured in three species of fish (yellowfin seabream [Acanthopagrus latus, a predatory fish]; Klunzinger's mullet [Liza klunzingeri, a pelagic fish]; and large-scaled tonguesole [Cynoglossus arel, a demersal fish]) collected from two sites in the northwestern part of the Arabian Gulf, a marginal sea of the tropical Indo-Pacific Ocean. Concentrations of ΣPBDEs ranged from 11 to 57 ng g(-1) lipid weight (lw) for mullet, 5.0-38 ng g(-1) lw for tonguesole, and 2.8-48 ng g(-1) lw for seabream in Kuwait Bay, whereas in the open gulf, concentrations ranged from 6.0 to 160 lw for mullet, 8.3-190 lw for tonguesole, and 7.1-62 for lw for seabream. The congener composition in all species from both sites was dominated by BDEs 47, 99, and 100, which together constituted approximately 90% of the congeners detected. Although no statistically significant intersite differences were found, ΣPBDEs concentrations in mullet were significantly higher than those in seabream (p = 0.01). However, no significant differences existed between mullet and tonguesole (p = 0.28) or between tonguesole and seabream (p = 0.06). ΣPBDE concentrations were negatively correlated with fish mass for all species; however, the correlations were statistically insignificant, suggesting a growth dilution effect.

Spatial variations in the levels and isomeric patterns of PBDEs and HBCDs in the European eel in Flanders

Pooled yellow eel (Anguilla anguilla L.) samples, consisting of 3-10 eels, from 50 locations collected in the period 2000-2006 were used to assess the pollution with PBDEs and HBCDs in Flemish waters (Belgium). Results from this monitoring network are presented and the spatial aspect throughout Flanders is included, linking POP levels to the industrial characteristics of the different sampling locations. The following PBDE congeners were measured using GC/MS: 28, 47, 49, 66, 85, 99, 100, 153, 154, 183 and 209. Concentrations of summation sigmaPBDE ranged between 10 and 5811 ng/g lipid weight (lw) with a median value of 81 ng/glw. BDE 47 dominated the PBDE profile in the majority of the eel samples, except for six samples, in which BDE 209 was the dominating congener. These latter samples are probably associated with recent exposure to the Deca-BDE mixture. Three HBCD diastereoisomers (alpha-, beta- and gamma-HBCD) were measured using LC/MS-MS. summation sigmaHBCDs ranged between 16 and 4397 ng/glw, with a median value of 73 ng/glw. alpha-HBCD was the dominant isomer in all eel samples. Sediment concentrations of PBDEs were available from four locations and were used to compare the PBDE profile with those in eel. An important shift in the profile was observed, especially for BDE 209. While BDE 209 was only found in 12 eel samples, it was the dominant congener in all sediment samples. This could be due to its metabolisation or degradation in biota combined with the poor uptake of BDE 209 from sediments and its very low water solubility. No HBCDs were detected in any of the sediment samples. No significant correlation could be found between concentrations of PBDEs in eel and sediment from the same location. Comparison with previous studies shows that PBDE and HBCD levels in Flemish eels have decreased rapidly between 2000 and 2006 at particular sites, but alarming concentrations can still be found at industrialized hot spots. This finding is reflected in the human exposure to PBDEs and HBCDs through eel consumption. For average consumers (2.9 geel/day), intakes ranged between 3 and 2295 ng/day for summation sigmaPBDEs (with a median value of 16 ng/day) and between 3 and 1110 ng/day for summation sigmaHBCDs (with a median value of 18 ng/day), respectively. Additionally, human intakes were calculated for recreational fishermen, eating up to 12 g or 86 geel/day. Intakes of those risk groups were higher in comparison with average consumers and were above reference doses described in literature which may induce adverse effects.

Risk assessment of polycyclic aromatic hydrocarbons in a Mediterranean semi-enclosed basin affected by human activities (Abu Qir Bay, Egypt)

The contamination of sediments and mussels sampled from Abu Qir Bay by polycyclic aromatic hydrocarbons (PAHs) was investigated. Concentrations of PAHs recorded in the bay sediments ranged from less than MDL to 2660 microg/kg dw. In general, concentrations of PAHs in mussels were higher than their corresponding sediment concentrations reflecting their great bioavailability (242-3880 microg/kg dw). The highest concentration was observed in the western part of the bay, a location affected by intensive shipping activities. The distribution pattern of PAHs was similar for mussels and sediments, particularly for sediments characterized by high contamination level, and they were dominated by the high molecular weight PAHs (4-6-rings). Applying different PAHs ratios, it was found that PAHs originated predominantly from the pyrogenic source either from the combustion of grass, wood and coal (majority of the samples) or from petroleum combustion (harbour area). The output of a Screening Level Ecological Risk Assessment (SLERA) on the bay sediments revealed that adverse ecological effects to benthic organisms are expected to occur in only one sample, and thus PAHs are not considered as contaminants of concern in Abu Qir Bay. Also adverse health effects are not expected to occur from the consumption of the investigated mussels with respect to PAHs in Abu Qir Bay.

