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.

Antibiotics in the Basque coast (N Spain): Occurrence in waste and receiving waters, and risk assessment (2017-2020).

The study of the presence of antibiotics in the aquatic environment is a preliminary step to analyse their possible harmful effects on aquatic ecosystems. In order to monitor their occurrence in the aquatic environment, the European Commission established in 2015, 2018, and 2020 three Watch Lists of substances for Union-wide monitoring (Decisions (EU) 2015/495, 2018/840, and 2020/1161), where some antibiotics within the classes of macrolides, fluoroquinolones and penicillins were included. In the Basque coast, northern Spain, three macrolide antibiotics (erythromycin, clarithromycin, azithromycin) and ciprofloxacin were monitored quarterly from 2017 to 2020 (covering a period before and after the COVID19 outbreak), in water samples collected from two Waste Water Treatment Plants (WWTPs), and three control points associated with receiving waters (transitional and coastal water bodies). This work was undertaken for the Basque Water Agency (URA). The three macrolide antibiotics in water showed a frequency of quantification >65 % in the Basque coast, with higher concentrations in the WWTP emission stations than in receiving waters. Their frequency of quantification decreased from 2017 to 2020, as did the consumption of antibiotics in Spanish primary care since 2015. Ciprofloxacin showed higher frequencies of quantification in receiving waters than in wastewaters, but the highest concentrations were observed in the WWTP emission stations. Although consumption of fluoroquinolones (among which is ciprofloxacin) in primary care in the Basque Country has decreased in recent years, this trend was not observed in the waters sampled in the present study. On the other hand, concentrations of clarithromycin, azithromycin, and ciprofloxacin in receiving waters exceeded their respective Predicted No-Effect Concentrations, so they could pose an environmental risk. These substances are widely used in human and animal medicine, so, although only ciprofloxacin is included in the third Watch List, it would be advisable to continue monitoring macrolides in the Basque coast as well.

Contaminants of emerging concern in the Basque coast (N Spain): Occurrence and risk assessment for a better monitoring and management decisions.

The study of the presence in the aquatic environment of certain substances considered as contaminants of emerging concern (CEC) is a preliminary step to the analysis of the possible harmful effects on aquatic ecosystems and the establishment of the corresponding environmental quality standards. In order to monitor the occurrence of CECs in the aquatic environment, the European Commission established in 2015 and 2018 two watch-list of substances for Union-wide monitoring in the field of water policy (Decision (EU) 2015/495 and Decision (EU) 2018/840). In the coast of the Basque Country, southeast of the Bay of Biscay, 19 of these watch list substances were monitored quarterly from May 2017 to March 2019. Water samples were collected at the effluent of three wastewater treatment plants and five control points associated with receiving waters (transitional and coastal water bodies). The most frequently quantified substances were azithromycin (91%), imidacloprid (82%), clarithromycin (80%), diclofenac (78%) and erythromycin (73%), with frequencies of quantification higher in wastewaters (83-100%) than in receiving waters (70-85%). In general, concentrations in wastewater were also higher than in receiving waters, indicating a dilution effect in the environment. In receiving waters, six out of the nineteen substances monitored exceeded their respective Predicted No-Effect Concentrations: azithromycin (34%), imidacloprid (9%), 17ß-estradiol (E2) (9%), clarithromycin (7%), ciprofloxacin (7%), and diclofenac (5%); and therefore, their levels could pose an environmental risk.

'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.

Source characterization and spatio-temporal evolution of the metal pollution in the sediments of the Basque estuaries (Bay of Biscay).

According to Water Framework Directive requirements, Member States must identify and analyze effects derived from human pressures in aquatic systems. As different kind of pressures can impact water bodies at different scales, analyses of spatio-temporal evolution of water bodies becomes essential in order to understand ecosystem responses. In this investigation, an analysis of spatio-temporal evolution of sedimentary metal pollution (Cd, Cr, Cu, Hg, Ni, Pb, Zn) in 12 Basque estuaries (Bay of Biscay) is presented. Data collected in extensive sampling surveys is the basis for the GIS-based statistical approach used. The implementation of pollution abatement measures is reflected in a long-term decontamination process, mostly evident in estuaries with highest historical sediment pollution levels. Spatial evolution is determined by either naturally occurring or human driven processes. Such spatial processes are more obviously being reflected in estuaries with lower historical sediment pollution levels.

