The dynamics of metals in the American oyster, Crassostrea virginica. I. Seasonal effects (original) (raw)
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2016
Abstract: This study aims to assess baseline concentrations of heavy metals (Cd, Cr, Cu, Pb and Zn) in the oyster soft tissue as they relate to concentrations in the water column (particulate phase) and sediment in Apalachicola Bay. In order to conduct these assessments, a total of 360 samples, collected in two seasons (winter and summer) and were analyzed using atomic absorption spectrometry. Results indicated that elemental concentrations in particulate phase correlate significantly with concentration in the tissue than those in the sediment. Moreover, assessment of seasonal and spatial variations have indicated that oysters collected in the winter have significantly higher (P<0.05) Cu, Pb and Zn concentrations than oysters collected in the summer. However, metal concentrations in sediment did not show such patterns. These observations confirmed the fact that metals in the particulate phase are more bioavailable to oysters and that the oysters can be used as good indicators of ...
Bioaccumulation of heavy metals in oyster (Crassostrea virginica) tissue and shell
Environmental Geology, 2000
Oysters and sediment have been collected from most major US Gulf of Mexico bays and estuaries each year since 1986. Selected samples of oyster soft tissue, shell and sediments were analyzed for Cd, Cr, Cu, Fe, Mn, Pb, and Zn for this study. Concentrations varied considerably from place to place but ratios of metals remained relatively constant. Cu and Zn are greatly enriched in oyster tissues, which is related to their physiological function. Cd is enriched in oyster shell because of the easy substitution between Cd and Ca. The concentrations of Pb and Cr in oysters are significantly lower than that in sediment, suggesting a good discrimination against these metals by oysters. Metal variations are a result of both nature and human activity.
2005
This study aims to assess baseline concentrations of heavy metals (Cd, Cr, Cu, Pb and Zn) in the oyster soft tissue as they relate to concentrations in the water column (particulate phase) and sediment in Apalachicola Bay. In order to conduct these assessments, a total of 360 samples, collected in two seasons (winter and summer) and were analyzed using atomic absorption spectrometry. Results indicated that elemental concentrations in particulate phase correlate significantly with concentration in the tissue than those in the sediment. Moreover, assessment of seasonal and spatial variations have indicated that oysters collected in the winter have significantly higher (P<0.05) Cu, Pb and Zn concentrations than oysters collected in the summer. However, metal concentrations in sediment did not show such patterns. These observations confirmed the fact that metals in the particulate phase are more bioavailable to oysters and that the oysters can be used as good indicators of the spatia...
Marine Pollution Bulletin, 2016
A 5-month experiment combining a geochemical survey of metals with a bioaccumulation study in batches of Crassostrea gigas was conducted in two shellfish farming areas and a marina in Normandy (France). Various endpoints at different levels of biological organization were studied. ROCCH data showed differences in biota contamination between the two shellfish areas but the present study revealed only slight differences in metallic contamination and biomarkers. By contrast, significantly different values were recorded in the marina in comparison with the two other sites. Indeed, higher levels of Cd, Cu and Zn were measured in the oysters from the marina, and these oysters also showed a poorer physiological condition (e.g., condition index, histopathological alterations and neutral lipid content). For coastal monitoring, the multi-biomarker approach coupled with an assessment of metallic contamination in biota appeared to be suitable for discriminating spatial differences in environmental quality after only a few months of exposure.
Kinetics of metal elimination in oysters from a contaminated estuary
Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology, 2002
In oysters Crassostrea gigas translocated from a metal-enriched estuary (Gironde, France) to a comparatively clean site, the Bay of Bourgneuf (France), Cd, Cu and Zn concentrations were determined monthly in the whole soft tissues, or in different fractions (cytosolic or insoluble) of gills and digestive glands. In all cases, the concentrations of all of the three metals decreased logarithmically and half-lives were always shortest for Cd (86-251 days). After 4 months, the Cd concentration had become not significantly different from the threshold considered safe for human consumption (1 mg kg wet wt.). In the digestive gland, half-lives were similar in cytosolic and insoluble fractions. In contrast, in y1 the gills, elimination patterns differed markedly between these fractions. The long half-lives calculated for divalent metals in the insoluble fraction of the gills (1505 and 3010 days for Zn and Cu, respectively) is possibly due to a fossilization of metals in intracellular membrane-bound inclusions as shown previously in Ostrea edulis. It is interesting to underline that elimination is fastest for cytosolic metals compared to the insoluble fraction.
