Stable isotope ratios and mercury levels in red meat products from baleen whales sold in Japanese markets
Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, 1757, Ishikari-Tobetsu, Hokkaido 061-0293, Japan.Ecotoxicology and Environmental Safety (Impact Factor: 2.76). 02/2012; 79:35-41. DOI: 10.1016/j.ecoenv.2012.01.020
We analyzed the δ(13)C, δ(15)N and δ(18)O values and Hg concentration in red meat products originating from the predominant types sold in Japan for human consumption: two populations of common minke (J- and O-types), Bryde's and sei whales in the western North Pacific Ocean, and fin and Antarctic minke whales in the Southern Ocean. The order of the trophic positions, evaluated by δ(15)N values and Hg concentrations, coincided with their known feeding habits: common minke (J-type)=common minke (O-type)> Bryde's ≥ sei ≥ Antarctic minke ≥ fin. The Hg concentrations in the combined samples from the six samples were significantly correlated with their δ(15)N values (γ=0.455, n=66, p<0.05), reflecting overall differences in the trophic level. This correlation was not significant for within-species comparison for the common minke (J- and O-types) or the Bryde's whale, probably reflecting the higher δ(15)N value and lower Hg concentration in the North Pacific Ocean around Japan. Determination of δ(13)C, δ(15)N and δ(18)O could be used to discriminate between the red meat products originating from the whale species in the North Pacific and Southern Oceans. However, the four whale species or populations in the Pacific Ocean could not be discriminated on basis of these values, nor could the two species in the Southern Ocean. Positive correlations between the δ(13)C and δ(15)N values and negative correlations between the δ(15)N and δ(18)O values and the δ(13)C and δ(18)O values, probably reflecting migration patterns, were found in some whale species in the North Pacific and Southern Oceans.
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ABSTRACT: We analyzed the levels of total mercury (T-Hg), methylmercury (M-Hg) and Cd in the muscle and liver of kidako moray eels (Gymnothorax kidako) of different body lengths caught off Kochi Prefecture in southern Japan. Furthermore, we analyzed the levels of organohalogen compounds such as polychlorinated biphenyls (PCBs), p,p'-1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE), trans-nonachlor and 2,3,3',4,4',5,5'-heptachloro-1'-methyl-1-2'-bipyrrole (Q1) and stable isotope ratios of carbon (δ(13)C) and nitrogen (δ(15)N) in the muscle of eels. The concentrations of T-Hg and M-Hg in the muscle (edible part) were 0.31±0.08 µg/wet g and 0.25±0.06 µg/wet g (n=26), respectively, and those in large eels exceeded the Japanese legislated levels of T-Hg (0.4 µg/wet g) and M-Hg (0.3 µg/wet g) in fish and shellfish, respectively. The T-Hg and M-Hg concentrations in the liver were markedly higher than those in the muscle, respectively. The ratios of M-Hg to T-Hg in the muscle and liver were about 80 and 60%, respectively, and those ratios tended to decrease with increased body length. The Cd concentrations in the liver tended to increase proportionally with body length, while that in the muscle was trace (around or below 0.03 µg/wet g). The concentrations of PCBs, p,p'-DDE, trans-nonachlor in the muscle tended to increase proportionally with body length, while that of Q1 did not. The δ(13)C and δ(15)N values in the kidako moray eel were markedly higher than those in offshore habit predators reported elsewhere, which may reflect the inshore habitat of this eels.
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ABSTRACT: We analyzed stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) as well as mercury (Hg) concentration in the scalp hair of Japanese who consumed whale meat and those who did not, and investigated the relationships among the δ13C and δ15N values and Hg concentration. The average δ15N and δ13C values of whale meat-eaters (10.11‰ and -18.5‰) were significantly higher than those of non-eaters (9.28‰ and -18.9‰), respectively. The average Hg concentration of whale meat-eaters (20.6μg/g) was significantly higher than that of non-eaters (2.20μg/g). Significant positive correlations were found between the δ13C and δ15N values and between the δ15N value and Hg concentration in the hair of whale meat-eaters, while the correlation between the δ15N value and Hg concentration was not statistically significant in the non-eaters. The consumption of whale meat may increase Hg concentration as well as δ15N and δ13C values in scalp hair.
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