Assessment of Total Mercury and Methyl Mercury in Selected Subsistence Fish in Western Alaska PDF Download
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Author: Xiaoming Zhang
Publisher:
ISBN:
Category : Fishes
Languages : en
Pages : 236
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Book Description
"Total Hg (THg) and methylmercury (MeHg) were examined in muscle and liver samples of salmon species (Chinook: Oncorhynchus tshawytscha; Chum: O. keta; Sockeye: O. nerka; Coho: O. kisutch) and freshwater fish species (Pike: Esox lucius; Grayling: Thymallus arcticus; Whitefish: Caregonus nelsoni) collected in 1999 and 2000 from the Western Alaska rivers (Yukon, Kuskokwim, Nushagak and Kvichak). The THg in salmon muscles has a mean value of 62 ng/g (ww). In Pike muscles, THg has a mean value of 879 ng/g. The mean concentrations of THg in Grayling and Whitefish muscle are 153 ng/g and 32 ng/g respectively. In salmon muscle and liver the MeHg levels constitute 77% and 62% of the THg levels, respectively. In Pike muscle the MeHg levels constitute 100% of the THg levels. A significant correlation between Hg levels and fish length was found. Calculated consumption limits indicate that children may consume 0.05-1.5 kg of fish per month, depending on the species consumed. The study suggests that, from 1979 to 1998, nearly 21 kg of MeHg was transported by Sockeye salmon to the Alaskan rivers of the Bering Sea east coast"--Leaf 3.
Author: Xiaoming Zhang
Publisher:
ISBN:
Category : Fishes
Languages : en
Pages : 236
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Book Description
"Total Hg (THg) and methylmercury (MeHg) were examined in muscle and liver samples of salmon species (Chinook: Oncorhynchus tshawytscha; Chum: O. keta; Sockeye: O. nerka; Coho: O. kisutch) and freshwater fish species (Pike: Esox lucius; Grayling: Thymallus arcticus; Whitefish: Caregonus nelsoni) collected in 1999 and 2000 from the Western Alaska rivers (Yukon, Kuskokwim, Nushagak and Kvichak). The THg in salmon muscles has a mean value of 62 ng/g (ww). In Pike muscles, THg has a mean value of 879 ng/g. The mean concentrations of THg in Grayling and Whitefish muscle are 153 ng/g and 32 ng/g respectively. In salmon muscle and liver the MeHg levels constitute 77% and 62% of the THg levels, respectively. In Pike muscle the MeHg levels constitute 100% of the THg levels. A significant correlation between Hg levels and fish length was found. Calculated consumption limits indicate that children may consume 0.05-1.5 kg of fish per month, depending on the species consumed. The study suggests that, from 1979 to 1998, nearly 21 kg of MeHg was transported by Sockeye salmon to the Alaskan rivers of the Bering Sea east coast"--Leaf 3.
Author:
Publisher:
ISBN:
Category : Medicine
Languages : en
Pages : 2098
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Book Description
Vols. for 1963- include as pt. 2 of the Jan. issue: Medical subject headings.
Author: Michael S. Bank
Publisher: Univ of California Press
ISBN: 0520951395
Category : Nature
Languages : en
Pages : 361
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Book Description
Mercury pollution and contamination are widespread, well documented, and continue to pose a public health concern in both developed and developing countries. In response to a growing need for understanding the cycling of this ubiquitous pollutant, the science of mercury has grown rapidly to include the fields of biogeochemistry, economics, sociology, public health, decision sciences, physics, global change, and mathematics. Only recently have scientists begun to establish a holistic approach to studying mercury pollution that integrates chemistry, biology, and human health sciences. Mercury in the Environment follows the process of mercury cycling through the atmosphere, through terrestrial and aquatic food webs, and through human populations to develop a comprehensive perspective on this important environmental problem. This timely reference also provides recommendations on mercury remediation, risk communication, education, and monitoring.
Author: Roger F. N. Rothschild
Publisher:
ISBN:
Category : Mercury
Languages : en
Pages : 172
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Book Description
"Food containing mercury has been identified as a possible health risk. Total mercury (THg), which is inorganic (Hg2), and methylmercury (MeHg) species, has been found in the arctic food web. In Alaska, birds are an important seasonal component of the diet, but have not been studied extensively and characterized for the presence of mercury. Birds are good subjects for examination because they feed at different trophic levels, can be long-lived, and are both abundant and widely distributed. Not only can birds monitor local Alaskan food webs, but, if they are migratory, can be used to compare exposure in different regions. Mercury levels in muscle, brain, and bone tissue of 140 birds taken by subsistence hunters across southwestern Alaska were determined. I tested the null hypothesis of no interspecific differences in total mercury levels in the 18 species of Alaska birds surveyed. There were interspecific differences with the Lesser Scaup (Aythyra marila mariloides), and the Black Scoter (Melanita nigra Americana), having the highest levels of mercury. In general, mercury levels were higher in muscle than in brain or bone. The mean values for mercury in the species studied were lower than the levels known to cause adverse reproductive or behavioral effects"--Leaf iii.
Author: Michelle Trifari
Publisher:
ISBN:
Category : Fishes
Languages : en
Pages : 0
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Total mercury (THg) concentrations exceed thresholds of concern in some Steller sea lion (Eumetopias jubatus; SSL) tissues from certain portions of the Aleutian Islands, Alaska. Here, compound-specific stable isotope analyses (CSIA) of carbon in essential amino acids ([delta]13CEAA values) and nitrogen in AAs ([delta]15NAA values) in fish muscle tissue was applied to quantify the proportional contributions of primary production sources and trophic positions of eight prey species (n = 474 total) that are part of SSL diets. Previous THg analyses of fish muscle, coupled with additional monomethylmercury (MMHg) analyses of a subset of samples, substantiated previous findings that fishes from the west of Amchitka Pass, a discrete oceanographic boundary of the Aleutian Archipelago, have higher muscle THg concentrations relative to fishes from east of the pass. All fish muscle samples were analyzed separately for, both, CSIA-AA of carbon and nitrogen. The [delta]13CEAA values in fish muscle demonstrated that although most fishes obtained their EAAs primarily from algae, some species varied in the extent to which they relied on this primary production source. Certain [delta]15NAA values of the same fish samples indicated that trophic positions of fishes were higher from the west relative to the east of the pass for some species. Total Hg was positively correlated with bulk [delta]15N values, [delta]15N values of glutamic acid ([delta]15NGlu), and trophic positions. However, only trophic magnification slopes using [delta]15NGlu values indicated a higher rate of Hg biomagnification to the west of Amchitka Pass. Broad and species-level multiple linear regression models revealed that trophic position was the most important driver of fish muscle THg with a smaller amount of variation explained by other parameters, such as proportional contributions of primary production sources, fish body condition, and catch location. Collectively, results indicate that differences in fish trophic positions were the most consistent determinants of the higher fish THg concentrations to the west of Amchitka Pass. However, a higher rate of THg biomagnification to the west of Amchitka Pass may also play a role in the regional differences in fish muscle THg.
Author:
Publisher: DIANE Publishing
ISBN: 1428903720
Category :
Languages : en
Pages : 1811
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Author: Nazirah Ariffin
Publisher:
ISBN:
Category : Fishes
Languages : en
Pages : 104
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Author:
Publisher: DIANE Publishing
ISBN: 1428953817
Category :
Languages : en
Pages : 293
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Book Description
Author:
Publisher:
ISBN:
Category : Factory and trade waste
Languages : en
Pages : 190
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Book Description
Author:
Publisher:
ISBN:
Category : Mercury
Languages : en
Pages : 30
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Book Description
