Óscar Nieto | Universidade de Vigo (original) (raw)

Papers by Óscar Nieto

Ciencias Marinas, 2003

13 páginas, 3 tablas, 4 figurasSpanish Ministry of Science and Technology (FPI Grant)Peer reviewe

Fresenius' Journal of Analytical Chemistry, 2000

A method for the determination of carbendazim (MBC) by anodic stripping voltammetry using a carbo... more A method for the determination of carbendazim (MBC) by anodic stripping voltammetry using a carbon fiber ultramicroelectrode was developed. The ultramicroelectrode was made in our laboratory and its electrochemical behavior was characterized by measuring the electrochemical response with a solution of potassium ferricyanide. The optimum parameters used for the determination of MBC are the following: 0.05 M phosphate buffer at pH 2.0 as supporting electrolyte; a scan rate of v = 10.00 V s-1 and an accumulation potential of Eac = 0.00 V. The MBC was determined in a soil sample with the method proposed and the results found were comparable to those obtained by HPLC.

Talanta, 1998

A study on electrochemical characterisation of three isoforms of human foetal liver Zn-metallothi... more A study on electrochemical characterisation of three isoforms of human foetal liver Zn-metallothioneins, labelled MT-0, MT-1 and MT-2, has been performed by using differential pulse polarography (DPP). Two different peaks, attributed to two different Zn complexes with metallothioneins, have been detected. The electrochemical behaviour is similar for the three studied isoforms. Studies on the addition of Cd 2 + and Zn 2 + as well as studies as a function of pH have been carried out. The association and dissociation equilibria of metal ions with MTs are reversible in the studied pH range. The behaviour of Zn complexes in human foetal liver Zn-metallothioneins is comparable to the Cd complexes obtained using other mammalian Cd, Zn-metallothioneins, particularly as a function of pH.

Environmental Monitoring and Assessment, 2012

This study refers to the integrative assessment of sediment quality in three harbour areas at the... more This study refers to the integrative assessment of sediment quality in three harbour areas at the Spanish Atlantic Coast: Vigo (Northwestern Spain), Bilbao and Pasajes (Northern Spain). At each site, two lines of evidence have been considered: chemical analyses (metal, PAH and PCB concentrations in sediments and ammonia concentration in bioassays) and toxicity tests (Microtox®, Corophium sp. marine amphipod and Paracentrotus lividus sea urchin larvae). Chemical and ecotoxicological results have been integrated by means of a tabular matrix and a multivariate factorial analysis (FA). Highly toxic samples have been characterised in Vigo and Pasajes harbours while Bilbao samples present toxicity levels ranging from non-toxic to moderately toxic. High toxicity is associated with high levels of contaminants whereas confounding factors (ammonia, organic matter and mud) have been identified to be the main cause of low to moderate toxicity. Based on the obtained results, it can be concluded that deriving potential toxicity of sediments based on comparison with Sediment Quality Guidelines (SQGs) is in agreement to toxicity results in areas presenting high levels of contaminants. However, at lower levels of toxicity (low to moderate), the mismatch between the potential toxicity (SQG approach) and the toxicity measured by bioassays is greater, as the former only accounts for chemical concentrations, without considering the interaction between contaminants and the effect of confounding factors. Contrarily, the multivariate analysis seems to be a robust tool for the integration and interpretation of different lines of evidence in areas affected by different sources of contamination.

Aquatic Toxicology, 2002

The effects of humic acid (HA) on the toxicity of copper to sea urchin Paracentrotus lividus larv... more The effects of humic acid (HA) on the toxicity of copper to sea urchin Paracentrotus lividus larvae were studied in chemically defined seawater. Square Wave Anodic Stripping Voltammetry (SWASV) was employed to study the complexation of copper in seawater medium. A simple complexation model assuming one ligand type and a 1:1 reaction stoichiometry successfully explained the inverse titration experiments. A conditional stability constant of 6.53+/-0.05 and a complexating capacity of 230+/-7 micromol Cu/g HA were obtained. Sea urchin bioassay tests with two endpoints, embryogenesis success and larval growth were carried out in order to study the toxicity of dissolved copper in both the presence and absence of HA. The toxicity data obtained fitted well into a logistic model, and the high sensitivity of both endpoints (EC(50) were 41.1 microg Cu/l and 32.9 microg Cu/l, respectively) encourages their use for biomonitoring. The HA had a clearly protective effect, reducing the toxicity of Cu to the sea urchin larvae. The labile copper, rather than the total copper concentrations, explained the toxicity of the Cu-HA solutions, and the Cu-HA complexes appeared as non-toxic forms. These results are in agreement with the Free Ion Activity Model, because the labile Cu concentrations in this buffered and chemically defined medium covary with the free ion activity of the Cu, validating the model to naturally occurring HA in the marine environment.

