Time series data (2008-2023) of polychlorinated dibenzo-p-dioxins, dibenzofurans and polychlorinated biphenyls in bivalves from Shellfish Production Areas of the Basque coast (SE Bay of Biscay).

The accumulation of contaminants in aquatic organisms is of concern to human health due to the potential for exposure through the consumption of seafood. This dataset presents the levels of 17 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and 12 dioxin-like polychlorinated biphenyls (DL-PCBs) (PCB-81, PCB-77, PCB-126, PCB-169, PCB-123, PCB-118, PCB-114, PCB-105, PCB-167, PCB-156, PCB-157 and PCB-189) in bivalves collected annually between 2008 and 2023 from the four Shellfish Production Areas of the Basque coast (southeastern Bay of Biscay). Additionally, data on 6 non-dioxin like polychlorinated biphenyls (NDL-PCBs) (PCB-28, PCB-52, PCB-101, PCB-153, PCB-138 and PCB-180) is provided for the 2012-2023 time period. Depending on the availability of bivalves at each Shellfish Production Area, different species, such as mussels (Mytilus galloprovincialis) and oysters (Magallana gigas and Ostrea edulis) were used for the evaluation. Bivalve samples were analyzed at the accredited Laboratory of Dioxins of the Institute of Environmental Assessment and Water Research - CSIC in Spain, following standardized methodologies according to the specific requirements established at the corresponding EU Regulation. Concentrations and the World Health Organization-Toxic Equivalents (WHO-TEQ) were calculated. Considering the data from the four Shellfish Production Areas and the study period, WHO-TEQ values ranged from 0.12 to 0.64 pg g-1 wet weight for PCDD/Fs and from 0.45 to 2.23 pg g-1 wet weight for DL-PCBs, whereas concentrations ranged from 7.45 to 51.10 ng g-1 wet weight for NDL-PCBs. This database is useful for (i) assessing the spatial and temporal trends of PCDD/Fs and various PCBs in bivalves from the Basque coast, (ii) determining the relative contribution of different congeners, (iii) comparison with levels for human consumption and environmental quality standards, as well as with levels of other biogeographical areas, and (iv) the management of Shellfish Production Areas on the Basque coast.

Data on growth performance and survival of black scallops (Mimachlamys varia (Linnaeus, 1758)) reared under suspended conditions in waters of the Basque coast (SE Bay of Biscay).

This dataset presents the growth performance and survival of black scallops (Mimachlamys varia) reared under suspended conditions using different growing systems at two different sites of the Basque coast (SE Bay of Biscay). Monthly data on environmental variables (temperature, salinity, oxygen saturation and chlorophyll "a" concentration) in the water column is also provided. Juveniles obtained from a hatchery with a mean length of 23.6 ± 4.12 mm and a mean wet weight of 2.06 ± 1.09 g were deployed in cages and pots at two experimental sites: a raft installed in sheltered waters and a longline located at offshore waters. The experiment was run from June 2019 to August 2020 (447 days). Black scallops were collected every one or two months and at each sampling time a cage and a pot were retrieved from each site. Black scallop survival and growth performance were determined. This database is useful for (i) assessing the viability of the species on the Basque coast, (ii) determining the time needed for black scallops to reach commercial size, (iii) promoting species diversification in the emerging offshore aquaculture sector in the Basque Country and, (iv) for comparison with other biogeographical areas.

Biological responses and toxicopathic effects elicited in Solea senegalensis juveniles by waterborne exposure to benzo[a]pyrene.

Polycyclic aromatic hydrocarbons (PAHs) are priority contaminants in coastal and estuarine ecosystems under anthropogenic pressure. Although PAHs tend to accumulate in the sediment, toxicity for benthic flat fish such as soles may be caused by PAHs released from the sediment to the water column. Within this context, the present investigation aims at recognizing toxicopathic effects elicited after waterborne exposure to benzo[a]pyrene B[a]P, a model individual PAH compound, in juvenile Solea senegalensis. Sole juveniles were exposed to various concentrations of waterborne B[a]P for 3 and 7 days. Brain, liver, gills and gonad were the target tissues selected to determine biochemical and lysosomal biomarkers, and histopathology. Biological responses and toxicopathic effects were consistent with B[a]P concentration and exposure time. From day 3, hepatic catalase inhibition indicated potential oxidative effects of B[a]P. At day 7, contaminant exposure produced hepatic glutathione-S-transferase induction at low concentrations and inhibition at higher levels, evidencing a bell-shaped response. A clear gradient in lysosomal membrane destabilisation was observed in relation with B[a]P concentrations. Histopathological lesions were more frequent at day 7 and at higher contaminant levels. It seems that environmentally relevant waterborne concentrations of B[a]P (1000 ng/l) would suffice to cause toxicopathic effects on sole juveniles in relatively short exposure times. In agreement, the Integrative Biological Response index (IBR/n) indicated a dose-dependent decline in health condition upon exposure to B[a]P (IBR/nHighB[a]P > IBR/nMidB[a]P > IBR/nLowB[a]P > IBR/nDMSO > IBR/nControl). Overall, changes in antioxidant enzymes activity, lysosomal biomarkers and gill and liver histopathology are responsive early-warning signs of health disturbance in sole juveniles exposed to waterborne PAHs.

