JOSE TARAZONA - Academia.edu (original) (raw)

Papers by JOSE TARAZONA

Aquatic Toxicology, 2002

A cost /effective innovative approach combining three freshwater invertebrates: the cladoceran Da... more A cost /effective innovative approach combining three freshwater invertebrates: the cladoceran Daphnia magna, the insect Chironomus prasinus and the basommatophoran snail Lymnaea peregra, in a single system is presented. The selection combines different reproductive strategies: parthenogenesis, sexual reproduction and hermaphroditism, respectively, and covers water column, sediment, food and contact exposure. Results confirm the system's capacity. In 46 days, multi-generation, whole-life-cycle, and chronic reproduction assays can be achieved for D. magna, C. prasinus and L. peregra, respectively. The 21-day D. magna test is commonly used to assess the effects of chemicals on aquatic invertebrates. Wide concerns on its suitability for testing endocrine disrupting chemicals have been raised, particularly for substances with estrogenic activities. The combination of three species with different reproductive strategies offer a suitable approach for assessing ecologically relevant effects related to any mechanism of action, including endocrine disruption.

Aquatic Toxicology, 1996

Algae play a major role in the accumulation of hydrophobic pollutants. The accumulation of hexach... more Algae play a major role in the accumulation of hydrophobic pollutants. The accumulation of hexachlorobenzene (HCB) in algae is very rapid, reaching equilibrium after a few hours. The elimination of HCB from algae has been described by a two-compartment nonequilibrium model. This paper describes the elimination kinetics of HCB from the second (slow rate) compartment in Chlorellu vulgaris, and the bioavailability of the HCB bound to algae on Duphnia magna. First-order elimination kinetics was observed. The elimination rate constant and the half life were 0.43 day-l and 1.6 days, respectively. The algal growth curve showed a growth rate constant of 0.27 day-l and a duplication time of 2.56 days. Comparisons among these values indicate that the dilution effect associated with algal growth accounts for more than 60% of the observed reduction.

Science of The Total Environment, 2000

Hazard assessment constitutes an essential tool in order to evaluate the potential effects of che... more Hazard assessment constitutes an essential tool in order to evaluate the potential effects of chemical substances on organisms and ecosystems. It includes as a first step, hazard identification, which must detect the potential dangers of the substance (i.e. the kind of effects that the substance may produce), and a second step to quantify each danger and to set the expected dose/response relationships. Hazard assessment plays a key role in the regulation of chemical substances, including pollution control and sustainable development. However, the aquatic environment has largely received more attention than terrestrial ecosystems. This paper presents the extrapolation of several basic concepts from the aquatic to the terrestrial compartment, and suggests possibilities for their regulatory use. Two specific proposals are discussed. The first focuses on the scientific basis of the hazard identification-classification criteria included in the EU regulations and their extrapolation to the terrestrial environment. The second focuses on the OECD programme for environmental indicators and the development of a soil pollution pressure indicator to quantify the potential hazards for the soil compartment and its associated terrestrial ecosystem related to the toxic chemicals applied deliberately (i.e. pesticides) or not (i.e. heavy metals in sludge-based fertilisers; industrial spills) to the soil.