Polychlorinated biphenyl and organochlorine pesticide contamination signatures in deep-sea fish from the Mediterranean Sea

Polychlorinated biphenyl (PCB) and OCP concentrations were determined in the livers of two deep-sea fish species, roughsnout grenadier and hollowsnout grenadier, from the Adriatic Sea. In both species, contaminant concentrations were in the following order: PCBs>DDTs>>HCB. Contaminant load was higher in roughsnout grenadier (PCB: 12,327ngg(-1); DDTs: 5357ngg(-1); HCB: 13.1ngg(-1)) than in hollowsnout grenadier (PCB: 1234ngg(-1); DDTs: 763ngg(-1); HCB 6.3ngg(-1)). PCB patterns were dominated by higher chlorinated congeners (hexa-CBs: 50.3-52.1%, hepta-CBs: 29.6-35.5%, penta-CBs: 8.0-11.1% and octa-CBs :5.2-5.4%). PCBs 138, 153 180 and 187 were the most abundant. Regarding the DDT pattern, p,p'-DDE was prevalent in both species (roughsnout grenadier: 99.7%, hollowsnout grenadier: 90%), suggesting no recent DDT input. In both species, the total 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalent (TEQ) concentrations (roughsnout grenadier: mean 43.77pg/g, hollowsnout grenadier: mean 20.49pg/g), calculated from non- and mono-ortho PCBs, reached those encountered in marine organisms at higher levels in the trophic chain.

Congener profiles of polychlorinated biphenyls in core sediments of Sunderban mangrove wetland (N.E. India) and their ecotoxicological significance

The paper presents the first comprehensive survey of congener profiles of polychlorinated biphenyls (PCBs) in core sediment samples (<63 microm particle size) covering seven sites in Sunderban mangrove Wetland, north-eastern part of the Bay of Bengal. Results pointed out a non-homogenous contamination of the wetland with Sigma23PCB values ranging from 0.5 to 26.9 ng g(-1) dry weight, reflecting very low to moderate contamination closely in conformity to other Asian coastal environment. The general decreasing order of the dominant congeners to the total load was: CB138 > 153 > 149 > 101, indicating the predominance of hexa-chlorinated congeners. The spatial distribution revealed significant differences in concentration related to local urbanization with industrial and land-based sources. No uniform temporal trend on PCB levels was recorded probably due to particular hydrological characteristics of the wetland and/or non-homogenous inputs from point sources. Strong positive correlations between the seven dominant congeners suggest their common sources and similar environmental behaviors. These results were also used for a risk assessment evaluation in the Sunderban wetland, showing that the present PCB levels were exceeding in few cases the lower limit of sediment quality guidelines of Environmental Protection Agency and Canadian Council of Ministers of the Environment.

PCBs contamination in seafood species at the Eastern Coast of Thailand

Polychlorinated biphenyls (PCBs) are a large group of persistent organic substances spread throughout the world. The most toxic PCBs are those that are dioxin-like (dl-PCBs). Environmental studies on PCBs in Thailand are limited, especially with regards to dl-PCBs. This study is one of the first in this country that demonstrates contamination of seafood with PCBs and determines the levels of PCBs and total dioxin like activity in mussels, oysters and shrimp, from the Eastern Coast of Thailand. Sixty pooled samples of mussels and twenty-seven pooled samples of oysters were collected from cultivation farms and twenty-one pooled samples of shrimp were collected from fisherman piers. Qualitative and quantitative measurements of 49 PCB congeners was obtained by HRGC-ECD analysis and total dioxin-like activity using the CAFLUX bioassay. Total PCB concentrations varied between three species, ranging between 19 and 1100 ng g(-1) lipid adjusted weight, and the levels of PCBs in shrimp was three time higher than that in mussels and oysters. With respected to the pattern of PCB congeners, it implied that the source of PCBs exposure in this area could be from the regional contamination. The calculated CAFLUX bioanalytical equivalents (BEQs) values ranged between 0.8 and 18 pg BEQ g(-1) lipid adjusted weight, and showed a good relationship with the chemical-derived TEQs. Therefore, the CAFLUX bioassay can be used for effective screening of dioxin-like activity in marine species effectively.

