The "bioeffect assessment index" (BAI). A concept for the quantification of effects of marine pollution by an integrated biomarker approach

Dissecting integrated indices of multiple biomarker responses: Think before use

The multiple biomarker approach is an effective tool to study the responses of aquatic organisms to contaminants. Summarizing multiple biomarker responses for facilitated communication of research findings has been aided by some integrated indices. Here we explain how existing integrated indices were built and why they turn out to be the wheel reinvented. We discuss the role of integrated indices in ecological risk assessment and recommend some changes in summarizing multiple biomarker results. Integr Environ Assess Manag 2023;19:302-311. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Integrated biomarker response to assess the effects of pesticide residues on Nile Tilapia in aquatic ecosystems contaminated by cotton-field effluents

An in-situ study combined with an integrated biomarker response was used to evaluate the impact of agricultural effluents in the physiological responses of Nile tilapia reared in cages and enclosures of water reservoirs in North Benin. Fish were distributed in fish farming systems at two sites: Songhai located outside the cotton basin and Batran located in the most productive commune. They were sampled for blood and organs before (BST), during (DST) and after (AST) pesticide treatment. Pesticide residues were analysed in water, sediments and fish muscles. Several biomarkers were investigated related to the immune (peroxidase, lysozyme and complement activities, superoxide anion production) and reproductive (sex steroids and vitellogenin levels) responses as well as neurotoxicity (cholinesterase activity) and tissue alterations. Biomarkers were assessed and analysed via the integrated biomarker response (IBR). The results showed that Batran water reservoir was a more harmful ecosystem for fish than Songhai one, especially by depressing some immune and reproductive functions in relation to a higher-level of pesticide contamination. They also demonstrated that the contact of fish to sediments in enclosures aggravated the pesticide burden on fish. Therefore, using males as bioindicators would improve the sensitivity of the used biomarkers since males seemed more affected than females especially due to pesticide estrogenic induction impacting their reproductive system.

Macrophage-mediated tissue response evoked by subchronic inhalation of lead oxide nanoparticles is associated with the alteration of phospholipases C and cholesterol transporters

Background

Inhalation of lead oxide nanoparticles (PbO NPs), which are emitted to the environment by high-temperature technological processes, heavily impairs target organs. These nanoparticles pass through the lung barrier and are distributed via the blood into secondary target organs, where they cause numerous pathological alterations. Here, we studied in detail, macrophages as specialized cells involved in the innate and adaptive immune response in selected target organs to unravel their potential involvement in reaction to subchronic PbO NP inhalation. In this context, we also tackled possible alterations in lipid uptake in the lungs and liver, which is usually associated with foam macrophage formation.

Results

The histopathological analysis of PbO NP exposed lung revealed serious chronic inflammation of lung tissues. The number of total and foam macrophages was significantly increased in lung, and they contained numerous cholesterol crystals. PbO NP inhalation induced changes in expression of phospholipases C (PLC) as enzymes linked to macrophage-mediated inflammation in lungs. In the liver, the subchronic inhalation of PbO NPs caused predominantly hyperemia, microsteatosis or remodeling of the liver parenchyma, and the number of liver macrophages also significantly was increased. The gene and protein expression of a cholesterol transporter CD36, which is associated with lipid metabolism, was altered in the liver. The amount of selected cholesteryl esters (CE 16:0, CE 18:1, CE 20:4, CE 22:6) in liver tissue was decreased after subchronic PbO NP inhalation, while total and free cholesterol in liver tissue was slightly increased. Gene and protein expression of phospholipase PLCβ1 and receptor CD36 in human hepatocytes were affected also in in vitro experiments after acute PbO NP exposure. No microscopic or serious functional kidney alterations were detected after subchronic PbO NP exposure and CD68 positive cells were present in the physiological mode in its interstitial tissues.

Conclusion

Our study revealed the association of increased cholesterol and lipid storage in targeted tissues with the alteration of scavenger receptors and phospholipases C after subchronic inhalation of PbO NPs and yet uncovered processes, which can contribute to steatosis in liver after metal nanoparticles exposure.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12989-022-00494-7.

Fitness of Isidorella newcombi Following Multi-generational Cu Exposures: Mortality, Cellular Biomarkers and Life History Responses

The effects of multigenerational Cu exposure on the freshwater gastropod Isidorella newcombi were investigated. Snails were exposed to a range of treatment-specific Cu concentrations in the parental to F₂ generations, and a common Cu concentration in the F₃ generation. In the parental to F₂ generations, some general responses to 3 days Cu exposures included reduced survival and feeding in snails exposed to higher Cu concentrations. This suggested that the snails exposed to the high Cu concentration were experiencing Cu-induced stress that may apply selection pressure. In the F₃ generation, when all treatments were exposed to a common Cu concentration, increased survival was correlated with the pre-exposure Cu concentration history. Snails that had been pre-exposed to Cu also displayed reduced stress at a sub-lethal level, indicated by lower lysosomal destabilisation (LD). Mortality and LD responses in the F₃ generation were not related to Cu tissue concentrations, indicating increased tolerance and reduced stress were not related to changes in Cu bioaccumulation. Total antioxidant capacity increased in the higher Cu concentration pre-exposure treatments which could be associated with lower Cu-induced stress, however, this is not supported by the oxidative damage marker lipid peroxidation, which also increased. While Cu tissue concentrations and oxidative stress markers were assessed to determine underlying reasons for increased tolerance in snails from a population with a multi-generational exposure history to Cu, the results were not conclusive. Despite this, it was demonstrated through increased survival and reduced LD that Cu tolerance can develop over a short evolutionary time scale.

Interest of a multispecies approach in active biomonitoring: Application in the Meuse watershed

A biomonitoring approach based on a single model species cannot be representative of the contaminations impacts on the ecosystem overall. As part of the Interreg DIADeM program ("Development of an integrated approach for the diagnosis of the water quality of the River Meuse"), a study was conducted to establish the proof of concept that the use of a multispecies active biomonitoring approach improves diagnostic of aquatic systems. The complementarity of the biomarker responses was tested in four model species belonging to various ecological compartments: the bryophyte Fontinalis antipyretica, the bivalve Dreissena polymorpha, the amphipod Gammarus fossarum and the fish Gasterosteus aculeatus. The species have been caged upstream and downstream from five wastewater treatment plants (WWTPs) in the Meuse watershed. After the exposure, a battery of biomarkers was measured and results were compiled in an Integrated Biomarker Response (IBR) for each species. A multispecies IBR value was then proposed to assess the quality of the receiving environment upstream the WWTPs. The effluent toxicity was variable according to the caged species and the WWTP. However, the calculated IBR were high for all species and upstream sites, suggesting that the water quality was already downgraded upstream the WWTP. This contamination of the receiving environment was confirmed by the multispecies IBR which has allowed to rank the rivers from the less to the most contaminated. This study has demonstrated the interest of the IBR in the assessment of biological impacts of a point-source contamination (WWTP effluent) but also of the receiving environment, thanks to the use of independent references. Moreover, this study has highlighted the complementarity between the different species and has emphasized the interest of this multispecies approach to consider the variability of the species exposition pathway and sensibility as well as the mechanism of contaminants toxicity in the final diagnosis.

Biomarker Studies in Stress Biology: From the Gene to Population, from the Organism to the Application

Endpoints assessed at the population or community level are most often the result of the sum of effects on individuals, arising from the effects at the cellular and molecular levels. Within this framework, these lower biological level endpoints are more responsive at an early stage of exposure, making them potential toolboxes to be used as early-warning markers to address stress. Given this, by linking responses and understanding organisms' metabolism and physiology, the possibilities for the use of biomarkers in stress biology are vast. Here, biomarker comprehensive examples are given to enlighten the need to link levels of biological organization, and their usefulness for a myriad of fields and applications is presented and discussed.

