Izaskun Zorita

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.

Application of two SH-based methods for metallothionein determination in mussels and intercalibration of the spectrophotometric method: laboratory and field studies in the Mediterranean Sea

Abstract Metallothionein (MT) induction is widely used as a biomarker of exposure to metals in mussels. The aims of the present work were first to compare the suitability of spectrophotometry and differential pulse polarography (DPP) for MT detection in mussels exposed to 200 ppb cadmium for 9 days in a laboratory experiment and in mussels sampled in different seasons from expected pollution gradients along the Mediterranean Sea; second, to intercalibrate the widely used spectrophotometric method using mussels from Saronikos Gulf. In the intercalibration of the spectrophotometric method, similar results (p>0.05) were obtained by two different research teams indicating a good reproducibility of the technique. However, polarographic and spectrophotometric methods gave significantly (p<0.05) different results in laboratory and field studies. In the laboratory experiment, MT values detected with DPP were nine times higher than with spectrophotometry. The results obtained by the two methods were significantly correlated. Both methods could discriminate between control and exposed mussels. In field studies, MT values obtained by DPP were 34–38-fold higher than with spectrophotometry, and MT concentrations measured by both methods were not correlated. This discrepancy could be due to several factors, including the low levels of bioavailable metals in the studied areas and the possibility that the different methods can measure MT isoforms differentially. Further work is needed to decipher the functions of MT isoforms in mussels. This information is relevant for the application of MT as a biomarker in biomonitoring programmes.

'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.

Assessment of lysosomal membrane stability and peroxisome proliferation in the head kidney of Atlantic cod (Gadus morhua) following long-term exposure to produced water components.

There is a need for sensitive biological effect methods by which to detect impacts of chronic exposure to low concentrations of contaminants. Two methods shown to be potentially useful for monitoring purposes in fish include lysosomal membrane stability and peroxisome proliferation. These biological endpoints were assessed in Atlantic cod (Gadus morhua) head kidney following exposure to a mixture of produced water components including polycyclic aromatic hydrocarbons, phenol, and alkylphenols. Lysosomal damage of head kidney cells occurred within the first two weeks and did not recover during the entire exposure period (32 weeks). Lysosomal membrane stability was not affected by gender and was responsive at low concentrations of contamination, indicating that lysosomal membrane stability measured in the head kidney could be a useful biomarker for effects of offshore pollution. Peroxisome proliferation, measured as acyl-CoA oxidase activity in the head kidney, appeared to be a potential biomarker in male cod exposed less than 16 weeks.

Monitoring the effectiveness of the European tributyltin regulation on the Basque coast (northern Spain) by assessing imposex in two gastropod species (Nassarius reticulatus and Nassarius nitidus)

Imposex and butyltin body burden were assessed in 2011 along the Basque coast (northern Spain) in two gastropod species (Nassarius reticulatus and Nassarius nitidus) four years after an initial survey in 2007. The aim of this re-survey was to monitor the effectiveness of the European ban on the use of tributyltin (TBT) based antifouling paints on ships’ hulls (EC 782/2003). Imposex levels in 2011 were lower than those determined in 2007 at most of the sampling sites. Accordingly, TBT concentrations in the female body burden of Nassarius reticulatus varied from 43 to 250 ng Sn/g in dry weight in 2011, which was a lower maximum than in 2007. Nevertheless, the results for the butyltin degradation index suggest that there have been recent inputs of TBT within the two main Basque harbours. Overall, the legislative measure is contributing to the reduction of TBT effects on the Basque coast although its presence is still evident.

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.