Bulletin of Environmental Contamination and Toxicology, 1994

Science of The Total Environment, 2000

Three biochemical parameters, DNA quantification in soil samples and two enzymatic activities, be... more Three biochemical parameters, DNA quantification in soil samples and two enzymatic activities, beta-galactosidase and dehydrogenase have been assessed as potential end-points for the use in cost-effective toxicity tests on soil microorganisms. The assessment included the development of a classical dose-response 24-h assay and the incorporation of measurements of the effects on microbial activities in soil column leaching studies and multispecies miniaturised terrestrial systems (MTS). Four different chemicals, copper, a new herbicide, thiabendazole and fenthion were studied. A rapid fluorescence DNA quantification technique did not produce adequate responses. The efforts to quantify DNA after extraction and clean-up procedures failed due to the presence of humic acids. From the protocol of the technique one could see that the technical procedure is time-consuming and expensive and, for this reason, not suitable for use as a parameter in rapid and cost-effective tests. However, the enzymatic activities showed their potential as toxicity end-points. Copper produced a concentration/response inhibition of beta-galactosidase and dehydrogenase with EC50 values of 78.39 and 24.77 mg Cu/kg soil, respectively. In the soil column study, these endpoints allowed the measurement of the microbial activities through the column. The effects of the new herbicide on beta-galactosidase and dehydrogenase activities were statistically significant for the highest application dose (40 g/ha). Thiabendazole affected the microbial activity when mixed within the soil, but no effects were observed when this fungicide was applied on the soil surface. Fenthion produced effects when applied either in the soil or on the soil surface. These results can be explained by the low mobility of thiabendazole. The results show the capabilities of these biochemical parameters to be included as endpoints in cost-effective bioassays.

Bulletin of Environmental Contamination and Toxicology, 1993

Critical Reviews in Toxicology, 2000

... Feminized male birds with an ovotestis (a gonad containing both ova-rial and testicular tissu... more ... Feminized male birds with an ovotestis (a gonad containing both ova-rial and testicular tissue) and/or reduced male copulatory behavior have ... Experimentally dis-turbed sex differentiation has also been re-ported in reptiles, amphibia, fish, and inver-tebrates such as marine ...

Marine Environmental Research, 1998

Juvenile turbot (Scophthalmus maximus) were exposed to benzo(a)pyrene (BaP) for 14 d using a glas... more Juvenile turbot (Scophthalmus maximus) were exposed to benzo(a)pyrene (BaP) for 14 d using a glass bead generator flow-through system. Exposure was followed by a recovery period of 16d. The highest BaP concentration in the edible portion of the fish, 16.5 f 4.3 kg BaPlkg, was observed on the jirst day. Then concentrations dropped following jirst-order kinetics. BaP was below detection level at the end of the experiment. A statistically significant increase in bileJluorescence was observed from day 9 until the end of the experiment, suggesting the elimination of BaP metabolites by this route. No signiJicant d@erences between control and exposed jish in EROD activity and CYPIA concentration, measured by immunodetection method, were observed. Intraperitoneal injection of 2.5 mg BaPlkg in juvenile turbot induced EROD activity. Under waterborne experimental conditions, bile$uorescence was observed to be a more sensitive biomarker of BaP exposure than EROD activity and CYPIA measurement. 0 1998 Elsevier Science Ltd. All rights reserved

Archives of Environmental Contamination and Toxicology, 1991

A toxicological assessment of water quality conditions (30 physical-chemical parameters and a scr... more A toxicological assessment of water quality conditions (30 physical-chemical parameters and a screening of organic pollutants by reverse-phase HPLC) was performed in Algeciras Bay, Cadiz, Spain in relation to problems in six floating ponds for gilthead (Sparus auratus) growth. The study was completed with a short-termArtemia toxicity test, and the measurement of heavy metal concentrations in molluscs from different sites of the Bay. Cadmium, lead, and cyanide at sublethal toxic concentrations were found in most of the analyzed samples, and very high concentrations of ammonia, phenols, nitrites, cyanide, and sulphide were found in some sampling sites. In addition, seven water samples showed toxicity onArtemia. The problems in the floating ponds (low growth rates, high mortality, and infectious diseases) can be related, in part, to the very bad water quality conditions.

