Environment & Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON K9L 0G2, Canada.
School of the Environment, Trent University, 1600 West Bank Drive, Peterborough, ON K9L 0G2, Canada.
Sci Total Environ. 2018 Jun 15;627:1228-1233. doi: 10.1016/j.scitotenv.2018.01.296. Epub 2018 Feb 7.
The use of isotope ratios to trace Hg contamination sources in environmental compartments is now generally accepted. However, for biota and especially for mammals, it is still unknown if and/or how Hg isotopes fractionate in vivo and which tissue is most representative of the source(s) of contamination. We measured fractionation of Hg in mink (Neovison vison) tissues (fur, brain, blood, liver, kidney) collected during a controlled feeding experiment where captive mink were fed differing amounts of methylmercury. There was no significant effect of dietary MeHg concentrations on Hg fractionation in most tissues. Net fractionation of Hg, i.e., fractionation corrected for diet (δHg-δHg) was observed in all tissues with the greatest net fractionation occurring in the mink liver (-1.39‰) and kidney (-0.95‰). Less net fractionation, occurred in the brain (-0.12‰), blood (0.38‰) and fur (0.30‰). In the absence of brain tissue, fur is a suitable proxy which is readily obtainable and can be non-lethally collected. In these mink, it appears that biochemical processes such as demethylation, contribute to significant fractionation of Hg in the liver and kidney, but not as much in the brain and fur, where transport of Hg via thiol-containing complexes may be more important.
利用同位素比值来追踪环境介质中汞污染的来源现在已经被广泛接受。然而，对于生物群，特别是对于哺乳动物，目前尚不清楚汞同位素是否以及/或者如何在体内发生分馏，以及哪种组织最能代表污染的来源。我们测量了在一项受控喂养实验中收集的貂（Neovison vison）组织（皮毛、大脑、血液、肝脏、肾脏）中的汞分馏，在该实验中，圈养的貂被喂食不同量的甲基汞。饮食中甲基汞浓度对大多数组织中的汞分馏没有显著影响。在所有组织中都观察到汞的净分馏（即，扣除饮食影响的分馏，δHg-δHg），其中貂的肝脏（-1.39‰）和肾脏（-0.95‰）的净分馏最大。大脑（-0.12‰）、血液（0.38‰）和皮毛（0.30‰）的净分馏较小。在没有脑组织的情况下，皮毛是一种合适的替代物，它容易获得并且可以非致死性地收集。在这些貂中，似乎是生物化学过程，如脱甲基化，导致了肝脏和肾脏中汞的显著分馏，但在大脑和皮毛中则不然，在这些组织中，通过含硫醇的复合物运输汞可能更为重要。
