Spatial and temporal trends of PCBs (polychlorinated biphenyls) in mussel from Galician coast (1998-2008)

Performance of mussel Mytilus galloprovincialis under variable environmental conditions and anthropogenic pressure: A survey of two distinct farming sites in the Adriatic Sea

Changes in natural conditions and anthropogenic pollutants, alone or in combination, pose a significant challenge to coastal bivalve populations. The susceptibility of economically important bivalves to potential stressors in their farming environment has not been sufficiently investigated, despite the increase in anthropogenic pressure along the coast and the remarkable warming of seawater in recent years. Thus, the aim of this study was to evaluate the performance of mussel (Mytilus galloprovincialis) from two important farming sites in the eastern Adriatic, namely Mali Ston Bay (MSB) and Lim Bay (LB), in relation to variations of seawater parameters, reproductive cycle dynamics and tissue content of potentially harmful pollutants. The complex seasonal and site-specific patterns of chemical pollutants were determined, with tissue levels of metals, As, PAHs and PCBs largely comparable to those previously reported for the Mediterranean region. Concentrations of organochlorinated pesticides were below the level of detection. Significantly higher Cd, As and Hg concentrations were detected in the tissues of the MSB mussels. The reproductive cycle was clearly associated with the bioaccumulation of pollutants. All biochemical response parameters varied to some extent across seasons and/or between farming sites. A very pronounced seasonality was recorded for acetylcholinesterase and glutathione S-transferase activity at both sites. Metallothionein concentration and superoxide dismutase activity were generally steady throughout the study period. The most striking difference between the two sites was recorded for lipid peroxides concentrations which were predominantly significantly higher in the MSB mussels, indicating expressed pro-oxidant conditions at this site. In particular, significant correlations were found between lipid peroxides and the potentially toxic metals (Cd, As, Hg) accumulated in the mussel tissue. Data reported here are valuable as baseline information for further studies related to stress in farmed bivalves caused by oscillations of environmental factors and increasing anthropogenic pressure along the coastline.

Polychlorinated biphenyls in mussels, small pelagic fish, tuna, turtles, and dolphins from the Croatian Adriatic Sea waters: an overview of the last two decades of monitoring

This review summarises our two decades of polychlorinated biphenyl (PCB) monitoring in different marine organisms along the eastern Adriatic Sea. The aim was to gain an insight into the trends of PCB distribution in order to evaluate the effectiveness of past and current legislation and suggest further action. Here we mainly focus on PCB levels in wild and farmed Mediterranean mussels, wild and farmed bluefin tuna, loggerhead sea turtles, common bottlenose dolphins, and small pelagic fish. The use of artificial intelligence and advanced statistics enabled an insight into the influence of various variables on the uptake of PCBs in the investigated organisms as well as into their mutual dependence. Our findings suggest that PCBs in small pelagic fish and mussels reflect global pollution and that high levels in dolphins and wild tuna tissues raise particular concern, as they confirm their biomagnification up the food chain. Therefore, the ongoing PCB monitoring should focus on predatory species in particular to help us better understand PCB contamination in marine ecosystems in our efforts to protect the environment and human health.

Environmental organic contaminant body burdens and GC-MS based untargeted metabolomics in mediterranean mussels from Port Phillip Bay, Australia☆

Mussels were collected from four coastal sites around Port Phillip Bay, Australia in Mar and Apr 2021). Body burdens of Polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) were measured and the possible sources of toxicants discussed. In addition, a gas chromatography-mass spectrometry (GC-MS) based untargeted metabolomics analysis was performed using the mantle tissues of mussels. Correlations between the results of contaminant body burdens and metabolic variations were investigated. The results demonstrated that high accumulations of low-molecular-weight PAHs were found in mussels. High body burdens of PCBs and OCPs were only found at mussels from the site close to the river mouth. Some of the metabolic pathways were correlated with the accumulation of PAHs. No correlations were found between PCB and OCP accumulations and metabolic abundances. According to the food and environmental standards of the European Union (EU), the PAH, PCB, and OCP accumulation in mussels in this study are a serious food safety concern.