Environmental Toxicology and Chemistry, 2006

Bioelectrochemistry and Bioenergetics, 1998

Ecotoxicology, 2011

To establish the connection between pollutant levels and their harmful effects on living resource... more To establish the connection between pollutant levels and their harmful effects on living resources, coastal monitoring programmes have incorporated biological tools, such as the scope for growth (SFG) in marine mussels and benthic macrofauna community indices. Although the relation between oxygen-depleting anthropogenic inputs and the alteration of benthic communities is well described, the effects of chemical pollutants are unknown because they are not expected to favour any particular taxa. In this study, the combined efforts of five research teams involved in the investigative monitoring of marine pollution allowed the generation of a multiyear data set for Ría de Vigo (NW Iberian Peninsula). Multivariate analysis of these data allowed the identification of the chemical-matrix combinations responsible for most of the variability among sites and the construction of a chemical pollution index (CPI) that significantly (P < 0.01) correlated with biological effects at both the individual and the community levels. We report a consistent reduction in the physiological fitness of local populations of mussels as chemical pollution increases. The energy balance was more sensitive to pollution than individual physiological rates, but the reduction in the SFG was primarily due to significantly decreased clearance rates. We also found a decrease in benthic macrofauna diversity as chemical pollution increases. This diversity reduction resulted not from altered evenness, as the classic paradigm might suggest, but from a loss of species richness.

Marine Environmental Research

Science of The Total Environment, 2008

Acute toxicity and phototoxicity of heavy fuel oil extracted directly from the sunken tanker Pres... more Acute toxicity and phototoxicity of heavy fuel oil extracted directly from the sunken tanker Prestige in comparison to a standard Marine fuel oil were evaluated by obtaining the water-accommodated fraction (WAF) and using mussel Mytilus galloprovincialis and sea urchin Paracentrotus lividus embryogenesis bioassays, and copepod Acartia tonsa and fish Cyprinodon variegatus survival bioassays. Aromatic hydrocarbon (AH) levels in WAF were measured by gas chromatography. Prestige WAF was not phototoxic, its median effective concentrations (EC50) were 13% and 10% WAF for mussel and sea urchin respectively, and maximum lethal threshold concentrations (MLTC) were 12% and 50% for copepod and fish respectively. Marine WAF resulted phototoxic for mussel bioassay. EC50s of Marine WAF were 50% for sea urchin in both treatments and 20% for mussel under illumination. Undiluted Marine WAF only caused a 20% decrease in mussel normal larvae. Similar sensitivities were found among sea urchins, mussels and copepods, whilst fish were less sensitive. Unlike Marine WAF, Prestige WAF showed EC50 values at dilutions below 20%, and its toxicity was independent of lighting conditions. The differences in toxicity between both kinds of fuel could not be explained on the basis of total AH content.

Environmental Toxicology and Chemistry, 2006

Copper speciation in the presence of fulvic acids (FAs) was studied in chemically defined seawate... more Copper speciation in the presence of fulvic acids (FAs) was studied in chemically defined seawater by square wave anodic stripping voltammetry (SQWASV). A simple complexation model assuming a single type of ligand and a 1:1 reaction stoichiometry successfully explained the measured data. A conditional stability constant of 5.80 6 0.07 and a complexing capacity of 610 6 80 mmol Cu/g