Biological responses and toxicopathic effects elicited in Solea senegalensis juveniles on exposure to contaminated sediments under laboratory conditions.

Whole-sediment toxicity assays contribute to elucidating the intricate association between the presence of contaminants in sediments and their toxicopathic effects in benthic fish. In the present study, Solea senegalensis juveniles were exposed under laboratory conditions to contaminated whole-sediments for 7 and 28 days. Sediments were obtained from a low to moderately polluted estuary, a highly polluted harbour and from the mixture of both field-collected sediments. Biometry data were recorded. Liver, brain, gills, and gonads were dissected out and processed to determine markers of oxidative stress, neurotoxicity and lysosomal biomarkers, and histopathology. Analyses of sediment granulometry and chemical profiles indicated different degrees of toxicity and suggested a distinct release of pollutants from each sediment in relation with their physicochemical properties. Interestingly, biological responses were in agreement with contaminant levels reported in source sediments. The most distinct toxicopathic effects were detected upon exposure to the harbour's sediment and particularly on day 28. Overall, enhanced hepatic glutathione-S-transferase activity and lysosomal enlargement were detected in all experimental groups, demonstrating a toxic effect from all sediments whilst catalase inhibition, lysosomal membrane destabilisation, changes in lysosomal content and liver histopathology were most pronounced in soles exposed to the harbour's sediment. The Integrative Biomarker Response index (IBR/n) evidenced that exposure to the three sediments caused an impact of diverse magnitude in sole health (IBR/nHarbour > IBR/nMixture > IBR/nEstuary). The magnitude of biological responses essentially depended on the presence of contaminants in source sediments, which seemed to be altered by the conditions imposed by whole-sediment toxicity assays.

Incidence of plastic ingestion in seabirds from the Bay of Biscay (southwestern Europe).

Seabirds have been widely used to monitor marine debris by the analysis of plastic ingestion. With the aim of obtaining the first data on ingestion of plastics by different seabird species in the Bay of Biscay and evaluating their suitability as biomonitors of plastic pollution in this area, a total of 159 seabirds of fifteen species were analyzed. Plastics were found in 26 birds (16% of the individuals) of nine species (60% of the species). Frequency of occurrence of plastics varied between 0% (Razorbill) and 100% (species of the family Procellariidae). Considering several criteria to assess their suitability as biomonitors of plastic pollution (frequency of occurrence of plastic ingestion, species abundances and stranding occurrence in the Bay of Biscay), the Common Guillemot and the Atlantic Puffin seem the most promising candidates. This study provides the first data on plastic ingestion in seabirds of the Bay of Biscay.

Assessment of biological effects of environmental pollution along the NW Mediterranean Sea using red mullets as sentinel organisms.

A biomonitoring program was carried out in spring and autumn in three pollution hot-spots and sensitive areas of the NW Mediterranean Sea using red mullets (Mullus barbatus) as sentinel organisms and a battery of biomarkers together with gonad histology. In fish from anthropogenic impacted areas (Fos-sur-mer, Cortiou, Arenzano, Delta of Ebro) lysosomal membrane destabilization occurred indicating disturbed health. There were no significant differences in metallothionein (MT) levels among stations. Peroxisomal acyl-CoA oxidase (AOX) activity was highest in fish from Cortiou. Both MT levels and AOX activities were significantly correlated with gamete development. Prevalence of melanomacrophage centers were high in Cortiou in all samplings and in Fos-sur-mer in September samplings. In conclusion, the application of a battery of biomarkers in red mullets provided relevant data for the assessment of environmental pollution in the NW Mediterranean Sea but also showed the difficulties of using native fish as sentinels. For future studies caging strategies are recommended.