Spatiotemporal bioavailability of PCDD/Fs and dl-PCBs in wild mussels from the Portuguese Atlantic coast

This study aimed to assess the spatiotemporal bioavailability of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in wild adult mussels, Mytilus galloprovincialis, collected along the Portuguese Atlantic coast between 2009 and 2020. The work is part of a national environmental monitoring program. The purpose was to evaluate the dioxins' temporal trends, the human and ecological risks, and the correlation between mussels' location and the main pollutant sources in Portugal. The levels and congener patterns of the most toxicity-relevant 17 PCDD/Fs and 12 dl-PCBs were determined, with the dl-PCBs dominant. The sum of Σ₁₇PCDD/Fs and Σ₁₂dl-PCBs values ranged from 2.0 to 4.0 ng WHO-TEQ kg^-1, (wet weight basis), below the limits established by the European Commission for contamination in fish and fishery products (6.5 ng per kg^-1). The study included five years - 2009, 2010, 2016, 2018 and 2020 -, allowing to verify the impact of European Directive 2013/39/UE against the pollution of water in Portugal; it was observed that dioxin levels in mussels diminished over the time. Statistical analysis allowed verification of different spatial trends of dl-PCB profiles along the Portuguese Atlantic coast. The mono-ortho dl-PCB pentachlorinated congener IUPAC #118 prevailed in 2009 and 2018 in all sampling sites, and it was predominant in 2010, 2016 and 2020, followed by the congeners IUPAC #105, #156 and #167. The IUPAC #167, #169 and #123 were the most abundant hexachlorinated congeners, and the IUPAC #77 the most abundant tetrachlorinated congener. This work emphasises the importance of monitoring dioxins and mapping the congeners in Atlantic coastal ecosystems, to contribute to their elimination.

Heavy metals and persistent organic pollutants contamination in river, estuary, and marine sediments from Atlantic Coast of Democratic Republic of the Congo

The pollution assessment and the evaluation of potential risks in the Atlantic Coastal Region of the Democratic Republic of the Congo are still very limited. Consequently, the present study investigates for the first time the concentrations of heavy metals and persistent organic pollutants (organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and polycyclic aromatic hydrocarbons (PAHs)) in river, estuary, and marine sediments from this area. The results highlighted high concentrations of Cr, Zn, As, and Pb exceeding the probable effect level (PEL) on aquatic life. Zn was the most dominant element detected at a range of 180-480 mg kg^-1 in marine sediment, 132-382 mg kg^-1 in estuary sediment, and 121-687 mg kg^-1 in river sediment. Total PCBs (∑7 × 4.3) ranged from 1995 to 20,156 μg kg^-1, 2013-12,058 μg kg^-1, and 1861-36,417 μg kg^-1 in marine, estuary, and river sediments, respectively. Total PCBs (∑7 × 4.3) were above PEL for all sediments, suggesting potential adverse effects on benthic organisms. The OCP, PBDE, and PAH levels were low to moderate for all sediments. Taking into consideration, the concentrations of Zn, Pb, PCBs, and DDTs, probable environmental risks, are present.

Optimal number of Fucus vesiculosus samples to differentiate between sites affected by distinct levels of heavy metal contamination

The presence of trace elements in marine habitats is a serious environmental problem which increasingly affects ecosystem and human health. The use of macroalgae as contamination biomonitors represents a valuable alternative approach to traditional physicochemical methods. The present study was carried out to determine the optimal number of samples of Fucus vesiculosus needed to detect statistically significant differences in the mean concentrations of Al, As, Cd, Co Cr, Cu, Fe, Hg, Ni, Pb, Zn, N and δ15N between two sampling sites affected by different levels of contamination. For this purpose, we plotted the density distributions of the concentrations of the different elements and examined the local variability at three sites. For sites with mean concentrations differing by more than 30 %, 20 samples were sufficient to detect significant differences for all of the elements, except Cr. The proposed methodology could be used in other studies in the absence of specific research on each species and region.