Integrated Biomarker Response for Environmental Assessment Using the Gastropod Phorcus turbinatus along the Northern and the Northeastern Coasts of Tunisia

This work aims to assess the spatial and temporal variations of four biomarkers activities and to integrate their biological responses in a battery using the gastropod Phorcus turbinatus. The monitoring was carried out during the period between April 2014 and January 2015 at six stations along the northern and the northeastern coasts of Tunisia. The Fulton condition factor was estimated and the activities of catalase, acetylcholinesterase and glutathione-S-transferase were evaluated by spectrophotometry. A multi-biomarker battery approach was used to assess ecosystems' condition and to identify environmental impacts on the organisms. The results suggest that the enzymatic activities of CAT and GST depend especially on seasons. As for AChE activity, it was similar between seasons and stations. The values of the integrated biological response were maximal at Jarzouna in summer and at Sidi Daoued in winter, indicating the presence of severe stressors suffered by the organisms. This perturbation may be due to the enrichment of the waters by xenobiotics, namely polycyclic aromatic hydrocarbons, insecticides, phosphate wastes, PCBs and pesticides. Thus, P. turbinatus seems to be a good bioindicator of chemical pollution, constituting an adequate tool for a bio-monitoring program.

Evaluation of Multivariate Biomarker Indexes Application in Ecotoxicity Tests with Marine Diatoms Exposed to Emerging Contaminants

Worldwide anthropogenic activities result in the production and release of potentially damaging toxic pollutants into ecosystems, thereby jeopardizing their health and continuity. Research studies and biomonitoring programs attend to this emerging problematic by applying and developing statistically relevant indexes that integrate complex biomarker response data to provide a holistic approach, reflecting toxically induced alterations at the organism or population level. Ultimately, indexes allow simple result communications, enhancing policy makers understanding, and contributing to better resource and environmental managing policies. In this study three indexes, the integrated biomarker response index (IBR), the bioeffects assessment index (BAI) and principal components analysis (PCA), were evaluated for their sensitivity in revealing toxically induced stress patterns in cells of the diatom Phaeodactylum tricornutum under contaminant exposure. The set of biomarkers selected for index construction comprised the anti-oxidant enzymes APX, CAT and SOD, and the lipid peroxidation marker TBARS. Several significant correlations with the applied concentration gradients were noticed for all indexes, although IBR excelled for its reliability in delivering statistically significant dose-response patterns for four out of the five tested compounds.

Integrated use of biomarkers to evaluate the reproductive physiology of Astyanax fasciatus and Hoplias malabaricus males (Teleostei: Characiformes) in polluted reservoirs

The reproductive physiology of fish can be changed by the presence of pollutants in the water, which act as endocrine disrupting compounds (EDC). We evaluated the impacts of water contaminants in polluted reservoirs acting as possible EDC on the reproductive physiology of Astyanax fasciatus and Hoplias malabaricus males. We used biomarkers with different levels of biological organization. Hoplias malabaricus adult males were collected in the summer and winter at five different sites in the Tietê River Basin: the Ponte Nova reservoir (PN), considered a reference site due to the low anthropogenic influence; the Billings reservoir (BIL) at two different branches; and the Guarapiranga reservoir (GUA) at two different branches. Astyanax fasciatus adult males were collected at PN and BIL. BIL and GUA are subjected to great anthropogenic action. We analyzed gonadal histomorphology, testosterone (T), 11-ketotestosterone (11-KT), estradiol (E₂) plasma levels, and gene expression of hepatic vitellogenin (vtgA) and pituitary follicle stimulating hormone (fshβ). In the PN reservoir (reference), the biomarkers analyzed in both species did not differ between the periods analyzed. This is an evidence that the animals keep the same reproductive activity during both seasons. The changes in the plasma concentration of gonadal steroids in both species in polluted reservoirs suggest the presence of EDC compounds in the water and/or adjusts of the physiological setpoint to allow the reproduction in such adverse conditions. The use of vtgA as biomarker suggests the presence of estrogenic compounds, mainly in BIL, but with a more evident response of H. malabaricus. However, even considering physiological changes, both species present testes during the maturation phase that allow the reproduction in an environment with a high degree of pollution.

Sediment quality in the semi-enclosed Lumparn Bay, Åland Islands, Baltic Sea

The Lumparn Bay, due to its nature, is prone both to natural and anthropogenic environmental pressures. It is a semi-enclosed rather large, but relatively shallow bay filled with glacial and postglacial sediments. Unlike any other areas in the world the seafloor in this area is filled with gas domes. Comparison with the chemistry of some 2000 surface core samples from the Gulf of Finland revealed that the concentrations of arsenic, cadmium, chromium, copper, mercury, molybdenum, nickel, lead, zinc, and sulphur from the Lumparn Bay were in general on a low level, indicating only minor pressures on the seafloor. However, when compared to established sediment quality guidelines there are a few points of possible concern as some samples exceed the probable effects level for arsenic and quite a few samples exceed the effects range - median level for nickel. Also a few comparably high molybdenum concentrations exceed the lowest effects level.

The Response of the Planorbid Snail Isidorella newcombi to Chronic Copper Exposure Over a 28-Day Period: Linking Mortality, Cellular Biomarkers, and Reproductive Responses

The native freshwater gastropod Isidorella newcombi attacks the roots of developing rice plants in southern Australia and is controlled using copper sulphate. The apparent tolerance of this species to moderate levels of copper (Cu) exposure led us to investigate its potential usefulness as a biomonitor species. To assess its response to chronic Cu exposure, adult I. newcombi were exposed to 0-120 µg L^-1 of Cu for 28 days. Lethal and sublethal responses were investigated. The relationships between subcellular biomarkers and life history traits also were explored. At exposure concentrations of 60 µg L^-1 Cu and above, 100% mortality was observed during the 28-day exposure period. In these treatments, there was an exposure concentration dependent decrease in the time that the snails survived. In the surviving snails, there was an exposure concentration-dependent increase in tissue Cu concentration. In the snails exposed to Cu concentrations above 15 µg L^-1, no eggs were produced during the final week of copper exposure, indicating that populations would not persist at Cu concentrations above 15 µg L^-1. The general stress biomarker lysosomal membrane destabilisation (LD) indicated organisms exposed to 10 µg L^-1 Cu and above were experiencing Cu induced stress. This suggests that LD could act as an early warning system for responses at higher levels of biological organisation in I. newcombi exposed to copper.

Biological effects of dumped chemical weapons in the Baltic Sea: A multi-biomarker study using caged mussels at the Bornholm main dumping site

After World War II, thousands of tons of highly toxic chemical warfare agents (CWA) were deposited in the Baltic Sea, the main dumping site locating in the Bornholm Basin. In the present study, Baltic mussels (Mytilus trossulus) were transplanted in the area in cages at two hotspot sites and a reference site at the depths of 35 and 65 m for 2.5 months to study bioaccumulation and biological effects of CWA possibly leaking from the corroding warfare materials. No traces of degradation products of the measured phenylarsenic CWA could be detected in the tissues of mussels. Nevertheless, several biochemical and histochemical biomarkers, geno- and cytotoxicity indicators, and bioenergetic parameters showed significant responses. The Integrated Biomarker Index calculated from the single biomarkers also showed a higher total response at the two hotspot areas compared to the reference site. Although no direct evidence could be obtained confirming the responses being caused specifically by exposure to CWA, the field exposure experiment showed unambiguously that organisms in this sea area are confronting environmental stress affecting negatively their health and this is likely related to chemical contamination, which is possibly connected to the sea-dumped CWA.

Bioaccumulation, cellular and molecular effects in adult zebrafish after exposure to cadmium sulphide nanoparticles and to ionic cadmium

Few works have addressed the effects provoked by the exposure to cadmium containing nanoparticles (NPs) on adult zebrafish (Danio rerio). We studied the effects of CdS NPs (5 nm) or ionic cadmium (10 μg Cd/L) after 3 and 21 d of exposure and at 6 months post-exposure (mpe). Acute toxicity was recorded after exposure to both forms of cadmium. Significant cadmium accumulation was measured in the whole fish after both treatments and autometallography showed a higher accumulation of metal in the intestine than that in the liver. Histopathological alterations, such as inflammation in gills and vacuolization in the liver, were detected after the exposure to both cadmium forms and, in a lower extent, at 6 mpe. X-ray analysis proved the presence of CdS NPs in these organs. The hepatic transcriptome analysis revealed that gene ontology terms such as "immune response" or "actin binding" were over-represented after 21 d of exposure to ionic cadmium respect to CdS NPs treatment. Exposure to CdS NPs caused a significant effect on pathways involved in the immune response and oxidative stress, while the exposure to ionic cadmium affected significantly pathways involved in DNA damage and repair and in the energetic metabolism. Oxidative damage to liver proteins was detected after the exposure to ionic cadmium, while a stronger destabilization of the hepatocyte lysosomal membrane was recorded under exposure to CdS NPs. In summary, although ionic cadmium provoked stronger effects than CdS NPs, both cadmium forms exerted an array of lethal and sublethal effects to zebrafish.