Ciencias …, 2003

Chemical speciation of dissolved lead was determined at four sampling sites in the Pontevedra Ría... more Chemical speciation of dissolved lead was determined at four sampling sites in the Pontevedra Ría (NW Spain) by differential pulse anodic stripping voltammetry (DPASV) with a HMDE. Sampling location was chosen due to its evident anthropogenic influence: one sample was taken in the Lérez River mouth (2.2-salinity) and other three samples were taken in the surroundings of the village of Marín (salinity 30-32). Lead concentrations were 0.64 nM (river sample) and 4.8-21.9 nM (saline samples). Speciation results showed that organic chelates of lead, 88-95% of total dissolved lead, are the dominant species of the metal even at these high concentrations. Two types of lead organic complexing ligands were detected in all samples. The river water sample showed the presence of a strong ligand with a concentration of ~7 nM with a conditional stability constant of K' Pb-L1 ≥ 10 11.1 , and a weaker ligand (K' Pb-L2 = 10 8.2 ) with a concentration of 53.4 nM. The three saline samples showed similar behavior: a strong ligand (K' Pb-L1 ~ 10 8.6 ) with concentration ranging from 33.0 to 53.5 nM, and a weaker complexing ligand (K' Pb-L2 ~ 10 7.5 ) with concentration ranging from 32.6 to 50.5 nM. All lead-organic ligand complexes (except the strong complex in the river water sample) showed labile behavior in the time scale of the technique.

Marine Pollution Bulletin

The toxicity of polycyclic aromatic hydrocarbons (PAHs) was determined using mussel, sea-urchin a... more The toxicity of polycyclic aromatic hydrocarbons (PAHs) was determined using mussel, sea-urchin and ascidian embryo-larval bioassays. Fluorescent light exposure enhanced phenanthrene, fluoranthene, pyrene and hydroxypyrene toxicity in comparison with dark conditions, but not naphthalene and fluorene toxicity. The toxicity of PAHs was inversely related to their K(OW) values following QSAR models derived for baseline toxicity of general narcotics, whereas the obtained regression using toxicity data from photoactivated PAHs significantly departed from the general narcosis model. Also, the mixture toxicity of five PAHs to the larval growth of the sea-urchin was compared with predictions derived from the concentration addition concept, indicating less than additive effects. Finally, we compared our toxicity data with worst-case environmental concentrations in order to provide a preliminary estimate of the risk to the marine environment. Naphthalene, fluorene and pyrene are not considered...

Continental Shelf Research

Elutriate embryo-larval bioassays with sea-urchins (Paracentrotus lividus) were conducted concurr... more Elutriate embryo-larval bioassays with sea-urchins (Paracentrotus lividus) were conducted concurrently with chemical analyses of sediments and biota as part of an integrative assessment of pollution in highly productive coastal regions. High metal contents and organic compounds in sediments and mussels were found in localised areas from the inner part of the estuaries indicating a clear anthropogenic influence. In particular, average maximum concentrations of 2803 mg Cu/kg dw, 776 mg Pb/kg dw, 2.5 mg Hg/kg dw and 5803 μg ∑7PAHs/kg dw were measured in sediments from the most polluted sites. Significant correlations were observed between sediment chemistry and toxicity bioassays. Moreover, the Mantel test revealed a significant correlation (rM=0.80; p<0.01) between sediment pollutant concentrations and toxicity data profiles. In addition, sediment quality criteria were used to help in the ecological interpretation of sediment chemistry data and to identify pollutants of concern. Th...

Science of The Total Environment, 2014

As part of an integrative monitoring campaign involving water and sediment chemistry, in situ bio... more As part of an integrative monitoring campaign involving water and sediment chemistry, in situ bioassays, and mussel bioaccumulation and biomarkers, Mytilus galloprovincialis mussels of standard size were transplanted from a clean location to five sites in two important harbours from the Atlantic coast of Spain (Vigo and Pasaia). After a 30-day field exposure, the concentrations of major contaminants (trace metals, polychlorinated biphenyls and polycyclic aromatic hydrocarbons) accumulated in mussel tissues were measured at each site, and a mussel bioaccumulation index (MBI) was calculated. The enzymatic activity levels of glutathione S-transferase (GST), glutathione peroxidase (GPx) and acetylcholinesterase (AChE) were quantified in the gills of transplanted mussels (n=12). Mussels from the most polluted sites consistently exhibited significantly higher GST and GPx activities compared to the control site, whereas AChE activity was significantly inhibited. The responses of the GST and GPx activities were related to MBI, trace metals and PAH concentrations in mussels, whereas AChE activity was related to the trace metals concentrations in mussels. The above results suggest that GST and AChE activities can be used as potential biomarkers for active monitoring in marine coastal ecosystems. However, at this moment, GPx activity is not robust enough to be applicable to harbour areas.

