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Arch Environ Contam Toxicol (2008) 54:504515 DOI 10.1007/s00244-007-9058-5
Biomagnication of Trace Elements in the Aquatic Food Web in the Mekong Delta, South Vietnam Using Stable Carbon and Nitrogen Isotope Analysis
Tokutaka Ikemoto Nguyen Phuc Cam Tu Noboru Okuda Akihisa Iwata Koji Omori Shinsuke Tanabe Bui Cach Tuyen Ichiro Takeuchi
Received: 28 September 2007 / Accepted: 1 October 2007 / Published online: 17 November 2007 Springer Science+Business Media, LLC 2007
Abstract In the present study, we report the concentrations of 21 trace elements (V, Cr, Mn, Co, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, Sn, Sb, Cs, Ba, Hg, Tl, Pb, and Bi), as well as the results of the analysis of stable carbon and nitrogen isotopes, of the various biota that make up the food web in the main stream of the Mekong Delta near Can Tho, South Vietnam. A signicant trophic level-dependent increase was found in concentrations of Se, Rb, and Hg with increasing d15N,
indicating that an overall biomagnication of these elements occurred. However, the increase of Hg concentration per trophic level was lower than in previous studies. In contrast, the concentration of Mn showed an opposite trend in the food web of the Mekong Delta. In addition to these overall trends, the present study revealed that the biomagnication proles
of trace metals differ between crustaceans and shes; concentrations of Mn, Cu, Zn, As, Sr, Mo, Ag, Cd, Sb, Cs, Ba, Tl, and Pb were signicantly higher in crustaceans, whereas shes showed higher concentrations of Cr, Rb, and Hg (trophic level determined by d15N). The differences in the biomagnication prole between the major taxa might be attributed to differences in metal accumulation and in detoxication abilities such as possessing a metal-binding protein, e.g., metallothionein (MT).
Introduction
Southeast and south Asian countries have undergone rapid economic development with increases of populations during the last several decades. Environmental pollution by trace metals and organochlorines, caused by increased anthropogenic activities, has been reported in recent studies (e.g., Monirith et al. 2003; Minh et al. 2003; Agusa et al. 2003). Notably, in several delta areas, i.e., the Bengal Delta in Bangladesh, the Mekong Delta, and the Red River Delta in Vietnam, as the use of groundwater has increased, people have been faced with the risk...