Nonlethal Biomarkers of Oxidative Stress in Oiled Sediment Exposed Southern Flounder (Paralichthys lethostigma): Utility for Field-Base Monitoring Exposure and Potential Recovery

The Deepwater Horizon (DWH) blowout resulted in the deposition of toxic polycyclic aromatic hydrocarbons (PAHs), in the coastal sediments of the Gulf of Mexico. The immediate effects on an ecosystem from an oil spill are clearly recognizable, however the long-term chronic effects and recovery after a spill are still not well understood. Current methodologies for biomonitoring wild populations are invasive and mostly lethal. Here, two potential nonlethal biomonitoring tools for the assessment of PAH toxicity and induced biological alterations in the field, were identified using laboratory-validated methods. In this study, subadult southern flounder (Paralichthys lethostigma) were chronically exposed to DWH surrogate oiled sediments for 35 days; a subset of these exposed flounder were then provided a clean nonexposure period to ascertain the utility of selected biomarkers to monitor recovery post exposure. After chronic exposure, there was an increase in gene expression of cytochrome P450 1A but not glutathione S-transferase. There was also a notable imbalance of oxidants to antioxidants, measured as reduced glutathione, oxidized glutathione, and their ratio in the blood. Evidence of subsequent oxidative damage due to chronic exposure was found through lipid peroxidation and DNA damage assessments of liver, gill, and blood.

Evaluation of combined toxicity of Siduron and cadmium on earthworm (Eisenia fetida) using Biomarker Response Index

Agrochemicals and heavy metals are widespread contaminants in urban soil and could co-exist as mixture, which could cause unexpected risk to terrestrial organism. To assess the joint effect of herbicide Siduron and Cd, a battery of sub-lethal biomarkers was studied using earthworm ecotoxicological assay. Most selected biomarkers appeared significant but complicated responses with the increasing concentration of contaminants after 28-day exposure. In order to quantify the overall effect of the mixture contaminants, Biomarker Response Index (BRI) was used to integrate the multiple responses. Concentration Addition Index (CAI) and Effect Addition Index (EAI) were introduced to assess types of joint effect. Results showed significantly dose-effect responses between BRI and contaminant exposure concentrations. Integrated toxicity increased obviously under joint treatments of Siduron and Cd compared to their individual treatments. According to CAI, a clear antagonism was observed at relatively lower effects and gradually transformed to slight synergism with an increase of effects, while EAI showed the joint effect of addition at the whole range of effect levels. Thus, compared to the simple analysis of those complicated responses, BRI is an effective method to determine the integrated toxicity of mixture and its combination with joint effect indices (CAI and EAI) provides more worthy risk assessment on toxicity interaction among compounds.

Effects of ocean warming and acidification on accumulation and cellular responsiveness to cadmium in mussels Mytilus galloprovincialis: Importance of the seasonal status

Ocean warming and acidification could represent an additional threat to marine organisms already coping with other anthropogenic impacts, such as chemical contamination in coastal areas. In this study, interactions between such multiple stressors and their synergistic effects in terms of accumulation, detoxification and biological effects of metals were investigated in the Mediterranean mussel Mytilus galloprovincialis. Organisms sampled during the winter period were exposed for 28 days to different combinations of two temperatures (10 °C and 15 °C), two pH/pCO₂ (8.20/∼400μatm and 7.4/∼3000μatm) and two cadmium concentrations (0 and 20 μg/L). Cadmium concentrations increased in digestive glands and gills of metal-exposed mussels and were further enhanced by co-exposure at higher temperature. Interactive effects of temperature and/or pH were observed on Cd-mediated metallothionein induction, responsiveness of antioxidant system and onset of oxidative damages in lipids, with tissue-specific effects. Immunological effects showed a generalized sensitivity of lysosomal membrane stability toward the investigated stressors with major effects in co-exposed organisms. Cadmium and temperature affected phagocytosis efficiency and composition of haemocyte populations probably influencing the micronucleus frequency through varied mitotic rate. Several differences were highlighted between these results and those previously obtained from mussels exposed in summer, supporting the importance of season when addressing the tolerance of temperate organisms to variations of environmental factors. The elaboration of the whole biomarker results through weighted criteria allowed to summarize specific hazard indices, highlighting tissue-specific sensitivity toward multiple stressors and the need of improving the knowledge on interactions between multiple stressors.

Comparison of the behavioural effects of pharmaceuticals and pesticides on Diamesa zernyi larvae (Chironomidae)

Several studies have indicated the presence of contaminants in Alpine aquatic ecosystems. Even if measured concentrations are far below those that cause acute effects, continuous exposure to sub-lethal concentrations may have detrimental effects on the aquatic species present in these remote environments. This may lead to a cascade of indirect effects at higher levels of the ecological hierarchy (i.e., the community). To improve the determination of ecologically relevant risk endpoints, behavioural alterations in organisms due to pollutants are increasingly studied in ecotoxicology. In fact, behaviour links physiological function with ecological processes, and can be very sensitive to environmental stimuli and chemical exposure. This is the first study on behavioural alteration in a wild population of an Alpine species. In the present study, a video tracking system was standardized and subsequently used to identify contaminant-induced behavioural alterations in Diamesa zernyi larvae (Diptera, Chironomidae). Diamesa zernyi larvae, collected in an Italian Alpine stream (Rio Presena, Trentino Region), were acclimated for 24 h and successively exposed to several aquatic contaminants (pesticides: chlorpyrifos, metolachlor, boscalid, captan; pharmaceuticals: ibuprofen, furosemide, trimethoprim) at concentrations corresponding to their Lowest Observed Effect Concentration (LOEC). After 24, 48, 72, and 96 h of exposure, changes in the distance moved, the average speed, and the frequency of body bends were taken to reflect contaminant- and time-dependent effects on larval behaviour. In general, metolachlor, captan, and trimethoprim tended to reduce all the endpoints under consideration, whereas chlorpyrifos, boscalid, ibuprofen, and furosemide seemed to increase the distances moved by the larvae. This could be related to the different mechanisms of action of the investigated chemicals. Independently of the contaminant, after 72 h a general slowing down of all the behavioural activities occurred. Finally, we propose a behavioural stress indicator to compare the overall behavioural effects induced by the various contaminants.

Linking sub-individual and supra-individual effects in Daphnia magna exposed to sub-lethal concentration of chlorpyrifos

The main objective of the present study was to investigate possible links between sub-individual and supra-individual levels (i.e. population level) biomarkers in D. magna exposed to sublethal concentrations of the insecticide chlorpyrifos (CPF). To achieve the aim, 8-day old individuals were exposed for 96 h to two environmentally relevant concentrations of CPF (50 and 250 ng/L). Sub-individual level effects were investigated by measuring the activity of antioxidant (SOD, CAT, and GPx) and detoxifying (GST) enzymes, as well as by measuring the acetylcholinesterase (AChE) inhibition. In addition, the effects at supra-individual level were assessed by using a video-tracking system and analyzing changes in swimming capabilities (i.e. percentage of activity time, distance moved, and velocity). Our data have shown that daphnids exposed to both CPF concentrations were in a condition of stress which was highlighted by changes in both sub- and supra-individual biomarkers. Moreover, our results highlighted that the lowest tested CPF concentration did not modulate the antioxidant and detoxifying enzymes, whereas, an inhibition of AChE and a decrease of some parameters related to swimming behaviour (distance moved and velocity) were noted. On the contrary, significant changes in all the sub-individual biomarkers were measured at the highest tested concentration. In addition, organisms recovered the movement capability (distance moved) and also activate a mechanism of avoidance (increased swimming velocity). On the other hand, a reduction in the percent of active time was measured and this was attributed to the energy spent by organisms to activate antioxidant and detoxifying enzymes and the mechanism of avoidance. Based on these results, our study suggests the existence of a link between sub- and supra-individual levels, as the activation or non-activation in the antioxidant and detoxifying enzymes activities can led to different modifications of the swimming behaviour in D. magna.