Aquatic Toxicology, 1994

Rainbow trout (Oncorhynchus mykiss) received 80/lg copper kg 1 body weight as an intravenous inje... more Rainbow trout (Oncorhynchus mykiss) received 80/lg copper kg 1 body weight as an intravenous injection of copper sulfate. Copper levels were analyzed by atomic absorption spectrometry in plasma samples collected before and at regular times after the copper injection. Plasma copper concentration-time curves were analyzed according to standard pharmacokinetic compartmental procedures. A two-compartment model was adapted to derive toxicokinetic parameters, including a time-independent component to assess the basal plasma copper levels before the copper injection. The volume of the central compartment 43 ml kg l was similar to that reported for rainbow trout plasma. Steady-state distribution volume was estimated in 178 ml kg ~. Distribution and final elimination half-lives were 7.2 and 195.5 rain, respectively. Steadystate distribution volume, the area under the curve, the copper clearance and the medium retention time calculated by the two-compartment model were similar to those estimated using non-compartmental equations. These toxicokinetic data suggest a rapid elimination of copper from the exchangeable pool. Thus, during long-term waterborne copper exposures, plasma copper concentration would achieve a steady-state situation after a few hours or days; further accumulation of copper would be related to the binding of copper to non-exchangeable ligands which would not have toxicological consequences. The large number of factors associated to the capability of the fish to offer and produce non-exchangeable binding sites would explain the variety of responses on copper accumulation described in the literature.

Science of The Total Environment, 1993

Seventy rainbow trouts were exposed to lethal copper conditions using water-borne copper, in orde... more Seventy rainbow trouts were exposed to lethal copper conditions using water-borne copper, in order to assess the diagnosis value of copper accumulation and its ratio to other essential metals. Poisoned fish showed a copper increase in some organs, but these changes did not always indicate significant differences versus control fish. Metal/copper ratios showed higher variations than did copper concentrations. In fact, significant decreases of Zn/Cu ratios were observed in tissues which did not show significant differences for copper. When experimental results were compared to copper and copper/metal ratios in different Spanish rainbow trout farms, individual variations between exposed and unexposed fish were observed. All unexposed animals showed gill Zn/Cu ratios higher than 0.5, and 90% higher than 1.5; while 93% of poisoned fish showed gill Zn/Cu ratios lower than 1.5, and 84% lower than 0.5. Similar findings were observed for opercle. Therefore, we propose gill and opercle Zn/Cu ratios to be considered as a possible method to diagnose acute copper poisoning in farmed rainbow trout.

Aquatic Toxicology, 2002

A cost /effective innovative approach combining three freshwater invertebrates: the cladoceran Da... more A cost /effective innovative approach combining three freshwater invertebrates: the cladoceran Daphnia magna, the insect Chironomus prasinus and the basommatophoran snail Lymnaea peregra, in a single system is presented. The selection combines different reproductive strategies: parthenogenesis, sexual reproduction and hermaphroditism, respectively, and covers water column, sediment, food and contact exposure. Results confirm the system's capacity. In 46 days, multi-generation, whole-life-cycle, and chronic reproduction assays can be achieved for D. magna, C. prasinus and L. peregra, respectively. The 21-day D. magna test is commonly used to assess the effects of chemicals on aquatic invertebrates. Wide concerns on its suitability for testing endocrine disrupting chemicals have been raised, particularly for substances with estrogenic activities. The combination of three species with different reproductive strategies offer a suitable approach for assessing ecologically relevant effects related to any mechanism of action, including endocrine disruption.

Aquatic Toxicology, 1996

Algae play a major role in the accumulation of hydrophobic pollutants. The accumulation of hexach... more Algae play a major role in the accumulation of hydrophobic pollutants. The accumulation of hexachlorobenzene (HCB) in algae is very rapid, reaching equilibrium after a few hours. The elimination of HCB from algae has been described by a two-compartment nonequilibrium model. This paper describes the elimination kinetics of HCB from the second (slow rate) compartment in Chlorellu vulgaris, and the bioavailability of the HCB bound to algae on Duphnia magna. First-order elimination kinetics was observed. The elimination rate constant and the half life were 0.43 day-l and 1.6 days, respectively. The algal growth curve showed a growth rate constant of 0.27 day-l and a duplication time of 2.56 days. Comparisons among these values indicate that the dilution effect associated with algal growth accounts for more than 60% of the observed reduction.

