Total and organic mercury concentrations in the white muscles of swordfish (Xiphias gladius) from the Indian and Atlantic oceans

Abstract

A total of 226 swordfish samples collected from Taiwanese fishing vessels in the Indian and Atlantic oceans were examined for total mercury (THg) and organic Hg (OHg). Analysis of 56 pooled white muscle samples showed that THg and OHg concentrations ranged from 0.056 to 3.97 (1.3 +/- 0.97) and from 0.043 to 3.92 (1.01 +/- 0.82) microg g(-1) flesh mass, respectively. These values were similar to those from various previous studies during the past three decades. THg and OHg were significantly linearly correlated with fork length (FL, cm) of the fish from Indian and Atlantic oceans; however, there was no significant OHg%-FL relationship. OHg and THg also were significantly correlated. Fishes with FL < or = 140 cm met the methyl Hg (meHg) regulatory standard set by the European Commission Decision (meHg < or = 1.0); and fish with FL < or = 211 cm met the Taiwanese Food and Hygiene Standard (meHg < or = 2.0). Weekly swordfish consumption rates and amounts are recommended accordingly.

Organic and total mercury levels in bigeye tuna,Thunnus obesus, harvested by Taiwanese fishing vessels in the Atlantic and Indian Oceans

“…The results are consistent with earlier studies in many kinds of fish (May et al 1987;Andersen and Depledge 1997;Wagemann et al 1997;Storelli et al 2002;Yamashita et al 2005). OHg and THg concentrations in the muscle of bigeye tuna were linearly correlated according to the equation: OHg ¼ 0.6498 THg þ 0.0808 (r 2 ¼ 0.9041, p50.0001; Figure 1), whereas the relationship in swordfish was OHg ¼ 0.8100 THg-0.0296 (Chen et al 2007). …”

“…The mercury concentrations detected in bigeye tuna in this study are quite similar to other studies around the world (Menasveta and Siriyong 1977; Boush and (Sun and Chang 1972;Kureishy et al 1979;Andersen and Depledge 1997;Adams 2004;Yamashita et al 2005;Besada et al 2006;Kojadinovic et al 2006;Chen et al 2007). Swordfish also contained the highest mean Hg concentrations in the two oceans (THg ¼ 1.20 and OHg ¼ 0.96 mg kg À1 wet weight for the Atlantic Ocean, and THg ¼ 1.47 and OHg ¼ 1.10 mg kg À1 wet weight for the Indian Ocean) (Sun and Chang 1972;Kureishy et al 1979;Andersen and Depledge 1997;Adams 2004;Yamashita et al 2005;Besada et al 2006;Kojadinovic et al 2006;Chen et al 2007).…”

“…THg and OHg levels from the Atlantic Ocean (THg ¼ 0.898 AE 0.466 (0.324-3.133) mg kg À1 wet weight, and OHg ¼ 0.656 AE 0.341 (0.220-2.222) mg kg À1 wet weight) were significantly higher than those of the Indian Ocean (THg ¼ 0.679 AE 0.231 (0.217-1.880) mg kg À1 wet weight, and OHg ¼ 0.529 AE 0.179 (0.143-1.525) mg kg À1 wet weight) (t-test, p50.0001). Such oceanic differences were not found in an earlier study on swordfish (Chen et al 2007). …”

“…Swordfish also contained the highest mean Hg concentrations in the two oceans (THg ¼ 1.20 and OHg ¼ 0.96 mg kg À1 wet weight for the Atlantic Ocean, and THg ¼ 1.47 and OHg ¼ 1.10 mg kg À1 wet weight for the Indian Ocean) (Sun and Chang 1972;Kureishy et al 1979;Andersen and Depledge 1997;Adams 2004;Yamashita et al 2005;Besada et al 2006;Kojadinovic et al 2006;Chen et al 2007). In addition, the mean THg concentrations of blackfin tuna, Thunnus atlanticus, and little tunny, Euthynnus alletteratus, caught in the Florida Atlantic Ocean also contained slightly higher Hg concentrations than the Hg levels of the bigeye tuna found in this study in the same ocean (Adams, 2004).…”

Temporal variability in atmospheric Hg released from natural and anthropogenic sources in central Taiwan

“…the USA and Canada) have established regulatory guidelines and consumer advisory panels for safe levels of Hg in fish and fish products [19][20][21]. Because >50% of total Hg in the muscle of fishes, except planktivores, is meHg [18][19][20][21][22], organic Hg concentrations in highly migratory sea fishes, such as swordfish, are very important when estimating the risk posed by meHg to the general public through dietary exposure to Hg [23]. Therefore, the Convention on Long-Range Transboundary Air Pollution [24] and its 1998 Aarhus Protocol on heavy metals (which targets three particularly harmful metals: cadmium, lead and mercury) were created to protect humans and their environment against air pollution and to endeavour to limit and, as far as possible, gradually reduce and prevent air pollution, including long-range transboundary air pollution.…”