Immune state correlates with histopathological level and reveals molluscan health in populations of Modiolus kurilensis by integral health index (IHI)

Quantitative analysis of the histopathological and immune parameters of bivalve Modiolus kurilensis collected from water areas with different level of ecotoxicological stress was performed. Significant differences between samples from polluted and non-polluted sites were revealed for total haemocyte count; percentage of agranulocytes; size and internal complexity of agranulocytes and granulocytes; phagocytic activity; percentage of NBT-positive cells; hemolytic activity and plasma protein concentration; percentage of the optical density of haemolymph major polypeptide bands at 55 kDa, 78 kDa, and 124 kDa; concretion coverage area in the kidney tubules; thickness of the tubular basement membrane; nephrocyte shape; and karyopyknosis of the kidneys; and hypervacuolisation; necrosis; karyopyknosis; haemocyte infiltration; fibrosis; and invasion of the digestive gland. Analysis of the global histopathological condition index based on the weighted indices also revealed that both the digestive gland and kidneys showed significantly greater histopathological changes in the bivalves collected from polluted water. Bivalve histopathology is an established tool in aquatic toxicology. However, it reflects a morphological picture of change, which, as a rule, can be clearly recorded only at the later stages of pathology, and in some cases, indicates an adaptation to stressors within the physiological norm. In this respect, a promising and highly sensitive biomarker of the functional state of bivalves, in terms of norm and pathology as well as their habitat, is the evaluation of immune status in combination with morphological changes. However, the use of different methods and scales of assessment and the diagnosis of biomarkers, characterised by different profiles of the stress response, makes it difficult to compare the results of different studies. We propose a reliable and powerful system for assessing the physiological state of bivalve molluscs, expressed in the integral health index (IHI) and based on the standardisation of the numerical values for all parameters that have significant differences between animals collected from impacted and non-impacted water areas. In our study, IHI calculated in three variants (for histopathological parameters, for immunological parameters, and in combination) showed the most significant differences in each of the cases, but the strongest difference (-4.07) was in calculating the total IHI, which included both the immune and histopathological parameters (p = 0.00005).

New Technologies for Monitoring Marine Mammal Health

Omics technologies have been developed in recent decades and applied to different subjects, although the greatest advancements have been achieved in human biology and disease. Genome sequencing and the exploration of its coding and noncoding regions are rapidly yielding meaningful answers to diverse questions, relating genome information to protein activity to environmental changes. In the past, marine mammal genetic and transcriptional studies have been restricted due to the lack of reference genomes. But the advance of high-throughput sequencing is revolutionizing the life sciences technologies. As long-lived organisms, at the top of the food chain, marine mammals play an important role in marine ecosystems and while their protected status is in favor of conservation of the species, it also complicates the researcher's approach to traditional measurements of health. Omics data generated by high-throughput technologies will represent an important key for improving the scientific basis for understanding both marine mammal and environment health.

Sub-chronic inhalation of lead oxide nanoparticles revealed their broad distribution and tissue-specific subcellular localization in target organs

BACKGROUND

Lead is well known environmental pollutant, which can cause toxic effects in multiple organ systems. However, the influence of lead oxide nanoparticles, frequently emitted to the environment by high temperature technological processes, is still concealed. Therefore, we investigate lead oxide nanoparticle distribution through the body upon their entry into lungs and determine the microscopic and ultramicroscopic changes caused by the nanoparticles in primary and secondary target organs.

METHODS

Adult female mice (ICR strain) were continuously exposed to lead oxide nanoparticles (PbO-NPs) with an average concentration approximately 106 particles/cm3 for 6 weeks (24 h/day, 7 days/week). At the end of the exposure period, lung, brain, liver, kidney, spleen, and blood were collected for chemical, histological, immunohistochemical and electron microscopic analyses.

RESULTS

Lead content was found to be the highest in the kidney and lungs, followed by the liver and spleen; the smallest content of lead was found in brain. Nanoparticles were located in all analysed tissues and their highest number was found in the lung and liver. Kidney, spleen and brain contained lower number of nanoparticles, being about the same in all three organs. Lungs of animals exposed to lead oxide nanoparticles exhibited hyperaemia, small areas of atelectasis, alveolar emphysema, focal acute catarrhal bronchiolitis and also haemostasis with presence of siderophages in some animals. Nanoparticles were located in phagosomes or formed clusters within cytoplasmic vesicles. In the liver, lead oxide nanoparticle exposure caused hepatic remodeling with enlargement and hydropic degeneration of hepatocytes, centrilobular hypertrophy of hepatocytes with karyomegaly, areas of hepatic necrosis, occasional periportal inflammation, and extensive accumulation of lipid droplets. Nanoparticles were accumulated within mitochondria and peroxisomes forming aggregates enveloped by an electron-dense mitochondrial matrix. Only in some kidney samples, we observed areas of inflammatory infiltrates around renal corpuscles, tubules or vessels in the cortex. Lead oxide nanoparticles were dispersed in the cytoplasm, but not within cell organelles. There were no significant morphological changes in the spleen as a secondary target organ. Thus, pathological changes correlated with the amount of nanoparticles found in cells rather than with the concentration of lead in a given organ.

CONCLUSIONS

Sub-chronic exposure to lead oxide nanoparticles has profound negative effects at both cellular and tissue levels. Notably, the fate and arrangement of lead oxide nanoparticles were dependent on the type of organs.

Feasibility of treating emulsified oily and salty wastewaters through coagulation and bio-regenerated GAC filtration

In the present study, chemical oxygen demand (COD) removal by coagulation and packed-columns of both fresh and bioregenerated granular activated carbon (GAC) is reported as a feasible treatment for saline and oily wastewaters (slops) generated from marine oil tankers cleaning. The use of Ferric chloride (FeCl₃), Aluminium sulphate (Al₂(SO₄)₃) and Polyaluminum chloride (Al₂(OH₃)Cl₃) was evaluated in the pre-treatment by coagulation of a real slop, after a de-oiling phase in a tank skimmer Comparison of coagulation process indicated that Polyaluminum chloride and Aluminium sulphate operate equally well (20-30% of COD removal) when applied at their optimal dose (40 and 90 mg/l respectively) but the latter should be preferred in order to significantly control the sludge production. The results from the column filtration tests indicated the feasibility of using the selected GAC (Filtrasorb 400 -Calgon Carbon Corporation) to achieve the respect of the discharge limits in the slops treatment with a carbon usage rate in the range 0.1-0.3 kg/m³ of treated effluent. Moreover, biological regeneration through Alcalinovorax borkumensis SK2 was proved to be a cost-effective procedure since the reuse of spent GAC through such regeneration process for further treatment could still achieve approximately 90% of the initial sorption capacity, reducing then costs for the use of new sorbents and also the need for waste disposal.

Integrated chemical and biological assessment of contaminant impacts in selected European coastal and offshore marine areas

This paper reports a full assessment of results from ICON, an international workshop on marine integrated contaminant monitoring, encompassing different matrices (sediment, fish, mussels, gastropods), areas (Iceland, North Sea, Baltic, Wadden Sea, Seine estuary and the western Mediterranean) and endpoints (chemical analyses, biological effects). ICON has demonstrated the use of a framework for integrated contaminant assessment on European coastal and offshore areas. The assessment showed that chemical contamination did not always correspond with biological effects, indicating that both are required. The framework can be used to develop assessments for EU directives. If a 95% target were to be used as a regional indicator of MSFD GES, Iceland and offshore North Sea would achieve the target using the ICON dataset, but inshore North Sea, Baltic and Spanish Mediterranean regions would fail.