Sampling optimization for biomonitoring metal contamination with marine macroalgae

The aim of the present study was to optimize the protocol for sampling marine macroalgae to be used to biomonitor heavy metal contamination in marine ecosystems. For this purpose, we collected 50 subsamples of the brown seaweed Fucus vesiculosus at random in each of three sampling sites (SS) and determined the concentrations of Al, As, Cd, Co, Cr, Cu, Fe, Hg, N, Ni, Pb, Zn and δ15N. We used semivariograms to explore the possible existence of spatial structure in the concentrations of the elements. Spatial structure was observed in 88% of the semivariograms studied, with element concentrations varying longitudinally and transversally along the SS. Using randomization techniques, we estimated that in each SS, a minimum of 30 evenly distributed subsamples should be collected within three bands parallel to the coastline (and also at different heights on the rocks if necessary), and analyzed in a single composite sample representative of the intra-SS variability.

Legacy and emerging pollutants in marine bivalves from the Galician coast (NW Spain)

The presence of pollutants in estuary and oceanic systems is a global problem and a serious concern to human and environmental health. Usually, environmental monitoring studies consider classical persistent organic pollutants (POPs). However, the lists of POPs keep continuously growing and new POPs and other emerging pollutants should be considered in new monitoring programs. So, this study aimed to investigate the distribution and profile of classical POPs (polychlorinated biphenyl (PCBs), organochlorine pesticides (OCPs), and polycyclic aromatic hydrocarbons (PAHs)), new POPs and emerging pollutants (polybrominated diphenyl ethers (PBDEs), perfluorinated compounds (PFCs), novel halogenated flame retardants (NFRs) and UV filters) in bivalve mollusc samples (both raft-cultivated and wild mussel, Mytilus galloprovincialis; cockle, Cerestoderma edule; and clam, Ruditapes descussatus) collected in nine Galician Rias during the period February 2012 to February 2013. A predominance of PAHs (6.8-317 ng/g dry weight (dw)) followed by PCBs (0.47-261 ng/g dw), UV filters (1.4-157 ng/g dw), PFCs (0.53-62 ng/g dw), OCPs (0.07-29 ng/g dw), PBDEs (0.31-6.6 ng/g dw) and NFRs (0.07-3.2 ng/g dw) was found in the studied bivalves, being the UV filter octocrylene the compound found at the highest concentration (141 ng/g dw in a cockle sample), while the PAHs chrysene and benzo(b)fluoranthene were the compounds with the highest average concentration (20 and 14 ng/g dw, respectively). Inter-species, temporal and geographical variations on pollutants concentration were assessed by multifactorial analysis of variance. Statistically significant differences among the type of mollusc were observed for levels of organochlorinated and organobrominated pollutants considered (PCBs, OCPs and PBDEs), which were detected at higher concentrations in wild mussel. On the other hand, the main PFCs and UV filters showed a higher detection frequency in cockle samples. Location played significant role for PAHs, PCBs and the main PBDEs, being the most polluted rias those more industrialized and populated, i.e. A Coruña, Ferrol and/or Vigo. Finally, sampling timepoint was also a significant factor for most of the families considered but with different profiles. Thus, PAHs and PCBs showed higher concentrations in both February 2012 and 2013 and lower in August 2012, while the main PBDEs were measured at higher concentrations in November 2012 and lower in February 2012; and the main NFRs, PFCs and UV filters were present at lower levels in February 2013.