Science of The Total Environment, 2008

Acute toxicity and phototoxicity of heavy fuel oil extracted directly from the sunken tanker Pres... more Acute toxicity and phototoxicity of heavy fuel oil extracted directly from the sunken tanker Prestige in comparison to a standard Marine fuel oil were evaluated by obtaining the wateraccommodated fraction (WAF) and using mussel Mytilus galloprovincialis and sea urchin Paracentrotus lividus embryogenesis bioassays, and copepod Acartia tonsa and fish Cyprinodon variegatus survival bioassays. Aromatic hydrocarbon (AH) levels in WAF were measured by gas chromatography. Prestige WAF was not phototoxic, its median effective concentrations (EC 50 ) were 13% and 10% WAF for mussel and sea urchin respectively, and maximum lethal threshold concentrations (MLTC) were 12% and 50% for copepod and fish respectively. Marine WAF resulted phototoxic for mussel bioassay. EC 50 s of Marine WAF were 50% for sea urchin in both treatments and 20% for mussel under illumination.

Marine Pollution Bulletin, 2008

The toxicity of polycyclic aromatic hydrocarbons (PAHs) was determined using mussel, sea-urchin a... more The toxicity of polycyclic aromatic hydrocarbons (PAHs) was determined using mussel, sea-urchin and ascidian embryo-larval bioassays. Fluorescent light exposure enhanced phenanthrene, fluoranthene, pyrene and hydroxypyrene toxicity in comparison with dark conditions, but not naphthalene and fluorene toxicity. The toxicity of PAHs was inversely related to their K OW values following QSAR models derived for baseline toxicity of general narcotics, whereas the obtained regression using toxicity data from photoactivated PAHs significantly departed from the general narcosis model. Also, the mixture toxicity of five PAHs to the larval growth of the sea-urchin was compared with predictions derived from the concentration addition concept, indicating less than additive effects. Finally, we compared our toxicity data with worst-case environmental concentrations in order to provide a preliminary estimate of the risk to the marine environment. Naphthalene, fluorene and pyrene are not considered to pose a risk to sea-urchin, mussel or ascidian larvae, whilst phenanthrene and fluoranthene may pose a risk for mussel and seaurchin. Moreover, a higher risk for those species is expected when we consider the photoactivation of the PAHs.

Marine Ecology Progress Series, 2006

We studied the temporal variation of polycyclic aromatic hydrocarbons (PAH) levels in the wild mu... more We studied the temporal variation of polycyclic aromatic hydrocarbons (PAH) levels in the wild mussel Mytilus galloprovincialis, water and sediment from 3 sampling sites on the Galician coast of Spain between the rias of Arousa and Muros, which were dramatically affected by the large oil spill from the oil tanker 'Prestige'. The samples were collected periodically, from November 22, 2002, 3 d after the tanker sank, until December 23, 2003. The total hydrocarbon content in the water and sediment samples was determined by fluorescence and expressed as concentration of chrysene. In addition, individual PAHs -analytes recommended by the US Environmental Protection Agency -were analysed in the mussel samples by HPLC using fluorimetric detection. A maximum concentration of 2.07 × 10 3 µg equiv. of chrysene l -1 was found in the water column at the sampling site of Furnas on November 29, 2002 which decreased to 0.21 µg l -1 by October 2003. Likewise, the concentrations of the sum of the 16 PAHs determined in the mussel samples collected at the sampling points were between 2.5 × 10 3 and 5.9 × 10 3 µg kg -1 dry weight in the days immediately following the oil spill and then decreased to 0.13 × 10 3 µg kg -1 in October 2003. However, no relevant information could be obtained from the PAH content of the sediment samples. A relation between parent PAHs accumulated in the mussels and their molecular weight (MW) has been found to provide an indication of hydrocarbon pollution. A good approximation was obtained when the total PAH content (ΣPAH) was represented versus the ratio of low MW PAHs to high MW PAHs (ΣLPAH:ΣHPAH). When the depuration rate r of individual PAHs by the mussels was fitted to an exponential model, 2 different values of r were found depending on the PAH concentration. The change from a slow to fast depuration rate was produced when the logarithm of the concentration was 1.0.

