Bioaccumulation of Metals in Sediment Elutriates and Their Effects on Growth, Condition Index, and Metallothionein Contents in Oyster Larvae (original) (raw)
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Metal bioaccumulation and metallothionein concentrations in larvae of Crassostrea gigas
Environmental Pollution, 2006
Larval stages of bivalve molluscs are highly sensitive to pollutants. Oysters from a hatchery from Normandy (English Channel) were induced to spawn, and fertilized eggs were exposed to copper or cadmium for 24 h. Metal accumulation (from 0.125 to 5 μg Cu L−1 and from 25 to 200 μg Cd L−1) and MT concentrations were measured in larvae. Compared to controls, larvae accumulated copper and cadmium with an increase in MT concentrations particularly with cadmium (i.e. 130.96 ng Cu (mg protein)−1 and 12.69 μg MT (mg protein)−1 at 1 μg Cu L−1 versus 23.19 ng Cu (mg protein)−1 and 8.92 μg MT (mg protein)−1 in control larvae; 334.3 ng Cd (mg protein)−1 and 11.70 μg MT (mg protein)−1 at 200 μg Cd L−1 versus 0.87 ng Cd (mg protein)−1 and 4.60 μg MT (mg protein)−1 in control larvae). Larvae were also obtained from oysters of a clean area (Arcachon Bay) and a polluted zone (Bidassoa estuary) and exposed to copper in the laboratory, their MT concentration was measured as well as biomarkers of oxidative stress. Biomarker responses and sensitivity to copper for the larvae from Arcachon oysters were higher than for those from Bidassoa.
Scientia Marina, 2010
The metallothionein levels and metal concentrations in whole body, digestive gland and gills of Crassostrea angulata were analyzed in field samples collected from the River Guadalquivir estuary over several years following a mining waste spill upstream. The subcellular distribution of metals was analyzed to determine the mechanisms involved in the detoxification process. The highest metallothionein levels were reported in the digestive gland shortly after the mining contamination event. In this organ, metals are stored preferentially in the non-cytosolic fraction when increased bioaccumulation takes place. In the cytosol of the gills, metals are associated with metallothionein, whereas in the digestive gland, the distribution of metals between metallothioneins and high molecular weight proteins is similar. Metallothionein variation cannot be explained by metals alone; other abiotic factors must be taken into account. In order to use metallothionein as a metal exposure biomarker in field studies, natural variability needs to be taken into account for the correct interpretation of results.
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.
The dynamics of metals in the American oyster, Crassostrea virginica. I. Seasonal effects
Chesapeake Science, 1975
The dynamics of Mn, Fe, Zn, Cu and Cd in the shell and soft tissues of the American oyster, Crassostrea virginica, were observed in oysters exposed in situ to a metal-contaiminated environment from September, 1972 until August, 1973. Zn and Cu accumulated in soft tissues of exposed oysters reaching levels of 4100 rg Zn/gm and 450 rg Cu/gm compared to 1700 pg Zn/gm and 60 pg Cu/gm for controls (dry weight basis). The relative enhancement of metals in oyster soft tissues exposed to the contaminated environment over controls reflected the pattern of metal contamination in sediments. Although growth of the oysters, as measured by soft tissue dry weight and shell dimension, was identical, shells of exposed oysters were significantly thinner than controls (16%). Trace metal incorporation into shell was affected with Mn deposition surpressed and Fe, Zn and Cu slightly increased. Uptake of metals by oyster soft tissues was seasonally dependent with rapid uptake occurring in the summer and fall but delayed uptake occurring in the early spring.
Scientia Marina, 2010
The metallothionein levels and metal concentrations in whole body, digestive gland and gills of Crassostrea angulata were analyzed in field samples collected from the River Guadalquivir estuary over several years following a mining waste spill upstream. The subcellular distribution of metals was analyzed to determine the mechanisms involved in the detoxification process. The highest metallothionein levels were reported in the digestive gland shortly after the mining contamination event. In this organ, metals are stored preferentially in the non-cytosolic fraction when increased bioaccumulation takes place. In the cytosol of the gills, metals are associated with metallothionein, whereas in the digestive gland, the distribution of metals between metallothioneins and high molecular weight proteins is similar. Metallothionein variation cannot be explained by metals alone; other abiotic factors must be taken into account. In order to use metallothionein as a metal exposure biomarker in field studies, natural variability needs to be taken into account for the correct interpretation of results.
Effects of heavy metals on the oyster (Crassostrea virginica) at Mandinga Lagoon, Veracruz, Mexico
Revista de biología …, 2009
The Mandinga Lagoon in the Mexican State of Veracruz is an important ecological zone that produces 32% of the oyster output in the state of Veracruz, the main oyster producer in Mexico. Samples of water, sediment, and oysters were collected in 2003 and 2004 to study heavy metal pollution. Metal concentrations were determined in water, soil, and oyster tissues from fresh and detoxified Crassostrea virginica, and histology samples were analyzed. Metal (Cr, Cd, and Pb) concentrations in water were within the Mexican legal limits. The recorded values in sediments corresponded to those not producing biological effects (ERL). In the tissues, the highest concentrations corresponded to Pb, above 5.84 µgg-1 dry weight (d.w.); Cd was of 2.23 µgg-1 d.w., and Cr above 6 µgg-1 d.w. The metal levels detected in oysters exceeded the maximum permissible limits (MPL) for Cd and Pb, and oysters were unable to eliminate the concentrations of the bioaccumulated metals during the detoxification stage. The histopathological analysis revealed lesions in the digestive gland, edema, atrophy of epithelia in the digestive tubules, the presence of brown vesicles, hemocytic reaction, and necrosis. During detoxification, a higher number of epithelia were observed in the tubules, as well as an increase in brown vesicles and hemocytic reaction. Forty seven percent of oysters presented histopathological lesions related to metal concentrations. It is important to monitor metal concentrations, to detect the source of pollution, andto evaluate the effects on organisms to establish culture areas and adequate criteria for the exploitation of such an important fishery resource.
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 ...
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.