Application of macroalgae analysis to assess the natural variability in selected pollution concentrations (N and Hg), and to detect sources of it in coastal environments

Here we present a new method in which algae are used to detect sources of heavy metal and organic pollution in coastal areas. The procedure involves characterization of the natural range of concentrations of the elements in areas not affected by local sources of pollution and subsequent comparison of concentrations in the study site to these natural range levels. To develop the method, the concentrations of various elements were determined in specimens of the macroalgae Fucus vesiculosus collected at >150 sampling sites along the shoreline. The natural variability in the element concentrations in these zones was established by determining the differences in the tissue concentrations of the elements between pairs of samples separated by different distances. The method was then tested in the surroundings of possible sources of nitrogen and was found to be a tool for detecting sources of small scale nitrogen contamination and for monitoring and evaluating water quality.

Assessment of PCB and chlorinated pesticide accumulation in mussels at Kaštela Bay (Eastern Adriatic)

The biological response of mussels Mytilus galloprovincialis, resident and transplanted to cages, to contamination with anthropogenic pollutants from Kaštela Bay, located in the central part of the eastern Adriatic coast, was investigated. The main purpose of this paper is to trace the accumulation of PCBs and chlorinated pesticides (HCB, lindane, heptachlor, aldrin, p,p'-DDTs) as a direct measure of potential contaminant availability to organisms, in a period from 2000 to 2011. In order to do so, cultured mussels (Mytilus galloprovincialis) of the same size and age were transplanted from the unpolluted Mali Ston Bay to the Kaštela Bay. Sampling was performed bimonthly, and the level of target contaminants in whole soft tissue was determined. After two months of exposure, the concentration of PCBs in transplanted mussels increased on average 6.5-times, and of DDTs 2-times, while the intensity of changes for HCB, lindane, heptachlor and aldrin was negligible. Seasonal variation of pesticide content was similar without a significant change throughout the experimental period, while that of PCBs was somewhat different showing increased accumulation in summer. Seasonal and spatial variation of organochlorines in the Kaštela Bay was likely the result of prevailing environmental rather than biological parameters. In accordance with prevailing hydrodynamic cycling, contaminant concentration decreased in acyclonic direction towards the exit of the Bay. Measurement of target contaminants in resident mussels sampled from the most contaminated area of the Bay exhibited decreasing concentrations of lindane, aldrin and p,p'-DDTs. However, PCBs exhibited statistically significant increasing concentrations in relation to the slightly increasing concentrations of HCB. With regard to human health, organochlorine (OC) levels in the mussel tissue were below prescribed limits for human consumption.

Levels of PCBs in Oysters Coming from Galicia Coast: Comparison to Mussels from the Same Region

PCBs were analyzed in two species of oyster (Crassostrea gigas and Ostrea edulis) cultured in intertidal beds and rafts coming from the Galician Rías during the period 2011-2014. PCBs were also analyzed in mussel (Mytilus galloprovincialis) collected in the same Rías during 2011. The main objective of this work is to investigate the distribution of PCBs in Galician oysters and to study their suitability as bioindicator in comparison to mussels. The levels of ΣPCBs (ten congeners) ranged from 5.58 to 179.49 ng g(-1) d.w. The effect of biological parameters (shell length, lipid content and condition index) on bioaccumulation of PCBs was also evaluated. ANOVA showed a statistically significant difference between species for higher chlorinated biphenyls (CBs 153 and 138). The spatial patterns were investigated. Principal Component Analysis (PCA) showed differences between geographical areas (Rías Altas, Centrales and Baixas) in the distribution of PCBs.

Geographical distribution and time trends of polychlorinated biphenyls in raft mussel from Galician coast (1998-2013)