Ciencias Marinas, 2003

13 páginas, 3 tablas, 4 figurasSpanish Ministry of Science and Technology (FPI Grant)Peer reviewe

Fresenius' Journal of Analytical Chemistry, 2000

A method for the determination of carbendazim (MBC) by anodic stripping voltammetry using a carbo... more A method for the determination of carbendazim (MBC) by anodic stripping voltammetry using a carbon fiber ultramicroelectrode was developed. The ultramicroelectrode was made in our laboratory and its electrochemical behavior was characterized by measuring the electrochemical response with a solution of potassium ferricyanide. The optimum parameters used for the determination of MBC are the following: 0.05 M phosphate buffer at pH 2.0 as supporting electrolyte; a scan rate of v = 10.00 V s-1 and an accumulation potential of Eac = 0.00 V. The MBC was determined in a soil sample with the method proposed and the results found were comparable to those obtained by HPLC.

Talanta, 1998

A study on electrochemical characterisation of three isoforms of human foetal liver Zn-metallothi... more A study on electrochemical characterisation of three isoforms of human foetal liver Zn-metallothioneins, labelled MT-0, MT-1 and MT-2, has been performed by using differential pulse polarography (DPP). Two different peaks, attributed to two different Zn complexes with metallothioneins, have been detected. The electrochemical behaviour is similar for the three studied isoforms. Studies on the addition of Cd 2 + and Zn 2 + as well as studies as a function of pH have been carried out. The association and dissociation equilibria of metal ions with MTs are reversible in the studied pH range. The behaviour of Zn complexes in human foetal liver Zn-metallothioneins is comparable to the Cd complexes obtained using other mammalian Cd, Zn-metallothioneins, particularly as a function of pH.

Environmental Monitoring and Assessment, 2012

This study refers to the integrative assessment of sediment quality in three harbour areas at the... more This study refers to the integrative assessment of sediment quality in three harbour areas at the Spanish Atlantic Coast: Vigo (Northwestern Spain), Bilbao and Pasajes (Northern Spain). At each site, two lines of evidence have been considered: chemical analyses (metal, PAH and PCB concentrations in sediments and ammonia concentration in bioassays) and toxicity tests (Microtox®, Corophium sp. marine amphipod and Paracentrotus lividus sea urchin larvae). Chemical and ecotoxicological results have been integrated by means of a tabular matrix and a multivariate factorial analysis (FA). Highly toxic samples have been characterised in Vigo and Pasajes harbours while Bilbao samples present toxicity levels ranging from non-toxic to moderately toxic. High toxicity is associated with high levels of contaminants whereas confounding factors (ammonia, organic matter and mud) have been identified to be the main cause of low to moderate toxicity. Based on the obtained results, it can be concluded that deriving potential toxicity of sediments based on comparison with Sediment Quality Guidelines (SQGs) is in agreement to toxicity results in areas presenting high levels of contaminants. However, at lower levels of toxicity (low to moderate), the mismatch between the potential toxicity (SQG approach) and the toxicity measured by bioassays is greater, as the former only accounts for chemical concentrations, without considering the interaction between contaminants and the effect of confounding factors. Contrarily, the multivariate analysis seems to be a robust tool for the integration and interpretation of different lines of evidence in areas affected by different sources of contamination.

Aquatic Toxicology, 2002

The effects of humic acid (HA) on the toxicity of copper to sea urchin Paracentrotus lividus larv... more The effects of humic acid (HA) on the toxicity of copper to sea urchin Paracentrotus lividus larvae were studied in chemically defined seawater. Square Wave Anodic Stripping Voltammetry (SWASV) was employed to study the complexation of copper in seawater medium. A simple complexation model assuming one ligand type and a 1:1 reaction stoichiometry successfully explained the inverse titration experiments. A conditional stability constant of 6.53+/-0.05 and a complexating capacity of 230+/-7 micromol Cu/g HA were obtained. Sea urchin bioassay tests with two endpoints, embryogenesis success and larval growth were carried out in order to study the toxicity of dissolved copper in both the presence and absence of HA. The toxicity data obtained fitted well into a logistic model, and the high sensitivity of both endpoints (EC(50) were 41.1 microg Cu/l and 32.9 microg Cu/l, respectively) encourages their use for biomonitoring. The HA had a clearly protective effect, reducing the toxicity of Cu to the sea urchin larvae. The labile copper, rather than the total copper concentrations, explained the toxicity of the Cu-HA solutions, and the Cu-HA complexes appeared as non-toxic forms. These results are in agreement with the Free Ion Activity Model, because the labile Cu concentrations in this buffered and chemically defined medium covary with the free ion activity of the Cu, validating the model to naturally occurring HA in the marine environment.

