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Background levels of metals (Ag, Cd, Cu, Cr, Hg, Ni, Pb and Zn) in biomonitors (Mytilus galloprovincialismussels andCrassostrea gigasoysters), in estuarine waters within the Basque Country (south-east Bay of Biscay) are estimated using non-parametric statistical tools and data are presented graphically, with the aim of being used in assessing the ecological status, within the European Water Framework Directive (WFD). The basis for this study was the statistical analysis of data compiled from monitoring programmes undertaken along the Basque coast, between 1990 and 2008. For this analysis, a heuristic method was adapted and used. Results showed different metal background ranges throughout the year for both mussels and oysters. Values corresponding to the upper limit of the background range (i.e. value of the upper whisker of the box-plot) are proposed as the ‘high/good’ status boundary, according to the WFD. [ABSTRACT FROM AUTHOR]

European Commission has approached the challenge of End-Of-Life (EOL) fishing gear and Abandoned, Lost, or otherwise Discarded Fishing Gear (ALDFG) by focusing on circular economy. Current directives highlight the need to provide a proper management to EOL fishing gears, fostering their separate collection, transport, and treatment from a circular perspective. They also request Member States to set collection and treatment targets. However, this is far from being widely implemented in a coordinated manner. In the quest to explore the Spanish case, this contribution aims at providing insights on the amount and type of EOL fishing gear and management practices carried out in different Spanish ports, as well as recycling options for such gears. Data was collected through an online survey, interviews to stakeholders, and visits to ports. Composition, degradation and mechanical recyclability of EOL samples were assessed. Yearly, 1643 tonnes of EOL fishing gear (mainly nets) are discarded in Spanish ports from trawling (97.5%), gillnet/trammel nets (2.3%) and purse seine (0.2%) fisheries. High-density polyethylene (from trawling nets) is the most common discarded polymer, followed by polyamide 6 (from gillnets/trammel net and purse seine nets). EOL fishing gear management is diverse in Spain as it depends on the nature of the port (who governs it, either regional or national govern), special agreements between local fishers' guilds and waste managing companies, the waste managers in port, etc. Polyamide nets are degraded but in good condition to be recycled mechanically; for trawl nets chemical recycling is more suited due to their degraded state. Currently, few recycling companies exists in Spain that are engaged on mechanical recycling of EOL fishing gears, none in chemical recycling. Therefore, a more comprehensive analysis, coordination, and smart logistics are needed to make the collection and recycling of EOL fishing gear possible., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

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., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Liver and gonad histopathology, biometric parameters and hepatic metal bioaccumulation were assessed monthly over a one-year period in common soles from the Basque continental shelf, in order to determine baseline levels and confounding factors within biomonitoring studies. Biometric parameters and hepatic metal bioaccumulation varied according to season and gender. Accordingly, hepatic histopathological traits presented seasonal variations related to the reproductive cycle. However, the hepatic histopathological index showed that seasonality and gender were not significant confounding factors. Conversely, the gonad histopathological index was modulated by season and gender. As for organ comparison, the liver endured more severe histopathological damage than the gonad. In brief, the sampling period and gender may not affect the estimation of hepatic histopathological indices for biomonitoring purposes. Nonetheless, due to different sensitivities to environmental 'noise' variables, the sampling period and gender differentiation should be thoroughly considered for the assessment of gonad histopathology, biometrics and metal bioaccumulation., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

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., (Copyright © 2015 Elsevier B.V. All rights reserved.)

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., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

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)., (Copyright 2009 Elsevier Ltd. All rights reserved.)

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.

Inorganic mercury and methylmercury are determined in natural waters by injecting the filtered samples onto a low cost commercial flow injection system in which an anion exchange microcolumn is inserted after the injection loop (FIA-IE). If hydrochloric acid is used as the carrier solution, the HgCl4(2-) species (inorganic mercury) will be retained by the anion exchanger while the CH3HgCI species (methylmercury) will flow through the resin with negligible retention. Four anion exchangers and seven elution agents were checked, in a batch mode, to search for the best conditions for optimal separation and elution of both species. Dowex M-41 and L-cysteine were finally selected. Mercury detection was performed by cold vapour-electrothermal atomic adsorption spectrometry (HG-ETAAS). Both systems were coupled to perform the continuous on-line separation/detection of both inorganic mercury and methylmercury species. Separation and detection conditions were optimized by two chemometric approaches: full factorial design and central composite design. A limit of detection of 0.4 microg L(-1) was obtained for both mercury species (RSD < 3.0% for 20 microg L(-1) inorganic and methylmercury solutions). The method was applied to mercury speciation in natural waters of the Nerbioi-lbaizabal estuary (Bilbao, North of Spain) and recoveries of more than 95% were obtained.