PCBs were analyzed in raft mussels cultured in several polygons from Galician Rías (Rías of Ares-Betanzos, Muros-Noia, Arousa, Pontevedra and Vigo) during the period 1998-2013. The main aim of this work is study the quality of culture marine environment in relation to PCBs compounds. We report the results of a monitoring. The mean levels of ΣPCBs (ten congeners) ranged from 7.41 to 59.50ngg(-1)dw. The isomer concentrations in the Mytilus galloprovincialis cultured in raft were in the order hexachlorobiphenyls>pentachlorobiphenyls>tetrachlorbiphenyls>trichlorobiphenyls. Some biological parameters of mussel were also investigated (shell length, lipid content and condition index) in order to know their influence on ability of PCBs accumulation. ANOVA analysis confirms that levels of most of congeners had a significant relation (p<0.05) with shell length. The geographical patterns and temporal variations of PCBs were also investigated. Principal Component Analysis (PCA) showed differences between geographic areas (Rías) in the distribution of PCBs levels. Samples coming from Rías of Vigo and Ares-Betanzos presented the highest levels of PCBs and samples from Rías of Arousa and Muros-Noia had the lowest levels of these compounds. Time trends (linear regressions) showed a decline of levels of PCB congeners along the period 1998-2013.

The brown mussel Perna perna (L., 1758) as a sentinel species for chlorinated pesticide and dioxin-like compounds

To contribute to the use of the tropical brown mussel Perna perna as a sentinel species for organochlorine pesticides (OCP) and polychlorinated biphenyls (PCB), the present study reports data on the toxicokinetics of these compounds in P. perna. Specifically, the authors present data on OCP and PCB bioaccumulation for eight sampling months from three bays (SE Brazil) and two transplant experiments (each 1 month long). Although seasonality is observed in the total lipid content of the whole soft tissue, with summer samples showing higher values, no such seasonality is observed in the OCP and PCB concentrations bioaccumulated by the mussel P. perna. Because no seasonal effect is observed in the annual OCP and PCB concentrations bioaccumulated by P. perna, the use of this species as a sentinel organism to monitor organochlorinated compounds is encouraged. One month of transplantation is not enough to allow the transplanted specimens to reach the concentrations observed in animals reared at the destination site. Nevertheless, P. perna showed a clear tendency to depurate the DDT metabolites p,p'-DDD and p,p'-DDE after 1 month of transplantation.

Concentrations of Contaminants with Regulatory Limits in Samples of Clam (Chamelea gallina) Collected along the Abruzzi Region Coast in Central Italy

Concentrations of pollutants with regulatory limits were determined in specimens of Chamelea gallina, a species of clam collected along the Abruzzi coastal region of the central Adriatic Sea. Nine sampling sites were selected to evaluate the distribution of contaminants in the environment and the health risk for consumers. The concentrations of all the examined compounds were lower than the maximums set by European legislation. Polycyclic aromatic hydrocarbons and total mercury were below the detection limit (0.18 μg/kg for benzo[a]anthracene, 0.30 μg/kg for chrysene, 0.12 μg/kg for benzo[b]fluoranthene, 0.08 μg/kg for benzo[a]pyrene, and 0.0050 mg/kg for total mercury) in all the analyzed samples. Mean concentrations of lead and cadmium were 0.104 and 0.110 mg/kg, respectively. Of the non-dioxin-like polychlorinated biphenyls, PCB-153, PCB-180, and PCB-138 were the most abundant at all sampling sites (1a to 9a) at 0.25 mi (ca. 0.4 km) and at some sampling sites (1b, 2b, 3b, 5b and 7b) at 0.35 mi (ca. 0.56 km). Principal component analysis revealed that the concentrations of dioxin-like polychlorinated biphenyls were similar at the majority of sampling sites, and O8CDD and 2,3,7,8-T4CDF were the predominant dioxin congeners.

Distribution of persistent organic pollutants (POPs) in cultured mussels from the Croatian coast of the Adriatic Sea

In this study we investigated the distribution of 7 organochlorine pesticides (OCPs) and 17 polychlorinated biphenyl (PCBs) congeners in the edible tissue of the blue mussels (Mytilusgalloprovincialis) collected at 15 shellfish breeding farms and 1 harvesting area along the Croatian Adriatic coast. All analyzed OCPs were found in all samples (0.011-1.47 ng g(-)(1) w.wt.). Concentrations of PCB congeners in positive samples ranged between 0.007 and 7.66 ng g(-)(1) w.wt. The most abundant compounds were γ-HCH, PCB-138 and PCB-153. Overall levels of PCBs and OCPs were in the lower end of the concentration ranges reported in literature. Significant differences of all contaminants were recorded between seasons, with higher values in the warmer part of the year. Results of the evaluation of the risks to human health associated with consumption of the mussels containing organic contaminants suggest that the levels of these compounds in mussels do not pose any threat for consumers of cultivated mussels.