Assessment of biological effects of environmental pollution along the NW Mediterranean Sea using mussels as sentinel organisms.

With the aim of assessing the biological effects of pollution along three gradients of pollution in the NW Mediterranean Sea, a biomonitoring survey was implemented using a battery of biomarkers (lysosomal membrane stability, lysosomal structural changes, metallothionein (MT) induction and peroxisome proliferation) in mussels over a period of two years as part of the EU-funded BEEP project. Mussels from the most impacted zones (Fos, Genova and Barcelona harbours) showed enlarged lysosomes accompanied by reduced labilisation period of lysosomal membranes, indicating disturbed health. MT levels did not reveal significant differences between stations and were significantly correlated with gonad index, suggesting that they were influenced by gamete development. Peroxisomal acyl-CoA oxidase (AOX) activity was significantly inhibited in polluted stations possibly due to interactions among mixtures of pollutants. In conclusion, the application of a battery of effect and exposure biomarkers provided relevant data for the assessment of biological effects of environmental pollution along the NW Mediterranean Sea.

Biomarkers in mussels from a copper site gradient (Visnes, Norway): an integrated biochemical, histochemical and histological study.

In the present work, mussels (Mytilus edulis) were transplanted into a copper (Cu) gradient in Visnes (Norway) for a period of 3 weeks during November 2003. Sites 1 and 2 showed similar low levels of Cu, site 3 had intermediate Cu levels and site 4 was the most polluted with Cu as confirmed by AAS of digestive gland tissue. Values of lysosomal membrane labilization period were significantly lower at sites 3 and 4 compared to sites 1 and 2. The volume density and size of lysosomes was significantly decreased at site 4. The volume density of neutral lipids was also significantly lower at site 4 compared with the rest of sites. The volume density of lipofuscins showed significantly higher values at sites 2 and 3 compared to the reference site 1. Similar results were obtained regarding bioavailable metal levels measured by autometallography. All together, results are indicative of exocytosis of metal-containing lysosomes and lipofuscins to the digestive tubule lumen in mussels from site 4. In fact, autometallographic metal deposits were detected in digestive tubule lumen, brown cells and stomach in site 4 mussels. In agreement, there was a loss of digestive cells in mussels from site 4 (atrophy of the digestive epithelium) and cell type replacement (diminished volume density of digestive cells and increased volume density of basophilic cells). In conclusion, selected biomarkers indicated that mussels transplanted to sites closest to the Cu mine showed significant differences in metal accumulation pattern and in organization of the digestive gland tissue. Finally, female mussels closest to the Cu mine showed advanced gametogenesis with higher gonad index and vitellogenin-like protein levels than mussels at sites 1 and 2.

'The past is the future of the present': Learning from long-time series of marine monitoring.

Using a long-term (1995-2014) monitoring network, from 51 sampling stations in estuaries and coasts of the Basque Country (Bay of Biscay), the objective of this investigation was to assess the responsiveness of 83 variables in water (18), sediments (27), biota (26), phytoplankton (2), macroinvertebrates (5) and fishes (5) to different human pressures and management actions. We used a total of 3247 series of data to analyse trends of improvement and worsening in quality. In a high percentage of the cases, the management actions taken have resulted in positive effects in the environment, as shown by the trend analysis in this investigation. Overall, much more trends of improvement than of worsening have been observed; this is true for almost all the media and biological components studied, with the exception of phytoplankton; and it applies as well to almost all the stations and water bodies, with the exception of those corresponding to areas with water treatment pending of accomplishment. In estuaries with decreasing human pressures during the period, the percentage of series showing quality improvement was higher (approx. 30%) than those showing worsening of quality (12%). Moreover, in those water bodies showing an increase of pressure, variables which can be considered indicators of anthropogenic effects showed negative trends (quality worsening). On the other hand, some of the variables analysed were more affected by natural variability than by changes in pressures. That was the case of silicate, nitrate and suspended solids, which followed trends correlated to salinity, which, in turn, was related to the rainfall regime during the study period.

Development of histopathological indices in the digestive gland and gonad of mussels: integration with contamination levels and effects of confounding factors.

