RESUMEN
Because sponges are promising bioindicators, we present here a multispecies comparison of the bioconcentration capacity for copper, zinc and the hydrocarbon fluoranthene. The spatial distribution of sponge populations was studied in 17 areas in intertidal zones on the Lower Normandy coast (France) to determine the most common species with the highest bioaccumulation capacity. Results are compared with published data on blue mussels Mytilus edulis from the Réseau d'Observation de la Contamination Chimique biomonitoring network. A total of 720 sponge samples were collected to assess species richness. Samples were analysed for metal concentrations by flame-mode atomic absorption spectrometry. Analyses of polycyclic aromatic hydrocarbon were sub-contracted. Species richness varies according to the water mass concerned. The most common species in the study area showing the highest bioconcentration in its soft tissues is Hymeniacidon perlevis, which contains about 20 times the zinc, 44 times the copper and 16 times the fluoranthene levels found in mussels. The variability of contaminant concentrations in H. perlevis is also systematically higher than those in mussels. The results obtained for this sponge closely reflect the heterogeneous distribution of contaminants. This study demonstrates that H. perlevis has a much higher capacity to accumulate in situ contaminants than the blue mussel M. edulis. H. perlevis meets all the requirements of a good bioindicator suitable for use in an integrated monitoring programme. In the near future, controlled cultivation of H. perlevis will allow us to produce sufficient quantities of this species to carry out ecotoxicological tests and in situ biomonitoring by caging.
Asunto(s)
Exposición a Riesgos Ambientales , Monitoreo del Ambiente/métodos , Poríferos/metabolismo , Contaminantes Químicos del Agua/metabolismo , Calidad del Agua , Animales , Cobre/metabolismo , Fluorenos/metabolismo , Francia , Cromatografía de Gases y Espectrometría de Masas , Metales , Poríferos/efectos de los fármacos , Estaciones del Año , Especificidad de la Especie , Espectrofotometría Atómica , Zinc/metabolismoRESUMEN
Two types of exposures were performed to assess the effects of zinc released from sacrificial anode degradation: a chronic exposure, in which oysters were exposed to 0.53±0.04 mg Zn L(-1) for 10 weeks, and an acute exposure, where oysters were exposed to 10.2±1.2 mg Zn L(-1) for 1 week. At the end of the acute exposure experiment, 81.8% mortality was recorded. In contrast, no mortality was detected after 10 weeks exposure. Moreover, all of the immune system biomarkers studied, except the number of circulating haemocytes, were stimulated by a moderate level of zinc and inhibited by a high level. Our exposure conditions did not induce SOD or MXR mRNA expression in gills and digestive gland. However, an increase of MT mRNA is observed in these tissues. The results indicate that oysters are sensitive to acute zinc toxicity but are only moderately affected by a mild zinc concentration.
Asunto(s)
Crassostrea/efectos de los fármacos , Monitoreo del Ambiente , Contaminantes Químicos del Agua/metabolismo , Zinc/metabolismo , Animales , Biomarcadores/metabolismo , Crassostrea/fisiología , Metalotioneína/metabolismo , ARN Mensajero/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Superóxido Dismutasa/genética , Superóxido Dismutasa/metabolismo , Contaminantes Químicos del Agua/toxicidad , Zinc/toxicidadRESUMEN
Sacrificial anodes made of zinc are currently used in marine environments to mitigate marine corrosion as part of CP systems of immerged metallic structures. The aim of this work was to study zinc bioconcentration in the oyster Crassostrea gigas by performing two in vivo tests during different time periods and at different zinc concentrations. The first test was conducted during a period of 10 weeks at a concentration of 0.53 ± 0.04 mg Zn L(-1) to simulate long-term exposure, and a second test was conducted during a 168-hour period at a concentration of 10.2 ± 1.2 mg Zn L(-1) to reproduce short-term exposure. In these experiments, the zinc source was an electrochemical device that included a sacrificial anode to mimic the in situ conditions. During the first 14 days of the long-term experiment, digestive glands of C oysters exhibited bioaccumulation of zinc that varied according to the oysters' reproductive cycle. Both a bioconcentration factor (BCF) of ≤ 13,397 and a zinc accumulation percentage of +297% of zinc occurred in this organ after 10 weeks. The results obtained from the short-term test showed a lower BCF of 405 but a faster bioaccumulation of zinc (starting from the first day) in the same organ. No mortality was observed in long-term assay, but 81.8% of the oysters died at the end of the short-term assay. These results demonstrate the great capacity of C. gigas to accumulate zinc released from the anode, especially when low concentrations are released, as in the case of anode dissolution used as CP. This study confirmed the necessity to monitor this zinc-contamination source in marine environments in relation to the usual oyster consumption by humans (especially in France). No implication for human health of this zinc-contamination source was demonstrated until now, and this was not the purpose of this study; however, zinc remains one of the most abundant nutritionally essential elements in the human body that may affect the human immune system at high-level uptake.