Environmental Toxicology and Chemistry, 2006

Bioelectrochemistry and Bioenergetics, 1998

Ecotoxicology, 2011

To establish the connection between pollutant levels and their harmful effects on living resource... more To establish the connection between pollutant levels and their harmful effects on living resources, coastal monitoring programmes have incorporated biological tools, such as the scope for growth (SFG) in marine mussels and benthic macrofauna community indices. Although the relation between oxygen-depleting anthropogenic inputs and the alteration of benthic communities is well described, the effects of chemical pollutants are unknown because they are not expected to favour any particular taxa. In this study, the combined efforts of five research teams involved in the investigative monitoring of marine pollution allowed the generation of a multiyear data set for Ría de Vigo (NW Iberian Peninsula). Multivariate analysis of these data allowed the identification of the chemical-matrix combinations responsible for most of the variability among sites and the construction of a chemical pollution index (CPI) that significantly (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01) correlated with biological effects at both the individual and the community levels. We report a consistent reduction in the physiological fitness of local populations of mussels as chemical pollution increases. The energy balance was more sensitive to pollution than individual physiological rates, but the reduction in the SFG was primarily due to significantly decreased clearance rates. We also found a decrease in benthic macrofauna diversity as chemical pollution increases. This diversity reduction resulted not from altered evenness, as the classic paradigm might suggest, but from a loss of species richness.

Marine Environmental Research

Science of The Total Environment, 2008

Acute toxicity and phototoxicity of heavy fuel oil extracted directly from the sunken tanker Pres... more Acute toxicity and phototoxicity of heavy fuel oil extracted directly from the sunken tanker Prestige in comparison to a standard Marine fuel oil were evaluated by obtaining the water-accommodated fraction (WAF) and using mussel Mytilus galloprovincialis and sea urchin Paracentrotus lividus embryogenesis bioassays, and copepod Acartia tonsa and fish Cyprinodon variegatus survival bioassays. Aromatic hydrocarbon (AH) levels in WAF were measured by gas chromatography. Prestige WAF was not phototoxic, its median effective concentrations (EC50) were 13% and 10% WAF for mussel and sea urchin respectively, and maximum lethal threshold concentrations (MLTC) were 12% and 50% for copepod and fish respectively. Marine WAF resulted phototoxic for mussel bioassay. EC50s of Marine WAF were 50% for sea urchin in both treatments and 20% for mussel under illumination. Undiluted Marine WAF only caused a 20% decrease in mussel normal larvae. Similar sensitivities were found among sea urchins, mussels and copepods, whilst fish were less sensitive. Unlike Marine WAF, Prestige WAF showed EC50 values at dilutions below 20%, and its toxicity was independent of lighting conditions. The differences in toxicity between both kinds of fuel could not be explained on the basis of total AH content.

Environmental Toxicology and Chemistry, 2006

Copper speciation in the presence of fulvic acids (FAs) was studied in chemically defined seawate... more Copper speciation in the presence of fulvic acids (FAs) was studied in chemically defined seawater by square wave anodic stripping voltammetry (SQWASV). A simple complexation model assuming a single type of ligand and a 1:1 reaction stoichiometry successfully explained the measured data. A conditional stability constant of 5.80 6 0.07 and a complexing capacity of 610 6 80 mmol Cu/g