Distribution and bioaccumulation of polychlorinated biphenyls and organochlorine pesticides residues in sediments and Manila clams (Ruditapes philippinarum) from along the Mid-Western coast of Korea

The distribution and bioaccumulation features of PCBs, DDTs, and HCHs were investigated in the sediments and Manila clams collected from along the Mid-Western coast of Korea. The measured concentrations of ΣPCBs, ΣDDTs and ΣHCHs were 1.08-3.5, 0.12-0.35 and 0.090-0.30 ng g(-1) dw in sediment, and 33-390, 7.4-46 and 6.3-27 ng g(-1) lipid in Manila clam, respectively. Their levels were found to be relatively lower than those of other contaminated areas and the consumption of Manila clam from these areas seems to be safe for human health according to calculated lifetime cancer risk and hazard indices. The ΣPCBs and ΣDDTs concentrations in sediments showed a significant relationship to those in clams. The significant correlation was observed between BSAF in clams and Kow for each PCB congeners and DDT metabolites. These findings support that the PCBs and DDTs levels, which are highly hydrophobic chemicals, in clam reflect the sediment pollution through bioaccumulation.

Distribution and trend of organochlorine pesticides in Galicia coast using mussels as bioindicator organisms. Possible relationship to biological parameters

Contamination of organochlorine pesticides (OCPs) such as DDT and its metabolites (ΣDDs), γ-HCH (hexachlorocyclohexane), HCB (hexachlorobenzene), aldrin, endrin, isodrin and trans-nonachlor were investigated in wild mussels (Mytilus galloprovincialis) collected from Galician Rías (Rías of Ferrol, A Coruña, Muros, Arousa, Pontevedra and Vigo) during the period 1998-2012. Biological parameters, lipid content, shell length and condition index, were also studied. The OCPs levels in the wild mussel were in the order ΣDDs>γ-HCH>HCB. The other pesticides, aldrin, endrin, isodrin and trans-nonachlor, were not detected or were below the analytical detection limit. All concentrations found in these samples were below the allowable limits for human consumption (Regulation (EC) no. 396/2005). Univariate analysis confirmed that levels of some compounds presented significant relation with biological parameters. Multivariate analysis of the OCPs levels revealed significantly differences between studied Rías, samples from Ría of Ferrol had the highest levels of these compounds (values of ΣDDs ranged from 3.9 to 4.2 ng g(-1) ww) and samples from Ría of Arousa, the lowest levels (values of ΣDDs from 1.3 to 2.4 ng g(-1) ww). Temporal trends showed a decrease of OCPs levels along the studied period 1998-2012 in the Galician Rías.

Contamination levels of polychlorinated biphenyls in wild versus cultivated samples of female and male mussels (Mytilus sp.) from the Northwest Coast of Iberian Peninsula--new application for QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) methodology

A newly analytical method based on QuEChERS extraction followed by gas chromatography with mass spectrometry (GC-MS) analysis was developed and validated for the quantification of 18 PCBs in wild (from Matosinhos Beach, Portugal) and cultivated (from Ria de Arousa, Spain) mussel samples, pooled by sex. Wild animals showed higher PCB levels than cultivated mussels, with males from both origins, presenting an upper contamination profile comparing with females. This fact seems to be correlated with few biometric parameters, but other interdependencies, not addressed herein, such as distinct lipid contents between sexes, as a consequence of the gametogenic stage, may also explain this data. Overall, data reiterate the importance of investigating the presence of PCBs in marine biological samples, which can act both as bioindicators of environmental contamination, either as food quality controls for human health.