Long-term trends in the prevalence of cancer and other major diseases among flatfish in the southeastern North Sea as indicators of changing ecosystem health

This paper analyses and discusses spatial and temporal patterns in the prevalence of major skin diseases (lymphocystis, epidermal hyperplasia/papilloma, ulcers), intestinal parasite Glugea sp., and liver cancer in dab (Limanda limanda) and flounder (Platichthys flesus) in the Dutch section of the North Sea since the mid-1980s. We have attempted to relate disease prevalence trends in both species to chemical contaminant exposure and other relevant environmental factors including fish condition factor, population density, fishing activity, and water temperature. We observed a long-term decline in chemical-related liver cancer in the populations of both species since the early 1990s. Lymphocystis and skin ulcer (flounder only) have also displayed a significant decrease since then. We conclude that the widespread decline in the prevalence of several skin diseases and liver cancer in dab and flounder in Dutch waters in the past two decades is most likely due to the improved water quality and health conditions in this region.

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.

Serum concentrations of neutral and phenolic organohalogens in pregnant women and some of their infants in The Netherlands

As part of a large European Union (EU)-funded comparative toxicology and human epidemiology study, EU-Compare, a selection of organohalogen compounds (OHCs) was analyzed in maternal serum, collected at the 35th week of pregnancy, and in cord serum of a number of their infants to determine maternal concentrations and to investigate the extent of transplacental transfer of these compounds. Eight neutral OHCs were analyzed: one polychlorinated biphenyl (PCB: CB-153),4,4'-DDE, five polybrominated diphenyl ethers (PBDEs: BDE-47, BDE-99, BDE-100, BDE-153, and BDE-154), and hexabromocyclododecane (HBCDD). Five phenolic OHCs were analyzed: three hydroxylated PCBs (40H-CB-107, 40H-CB-146, and 40H-CB-187), one hydroxylated PBDE (60H-BDE-47), and pentachlorophenol (PCP). All OHCs, except 60H-BDE-47, were present in maternal and cord serum. The historically identified OHCs showed the highest concentration: 4,4'-DDE (median value 89 ng/g lipid in maternal serum and 68 ng/g lipid in cord serum) and PCP (median value 970 pg/g serum in maternal serum and 1500 pg/g serum in cord serum). HBCDD and the PBDEs were present at much lower concentrations. We conclude that OHCs are present in the serum of pregnant women, and all compounds tested are transferred over the placenta. Because transfer is occurring at a critical stage of infant development, investigation of the health impact is urgent.

Historical trends of organic pollutants in sediment cores from Hong Kong

Recent studies have indicated the occurrence of a wide range of trace organic contaminants, including polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in the Hong Kong environment. These contaminants are potentially harmful to ecological systems, particularly in coastal areas. In this study, two sediment cores (4m) were collected from southern waters of Hong Kong in 2004 to study the historical trends, distribution patterns, and potential sources of trace organic contaminants. DDTs (p,p'-DDT, o,p'-DDT, p,p'-DDD, o,p'-DDD and p,p'-DDE), hexachlorohexanes (HCHs) (alpha and gamma), hexachlorobenzene (HCB), and PCBs were detected in the samples, whereas other target compounds were all below detection limits. Many OCPs have not been produced or used for many years due to toxicological or environmental concerns and PCB use is prohibited in Hong Kong. However, some compounds were still detectable in recent years, and were found to be widely distributed in the environment, likely because of pollutant inputs from the highly industrialized Pearl River Delta region. These results provide important information on current and historical contamination in Hong Kong, and help to reconstruct the pollution history of these trace organic pollutants in Hong Kong coastal waters.