Indirect effects of climate changes on cadmium bioavailability and biological effects in the Mediterranean mussel Mytilus galloprovincialis

Despite the great interest in the consequences of climate change on the physiological functioning of marine organisms, indirect and interactive effects of rising temperature and pCO₂ on bioaccumulation and responsiveness to environmental pollutants are still poorly explored, particularly in terms of cellular mechanisms. According to future projections of temperature and pH/pCO₂, this study investigated the main cellular pathways involved in metal detoxification and oxidative homeostasis in Mediterranean mussels, Mytilus galloprovincialis, exposed for 4 weeks to various combinations of two levels of pH/pCO₂ (8.2/∼400 μatm and 7.4/∼3000 μatm), temperature (20 and 25 °C), and cadmium addition (0 and 20 μg/L). Bioaccumulation was increased in metal exposed organisms but it was not further modulated by different temperature and pH/pCO₂ combinations. However, interactions between temperature, pH and cadmium had significant effects on induction of metallothioneins, responses of the antioxidant system and the onset of oxidative damages, which was tissue dependent. Multiple stressors increased metallothioneins concentrations in the digestive gland revealing different oxidative effects: while temperature and cadmium enhanced glutathione-dependent antioxidant protection and capability to neutralize peroxyl radicals, the metal increased the accumulation of lipid peroxidation products under acidified conditions. Gills did not reveal specific effects for different combinations of factors, but a general stress condition was observed in this tissue after various treatments. Significant variations of immune system were mainly caused by increased temperature and low pH, while co-exposure to acidification and cadmium enhanced metal genotoxicity and the onset of permanent DNA damage in haemocytes. Elaboration of the whole biomarker data in a cellular hazard index, corroborated the synergistic effects of temperature and acidification which increased the toxicological effects of cadmium. The overall results confirmed that climate change could influence ecotoxicological effects of environmental contaminants, highlighting the importance of a better knowledge of cellular mechanisms to understand and predict responsiveness of marine organisms to such multiple stressors.

Differential metabolic responses in three life stages of mussels Mytilus galloprovincialis exposed to cadmium

Cadmium (Cd) is one of the most important metal contaminants in the Bohai Sea. In this work, NMR-based metabolomics was used to investigate the toxicological effects of Cd at an environmentally relevant concentration (50 µg L^-1) in three different life stages (D-shape larval, juvenile and adult) of mussels Mytilus galloprovincialis. Results indicated that the D-shape larval mussel was the most sensitive life stage to Cd. The significantly different metabolic profiles meant that Cd induced differential toxicological effects in three life stages of mussels. Basically, Cd caused osmotic stress in all the three life stages via different metabolic pathways. Cd exposure reduced the anaerobiosis in D-shape larval mussels and disturbed lipid metabolism in juvenile mussels, respectively. Compared with the D-shape larval and juvenile mussels, the adult mussels reduced energy consumption to deal with Cd stress.

An integrative biomarker approach to assess the environmental stress in the north coast of Shandong Peninsula using native oysters, Crassostrea gigas

An integrative biomarker approach was employed to evaluate the environmental quality of the north coast of Shandong Peninsula along the southern Bohai Sea of China, where pollution is an imminent threat due to rapid urbanization and industrialization. A battery of biomarkers and the metal bioaccumulation in tissues of native oyster Crassostrea gigas were measured under field conditions. Integrative biomarker index (IBR) and metal body burden were calculated to differentiate the pollution status of seven sampling sites. According to our results, Xinzhuang (XZ) site was the most severely contaminated, with the highest IBR value of 3.58, while the lowest IBR value (0.04) was obtained at Penglai (PL). Such an integrated biomarker approach was proved as a useful method for environmental quality assessment in the study area.

Transcriptional and cellular effects of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) in experimentally exposed mussels, Mytilus galloprovincialis

The aim of the present investigation was to provide new insights on accumulation and possible adverse effects of various non-steroidal anti-inflammatory drugs (NSAIDs) in mussels, Mytilus galloprovincialis, exposed to an environmentally realistic concentration (0.5μg/L) of individual compounds, Acetaminophen (AMP), Diclofenac (DIC), Ibuprofen (IBU), Ketoprofen (KET) or Nimesulide (NIM). The measurement of drugs in mussel tissues was integrated with both functional alterations at cellular level and transcriptomic responses. Results indicated the capability of mussels to accumulate DIC and NIM, while AMP, IBU and KET were always below detection limit. A large panel of ecotoxicological biomarkers revealed the early onset of alterations induced by tested NSAIDs on immunological responses, lipid metabolism and DNA integrity. The gene transcription analysis through DNA microarrays, supported cellular biomarker results, with clear modulation of a large number of genes involved in the arachidonic acid and lipid metabolism, immune responses, cell cycle and DNA repair. The overall results indicated an ecotoxicological concern for pharmaceuticals in M. galloprovincialis, with transcriptional responses appearing as sensitive exposure biomarkers at low levels of exposure: such changes, however, are not always paralleled by corresponding functional effects, suggesting caution when interpreting observed effects in terms of perturbed cellular pathways. Fascinating similarities can also be proposed in the mode of action of NSAIDs between bivalves and vertebrate species.

Relationships between lines of evidence of pollution in estuarine areas: Linking contaminant levels with biomarker responses in mussels and with structure of macroinvertebrate benthic communities

Data obtained in a pollution survey performed in estuarine areas were integrated using multivariate statistics. The sites selected for the study were areas affected by treated and untreated urban discharges, harbours or industrial activities as well as reference sites. Mussels were transplanted to each site and after different times of exposure, samples of water, sediments and mussels were collected. Biomarkers were analysed on mussels after 3 and 21 days of transplant whereas concentrations of contaminants were measured in water, sediments and mussels after 21 days of transplant. The structure of macroinvertebrate benthic communities was studied in sediment samples. Studied variables were organised into 5 datasets, each one constituting a line of evidence (LOE): contaminants in water, contaminants in sediments, contaminants accumulated by transplanted mussels, biomarkers in transplanted mussels and changes in the structure of macroinvertebrate benthic communities of each sampling site. Principal Component Analysis (PCA) identified the variables of each LOE best explaining variability among sites. In order to know how LOEs relate to each other, Pearson's correlations were performed. Contaminants in sediments were not correlated with the rest of LOEs. Contaminants in water were significantly correlated with contaminants and biomarkers in mussels and with structure of macroinvertebrate benthic communities. Similarly, significant correlations were found between contaminants and biomarkers in mussels and between biomarkers in mussels and structure of macroinvertebrate benthic communities. In conclusion, biomarker responses give relevant information on pollution in estuarine areas and provide a link between chemical and ecological statuses of water bodies in the context of the Water Framework Directive.

Quality of the surface sediments of the northern coast of the Gulf of Finland, Baltic Sea

The Gulf of Finland is a shallow sea where a multitude of activities compete of space. Many of the activities include reworking of the sea floor. The gulf is known to have been rather largely contaminated by heavy metals during the last century, and although indications of recovery have been reported, it is crucial to know the levels of sea floor sediment contamination before any decisions of activities are taken by the authorities. In order to predict sediment toxicity the sediment concentrations acquired during a study from 2001 to 2004 are compared to Canadian sediment quality guidelines (SQG: s), which reveal that in the majority of the subsamples the metals and arsenic exceed the threshold levels of the used SQG: s, some exceed also the probable effect level. As, Cd, Hg, and especially Zn concentrations occur at unacceptably high levels in the coastal Gulf of Finland sediments.

Yes, caffeine, ibuprofen, carbamazepine, novobiocin and tamoxifen have an effect on Corbicula fluminea (Müller, 1774)

Reports indicating the presence of pharmaceutical in fresh water environment in the ngL(-1) to µgL(-1) range are occurring with increasing frequency. It is also a fact that pharmaceuticals may produce adverse effects on aquatic organisms. Nevertheless, there is still a lack of knowledge regarding how these emergent contaminants may affect aquatic biota. The goal of this research was to evaluate the sublethal responses in Corbicula fluminea such as, general stress (lysosomal membrane stability [LMS]), biomarkers of phase I and II (etoxyresorufin O-deethylase [EROD], dibenzylfluorescein dealkylase [DBF], gluthathione-S-transferase [GST]), oxidative stress (gluthathione reductase [GR], gluthathione peroxidase [GPX], lipid peroxidation [LPO]), and biomarkers of effect (DNA damage) after 21 days of exposure to caffeine, ibuprofen, carbamazepine, novobiocin and tamoxifen at 0.1, 1, 5, 10, 15, 50µgL(-1). Environmental concentrations tested in this study caused general stress and produced changes on biomarkers tested. LMS, responses from phase I and II enzymatic activity, oxidative stress, and biomarker of effect represent important ecotoxicological information, and will provide a useful reference for the assessment of selected drugs and the effects which these compounds may have on aquatic invertebrates, using C. fluminea as a bioindicator species.