Impact assessment of agricultural inputs into a Mediterranean coastal lagoon (Mar Menor, SE Spain) on transplanted clams (Ruditapes decussatus) by biochemical and physiological responses

The Mar Menor is a coastal lagoon threatened by the development of intensive agriculture in the surrounding areas. Large amounts of pesticides from these areas are discharged into El Albujón, a permanent watercourse flowing into the lagoon. We have used a multi-biomarker approach to assess the biological effects of agricultural pollution on a bivalve species. Biomarkers indicative of neurotoxicity (acetylcholinesterase, AChE), oxidative stress (catalase, CAT; glutathione reductase, GR and lipid peroxidation, LPO), phase II biotransformation of xenobiotics (glutathione S-transferase, GST) and physiological stress (scope for growth, SFG) were measured in clams transplanted to four sites of the lagoon (two reference sites and two sites affected by the dispersion of the effluent of the El Albujón), for exposure periods of 7 and 22 days. The hazards of this effluent were also examined by simultaneously measuring up to 83 contaminants (pesticides, PCBs, PAHs and others) in samples of fresh water from the watercourse mouth and seawater from the deployed sites, as well as the bioaccumulation of organochlorinated compounds and PAHs in the transplanted animals. Biomarker responses showed marked differences between reference and affected sites after 7 and 22 days. However it was only after 22 days that principal component analysis (PCA) of the biomarker responses distinguished between clams deployed in sites affected by the dispersion of the effluent of the watercourse and those from the reference sites. The chemical analysis of water showed high concentrations of pesticides close to El Albujón watercourse mouth, with the greatest input flux corresponding to the organophosphate chlorpyrifos, followed by pendimethalin and naphthalene, and at lower levels acenaphthene, terbuthylazine-desethyl and chlorpyrifos-methyl. In this regard, PCA analysis showed that the biological effects of the mixture of pesticides in caged clams after 22 days were reduced levels of AchE and SFG and increased levels of GR and phase II GST activity. An integrated biomarker response index was calculated from the combination of these biomarkers, proving useful for the assessment of the impact of agricultural pollution in caged clams.

Interspecific comparison of polycyclic aromatic hydrocarbons and persistent organochlorines bioaccumulation in bivalves from a Mediterranean coastal lagoon

The bioaccumulation of polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) was characterized in cockle, oyster and noble pen shell from nine areas in the Mar Menor lagoon with different hydrodynamic and pollutant sources. Biota, sediment and water samples were simultaneously collected in the spring and autumn of 2010. Considering all bivalve samples, PAH concentrations ranged from 8.98 to 370 μg·kg(-1) d.w., those of PCBs from 0.15 to 42.36 μg·kg(-1) d.w. and those of DDXs from below detection limit to 240.6 μg·kg(-1) d.w., where p,p'-DDE was the main fraction. The bioaccumulation of PAHs was similar for cockle, oyster and noble pen shell, being higher close to ports and wastewater effluents. However, DDX and PCB bioaccumulations in oyster and noble pen shell were significantly higher than in cockle in spring (p=0.02). The first organic pollutant bioaccumulation data for noble pen shell were obtained in this study, showing a preferential accumulation of pyrene. The increase of PAH bioaccumulation in autumn, as compared to spring, was low, due to high water temperatures during the summer, which favoured PAH dissipation processes. No significant seasonal variations were detected for OCPs and PCBs, except in some specific areas. The PAH, PCB and OCP levels detected in these bivalves were lower than OSPAR/MED POL environmental assessment criteria, except for p,p'-DDE in bivalves sited close to El Albujón watercourse mouth.

