Effect of exposure to benzo[a]pyrene on SODs, CYP1A1/1A2- and CYP2E1 immunopositive proteins in the blood clam Scapharca inaequivalvis

The effects of water-borne exposure to benzo[a]pyrene (36 h; celite-bound 0.44 mg L(-1) B[a]P) on cytochrome P450 (CYP) and superoxide dismutases (SODs) were examined in digestive gland of the blood clam, Scapharca inaequivalvis. B[a]P accumulation and elimination were rapid, with maximum whole-body concentrations of 1.78 ng g(-1) wet wt after 12 h of treatment, followed by a progressive decline to 0.89 ng g(-1) at 36 h. The presence of B[a]P resulted in an increase in total CYP of digestive gland microsomes from 54+/-14 to 108+/-21 pmol/mg protein (mean+/-SD; p<0.05, 24 h). Increases were also seen in microsomal CYP1A1/1A2-immunopositive protein (50.5 kDa app. mol. wt; p<0.05), but not CYP2E1-immunopositive protein (49 kDa app. mol. wt.), indicating a specific response of the former isoform. Exposure to B[a]P produced a steady increase in Mn-SOD digestive gland activity (p<0.01; p<0.05) but no significant change in Cu/Zn-SOD activity. The respective proteins, measured by western blotting, were not significant induced after B[a]P exposure. Cu/Zn-SOD and Mn-SOD activities were correlated with total CYP levels (r=0.96 and 0.63, respectively), indicating a role for CYP in reactive oxygen species (ROS) production during exposure. Both 'NADPH-independent' and NADPH-dependent metabolism of B[a]P by digestive gland microsomes was seen, producing mainly 1,6-, 3,6- and 6,12-diones, with some phenols and 7,8-dihydrodiol; putative protein adducts were also formed. Redox cycling of the diones may also have contributed to ROS production, leading to the increased SOD activities.     

The effect of long-term depuration on levels of oxidative stress biomarkers in mullets (Mugil cephalus) chronically exposed to contaminants

The present study aimed to obtain additional data on the effect of long-term depuration on the levels of oxidative stress biomarkers, and to clarify the role of mullets for monitoring pollution in River Douro estuary. Mullets chronically exposed to a mixture of contaminants in Douro estuary were captured in Spring of 2001, 2002 and 2003. The activities of antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPX); and oxidative damages in lipids (lipid peroxidation) and in proteins (protein carbonyl content) were assessed at capture day and after transfer to unpolluted seawater for 1, 4 and 8 months. An overall decrease in the activities of the antioxidant enzymes was detected, except for the GPX after 4 months depuration. CAT activity exhibited the more significant decrease at the end of the long-term depuration. The decrease in SOD activity after 1 month of depuration was then maintained during the remaining depuration period. Regarding oxidative damages, a decrease in lipid peroxidation as well as the content of oxidised proteins was observed during depuration. Indeed, at capture the activities of antioxidant defences were higher as a result of the formation of reactive oxygen species (ROS) from the metabolism of pollutants. The oxidative damaged molecules were repaired or degraded during the depuration period, supporting the use of such damages as indicators of exposure to pro-oxidant pollutants.     

Evaluation of the applicability of a fuzzy index of ecosystem integrity (FINE) to characterize the status of Tyrrhenian lagoons

The new index FINE, a multimetric, fuzzy-based index for the evaluation of environmental quality for Mediterranean transitional waters, was calculated using biotic data gathered between 2000 and 2006 at 15 stations in 4 Tyrrhenian transitional water ecosystems (Orbetello Lagoon, Padrongiano Delta, Stagno di S. Teodoro, and Stagno di Tortolì), i.e. in a different biogeographic sub-province respect to the one in which the index was developed and validated. The rationale of FINE is that certain attributes, selected on the basis of established principles of benthic ecology, are fundamental for lagoon ecosystem function. A set of other indices (Simpson's 1-lambda', the W-statistics, AMBI, and BOPA) was also calculated and compared to FINE outputs. FINE, 1-lambda', and the W-statistics were significantly correlated with sedimentary organic matter content. Some stations were unequivocally assigned to the same ecological status, independently from the index used; for others, some discrepancies were evident. Mediterranean transitional waters probably share ecosystem complexities which are not yet fully captured by indices developed and validated elsewhere.     

Beach morphodynamics forcements in oiled shorelines: Coupled physical and chemical processes during and after fuel burial

In November 2002, the sinking of the Prestige oil tanker off the Galician coast (N.W. Spain) caused the largest ecological catastrophe in the history of Spain, affecting the coast called the 'Costa da Morte' (Galicia, N.W. Spain). This work is focused on the study of the oil contamination of the intertidal area of two beaches located on this stretch of coast. The study of twenty cores extracted from both beaches has identified fuel embedded in the sedimentary column up to a depth of 2.38 m (this being the maximum depth of extraction). This, along with the presence of oil below the groundwater indicates the existence of a new factor which determines the burial of oil: the morphodynamic behaviour of the beach. Furthermore, this morphodynamic variation conditions the physical appearance of the buried oil. Four different types have been identified: tar-balls (cm), particles (mm), oil coatings on sediment grains and on emulsion, with distribution patterns conditioned by the degree of wave exposure. The analysis of the information obtained have permitted the development of a conceptual model of the burial and oil evolution in the sedimentary column in relation to wave exposure, and thus to the morphodynamic variability of the beach.     