Multiple biomarkers of biological effects induced by cadmium in clam Ruditapes philippinarum

Cadmium (Cd) is a known heavy metal pollutant in the Bohai Sea. Manila clam Ruditapes philippinarum is an important fishery species along the Bohai coast. In this study, the biological effects induced by two concentrations (20 and 200 μg/L) of Cd were characterized using multiple biochemical indices in the digestive glands of clam R. philippinarum. The total hemocyte counts, reactive oxygen species productions and antioxidant enzyme activities exhibited that Cd induced dose-dependent immune and oxidative stresses in clam digestive glands. Metabolic responses indicated that both Cd exposures caused immune stress marked by the elevated branched chain amino acids (valine, leucine and isoleucine), together with the disturbance in energy metabolism. The differential metabolic biomarkers related to osmotic stress, including homarine, betaine, tyrosine and phenylalanine, suggested the differential responsive mechanisms in clam digestive glands induced by Cd exposures. In addition, both Cd treatments enhanced the anaerobiosis metabolism in clam digestive glands via differential metabolic pathways.

Application of NMR-based metabolomics for environmental assessment in the Great Lakes using zebra mussel (Dreissena polymorpha)

Zebra mussel, Dreissena polymorpha, in the Great Lakes is being monitored as a bio-indicator organism for environmental health effects by the National Oceanic and Atmospheric Administration's Mussel Watch program. In order to monitor the environmental effects of industrial pollution on the ecosystem, invasive zebra mussels were collected from four stations-three inner harbor sites (LMMB4, LMMB1, and LMMB) in Milwaukee Estuary, and one reference site (LMMB5) in Lake Michigan, Wisconsin. Nuclear magnetic resonance (NMR)-based metabolomics was used to evaluate the metabolic profiles of the mussels from these four sites. The objective was to observe whether there were differences in metabolite profiles between impacted sites and the reference site; and if there were metabolic profile differences among the impacted sites. Principal component analyses indicated there was no significant difference between two impacted sites: north Milwaukee harbor (LMMB and LMMB4) and the LMMB5 reference site. However, significant metabolic differences were observed between the impacted site on the south Milwaukee harbor (LMMB1) and the LMMB5 reference site, a finding that correlates with preliminary sediment toxicity results. A total of 26 altered metabolites (including two unidentified peaks) were successfully identified in a comparison of zebra mussels from the LMMB1 site and LMMB5 reference site. The application of both uni- and multivariate analysis not only confirmed the variability of altered metabolites but also ensured that these metabolites were identified via unbiased analysis. This study has demonstrated the feasibility of the NMR-based metabolomics approach to assess whole-body metabolomics of zebra mussels to study the physiological impact of toxicant exposure at field sites.

The role of biomarkers in the assessment of aquatic ecosystem health

Ensuring the health of aquatic ecosystems and identifying species at risk from the detrimental effects of environmental contaminants can be facilitated by integrating analytical chemical analysis with carefully selected biological endpoints measured in tissues of species of concern. These biological endpoints include molecular, biochemical, and physiological markers (i.e., biomarkers) that when integrated, can clarify issues of contaminant bioavailability, bioaccumulation, and ecological effects while enabling a better understanding of the effects of nonchemical stressors. In the case of contaminant stressors, an understanding of chemical modes of toxicity can be incorporated with diagnostic markers of aquatic animal physiology to help understand the health status of aquatic organisms in the field. Furthermore, new approaches in functional genomics and bioinformatics can help discriminate individual chemicals, or groups of chemicals among complex mixtures that may contribute to adverse biological effects. Although the use of biomarkers is not a new paradigm, such approaches have been underused in the context of ecological risk assessment and natural resource damage assessment. From a regulatory standpoint, these approaches can help better assess the complex effects from coastal development activities to assessing ecosystem integrity pre- and post development or site remediation.

Effect of increasing temperature in the differential activity of oxidative stress biomarkers in various tissues of the Rock goby, Gobius paganellus

Oxidative stress biomarkers have been widely used in the development of ecological indices and in the assessment of exposure of aquatic organisms to contaminants from agricultural, industrial and urban pollution. However, temperature is known to also have a significant effect on oxidative stress biomarkers. This way, temperature is a confounding factor that may result in difficulties in the interpretation of oxidative stress biomarkers response patterns. Since climate change is expected to result in more frequent and intense heat wave events it is pertinent to investigate the effect of increasing temperature in the oxidative stress response of common aquatic organisms. It is also important to assess the differential response of different body tissues, given that they are differently exposed to temperature depending on their location and physiological function. This study investigates the effect of increasing temperature (20 °C-34 °C) in the response of multiple biomarkers of oxidative stress: lipid peroxidation, glutathione-S-transferase, superoxide dismutase and catalase activities, in the muscle, liver and gills of a common coastal fish, the Rock goby, Gobius paganellus. The response of the oxidative stress biomarkers analysed were always higher in the gills than in the other tissues. Muscle generally presented the lower levels of any of the biomarkers tested when compared to other tissues. Nevertheless, muscle tissue always responded significantly to temperature, as did the liver, while the gills were unresponsive in terms of lipid peroxidation and glutathione-S-transferase. Unresponsive tissues to temperature may be particularly interesting as indicators of pollution, given that temperature will not be a confounding variable in their oxidative stress response.

A multidisciplinary weight of evidence approach for environmental risk assessment at the Costa Concordia wreck: Integrative indices from Mussel Watch

A complex framework of chemical, biological and oceanographic activities was immediately activated after the Costa Concordia shipwreck, to assess possible contamination events and the environmental impact during both emergency and wreck removal operations. In the present paper, we describe the results obtained with caged mussels, Mytilus galloprovincialis, chosen as bioindicator organisms to detect variations of bioavailability and the early onset of molecular and cellular effects (biomarkers). Seven translocation experiments were carried out during the first year from the incident, with organisms deployed at 2 depths in 3 different sites. After 4-6 weeks, tissue concentrations were measured for the main classes of potentially released chemicals (trace metals, polycyclic aromatic hydrocarbons, volatile and aliphatic hydrocarbons, polychlorinated biphenyls, halogenated pesticides, organotin compounds, brominated flame retardants, anionic surfactants); a wide battery of biomarkers covered responses indicative of exposure, detoxification, oxidative stress, cell damage and genotoxic effects. Results excluded serious contamination events or a consistent increase of environmental pollution although some episodic spills with reversible effects were detected. Data were elaborated within a quantitative weight of evidence (WOE) model which provided synthetic hazard indices for each typology of data, before their overall integration in an environmental risk index, which generally ranged from slight to moderate. The proposed WOE model was confirmed a useful tool to summarize large datasets of complex data in integrative indices, and to simplify the interpretation for stakeholders and decision makers, thus supporting a more comprehensive process of "site-oriented" management decisions.

Effect of temperature in multiple biomarkers of oxidative stress in coastal shrimp

Various studies in captivity and in the wild have pointed to the effect of season, and temperature in particular, in the levels of the oxidative stress biomarkers currently used for environmental quality assessment. However, knowledge on how temperature affects the oxidative stress response is unavailable for most species. This study investigated the effect of increasing temperature on lipid peroxidation, catalase activity, superoxide dismutase and glutathione-S-transferase in the shrimps, Palaemon elegans and Palaemon serratus. It was concluded that increasing temperatures significantly affect all the biomarkers tested in both species, with the exception of superoxide dismutase in P. serratus which was not affected by temperature. The oxidative stress response was more intense in P. elegans, than in P. serratus, producing higher peaks of all biomarkers at temperatures between 22°C and 26°C, followed by low levels at higher temperatures. It was concluded that monitoring of ecosystems using oxidative stress biomarkers should take into account the species and thermal history of the organisms. Sampling should be avoided during heat waves and immediately after heat waves.