Environmental Geochemistry and Health, 2018
The Pacific oyster (Crassostrea gigas) is one of the world's most widespread bivalves and a suitable species for biomonitoring metals in coastal environments. In the present research, wild individuals were collected from an Argentinian estuary and the coastal beaches nearby. The concentrations of eight metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) were quantified in the soft tissues of the Pacific oyster. Among the metals, Cu, Fe and Zn reached the highest concentrations in the soft tissues over the rest of the elements. The results showed the highest values to be estuary related, with the beach site achieving the lowest values. These results possibly lie on the impact of human activities surrounding the estuary, as well as streams and rivers that outflow within it. Higher Cu and Zn levels, both port related, were mainly found toward the outer estuary. On the other hand, high levels of Cr, Fe and Mn were found toward the inner zone of the estuary, an area with sewage sludge from the cities located on the margins of the BBE. Regarding the potential risk to public health, Cu and Zn levels found in C. gigas were above national and international safety guidelines in 100% and 11% of the samples, respectively.
Estuaries, 1998
from the upper Patuxent River estuary analyzed since 1986 (Cd since 1991) were high relative to concentrations in other sites in the United States analyzed by the National Oceanic and Atmospheric Administration National Status and Trends program. Patuxent River oysters had above average concentrations of Ag and Cu, and unusually high concentrations of Cd. Metal concentrations were highest in summer, a period in which oyster meat condition index was relatively low. Copper values were highest in 1986-1987, likely elevated by erosion from Cu-Ni alloy condensers at a local power plant. Silver and Cd values exhibited more year-to-year variation. A number of factors were examined as candidates to explain the interannual differences, including river flow, salinity, and oyster condition, but none was able to explain the high and low years. Samples collected in spring and late summer of 1996 at a number of oyster bars located along the length of the Patuxent River showed that concentrations of ail three metals increased with distance up-river. For Cd, the upstream increase was linear with distance, while for Ag and Cu, there was a secondary maximum near river km 16. A close correlation was observed between Ag and Cu for individuals at each site, with a poorer correlation between Cd and either Ag or Cu. in '
Estuaries, 1998
from the upper Patuxent River estuary analyzed since 1986 (Cd since 1991) were high relative to concentrations in other sites in the United States analyzed by the National Oceanic and Atmospheric Administration National Status and Trends program. Patuxent River oysters had above average concentrations of Ag and Cu, and unusually high concentrations of Cd. Metal concentrations were highest in summer, a period in which oyster meat condition index was relatively low. Copper values were highest in 1986-1987, likely elevated by erosion from Cu-Ni alloy condensers at a local power plant. Silver and Cd values exhibited more year-to-year variation. A number of factors were examined as candidates to explain the interannual differences, including river flow, salinity, and oyster condition, but none was able to explain the high and low years. Samples collected in spring and late summer of 1996 at a number of oyster bars located along the length of the Patuxent River showed that concentrations of ail three metals increased with distance up-river. For Cd, the upstream increase was linear with distance, while for Ag and Cu, there was a secondary maximum near river km 16. A close correlation was observed between Ag and Cu for individuals at each site, with a poorer correlation between Cd and either Ag or Cu. in '
Archives of Environmental Contamination and Toxicology, 2007
The bioavailability of Cd, Cu, Zn, and Pb from two metal-contaminated sediments (Bidassoa and Dunkerque) was studied using Crassostrea gigas larvae exposed to sediment elutriates. The metal contents within the sediments, the larvae and larval growth, the condition index, and the induction of metallothionein in the larvae were measured. The larval growth and condition index were only affected after exposure to the highest elutriates concentration (5 to 25%) from the most contaminated sediment (Dunkerque). Bioaccumulation of all metals was observed in larvae exposed to Dunkerque elutriatre; only Cu bioaccumulation was observed in the Bidassoa elutriate. The results from larvae exposed to both sediment elutriates show a strong correlation between bioaccumulated metal considered individually or in combination and the metallothionein level in larvae presenting no detrimental effect. On the other hand, in the case of larvae exposed to the highest Dunkerque elutriate concentration and showing the highest metal body burden, we observed a drop in the metallothionein level. These results indicate that metallothionein is a more sensitive indicator of heavy metal pollution than physiological endpoints taken into account in bioassays and could be proposed as an early biomarker of metal exposure in larvae. However, care must be taken with "fault control" due to the toxicological effect on larvae metabolism in the case of substantial contaminant exposure.
Marine Pollution Bulletin, 2014
The current study aimed to examine the relationship between metals in sediments and metal bioaccumulation in oyster tissue in a highly-modified estuary (Sydney estuary, Australia). While extensive metal contamination was observed in surficial sediments, suspended particulate matter and oyster tissue, a significant relationship between these media could not be established. No relationship was determined between sediment quality guidelines and oyster size or weight, nor with human consumption levels for metals in oyster tissue. Moreover, oyster tissue metal concentrations varied greatly at a single locality over temporal scales of years. Oyster tissue at all 19 study sites exceeded consumptions levels for Cu. Bioaccumulation of metals in oyster tissue is a useful dynamic indicator of anthropogenic influence within estuaries, however oysters cannot be used in Sydney estuary as a valid biomonitor due to overriding internal regulation (homoestasis) by the animal, or by external natural (sediment resuspension) and anthropogenic (sewer/stormwater discharges) pressures, or both.