Influence of salinity and fish species on PAH uptake from dispersed crude oil

The use of chemical oil dispersants to minimize spill impacts causes a transient increase in hydrocarbon concentrations in water, which increases the risk to aquatic species if toxic components become more bioavailable. The risk of effects depends on the extent to which dispersants enhance the exposure to toxic components, such as polycyclic aromatic hydrocarbons (PAH). Increased salinities can reduce the solubility of PAH and the efficiency of oil dispersants. This study measured changes in the induction of CYP1A enzymes of fish to demonstrate the effect of salinity on PAH availability. Freshwater rainbow trout and euryhaline mummichog were exposed to water accommodated fractions (WAF), and chemically-enhanced water accommodated fractions (CEWAF) at 0 per thousand, 15 per thousand, and 30 per thousand salinity. For both species, PAH exposure decreased as salinity increased whereas dispersant effectiveness decreased only at the highest salinity. Hence, risks to fish of PAH from dispersed oil will be greatest in coastal waters where salinities are low.     

Cell and tissue biomarkers in mussel, and histopathology in hake and anchovy from Bay of Biscay after the Prestige oil spill (Monitoring Campaign 2003)

In order to assess the biological effects of the Prestige oil spill (POS), mussels (Mytilus galloprovincialis), European hake (Merluccius merluccius) and European anchovy (Engraulis encrasicolus) were sampled between April and September 2003 in various geographical areas of Bay of Biscay: Galicia, Central Cantabrian and East Cantabrian. In mussels, several cell and tissue biomarkers were measured: peroxisome proliferation as induction of acyl-CoA oxidase (AOX) activity, lysosomal responses as changes in the structure (lysosomal volume density, V(V(L)), surface-to-volume ratio, S/V(L), and numerical density, N(V(L))) and in membrane stability (labilization period, LP), cell type replacement as relative proportion of basophilic cells (volume density of basophilic cells, V(V(BAS))) in digestive gland epithelium, and changes in the morphology of digestive alveoli as mean luminal radius to mean epithelial thickness (MLR/MET). Additionally, flesh condition index (FCI) and gonad index (GI) were measured as supporting parameters. In hake and anchovy, liver histopathology was examined to determine the prevalence of parasites, melanomacrophage centers, non-specific lesions (inflammatory changes, atrophy, necrosis, apoptosis), early non-neoplastic toxicopathic lesions (i.e., hepatocellular nuclear polymorphism), foci of cellular alteration, benign and malignant neoplasms. In mussels, AOX induction was noticeable in April except in Galicia. LP values were low in all the geographical areas studied, indicating disturbed health, especially in Galicia. Alike, lysosomal enlargement was observed in most stations as shown by the extremely low S/V(L) values. V(V(BAS)) and MLR/MET values were markedly high. Overall, employed biomarkers detected exposure to toxic chemicals and disturbed health in mussels from Bay of Biscay, with impact decreasing from April to September. Although hepatocellular nuclear polymorphism and nematode parasitization in fish liver were remarkably prominent in some areas, they cannot be hitherto related to POS, since we lack historical data to determine whether the prevalences found were normal or significantly raised after POS.     

The effect of the "Prestige" oil spill on the plankton of the N-NW Spanish coast

Chlorophyll, primary production, zooplankton biomass and the species composition of phytoplankton and zooplankton were studied in 2003, after the Prestige shipwreck. The information obtained was compared to previous data series available for the area affected by the spill. A large data series on plankton variables for the N-NW Spanish coast existed, and therefore a realistic evaluation of the effects by comparison with the range of natural variability could be carried out. We emphasized the evaluation of impact during the spring bloom, the first important biological event after the spill. Some minor changes were observed occasionally, but they did not show any clear pattern and were more related to the natural variability of the ecosystem than to effect of the spill. Plankton community structure did not undergo any changes. Only a few species were more abundant during spring 2003 than in previous years. No significant changes were detected in the planktonic community during productive periods, such as the spring bloom and the summer blooms related to intrusions of East North Atlantic Central Waters. The lack of evidence of the effects of the spill on planktonic communities is discussed in terms of the characteristics of the fuel, the high dynamics of the water masses, the biological mechanisms through which the fuel from the surface waters is transferred to the sea floor and, particularly, the influence of the natural variability by means of large and meso-scale hydrographic processes in the area under study. At the present time it is not possible to determine any minor effects the spill may have had on the plankton owing to the great variability of the planktonic cycles and the short-term impact of the oil from the Prestige on the pelagic system.     