Asunto(s)
Crassostrea/metabolismo , Electrodos , Zinc/farmacocinética , Animales , Acuicultura , Crassostrea/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Exposición a Riesgos Ambientales , Francia , Agua de Mar , Factores de Tiempo , Pruebas de Toxicidad/métodos , Contaminantes Químicos del Agua/farmacocinética , Contaminantes Químicos del Agua/toxicidad , Zinc/toxicidadRESUMEN
Since the early 1960s, the application of aluminum alloy sacrificial anodes to mitigate marine corrosion has been well known. The aim of this work was to study aluminum bioconcentration in Mytilus edulis by an in vitro test performed in two tanks: the first containing non-contaminated water (NCW) and the second containing aluminum-contaminated water (CW) (530 µg L(-1)) released by sacrificial anode. The mussels were collected and examined over a period of 8 weeks. A comparison between the aluminum concentrations in the digestive glands of mussels from the CW and NCW tanks shows that the highest value (1700 mg/kg d.w.) was found in the CW mussels collected after 13 days. In NCW, the mean aluminum concentration in digestive glands during the test was 281 mg/kg d.w. The rapid concentration decrease in digestive glands is probably due to the inhibition of filtering activity due to valve closure at the high concentration as well as the induction of the detoxification response.
Asunto(s)
Aluminio/farmacocinética , Monitoreo del Ambiente/métodos , Mytilus edulis/efectos de los fármacos , Contaminantes Químicos del Agua/farmacocinética , Aluminio/análisis , Aluminio/toxicidad , Animales , Técnicas Electroquímicas , Electrodos , Inactivación Metabólica , Mytilus edulis/metabolismo , Agua de Mar/análisis , Factores de Tiempo , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/toxicidadRESUMEN
The toxicity of aluminum or zinc from either sacrificial anodes (SA) or their sulfate salts (SS) was evaluated in sea urchin (Paracentrotus lividus) embryos or sperm exposed to Al(III) or Zn(II) (SA or SS, 0.1-10 microM), scoring developmental defects (DDs), fertilization rate (FR), and mitotic abnormalities. A significant DD increase was observed in SS, but not SA Al(III)- and Zn(II)-exposed embryos vs. controls. Both Al(III) and Zn(II), up to 10 microM, from SA and SS, inhibited mitotic activity and induced mitotic aberrations in exposed embryos. SA-Al(III)-exposed sperm displayed a significant FR increase, unlike Al(III) sulfate overlapping with controls. Both SA-Zn(II) and Zn(II) sulfate sperm exposure resulted in a significant FR increase. The offspring of SA-Al(III)-exposed sperm displayed a significant DD decrease, unlike Al(III) sulfate exposure. Zinc sulfate sperm exposure resulted in a significant increase in offspring DDs, whereas SA-Zn(II) sperm exposure decreased DDs. Together, exposures to SA-dissolved Al(III) or Zn(II) resulted in lesser, if any toxicity, up to hormesis, compared to SS. Studies of metal speciation should elucidate the present results.
Asunto(s)
Compuestos de Alumbre/toxicidad , Electrodos , Embrión no Mamífero/efectos de los fármacos , Erizos de Mar/efectos de los fármacos , Espermatozoides/efectos de los fármacos , Contaminantes Químicos del Agua/toxicidad , Sulfato de Zinc/toxicidad , Compuestos de Alumbre/química , Animales , Aberraciones Cromosómicas/inducido químicamente , Relación Dosis-Respuesta a Droga , Desarrollo Embrionario/efectos de los fármacos , Desarrollo Embrionario/genética , Fertilización/efectos de los fármacos , Masculino , Mitosis/efectos de los fármacos , Anomalías Musculoesqueléticas/inducido químicamente , Anomalías Musculoesqueléticas/embriología , Erizos de Mar/embriología , Erizos de Mar/genética , Solubilidad , Espectrofotometría Atómica , Contaminantes Químicos del Agua/química , Purificación del Agua/instrumentación , Sulfato de Zinc/químicaRESUMEN
Environmental pollutants such as heavy metals exert immunotoxic effects on aquatic organisms. The immune defence of molluscs is comprised of cell-mediated and humoral mechanisms, in which haemocytes play a key role. In this study, a model based on primary cultured haemocytes from the gastropod mollusc Haliotis tuberculata was established to investigate the effects of zinc in vitro. Cells were exposed for 24 h to ZnCl(2) concentrations of 0, 10, 100 or 1000 microM. The effects of zinc on haemocyte parameters were investigated using morphological, spectrophotometric and flow cytometry analysis. Immunotoxicity was reflected by a significant decrease in the number of viable haemocytes (LC(50)(24 h) = 314 microM). Moreover, the cell area was dramatically reduced, and the percentage of rounded cells increased with increasing zinc concentrations. Exposure to 1000 muM zinc induced a significant reduction in acid phosphatase activity, phagocytic activity and reactive oxygen species production in haemocytes. However, several haemocyte parameters increased significantly after 24 h of zinc exposure. In response to a 1000 microM exposure, the phenoloxidase level was 26-fold higher than that of the control, and non-specific esterase activity was increased by 69% above that of the control. These results suggest a relationship between zinc exposure and alterations in the functional responses of haemocytes from H. tuberculata.