Assessing the spatial variability, level and source of organic chemical contaminants in bivalve fishing grounds on the Galician coast (NW Spain)

Polychlorinated biphenyls, organochlorine pesticides, organotin compounds and triazines were quantified in sediments and bivalves collected in four areas on the Galician coast. One or several species were analysed at each site depending on their availability, including mussels (Mytilus galloprovincialis), cockles (Cerastoderma edule), clams (Venerupis pullastra and Ruditapes decussatus) and razor shells (Ensis siliqua). The general spatial distribution of contaminants was consistent in spite of the different sources of contamination. High inter-species variability was also observed. M. galloprovincialis and V. pullastra showed the highest levels of contaminants and intra-spatial variability, which highlights them as suitable species to be used as sentinel organisms. The area of O Burgo showed some worrisome results: PCB sediment concentrations were within the range that could cause biological effects. Also the level of heptachlor observed in V. pullastra was above limits accepted on edible seafood. Finally TBT concentration in mussels correlated with concentrations causing imposex in snails.

Organochlorine accumulation on a highly consumed bivalve (Scrobicularia plana) and its main implications for human health

Contamination by polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) was investigated along a spatial gradient in water, sediments and in commercially important bivalve species Scrobicularia plana, from Ria de Aveiro (Portugal). Organochlorines dissolved in water were below detection limit and concerning suspended particulate matter, only PCBs were quantified, ranging from 3.8 to 5.8 ng∙g(-1) DW (Σ13PCBs). There was a distinct spatial gradient regarding PCB accumulation in sediments. The highest concentrations were found in deeper layers and closest to the pollution source, decreasing gradually along a 3 km area. Contamination in sediments exceeded the Canadian and Norwegian sediment quality guidelines, inducing potential toxic effects in related biota. PCBs tended to bioaccumulate throughout S. plana lifespan but with different annual rates along the spatial gradient. The maximum values were found in older individuals up to 3+ years old, reaching 19.4 ng∙g(-1) DW. HCB concentrations were residual and no bioaccumulation pattern was evident. Congeners 138, 153 and 180 were the most accumulated due to their abundance and long-term persistence in the environment. In the inner area of the Laranjo Bay (0.6 km(2)), the species was able to remove up to 0.4 g of PCBs annually from sediments into their own tissues, which is consequently free for trophic transfer (biomagnification). Concerning human health, and despite the high concentrations found in sediments, PCB levels in bivalves do not exceed the limit established by the European Union for fishery products and are largely below tolerable daily intake. Although PCBs in Scrobicularia plana are present at low levels, their impact to human health after consumption over many years might be harmful and should be monitored in future studies.

PCBs in wild mussels (Mytilus galloprovincialis) from the N-NW Spanish coast: current levels and long-term trends during the period 1991-2009

Concentrations of polychlorinated biphenyls (PCBs) were determined in wild mussels (Mytilus galloprovincialis) from seven areas of the N-NW Spanish coast, during the period 1991-2009. The studied area is comprised of highly productive ecosystems which support important commercial fishing and shellfishing activities. The seven PCBs indicator congeners recommended by ICES (IUPAC nos. 28, 52, 101, 118, 138, 153 and 180), were analysed by gas chromatography with an electron capture detector (GC-ECD). Lowest average concentrations of PCBs were recorded in Arousa (1.04 μg kg(-1) wet weight), a low populated area with no industry; while the highest levels were found in areas near cities and/or showing a high industrial activity such as: Bilbao Ziérbena (139 μg kg(-1) ww) or A Coruña (55 μg kg(-1) ww). The hexachlorinated congeners CB153 and CB138 dominated the profiles in all wild mussel populations, although a geographical pattern was found in which the relative contributions of the lower chlorinated congeners were higher in the west coast (Rías of Vigo, Pontevedra and Arousa), which may reflect the occurrence of recent inputs of those compounds in the area. Finally, the application of the Mann-Kendall's test demonstrate the existence of a significant decrease in PCBs levels since 1991 up to 1996 in the studied area, whereas either a slow decrease or stable concentrations were registered over the past decade.