Frequency of hepatocellular fibrillar inclusions in European flounder (Platichthys flesus) from the Douro River estuary, Portugal

Liver lesions in wild fish have been associated with xenobiotic exposure. Facing reports of pollution in the Douro River estuary (north of Portugal), we have been making field surveys using fishes and targeting histopathological biomarkers of exposure and effect. Herein, we intended to better characterize and report the rate of one poorly understood lesion-hepatocellular fibrillar inclusions (HFI)-found in European flounder (Platichthys flesus). With this report, we aimed to establish sound baseline data that could be viewed as a starting point for future biomonitoring, while offering the world's second only pool of field data on such a liver toxicopathic lesion, which could be compared with data available from the UK estuaries. Sampling was done in the Douro River estuary over 1 year. A total of 72 animals were fished with nets, in spring-summer (SS) and autumn-winter (AW) campaigns. Livers were processed for histopathology and both routine and special staining procedures (alcian blue, periodic acid Schiff (PAS), tetrazonium coupling reaction). Immunohistochemistry targeted AE1/AE3 (pan cytokeratins). The severity of the HFI extent was graded using a system with four levels, varying from 0 (absence of HFI) to 3 (high relative density of cells with HFI). Cells (isolated/groups) with HFI appeared in 35 % or more of the fish, in the total samples of each season, and over 40 % in more homogeneous sub-samples. There were no significant differences when comparing samples versus sub-samples or SS versus AW. When merging the data sets from the two seasons, the frequency of fish with HFI was ≈36 % for the total sample and ≈49 % for the sub-sample. The extreme group (biggest and smallest fish) revealed a HFI frequency of only 16 %, which differed significantly from the total and sub-sampled groups. Immunostaining and PAS were negative for the HFI, and alcian blue could, at times, faintly stain the inclusions. These were positive with the tetrazonium reaction. We showed the presence of HFI in European flounder from the Douro River estuary, proving that they are essentially protein in nature, that no seasonal changes existed in the HFI frequency, and that it was rarer in the smallest and biggest fish groups. Within the ranges of weight/size of our total sample, we estimate that the frequency of HFI in the local flounder is ≈35 %. That rate stands as a baseline value for future assessments, namely for biomonitoring purposes targeting correlations with the estuary pollution status.

The integrated biomarker response revisited: optimization to avoid misuse

The growing need to evaluate the quality of aquatic ecosystems led to the development of numerous monitoring tools. Among them, the development of biomarker-based procedures, that combine precocity and relevance, is recommended. However, multi-biomarker approaches are often hard to interpret, and produce results that are not easy to integrate in the environmental policies framework. Integrative index have been developed, and one of the most used is the integrated biomarker response (IBR). However, an analysis of available literature demonstrated that the IBR suffers from a frequent misuse and a bias in its calculation. Then, we propose here a new calculation method based on both a more simple formula and a permutation procedure. Together, these improvements should rightly avoid the misuse and bias that were recorded. Additionally, a case study illustrates how the new procedure enabled to perform a reliable classification of site along a pollution gradient based on biomarker responses used in the IBR calculations.

Development of tools for integrated monitoring and assessment of hazardous substances and their biological effects in the Baltic Sea

The need to develop biological effects monitoring to facilitate a reliable assessment of hazardous substances has been emphasized in the Baltic Sea Action Plan of the Helsinki Commission. An integrated chemical-biological approach is vitally important for the understanding and proper assessment of anthropogenic pressures and their effects on the Baltic Sea. Such an approach is also necessary for prudent management aiming at safeguarding the sustainable use of ecosystem goods and Services. The BEAST project (Biological Effects of Anthropogenic Chemical Stress: Tools for the Assessment of Ecosystem Health) set out to address this topic within the BONUS Programme. BEAST generated a large amount of quality-assured data on several biological effects parameters (biomarkers) in various marine species in different sub-regions of the Baltic Sea. New indicators (biological response measurement methods) and management tools (integrated indices) with regard to the integrated monitoring approach were suggested.

Fish biological effect monitoring of chemical stressors using a generalized linear model in South Sea, Korea

To evaluate the health status at six different study areas, we used the generalized linear model approach with selected biochemical markers in resident fish from uncontaminated and contaminated sites. We also confirmed the independence between the biochemical indices and the morphometric indices including the hepato-somatic index (HSI), gonado-somatic index (GSI), and condition factor (CF) in fish from the sampling areas. The effect of area on the presence of biotransformation markers (ethoxyresorufin-O-deethylase activity; EROD) was significantly high in Masan Bay. The area with the greatest effect on acetylcholinesterase (AChE) activity was Jindong Bay, while there was no significant effect of GSI, HSI, CF, and sex in the EROD model and HSI, CF and sex in the AChE model. These results clarify that fish from Masan, Gwangyang and Jindong Bay were affected by pollutant stress, and the analysis of sensitive biochemical responses allowed for an improved interpretation of the results.

Development of a decision support system to manage contamination in marine ecosystems

In recent years, contamination and its interaction with climate-change variables have been recognized as critical stressors in coastal areas, emphasizing the need for a standardized framework encompassing chemical and biological data into risk indices to support decision-making. We therefore developed an innovative, expert decision support system (Exp-DSS) for the management of contamination in marine coastal ecosystems. The Exp-DSS has two main applications: (i) to determine environmental risk and biological vulnerability in contaminated sites; and (ii) to support the management of waters and sediments by assessing the risk due to the exposure of biota to these matrices. The Exp-DSS evaluates chemical data, both as single compounds and as total toxic pressure of the mixture, to compare concentrations to effect-based thresholds (TELs and PELs). Sites are then placed into three categories of contamination: uncontaminated, mildly contaminated, and highly contaminated. In highly contaminated sites, effects on high-level ecotoxicological endpoints (i.e. survival and reproduction) are used to determine risk at the organism-population level, while ecological parameters (i.e. alterations in community structure and ecosystem functions) are considered for assessing effects on biodiversity. Changes in sublethal biomarkers are utilized to assess the stress level of the organisms in mildly contaminated sites. In Triad studies, chemical concentrations, ecotoxicological high-level effects, and ecological data are combined to determine the level of environmental risk in highly contaminated sites; chemical concentration and ecotoxicological sublethal effects are evaluated to determine biological vulnerability in mildly contaminated sites. The Exp-DSS was applied to data from the literature about sediment quality in estuarine areas of Spain, and ranked risks related to exposure to contaminated sediments from high risk (Huelva estuary) to mild risk (Guadalquivir estuary and Bay of Cadiz). A spreadsheet-based version of the Exp-DSS is available at the MEECE and DiSIT web sites (www.meece.eu and www.disit.unipmn.it).

Catalasic activity in fish liver: improvement of the UV to visible analytic method

Antioxidative defenses and more especially catalasic activity (CAT) are studied in a large range of scientific research thematics. In environmental sciences, the problematic of oxidative stress is of great interest as pollutants can induce perturbations of redox homeostasis. Consequently, changes in antioxidative defenses levels in fish tissues and particularly in liver are used as potential biomarkers of pollution. In most studies, the CAT was assayed by following during 5 min the consumption of H2O2 in cytosolic buffered extracts at 240 nm (UV-method). This study proposed a development of this method in the visible, using permanganate and a 525-nm detection, which was more accurate, sensitive, and rapid. Moreover, the hepatic CAT of six different fish species [a cyclidae (Nimbochromis linni), 3 cyprinidae (Brachydanio rerio, Rutilus rutilus, Cyprinus carpio), an anguillidae (Anguilla anguilla), and a percidae (Perca fluviatilus)] was evaluated with the two protocols (UV- and KMnO4-method). The results but also the thermal optimum of the reaction and the interest of CAT as biomarker in ecotoxicology were discussed.

Using lysosomal membrane stability of haemocytes in Ruditapes philippinarum as a biomarker of cellular stress to assess contamination by caffeine, ibuprofen, carbamazepine and novobiocin

Although pharmaceuticals have been detected in the environment only in the range from ng/L to microg/L, it has been demonstrated that they can adversely affect the health status of aquatic organisms. Lysosomal membrane stability (LMS) has previously been applied as an indicator of cellular well-being to determine health status in bivalve mussels. The objective of this study is to evaluate LMS in Ruditapes philippinarum haemolymph using the neutral red retention assay (NRRA). Clams were exposed in laboratory conditions to caffeine (0.1, 5, 15, 50 microg/L), ibuprofen (0.1, 5, 10, 50 microg/L), carbamazepine and novobiocin (both at 0.1, 1, 10, 50 microg/L) for 35 days. Results show a dose-dependent effect of the pharmaceuticals. The neutral red retention time measured at the end of the bioassay was significantly reduced by 50% after exposure to environmental concentrations (p < 0.05) (caffeine = 15 microg/L; ibuprofen = 10 microg/L; carbamazepine = 1 microg/L and novobiocin = 1 microg/L), compared to controls. Clams exposed to these pharmaceuticals were considered to present a diminished health status (retention time < 45 min), significantly worse than controls (96 min) (p < 0.05). The predicted no environmental effect concentration (PNEC) results showed that these pharmaceuticals are very toxic at the environmental concentrations tested. Measurement of the alteration of LMS has been found to be a sensitive technique that enables evaluation of the health status of clams after exposure to pharmaceuticals under laboratory conditions, thus representing a robust Tier-1 screening biomarker.