Ciencias …, 2003

Chemical speciation of dissolved lead was determined at four sampling sites in the Pontevedra Ría... more Chemical speciation of dissolved lead was determined at four sampling sites in the Pontevedra Ría (NW Spain) by differential pulse anodic stripping voltammetry (DPASV) with a HMDE. Sampling location was chosen due to its evident anthropogenic influence: one sample was taken in the Lérez River mouth (2.2-salinity) and other three samples were taken in the surroundings of the village of Marín (salinity 30-32). Lead concentrations were 0.64 nM (river sample) and 4.8-21.9 nM (saline samples). Speciation results showed that organic chelates of lead, 88-95% of total dissolved lead, are the dominant species of the metal even at these high concentrations. Two types of lead organic complexing ligands were detected in all samples. The river water sample showed the presence of a strong ligand with a concentration of ~7 nM with a conditional stability constant of K' Pb-L1 ≥ 10 11.1 , and a weaker ligand (K' Pb-L2 = 10 8.2 ) with a concentration of 53.4 nM. The three saline samples showed similar behavior: a strong ligand (K' Pb-L1 ~ 10 8.6 ) with concentration ranging from 33.0 to 53.5 nM, and a weaker complexing ligand (K' Pb-L2 ~ 10 7.5 ) with concentration ranging from 32.6 to 50.5 nM. All lead-organic ligand complexes (except the strong complex in the river water sample) showed labile behavior in the time scale of the technique.

Marine Pollution Bulletin

The toxicity of polycyclic aromatic hydrocarbons (PAHs) was determined using mussel, sea-urchin a... more The toxicity of polycyclic aromatic hydrocarbons (PAHs) was determined using mussel, sea-urchin and ascidian embryo-larval bioassays. Fluorescent light exposure enhanced phenanthrene, fluoranthene, pyrene and hydroxypyrene toxicity in comparison with dark conditions, but not naphthalene and fluorene toxicity. The toxicity of PAHs was inversely related to their K(OW) values following QSAR models derived for baseline toxicity of general narcotics, whereas the obtained regression using toxicity data from photoactivated PAHs significantly departed from the general narcosis model. Also, the mixture toxicity of five PAHs to the larval growth of the sea-urchin was compared with predictions derived from the concentration addition concept, indicating less than additive effects. Finally, we compared our toxicity data with worst-case environmental concentrations in order to provide a preliminary estimate of the risk to the marine environment. Naphthalene, fluorene and pyrene are not considered...

Continental Shelf Research

Elutriate embryo-larval bioassays with sea-urchins (Paracentrotus lividus) were conducted concurr... more Elutriate embryo-larval bioassays with sea-urchins (Paracentrotus lividus) were conducted concurrently with chemical analyses of sediments and biota as part of an integrative assessment of pollution in highly productive coastal regions. High metal contents and organic compounds in sediments and mussels were found in localised areas from the inner part of the estuaries indicating a clear anthropogenic influence. In particular, average maximum concentrations of 2803 mg Cu/kg dw, 776 mg Pb/kg dw, 2.5 mg Hg/kg dw and 5803 μg ∑7PAHs/kg dw were measured in sediments from the most polluted sites. Significant correlations were observed between sediment chemistry and toxicity bioassays. Moreover, the Mantel test revealed a significant correlation (rM=0.80; p<0.01) between sediment pollutant concentrations and toxicity data profiles. In addition, sediment quality criteria were used to help in the ecological interpretation of sediment chemistry data and to identify pollutants of concern. Th...

Science of The Total Environment, 2014

As part of an integrative monitoring campaign involving water and sediment chemistry, in situ bio... more As part of an integrative monitoring campaign involving water and sediment chemistry, in situ bioassays, and mussel bioaccumulation and biomarkers, Mytilus galloprovincialis mussels of standard size were transplanted from a clean location to five sites in two important harbours from the Atlantic coast of Spain (Vigo and Pasaia). After a 30-day field exposure, the concentrations of major contaminants (trace metals, polychlorinated biphenyls and polycyclic aromatic hydrocarbons) accumulated in mussel tissues were measured at each site, and a mussel bioaccumulation index (MBI) was calculated. The enzymatic activity levels of glutathione S-transferase (GST), glutathione peroxidase (GPx) and acetylcholinesterase (AChE) were quantified in the gills of transplanted mussels (n=12). Mussels from the most polluted sites consistently exhibited significantly higher GST and GPx activities compared to the control site, whereas AChE activity was significantly inhibited. The responses of the GST and GPx activities were related to MBI, trace metals and PAH concentrations in mussels, whereas AChE activity was related to the trace metals concentrations in mussels. The above results suggest that GST and AChE activities can be used as potential biomarkers for active monitoring in marine coastal ecosystems. However, at this moment, GPx activity is not robust enough to be applicable to harbour areas.