Science of The Total Environment, 2000

Hazard assessment constitutes an essential tool in order to evaluate the potential effects of che... more Hazard assessment constitutes an essential tool in order to evaluate the potential effects of chemical substances on organisms and ecosystems. It includes as a first step, hazard identification, which must detect the potential dangers of the substance (i.e. the kind of effects that the substance may produce), and a second step to quantify each danger and to set the expected dose/response relationships. Hazard assessment plays a key role in the regulation of chemical substances, including pollution control and sustainable development. However, the aquatic environment has largely received more attention than terrestrial ecosystems. This paper presents the extrapolation of several basic concepts from the aquatic to the terrestrial compartment, and suggests possibilities for their regulatory use. Two specific proposals are discussed. The first focuses on the scientific basis of the hazard identification-classification criteria included in the EU regulations and their extrapolation to the terrestrial environment. The second focuses on the OECD programme for environmental indicators and the development of a soil pollution pressure indicator to quantify the potential hazards for the soil compartment and its associated terrestrial ecosystem related to the toxic chemicals applied deliberately (i.e. pesticides) or not (i.e. heavy metals in sludge-based fertilisers; industrial spills) to the soil.

Bulletin of Environmental Contamination and Toxicology, 1994

Science of The Total Environment, 2000

Three biochemical parameters, DNA quantification in soil samples and two enzymatic activities, be... more Three biochemical parameters, DNA quantification in soil samples and two enzymatic activities, beta-galactosidase and dehydrogenase have been assessed as potential end-points for the use in cost-effective toxicity tests on soil microorganisms. The assessment included the development of a classical dose-response 24-h assay and the incorporation of measurements of the effects on microbial activities in soil column leaching studies and multispecies miniaturised terrestrial systems (MTS). Four different chemicals, copper, a new herbicide, thiabendazole and fenthion were studied. A rapid fluorescence DNA quantification technique did not produce adequate responses. The efforts to quantify DNA after extraction and clean-up procedures failed due to the presence of humic acids. From the protocol of the technique one could see that the technical procedure is time-consuming and expensive and, for this reason, not suitable for use as a parameter in rapid and cost-effective tests. However, the enzymatic activities showed their potential as toxicity end-points. Copper produced a concentration/response inhibition of beta-galactosidase and dehydrogenase with EC50 values of 78.39 and 24.77 mg Cu/kg soil, respectively. In the soil column study, these endpoints allowed the measurement of the microbial activities through the column. The effects of the new herbicide on beta-galactosidase and dehydrogenase activities were statistically significant for the highest application dose (40 g/ha). Thiabendazole affected the microbial activity when mixed within the soil, but no effects were observed when this fungicide was applied on the soil surface. Fenthion produced effects when applied either in the soil or on the soil surface. These results can be explained by the low mobility of thiabendazole. The results show the capabilities of these biochemical parameters to be included as endpoints in cost-effective bioassays.

Bulletin of Environmental Contamination and Toxicology, 1993

Critical Reviews in Toxicology, 2000

... Feminized male birds with an ovotestis (a gonad containing both ova-rial and testicular tissu... more ... Feminized male birds with an ovotestis (a gonad containing both ova-rial and testicular tissue) and/or reduced male copulatory behavior have ... Experimentally dis-turbed sex differentiation has also been re-ported in reptiles, amphibia, fish, and inver-tebrates such as marine ...

Marine Environmental Research, 1998

Juvenile turbot (Scophthalmus maximus) were exposed to benzo(a)pyrene (BaP) for 14 d using a glas... more Juvenile turbot (Scophthalmus maximus) were exposed to benzo(a)pyrene (BaP) for 14 d using a glass bead generator flow-through system. Exposure was followed by a recovery period of 16d. The highest BaP concentration in the edible portion of the fish, 16.5 f 4.3 kg BaPlkg, was observed on the jirst day. Then concentrations dropped following jirst-order kinetics. BaP was below detection level at the end of the experiment. A statistically significant increase in bileJluorescence was observed from day 9 until the end of the experiment, suggesting the elimination of BaP metabolites by this route. No signiJicant d@erences between control and exposed jish in EROD activity and CYPIA concentration, measured by immunodetection method, were observed. Intraperitoneal injection of 2.5 mg BaPlkg in juvenile turbot induced EROD activity. Under waterborne experimental conditions, bile$uorescence was observed to be a more sensitive biomarker of BaP exposure than EROD activity and CYPIA measurement. 0 1998 Elsevier Science Ltd. All rights reserved

