To understand the present status of metal contamination along the Haiphong-Halong coast, the conc... more To understand the present status of metal contamination along the Haiphong-Halong coast, the concentrations of As, Cd, Cr, Cu, Pb, and Zn were seasonally determined in rock oysters from four sites during 2013. The results indicated that a high concentration of heavy metals was found in oysters. The average concentrations of Zn and Cu were extremely high, ranging from 823.6–3201.6 and 238.1–1597.8 mg/kg dry wt., respectively, followed by As, Cd, Pb and Cr with concentrations of 10.10–19.33, 3.53–12.74, 0.79–6.20, and 0.81–4.47 mg/kg dry wt., respectively. The highest concentrations of heavy metals, Cd, Cr, Pb and Zn, found in Dinh Vu could be influenced by anthropogenic inputs. In addition, the runoff in the rainy season greatly influences the accumulation of heavy metals in oysters from Dinh Vu and Do Son. The maximum levels of Cd, Cu, Zn and As could potentially create toxicological concerns from a human health point of view and rocky oysters from the polluted sites should not be consumed.
This study investigated trace metals in water, sediment, and various organs of the mature eel Ang... more This study investigated trace metals in water, sediment, and various organs of the mature eel Anguilla marmorata in the Ba River, Vietnam. The metal concentrations in water and sediment did not exceed the Vietnam water criteria and sediment background concentration, except for Mn and Pb in sediment. The results of metal analysis in eel specimens indicated that the liver and kidney were the dominant organs for almost all trace metals, whereas muscle tended to accumulate high levels of Hg and approximately 87.4–100% of Hg was methylmercury. A strong positive correlation between mercury levels in muscle and age were found, but there was no correlation between mercury and body size. Interestingly, a high concentration of Zn was found in the gonad and liver; this indicated that high levels of Zn in the liver might play a physiologically important role in the eel's biological mechanisms during gonadal maturation. Though almost none of the metal concentrations in the muscle exceeded the reference doses of the U.S. EPA, approximately 80% of eels from the river contained mercury exceeding the recommended levels (0.30 lg/g) of the U.S. EPA and might present a risk for human consumption. Carnivorous fish species can be considered top consumers in aquatic ecosystems. As a consequence, pollutants discharged in the aquatic environment are likely to accumulate in fish and represent a potential risk not only to the fish, but also to other fish consumers, particularly humans.
The patterns of use of marine and freshwater habitats by the tropical anguillid eels Anguilla mar... more The patterns of use of marine and freshwater habitats by the tropical anguillid eels Anguilla marmorata and A. bicolor pacifica were examined by analysing the otolith strontium (Sr) and calcium (Ca) concentrations of yellow (immature) and silver (mature) stage eels collected in Vietnamese waters. In A. marmorata, the change in the Sr:Ca ratios outside water with no freshwater residence. The mean Sr:Ca ratio value after recruitment to coastal waters ranged from 1.73 to 5.67 9 10-3 (mean 3.2 9 10-3) in A. marmorata and from 2.53 to 6.32 9 10-3 (mean 4.3 9 10-3) in A. bicolor pacifica. The wide range of otolith Sr:Ca ratios in both species indicated that the habitat use of these tropical eels was facultative among fresh, brackish, and marine waters during their growth phases after recruitment to coastal areas. Tropical eel species may have the same behavioural plasticity as temperate anguillid species regarding whether to enter freshwater or to remain in estuarine and marine environmen...
Archives of Environmental Contamination and Toxicology, 2010
This study investigated trace metals in water, sediment, and various organs of the mature eel Ang... more This study investigated trace metals in water, sediment, and various organs of the mature eel Anguilla marmorata in the Ba River, Vietnam. The metal concentrations in water and sediment did not exceed the Vietnam water criteria and sediment background concentration, except for Mn and Pb in sediment. The results of metal analysis in eel specimens indicated that the liver and kidney were the dominant organs for almost all trace metals, whereas muscle tended to accumulate high levels of Hg and approximately 87.4–100% of Hg was methylmercury. A strong positive correlation between mercury levels in muscle and age were found, but there was no correlation between mercury and body size. Interestingly, a high concentration of Zn was found in the gonad and liver; this indicated that high levels of Zn in the liver might play a physiologically important role in the eel’s biological mechanisms during gonadal maturation. Though almost none of the metal concentrations in the muscle exceeded the reference doses of the U.S. EPA, approximately 80% of eels from the river contained mercury exceeding the recommended levels (0.30 μg/g) of the U.S. EPA and might present a risk for human consumption.