Variation, levels and profiles of organochlorines and brominated flame retardants in great tit (Parus major) eggs from different types of sampling locations in Flanders (Belgium)

Small-scale geographical variation in the occurrence of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs) was investigated using the eggs of a terrestrial residential songbird species, the great tit (Parus major). In addition, we investigated the influence of the type of sampling location on the presence of these pollutants. To achieve this, 10 different sampling locations in Flanders (Belgium) were classified into 3 groups based on the extent of urbanisation, industrialisation and agriculture. The higher variance among sampling locations for the levels and profiles of PCBs and OCPs, suggests that local contamination sources are more important for the PCBs and OCPs compared to the PBDEs. Levels of PCBs and PBDEs were significantly higher in the industrialised sampling locations compared to the other locations. Sum PCB and sum PBDE levels reached up to 6050 and 79 ng/g lipid weight, respectively. PCBs and PBDEs were highly positively correlated for all groups, suggesting similar exposure pathways and/or mechanisms of accumulation. Significantly higher levels of OCPs (sum OCPs up to 2683 ng/g lipid weight) were detected in the rural sampling locations situated in a residential area. This suggests that local historical usage of OCPs by inhabitants may be an important source of contamination in Flanders. Contamination profiles differed also among the sampling locations. The rural sampling locations had a higher contribution of lower brominated BDE congeners, whereas the industrialised locations had a higher contribution of higher brominated congeners. The differences in contamination profiles among the sampling locations are probably due to differences in exposure. In conclusion, our results showed that the characteristics of a sampling location influence both the levels and profiles of PCBs, OCPs and PBDEs.

Organochlorine and mercury contamination in fish tissues from the River Nestos, Greece

Polychlorinated biphenyls (PCBs), hexachlorocyclohexane (HCH) isomers, dichlorodiphenyltrichloroethane (DDT) and its metabolites, other organochlorine pesticides such as hexachlorobenzene (HCB), chlordane compounds (CHLs, including trans-chlordane and cis- and trans-nonachlor) and the heavy metal mercury were quantified in muscle and liver of the European chub (Leuciscus cephalus, Linnaeus, 1758) and in the muscle of the barbel (Barbus cyclolepis, Heckel, 1837) at two sampling sites of the River Nestos, Greece. PCBs in muscle and DDTs in the liver tissues were the predominant organochlorinated contaminants. Among the PCBs, congeners 47 (up to 9.60 ng g(-1) wet wt.), 180 (up to 1.15 ng g(-1) wet wt.) and 190 (up to 1.50 ng g(-1) wet wt.) were the most frequent and abundant. The contamination degree by the sum of PCBs on the fish tissue samples from the River Nestos is lower or similar to PCB levels found in other ecosystems. Among the organochlorine pesticides, essentially only p,p'-DDD, p,p'-DDE and alpha-, beta- and gamma-HCH were found, with the former appearing at mean levels up to 30.71 ng g(-1) wet wt. From a public health standpoint, residue organochlorine pesticide levels from our work are considerably lower than the recommended tolerance limits. Finally, mean values of Hg in chub were significant lower (up to 31.04 ng g(-1) wet wt.) compared to those detected on barbel (up to 169.27 ng g(-1) wet wt.). The concentrations of Hg in fresh water fish from the River Nestos did not exceed WHO and US EPA health guidelines, and were suitable for human consumption.

Arsenic in sediments from the southeastern Baltic Sea

Arsenic occurs as a persistent constituent in many of the chemical weapons dumped into the Baltic Sea; it can be used as an indicator of leakage and dispersal of released munitions to the marine environment. Total arsenic was analysed in sediment samples taken from the Lithuanian economic zone in the Baltic Sea, which included samples from the chemical munitions dumpsite in the Gotland Basin and national monitoring stations in the southeastern Baltic Sea. Arsenic concentrations in sediments ranged from 1.1 to 19.0 mg kg(-1), with an average of 3.4 mg kg(-1). Although there was evidence of slightly elevated arsenic content in sediments near the weapons dumpsite, arsenic concentrations were nevertheless quite low relative to other investigations in the Baltic and North Seas.

Nonabsorbable dietary fat enhances disposal of 2,2',4,4'-tetrabromodiphenyl ether in rats through interruption of enterohepatic circulation

Polybrominated diphenyl ethers are lipophilic persistent organic pollutants (POPs), which accumulate in the environment, leading to human exposure. The compounds exert a negative impact on human health. Strategies to prevent or diminish their accumulation in humans are required. We investigated in rats whether the disposal rate of 14C-labeled tetrabromodiphenyl ether (BDE-47) could be enhanced by increasing fecal fat excretion through dietary treatment with nonabsorbable fat (sucrose polyester, SPE). As compared to control rats, SPE treatment increased fecal excretion rates of fat (+188%, p < 0.05) and 14C-BDE-47 (+291%, p < 0.05). On the basis of biliary secretion and fecal excretion rates of 14C-BDE-47, SPE effectively inhibited the enterohepatic circulation of 14C-BDE-47. In conclusion, dietary supplementation of nonabsorbable fat can enhance excretion of hydrophobic POPs by interruption of their enterohepatic circulation. Our data indicate that this strategy could decrease concentrations of hydrophobic POPs in the human body and thereby their impact on human health.