Bivalve histopathology has become an important tool in aquatic toxicology, having been implemented in many biomonitoring programmes worldwide. However, there are various gaps in the knowledge of many sentinel organisms and the interference of confounding factors. This work aimed (i) to develop a detailed semi-quantitative histopathological index of the digestive gland and gonad of the Mytilus galloprovincialis mussel collected from five sites contaminated with distinct patterns of organic and inorganic toxicants along the Basque coast (SE Bay of Biscay) and (ii) to investigate whether seasonal variability and parasitosis act as confounding factors. A total of twenty-three histopathological alterations were analysed in the digestive gland and gonad following a weighed condition index approach. The alterations were integrated into a single value for a better understanding of the mussels' health status. The digestive gland was consistently more damaged than the gonad. Mussels from the most impacted sites endured the most significant deleterious effects showing inflammation-related alterations together with digestive tubule atrophy and necrosis. Neoplastic diseases were scarce, with only a few cases of fibromas (benign neoplasia). In contrast, in moderately or little impacted sites, contamination levels did not cause significant tissue damage. However, parasites contributed to overestimating the values of histopathological indices (i.e. more severe tissue damage) in mussels from little impacted sites, whilst the opposite occurred in mussels from highly polluted sites. Accordingly, inter-site differences were more pronounced in autumn when natural physiological responses of advanced maturation stages did not interfere in the histological response. In conclusion, although seasonal variability and parasitosis mask the response of histopathological indices, this biomonitoring approach may provide good sensitivity for assessing the health status of mussels if fluctuations of these confounding factors are considered.

Histopathological indices in sole (Solea solea) and hake (Merluccius merluccius) for implementation of the European Marine Strategy Framework Directive along the Basque continental shelf (SE Bay of Biscay).

Sole and hake, together with sediments, were collected during two campaigns along the Basque continental shelf to study the utility of two existing histopathological indices for assessing the biological effects of contaminants to implement the European Marine Strategy Framework Directive. Hepatic and gonadal histopathology were measured, and metal and/or organic contaminants were determined in both liver and sediments. Sediments from the Basque continental shelf were found to be moderately impacted by metals but non-impacted by organic compounds. Metal bioaccumulation and histopathological lesions in liver were higher in sole than in hake, although non-specific and early non-neoplastic toxicopathic lesions were observed in both species. No gross alterations were recorded in gonad. The two histopathological indices applied were highly correlated in both organs but the lack of correlation between sediment contamination levels, bioaccumulation and histopathological indices suggests that other factors, rather than pollution alone, are responsible for the biological effects observed.

Combined use of native and caged mussels to assess biological effects of pollution through the integrative biomarker approach.

Native and caged mussels were used in combination for the monitoring of pollution biological effects through an integrative biomarker approach. Mussels (Mytilus galloprovincialis) were deployed in cages in two well-known model localities with different pollution levels in the Basque coast. After 3 weeks caged and native mussels were collected from each site and a suite of effect and exposure biomarkers (from molecular/cellular to organism level) was applied and chemical contaminants (metals, PAHs, PCBs, phthalates and nonylphenol ethoxylates) were analytically determined. Integrative biomarker indices and pollutant indices of tissues were calculated. Several biomarkers used herein responded similarly in native and caged mussels, whereas others exhibited significant differences. Overall, biomarkers in-a-suite depicted site-specific profiles useful for the diagnostic of mussel health status and therefore for ecosystem health assessment in marine pollution biomonitoring. On the other hand, biomarkers and bioaccumulation exhibited different response times, which was especially evident when comparing biomarker and pollutant indices of tissues. The suite of biomarkers was more sensitive after caging (short-term response), whereas tissue pollutant concentrations were more sensitive in native mussels (long-term response). Thus, the combination of native and caged mussels is highly recommended to monitor biological effects of pollution in mussels through the integrative biomarker approach, especially in chronically polluted sites.

Implementation of the European Marine Strategy Framework Directive: a methodological approach for the assessment of environmental status, from the Basque Country (Bay of Biscay).

The implementation of the Marine Strategy Framework Directive (MSFD) is directing European marine research towards the coordinated and integrated assessment of sea environmental status, following the ecosystem-based approach. The MSFD uses a set of 11 descriptors which, together, summarise the way in which the whole system functions. As such, the European Commission has proposed an extensive set of indicators, to assess environmental status. Hence, taking account of the large amount of data available for the Basque coast (southern Bay of Biscay), together with a recent proposal for assessment within the MSFD, an integrated environmental status assessment approach is developed (for the first time) in this contribution. The strengths and weaknesses of the method, combined with proposals from the MSFD, are discussed.