To understand the present status of metal contamination along the Haiphong-Halong coast, the conc... more To understand the present status of metal contamination along the Haiphong-Halong coast, the concentrations of As, Cd, Cr, Cu, Pb, and Zn were seasonally determined in rock oysters from four sites during 2013. The results indicated that a high concentration of heavy metals was found in oysters. The average concentrations of Zn and Cu were extremely high, ranging from 823.6–3201.6 and 238.1–1597.8 mg/kg dry wt., respectively, followed by As, Cd, Pb and Cr with concentrations of 10.10–19.33, 3.53–12.74, 0.79–6.20, and 0.81–4.47 mg/kg dry wt., respectively. The highest concentrations of heavy metals, Cd, Cr, Pb and Zn, found in Dinh Vu could be influenced by anthropogenic inputs. In addition, the runoff in the rainy season greatly influences the accumulation of heavy metals in oysters from Dinh Vu and Do Son. The maximum levels of Cd, Cu, Zn and As could potentially create toxicological concerns from a human health point of view and rocky oysters from the polluted sites should not be consumed.
This study investigated trace metals in water, sediment, and various organs of the mature eel Ang... more This study investigated trace metals in water, sediment, and various organs of the mature eel Anguilla marmorata in the Ba River, Vietnam. The metal concentrations in water and sediment did not exceed the Vietnam water criteria and sediment background concentration, except for Mn and Pb in sediment. The results of metal analysis in eel specimens indicated that the liver and kidney were the dominant organs for almost all trace metals, whereas muscle tended to accumulate high levels of Hg and approximately 87.4–100% of Hg was methylmercury. A strong positive correlation between mercury levels in muscle and age were found, but there was no correlation between mercury and body size. Interestingly, a high concentration of Zn was found in the gonad and liver; this indicated that high levels of Zn in the liver might play a physiologically important role in the eel's biological mechanisms during gonadal maturation. Though almost none of the metal concentrations in the muscle exceeded the reference doses of the U.S. EPA, approximately 80% of eels from the river contained mercury exceeding the recommended levels (0.30 lg/g) of the U.S. EPA and might present a risk for human consumption. Carnivorous fish species can be considered top consumers in aquatic ecosystems. As a consequence, pollutants discharged in the aquatic environment are likely to accumulate in fish and represent a potential risk not only to the fish, but also to other fish consumers, particularly humans.
The patterns of use of marine and freshwater habitats by the tropical anguillid eels Anguilla mar... more The patterns of use of marine and freshwater habitats by the tropical anguillid eels Anguilla marmorata and A. bicolor pacifica were examined by analysing the otolith strontium (Sr) and calcium (Ca) concentrations of yellow (immature) and silver (mature) stage eels collected in Vietnamese waters. In A. marmorata, the change in the Sr:Ca ratios outside water with no freshwater residence. The mean Sr:Ca ratio value after recruitment to coastal waters ranged from 1.73 to 5.67 9 10-3 (mean 3.2 9 10-3) in A. marmorata and from 2.53 to 6.32 9 10-3 (mean 4.3 9 10-3) in A. bicolor pacifica. The wide range of otolith Sr:Ca ratios in both species indicated that the habitat use of these tropical eels was facultative among fresh, brackish, and marine waters during their growth phases after recruitment to coastal areas. Tropical eel species may have the same behavioural plasticity as temperate anguillid species regarding whether to enter freshwater or to remain in estuarine and marine environmen...
Archives of Environmental Contamination and Toxicology, 2010
This study investigated trace metals in water, sediment, and various organs of the mature eel Ang... more This study investigated trace metals in water, sediment, and various organs of the mature eel Anguilla marmorata in the Ba River, Vietnam. The metal concentrations in water and sediment did not exceed the Vietnam water criteria and sediment background concentration, except for Mn and Pb in sediment. The results of metal analysis in eel specimens indicated that the liver and kidney were the dominant organs for almost all trace metals, whereas muscle tended to accumulate high levels of Hg and approximately 87.4–100% of Hg was methylmercury. A strong positive correlation between mercury levels in muscle and age were found, but there was no correlation between mercury and body size. Interestingly, a high concentration of Zn was found in the gonad and liver; this indicated that high levels of Zn in the liver might play a physiologically important role in the eel’s biological mechanisms during gonadal maturation. Though almost none of the metal concentrations in the muscle exceeded the reference doses of the U.S. EPA, approximately 80% of eels from the river contained mercury exceeding the recommended levels (0.30 μg/g) of the U.S. EPA and might present a risk for human consumption.
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