Marine monitoring: Its shortcomings and mismatch with the EU Water Framework Directive's objectives

The main goal of the EU Water Framework Directive (WFD) is to achieve good ecological status across European surface waters by 2015 and as such, it offers the opportunity and thus the challenge to improve the protection of our coastal systems. It is the main example for Europe's increasing desire to conserve aquatic ecosystems. Ironically, since c. 1975 the increasing adoption of EU directives has been accompanied by a decreasing interest of, for example, the Dutch government to assess the quality of its coastal and marine ecosystems. The surveillance and monitoring started in NL in 1971 has declined since the 1980s resulting in a 35% reduction of sampling stations. Given this and interruptions the remaining data series is considered to be insufficient for purposes other than trend analysis and compliance. The Dutch marine managers have apparently chosen a minimal (cost-effective) approach despite the WFD implicitly requiring the incorporation of the system's 'ecological complexity' in indices used to evaluate the ecological status of highly variable systems such as transitional and coastal waters. These indices should include both the community structure and system functioning and to make this really cost-effective a new monitoring strategy is required with a tailor-made programme. Since the adoption of the WFD in 2000 and the launching of the European Marine Strategy in 2002 (and the recently proposed Marine Framework Directive) we suggest reviewing national monitoring programmes in order to integrate water quality monitoring and biological monitoring and change from 'station oriented monitoring' to 'basin or system oriented monitoring' in combination with specific 'cause-effect' studies for highly dynamic coastal systems. Progress will be made if the collected information is integrated and aggregated in valuable tools such as structure- and functioning-oriented computer simulation models and Decision Support Systems. The development of ecological indices integrating community structure and system functioning, such as in Ecological Network Analysis, are proposed to meet a cost-effective approach at the national level and full assessment of the ecosystem status at the EU level. The WFD offers the opportunity to re-consider and re-invest in environmental research and monitoring. Using examples from the Netherlands and, to a lesser extent, the United Kingdom, the present paper therefore reviews marine monitoring and marine environmental research in combination and in the light of such major policy initiatives such as the WFD.     

Environmental pollution and natural populations: a biomarkers case study from the Iberian Atlantic coast

The degradation of estuaries is a result of human activities which overloads the environment with substances of both industrial and/or natural origins. Bioindicators have been consistently used to interpret effects of contaminants in the environment. In this study, the use of biomarkers (particular measurable characteristics of a bioindicator organism) was used to evaluate the contamination by xenobiotics of Crangon crangon natural populations. The central aim was to evaluate the capability of a battery of biomarkers to discriminate sites with different types of contamination. The activity of the enzymes cholinesterases (ChE), lactate dehydrogenase (LDH) and glutathione S-transferases (GST) were used as biomarkers. In addition, the ChE form(s) present in the cephalotorax of C. crangon were characterised. Organisms were seasonally sampled from winter 2001/2002 to autumn of 2002, at "reference" sites and at sites that receive agricultural, industrial and/or urban effluents. Results obtained in the characterisation of ChE with different substrates and selective inhibitors demonstrate that the form of ChE present in the cephalotorax of C. crangon shows proprieties of vertebrates' AChE and therefore it may be classified as true AChE-like ChE. The battery of biomarkers exhibited seasonal and local variations, apparently related to agricultural, industrial or urban effluent contamination. The tested biomarkers proved to be able to discriminate sources of environmental contamination, and confirms C. crangon as a sensitive species suitable to be used as a bioindicator.     

Bioaccumulation of heavy metals and radionuclides from seawater by encased embryos of the spotted dogfish Scyliorhinus canicula

Encased embryos of spotted dogfish Scyliorhinus canicula absorbed six radio-isotopes (241Am, 109Cd, 57Co, 134Cs, 54Mn and 65Zn) directly from seawater during short-term experimental exposure, demonstrating the permeability of the egg-case to these contaminants. Embryo to water concentration factors (CFs) ranged from 0.14 for 134Cs to 7.4 for 65Zn. The 65Zn and 57Co CFs increased exponentially with embryo length, whereas the CF for 109Cd declined with length. Among different components of the encased embryo the egg case was the major repository (69-99%) of all six radio-isotopes that were distributed throughout its wall. Egg-case CFs were as high as 10(3) for 57Co and 65Zn, making it the major source of gamma radiation exposure to the embryo and potentially of radio-isotopes for continued absorption by the embryo, following the uptake phase of the experiment. The patterns of uptake by the egg-case approximated linearity for most isotopes and loss rates were isotope-specific; egg-case biokinetics were not greatly affected by the viability of the contained embryo. Within the embryo initial data on radio isotopic distribution show that the skin is their major site of uptake, as previously demonstrated for juveniles.