Archives of Environmental Contamination and Toxicology, 1991

A toxicological assessment of water quality conditions (30 physical-chemical parameters and a scr... more A toxicological assessment of water quality conditions (30 physical-chemical parameters and a screening of organic pollutants by reverse-phase HPLC) was performed in Algeciras Bay, Cadiz, Spain in relation to problems in six floating ponds for gilthead (Sparus auratus) growth. The study was completed with a short-termArtemia toxicity test, and the measurement of heavy metal concentrations in molluscs from different sites of the Bay. Cadmium, lead, and cyanide at sublethal toxic concentrations were found in most of the analyzed samples, and very high concentrations of ammonia, phenols, nitrites, cyanide, and sulphide were found in some sampling sites. In addition, seven water samples showed toxicity onArtemia. The problems in the floating ponds (low growth rates, high mortality, and infectious diseases) can be related, in part, to the very bad water quality conditions.

Aquatic Toxicology, 1994

Rainbow trout (Oncorhynchus mykiss) received 80/lg copper kg 1 body weight as an intravenous inje... more Rainbow trout (Oncorhynchus mykiss) received 80/lg copper kg 1 body weight as an intravenous injection of copper sulfate. Copper levels were analyzed by atomic absorption spectrometry in plasma samples collected before and at regular times after the copper injection. Plasma copper concentration-time curves were analyzed according to standard pharmacokinetic compartmental procedures. A two-compartment model was adapted to derive toxicokinetic parameters, including a time-independent component to assess the basal plasma copper levels before the copper injection. The volume of the central compartment 43 ml kg l was similar to that reported for rainbow trout plasma. Steady-state distribution volume was estimated in 178 ml kg ~. Distribution and final elimination half-lives were 7.2 and 195.5 rain, respectively. Steadystate distribution volume, the area under the curve, the copper clearance and the medium retention time calculated by the two-compartment model were similar to those estimated using non-compartmental equations. These toxicokinetic data suggest a rapid elimination of copper from the exchangeable pool. Thus, during long-term waterborne copper exposures, plasma copper concentration would achieve a steady-state situation after a few hours or days; further accumulation of copper would be related to the binding of copper to non-exchangeable ligands which would not have toxicological consequences. The large number of factors associated to the capability of the fish to offer and produce non-exchangeable binding sites would explain the variety of responses on copper accumulation described in the literature.

Science of The Total Environment, 1993

Seventy rainbow trouts were exposed to lethal copper conditions using water-borne copper, in orde... more Seventy rainbow trouts were exposed to lethal copper conditions using water-borne copper, in order to assess the diagnosis value of copper accumulation and its ratio to other essential metals. Poisoned fish showed a copper increase in some organs, but these changes did not always indicate significant differences versus control fish. Metal/copper ratios showed higher variations than did copper concentrations. In fact, significant decreases of Zn/Cu ratios were observed in tissues which did not show significant differences for copper. When experimental results were compared to copper and copper/metal ratios in different Spanish rainbow trout farms, individual variations between exposed and unexposed fish were observed. All unexposed animals showed gill Zn/Cu ratios higher than 0.5, and 90% higher than 1.5; while 93% of poisoned fish showed gill Zn/Cu ratios lower than 1.5, and 84% lower than 0.5. Similar findings were observed for opercle. Therefore, we propose gill and opercle Zn/Cu ratios to be considered as a possible method to diagnose acute copper poisoning in farmed rainbow trout.