A novel "Integrated Biomarker Response" calculation based on reference deviation concept

Multi-biomarker approaches are used to assess ecosystem health and identify impacts of environmental stress on organisms. However, exploration of large datasets by environmental managers represents a major challenge for regulatory application of this tool. Several integrative tools were developed to summarize biomarker responses. The aim of the present paper is to update calculation of the "Integrated Biological Response" (IBR) described by Beliaeff and Burgeot (Environ Toxicol Chem 21:1316-1322, 2002) to avoid weaknesses of this integrative tool. In the present paper, a novel index named "Integrated Biological Responses version 2" based on the reference deviation concept is presented. It allows a clear discrimination of sampling sites as for the IBR, but several differences are observed for contaminated sites according to up- and downregulation of biomarker responses. This novel tool could be used to integrate multi-biomarker responses not only in large-scale monitoring but also in upstream/downstream investigations.

Marine ecosystem health status assessment through integrative biomarker indices: a comparative study after the Prestige oil spill "Mussel Watch"

Five integrative biomarker indices are compared: Bioeffects Assessment Index (BAI), Health Status Index (HSI), integrated biological response (IBR), ecosystem health condition chart (EHCC) and Integrative Biomarker Index (IBI). They were calculated on the basis of selected biomarker data collected in the framework of the Prestige oil spill (POS) Mussel Watch monitoring (2003-2006) carried out in Galicia and the Bay of Biscay. According to the BAI, the health status of mussels was severely affected by POS and signals of recovery were evidenced in Galicia after April-04 and in Biscay Bay after April-05. The HSI (computed by an expert system) revealed high levels of environmental stress in 2003 and a recovery trend from April-04 to April-05. In July-05, the health status of mussels worsened but in October-05 and April-06 healthy condition was again recorded in almost all localities. IBR/n and IBI indicated that mussel health was severely affected in 2003 and improved from 2004 onwards. EHCC reflected a deleterious environmental condition in 2003 and a recovery trend after April-04, although a healthy ecosystem condition was not achieved in April-06 yet. Whereas BAI and HSI provide a basic indication of the ecosystem health status, star plots accompanying IBR/n and IBI provide complementary information concerning the mechanisms of biological response to environmental insult. Overall, although the integrative indices based on biomarkers show different sensitivity, resolution and informative output, all of them provide coherent information, useful to simplify the interpretation of biological effects of pollution in marine pollution monitoring. Each others' advantages, disadvantages and applicability for ecosystem health assessment are discussed.

Generation of free radicals in haemocytes of mussels after exposure to low molecular weight PAH components: immune activation, oxidative and genotoxic effects

Polycyclic aromatic hydrocarbons (PAHs) constituents, such as phenanthrene (PH) and anthracene (AN), are considered toxic for marine organisms, including bivalve mollusks. The present study showed that the perturbation of health status in mussels, as well as their inability to survive in air (stress on stress response), following exposure to either PH or AN (at a final concentration of 0.1 mg/L respectively), and a mixture of them (ration 1:1, at a final concentration of 0.2 mg/L) for 7 days, is probably related with alterations occurred in their haemocytes. According to the present study, PH and AN, either alone or in a mixture, could induce elevated levels of superoxide anions ((•)O(2)(-)) within haemocytes of mussels, thus leading to immune susceptibility as indicated by the increased levels of cell death and the elevated levels of lysosomal membrane acid phosphatase (AcP) activity, probably occurred via its overproduction or its release into the cytosol after lysosomal membrane destabilisation. PAH-mediated oxidative and genotoxic effects, indicated by the increased levels of both lipid peroxidation (MDA content) and nuclear abnormalities (MN test) could be related with haemocytes' inability to overcome free radical generation, thus leading to attenuation of general health status, before other disturbances, such as death, occur.

Aspects of the digestive gland cells of the mussel Mytilus galloprovincialis, in relation to lysosomal enzymes, lipofuscin presence and shell size: contribution in the assessment of marine pollution biomarkers

The present study investigates the histochemical localization of N-acetyl-β-hexozaminidase (Hex), acid phosphatase (AcP) and β-glucuronidase (β-Gus) in the digestive gland of mussels Mytilus galloprovincialis, as well as the clarification of suitable enzyme for biomarkers' application dealing with lysosomes. The results show more intense and homogenous localization of Hex, in relation to AcP and β-Gus and, thus, Hex histochemistry is supported as more suitable procedure for the evaluation of "lysosomal membrane stability" and "morphometrical alterations of lysosomes". The affection of lipofuscin granules on lysosomal enzymes' activity is also discussed. Additionally, the present study examines the response of small- and large-sized mussels M. galloprovincialis by assessing the "lysosomal membrane stability", "morphometrical alterations of lysosomes", "lysosomal response index (LRI)" and "structural epithelial changes in digestive tubules". The results indicate appreciable alterations of the above parameters in large-sized mussels, supporting their greater influence by the environmental factors, in relation to small-sized ones.

Active biomonitoring in Greek coastal waters: application of the integrated biomarker response index in relation to contaminant levels in caged mussels

An integrated approach using biomarkers and contaminant levels in mussels Mytilus galloprovincialis L. was employed to assess chemical contamination in Greek coastal waters within the framework of the MYTIMED program. Biomarkers (metallothioneins, glutathione S-transferase, catalase, acetylcholinesterase and RNA:DNA ratio) have been previously described in mussels caged at 14 sites in coastal areas influenced by different types of anthropogenic activities. This study applied a biomarker index, the Integrated Biomarker Response (IBR) to summarize biomarker responses and relate stress levels to concentrations of organochlorine compounds (PCBs, DDTs), polycyclic aromatic hydrocarbons (PAHs), and metals (Cu, Ni, Fe, Zn) measured in the mussel tissues. The IBR index indicated environmental stress at sites near cities and industries and was overall related to organic contaminants, but also elevated metal concentrations at certain sites. Slightly increased IBR values at few sites away from known pollution sources were not accompanied with increased contaminant levels suggesting stress possibly caused by natural factors. Results confirmed the usefulness of integration of biological effects measurements and chemical analysis for the assessment of chemical contamination in coastal waters.

Assessing sediment hazard through a weight of evidence approach with bioindicator organisms: a practical model to elaborate data from sediment chemistry, bioavailability, biomarkers and ecotoxicological bioassays

Quality assessments are crucial to all activities related to removal and management of sediments. Following a multidisciplinary, weight of evidence approach, a new model is presented here for comprehensive assessment of hazards associated to polluted sediments. The lines of evidence considered were sediment chemistry, assessment of bioavailability, sub-lethal effects on biomarkers, and ecotoxicological bioassays. A conceptual and software-assisted model was developed with logical flow-charts elaborating results from each line of evidence on the basis of several chemical and biological parameters, normative guidelines or scientific evidence; the data are thus summarized into four specific synthetic indices, before their integration into an overall sediment hazard evaluation. This model was validated using European eels (Anguilla anguilla) as the bioindicator species, exposed under laboratory conditions to sediments from an industrial site, and caged under field conditions in two harbour areas. The concentrations of aliphatic hydrocarbons, polycyclic aromatic hydrocarbons and trace metals were much higher in the industrial compared to harbour sediments, and accordingly the bioaccumulation in liver and gills of exposed eels showed marked differences between conditions seen. Among biomarkers, significant variations were observed for cytochrome P450-related responses, oxidative stress biomarkers, lysosomal stability and genotoxic effects; the overall elaboration of these data, as those of standard ecotoxicological bioassays with bacteria, algae and copepods, confirmed a higher level of biological hazard for industrial sediments. Based on comparisons with expert judgment, the model presented efficiently discriminates between the various conditions, both as individual modules and as an integrated final evaluation, and it appears to be a powerful tool to support more complex processes of environmental risk assessment.