Organotin accumulation in an estuarine food chain: comparing field measurements with model estimations

The bioaccumulation model OMEGA (optimal modelling for ecotoxicological applications) is used to explore accumulation of organotins in the Western Scheldt food chain, consisting of herbi-detritivores, primary and secondary carnivorous fish and a piscivorous bird. Organotins studied are tributyltin (TBT) and triphenyltin (TPT) and the respective di- and mono-organotin metabolites. Empirical elimination rate constants are compared to model predictions for organic substances and metals. It is found that field bioaccumulation ratios are higher than predicted based on elimination kinetics relevant for organic compounds. The results indicate that uptake of organotins mainly occurs via hydrophobic mechanisms, whereas elimination may occur via metal-like kinetics. This results in very low elimination rates, which are comparable to model predictions for metals.

Assessment of edible marine species in the Adriatic Sea for contamination from polychlorinated biphenyls and organochlorine insecticides

It is estimated that 90% of human exposure to persistent organic pollutants is through food, and fish and shellfish represent an important source of contamination for polychlorinated biphenyls (PCBs) and organochlorine insecticides. To evaluate the levels of seafood contamination coming from the central Adriatic Sea, Italy, a study involving several pools of shellfish, crustaceans, and fish was carried out. Several marine species were selected by their abundance, wide distribution, and common use in the Italian diet and sampled and analyzed during 2004. The concentration of total (sigma) PCBs exceeded that of total dichlorodiphenyltrichloroethanes (DDTs) in all samples. Atlantic mackerel showed the highest concentrations of PCBs, ranging from 514 to 1772 ng/g of fat weight, and DDTs, ranging from 52 to 656 ng/g of fat weight. The lowest concentrations of PCBs and DDTs were found in cephalopods and mussels. Despite this, to protect human health from these pollutants, legal limits have been established for fish and shellfish for DDTs but not PCBs. The most common representative PCB congeners, in all species, were PCB 153 and PCB 138; the most common DDT was p,p'-dichlorodiphenyldichloroethylene.

Accumulation of organochlorines and brominated flame retardants in estuarine and marine food chains: field measurements and model calculations

Food chain accumulation of organochlorines and brominated flame retardants in estuarine and marine environments is compared to model estimations and fresh water field data. The food chain consists of herbivores, detritivores and primary and secondary carnivores i.e. fish, fish-eating birds and marine mammals. Accumulation of polychlorinated biphenyls is predicted well by OMEGA for herbi-detritivores and primary and secondary carnivorous fish. Ratios are similar to those found for fresh water species. Accumulation ratios for fish-eating birds and mammals are overestimated by the model, which is attributed partly to biotransformation of meta-para unsubstituted congeners. Additionally, birds may feed in other less polluted areas. For brominated diphenylethers (BDE) accumulation patterns are highly species and congener specific. Accumulation depends on both K(ow) and metabolization capacities. BDE47 is the predominant congener in lower trophic levels. For marine birds and mammals accumulation ratios of BDE99 and 100 are similar to or higher than ratios of persistent PCBs.

Comparison of three fish bioaccumulation models for ecological and human risk assessment and validation with field data

This article compares two bioconcentration Quantitative Structure Activity Relationships (QSARs) for fish applied in human risk assessments with the mechanistic bioaccumulation model OMEGA and field data. It was found that all models are virtually similar up to a Kow of 10(6). For substances with a Kow higher than 10(6), the fish bioconcentration curve in the risk assessment model EUSES decreases parabolically. In contrast, OMEGA bioaccumulation outcomes approximately show a linear increase, based on mechanistic bioconcentration and biomagnification properties of chemicals. The OMEGA-outcomes are close to the fish bioconcentration outcomes of the risk assessment model CalTOX. For very hydrophobic substances, field accumulation data in freshwater and marine fish species are closer to OMEGA- and CalTOX-outcomes compared to EUSES. The results also show that it is important to include biomagnification in fish and lipid content of fish in human exposure models.