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.

Baseline of butyltin pollution in coastal sediments within the Basque Country (northern Spain), in 2007-2008.

Tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT) were measured in surficial sediments at, the ports of Pasaia and Bilbao, together with other mid- and small-size harbours of the Basque Country (northern Spain), in 2007-2008. The highest values of the sum of the three measured butyltin species (3523-3640 ng g(-1), as Sn) were found at sampling stations near to shipyards located within the port of Pasaia. The highest value of TBT concentration (3143 ng g(-1), as Sn) was found at the marina of Getxo, in the port of Bilbao. The degree of TBT degradation varied greatly between sampling stations, being found to be generally higher in those sediments with higher values of redox potential and lower values of TBT concentration (normalized by organic matter content).

Using multiple ecosystem components, in assessing ecological status in Spanish (Basque Country) Atlantic marine waters.

The European Water Framework and Marine Strategy Directives relate to the assessment of ecological quality, within estuarine and coastal systems. This legislation requires quality to be defined in an integrative way, using several biological elements (phytoplankton, benthos, algae, phanerogams, and fishes), together with physico-chemical elements (including pollutants). This contribution describes a methodology that integrates all of this information into a unique quality assessment for 51 stations from 18 water bodies, within the Basque Country. These water bodies are distributed into four typologies, including soft-bottom coastal areas and three types of estuaries. For each station, decision trees were used to integrate (i) water, sediment and biomonitor chemical data to achieve an integrated physico-chemical assessment and (ii) multiple biological ecosystem elements into an integrated biological assessment. Depending on the availability of ecological quality ratios or global quality values, different integration schemes were used to combine station assessments into water body assessments on a single scale. Several examples from each element have been selected, to illustrate their responses to different pressures; likewise, to establish how the assessed integrated quality has changed, over time. The results made biological and ecological sense and physico-chemical improvements were often correlated with improvements in the quality of benthos and fishes. These tools permit policy makers and managers to take decisions, based upon scientific knowledge, in water management, regarding the mitigation of human pressures and associated recovery processes.

Investigative monitoring within the European Water Framework Directive: a coastal blast furnace slag disposal, as an example.

The European Water Framework Directive (WFD) establishes a framework for the protection of estuarine and coastal waters, with the most important objective being to achieve 'good ecological status' for all waters, by 2015. Hence, Member States are establishing programmes for the monitoring of water quality status, through the assessment of ecological and chemical elements. These monitoring programmes can be of three types: surveillance monitoring; operational monitoring (both undertaken on a routine basis); and investigative monitoring (carried out where the reason of any exceedance for ecological and chemical status is unknown). Until now, nothing has been developed in relation to investigative monitoring and no clear guidance exists for this type of monitoring, as it must be tackled on a 'case-by-case' basis. Consequently, the present study uses slag disposal from a blast furnace, into a coastal area, as a case-study in the implementation of investigative monitoring, according to the WFD. In order to investigate the potential threat of such slags, this contribution includes: a geophysical study, to determine the extent of the disposal area; sediment analysis; a chemical metal analysis; and an ecotoxicological study (including a Microtox test and an amphipod bioassay). The results show that metal concentrations are several times above the background concentration. However, only one of the stations showed toxicity after acute toxicological tests, with the benthic communities being in a good status. The approaches used here show that contaminants are not bioavailable and that no management actions are required with the slags.

Implementation of the European water framework directive from the Basque country (northern Spain): a methodological approach.

The European Water Framework Directive provides a challenge in the development of new and accurate methodologies. It addresses assessment of Ecological Quality Status within European rivers, lakes, groundwaters, estuaries and coasts. Although this directive is simple and flexible in its concept, it is necessary to develop an approach based upon scientific knowledge; however, at the same time it should be as simple as possible, in order to achieve both requirements and comparability of results throughout European waters. This contribution presents the first methodological approach to the problem, as used for estuaries and coasts of the Basque Country (northern Spain), in: selecting typologies and reference conditions; determining biological quality and ecological status; and identifying some problems in implementing the WFD. As such, the present paper could serve as the basis for a discussion document for other regions and countries, throughout Europe.