Science of The Total Environment, 2008

Acute toxicity and phototoxicity of heavy fuel oil extracted directly from the sunken tanker Pres... more Acute toxicity and phototoxicity of heavy fuel oil extracted directly from the sunken tanker Prestige in comparison to a standard Marine fuel oil were evaluated by obtaining the wateraccommodated fraction (WAF) and using mussel Mytilus galloprovincialis and sea urchin Paracentrotus lividus embryogenesis bioassays, and copepod Acartia tonsa and fish Cyprinodon variegatus survival bioassays. Aromatic hydrocarbon (AH) levels in WAF were measured by gas chromatography. Prestige WAF was not phototoxic, its median effective concentrations (EC 50 ) were 13% and 10% WAF for mussel and sea urchin respectively, and maximum lethal threshold concentrations (MLTC) were 12% and 50% for copepod and fish respectively. Marine WAF resulted phototoxic for mussel bioassay. EC 50 s of Marine WAF were 50% for sea urchin in both treatments and 20% for mussel under illumination.

Marine Pollution Bulletin, 2008

The toxicity of polycyclic aromatic hydrocarbons (PAHs) was determined using mussel, sea-urchin a... more The toxicity of polycyclic aromatic hydrocarbons (PAHs) was determined using mussel, sea-urchin and ascidian embryo-larval bioassays. Fluorescent light exposure enhanced phenanthrene, fluoranthene, pyrene and hydroxypyrene toxicity in comparison with dark conditions, but not naphthalene and fluorene toxicity. The toxicity of PAHs was inversely related to their K OW values following QSAR models derived for baseline toxicity of general narcotics, whereas the obtained regression using toxicity data from photoactivated PAHs significantly departed from the general narcosis model. Also, the mixture toxicity of five PAHs to the larval growth of the sea-urchin was compared with predictions derived from the concentration addition concept, indicating less than additive effects. Finally, we compared our toxicity data with worst-case environmental concentrations in order to provide a preliminary estimate of the risk to the marine environment. Naphthalene, fluorene and pyrene are not considered to pose a risk to sea-urchin, mussel or ascidian larvae, whilst phenanthrene and fluoranthene may pose a risk for mussel and seaurchin. Moreover, a higher risk for those species is expected when we consider the photoactivation of the PAHs.

Marine Ecology Progress Series, 2006

We studied the temporal variation of polycyclic aromatic hydrocarbons (PAH) levels in the wild mu... more We studied the temporal variation of polycyclic aromatic hydrocarbons (PAH) levels in the wild mussel Mytilus galloprovincialis, water and sediment from 3 sampling sites on the Galician coast of Spain between the rias of Arousa and Muros, which were dramatically affected by the large oil spill from the oil tanker 'Prestige'. The samples were collected periodically, from November 22, 2002, 3 d after the tanker sank, until December 23, 2003. The total hydrocarbon content in the water and sediment samples was determined by fluorescence and expressed as concentration of chrysene. In addition, individual PAHs -analytes recommended by the US Environmental Protection Agency -were analysed in the mussel samples by HPLC using fluorimetric detection. A maximum concentration of 2.07 × 10 3 µg equiv. of chrysene l -1 was found in the water column at the sampling site of Furnas on November 29, 2002 which decreased to 0.21 µg l -1 by October 2003. Likewise, the concentrations of the sum of the 16 PAHs determined in the mussel samples collected at the sampling points were between 2.5 × 10 3 and 5.9 × 10 3 µg kg -1 dry weight in the days immediately following the oil spill and then decreased to 0.13 × 10 3 µg kg -1 in October 2003. However, no relevant information could be obtained from the PAH content of the sediment samples. A relation between parent PAHs accumulated in the mussels and their molecular weight (MW) has been found to provide an indication of hydrocarbon pollution. A good approximation was obtained when the total PAH content (ΣPAH) was represented versus the ratio of low MW PAHs to high MW PAHs (ΣLPAH:ΣHPAH). When the depuration rate r of individual PAHs by the mussels was fitted to an exponential model, 2 different values of r were found depending on the PAH concentration. The change from a slow to fast depuration rate was produced when the logarithm of the concentration was 1.0.