Flame retardants, surfactants and organotins in sediment and mysid shrimp of the Scheldt estuary (The Netherlands)

Sediment and mysids from the Scheldt estuary, one of the largest and most polluted estuaries in Western Europe, were analyzed for a number of contaminants that have been shown to possess endocrine-disrupting activity, i.e. organotins, polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), tetrabromobisphenol A (TBBPA), nonylphenol ethoxylates (NPE) and transformation products, nonylphenol (NP) and nonylphenol ether carboxylates (NPEC). In addition, in vitro estrogenic and androgenic potencies of water and sediment extracts were determined. Total organotin concentrations ranged from 84 to 348 ng/g dw in sediment and 1110 to 1370 ng/g dw in mysid. Total PBDE (excluding BDE-209) concentrations ranged from 14 to 22 ng/g dw in sediment and from 1765 to 2962 ng/g lipid in mysid. High concentrations of BDE-209 (240-1650 ng/g dw) were detected in sediment and mysid (269-600 ng/g lipid). Total HBCD concentrations in sediment and mysid were 14-71 ng/g dw and 562-727 ng/g lipid, respectively. Total NPE concentrations in sediment were 1422 ng/g dw, 1222 ng/g dw for NP and 80 ng/g dw for NPEC and ranged from 430 to 1119 ng/g dw for total NPE and from 206 to 435 ng/g dw for NP in mysid. Significant estrogenic potency, as analyzed using the yeast estrogen assay, was detected in sediment and water samples from the Scheldt estuary, but no androgenic activity was found. This study is the first to report high levels of endocrine disruptors in estuarine mysids.

Polybrominated diphenyl ethers, polychlorinated biphenyls and organochlorine pesticides in sediment cores from the Western Scheldt river (Belgium): analytical aspects and depth profiles

A rapid and simple analytical method for the determination of organochlorines, such as polychlorinated biphenyls (PCBs) and selected organochlorinated pesticides (OCPs) and organobromines, such as polybrominated diphenyl ethers (PBDEs), in sediment samples was optimised using CRM 536 (PCBs in freshwater sediment). The method involved a hot Soxhlet extraction that reduced the extraction time to 2 h. Elemental sulphur, which is present in sediments and may interfere during the analysis, was removed by means of copper powder added to the sediment during extraction and into the clean-up cartridge. The analysis of PCBs and OCPs was accomplished by gas chromatography with electron capture or mass spectrometric detection. Similar quantitative results for PCB congeners in CRM 536 were obtained using a 50-m capillary column and a 10-m narrow bore column suited for fast analysis. The analysis of PBDEs was done by mass spectrometry in negative chemical ionisation mode. Concentrations of organic pollutants in two sediment cores (approximately 50 cm depth) from the Scheldt river (south of Antwerp, Belgium) showed a relative steady state for PCBs and DDTs, with a slight decrease in the top layers, suggesting a slight decline in their concentrations due to restrictions in their usage. On the contrary, PBDEs were showing an increase in their concentrations in the top layers (up to 270 and 8400 ng/g dry weight for sum of tri- to hexa-BDE congeners and for BDE 209, respectively). This suggests an increasing trend in the concentrations of PBDEs in the Belgian environment.

Analysis of organochlorines in harbor seal (Phoca vitulina) tissue samples from Alaska using gas chromatography/ion trap mass spectrometry by an isotopic dilution technique

A gas chromatography/ion trap mass spectrometry (GC/ITMS) method was developed for the determination of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs) in harbor seal (Phoca vitulina) tissues. Tissue samples were homogenized, lyophilized and fortified with (13)C-PCBs 28, 123, 169 and 170, and then extracted with an accelerated solvent extractor with a mixture of hexane and methylene chloride (1:1, v/v). After lipid removal using a 40% H(2)SO(4)-modified silica gel column, all organochlorines were collected in one fraction and further fractionated with an activated carbon/silica gel (1:20) column into a first fraction containing OCPs, non-coplanar PCBs and (13)C-PCBs 28, 123 and 170, and a second containing PCNs, coplanar PCBs and (13)C-PCB 169. Prior to GC/MS/MS analysis, (13)C-PCB 169 was added into the first fraction as an injection standard and (13)C-PCB 170 into the second fraction to calibrate the recoveries of the fortified internal standards. This method can effectively eliminate matrix interferences, and has high selectivity and sensitivity. Recoveries averaged 45-86% for OCPs with relative standard deviations (RSDs) of 2-14%, 52-137% for PCBs with RSDs of 3-29% and 36-152% for PCNs with RSDs of 7-29% from lard and chicken heart samples, which were used as alternative matrices to harbor seal samples in recovery studies. The limits of detection for OCPs, PCBs and PCNs were 0.7-1.9, 1.5-8.9 and 0.5-10 pg/g dry weight, respectively. This method can be used to analyze OCPs, PCBs and PCNs in harbor seal blubber, liver and kidney samples.