Methylmercury, total mercury and total selenium in four common freshwater fish species from Ya-Er Lake, China

Abstract

Snakehead fish (Ophiocephalus argus cantor), silver carp (Hypophthalmichthys molitrtix), crucian carp (Carassius carassius), and common carp (Cyprinus carpio) are four common freshwater fish species in China. In this study, the level of methylmercury (MeHg), total mercury (T-Hg), and total selenium (T-Se) in muscle samples of these four fish species from Ya-Er Lake, China, were analyzed using atomic fluorescence spectrometry coupled with high-performance liquid chromatography, and inductively coupled plasma mass spectrometry. The concentrations of MeHg in all the fish species were significantly correlated with those of T-Hg. Higher T-Hg and MeHg concentrations had accumulated in the snakehead fish, which is a strongly predatory fish, than in the other three species. The concentration ratios of MeHg and T-Hg in the muscles of these four fish species were almost equal. Conversely, there was negative correlation between the concentrations of T-Hg and T-Se, which implies that there is a competition between these two elements with respect to bioaccumulation. It is noteworthy that of all the muscle samples tested, the level of T-Hg exceeded the maximum allowable limit in fish [0.4 mg kg )1 (w/w) recommended by the World Health Organization] in 38.46% of those of the silver carp, 18.18% of those of the crucian carp, and 100% of those of snakehead fish. These results show that the consumption of contaminated fish is a potential threat to human health and that necessary preventive measures to safeguard public health should be emphasized.

Toxicity Reference Values and Tissue Residue Criteria for Protecting Avian Wildlife Exposed to Methylmercury in China

“…In the present study, information for ten species was used to construct the SSD for MeHg, with the log-normal function providing an accepted fi t to the distribution, which was tested by use of the Anderson-Darling and Kolmogorov-Smirnov tests. The dietary TRC of 9.56 ng MeHg/g (wwt), derived by SSD, was slightly less than the value of 15.47 ng MeHg/g (wwt) that resulted from (Yan et al 2008 ) , Hongfeng Lake (He et al 2010 ) , Songhua River (Zhu et al 2012 ) , Ya-er Lake (Jin et al 2006 ) Tai Lake, and Poyang Lake (Zhang et al 2006 ) CSA, but the results were similar. Because this assessment, the results of which are reported here, utilized data for ten species, the assessment resolution was no better than 10% (1 of 10).…”

“…3 ). Concentrations of MeHg found in fi shes of Ya-er Lake (Jin et al 2006 ) and prey of little egrets in Tai Lake were greater than the dietary-based TRC of 15.47 ng MeHg/g (wwt) derived by CSA, especially that of Ya-er Lake, which was signi fi cantly different from the TRC ( p < 0.05 by t -test). Therefore, there is a signi fi cant risk of MeHg causing adverse effects on avian wildlife populations in the Songhua River, and Ya-er and Tai Lakes, but a lesser risk in Baihua, Hongfeng, and Poyang Lakes.…”

“…According to a conservative assumption that vertebrates have >50% of the THg as MeHg in muscle (Albers et al 2007 ;Eisler 2000 ) , and that the moisture content is 80%, the estimated MeHg concentrations in the prey of little egrets in Tai Lake and Poyang Lake would be 0.024 and 0.01 m g MeHg/g (wwt), respectively. Concentrations of MeHg in fi sh from Baihua Lake (Yan et al 2008 ) , Hongfeng Lake (He et al 2010 ) , Songhua River (Zhu et al 2012 ) , and Ya-er Lake (Jin et al 2006 ) were also available for comparison (Fig. 3 ).…”

“…These results are consistent with the pollution characteristics of these water bodies. The Songhua River (Zhu et al 2012 ) , and Ya-er (Jin et al 2006 ) and Tai Lakes are known to be more polluted than Poyang Lake (Zhang et al 2006 ) . Although both Baihua and Hongfeng Lakes were polluted by Hg from chemical plants in southwest China, the special characteristics of the water environment (e.g., alkaline water, eutrophication, low-dissolved organic carbon, and short food chain) limited accumulation of Hg in fi sh (He et al 2010 ;Yan et al 2008 ) .…”

“…Concentrations of Hg from anthropogenic emissions that are greater than the historical and regional background levels (Zheng et al 2010 ) are extensively distributed, and have been detected in surface waters and tissues of birds (Feng 2005 ;He et al 2010 ;Jin et al 2006 ;Zhu et al 2012 ) . However, no speci fi c guidelines, standards, or criteria have been established for the risk that MeHg may pose to wildlife in China.…”