IASOS, University of Tasmania, Hobart, Australia.
Mar Environ Res. 2010 Feb;69(1):18-26. doi: 10.1016/j.marenvres.2009.07.006. Epub 2009 Aug 7.
Total mercury (THg) and monomethylmercury (MMHg) concentrations were determined in the tissues of demersal shark (Order Squaliformes and the Families: Scyliorhinidae, Hexanchidae) and chimaera species (Families: Chimaeridae and Rhinochimaeridae) from continental shelf and slope waters off southeast Australia, including embryos, juveniles and adults. The distribution of THg in various tissues (muscle, liver, kidney and skin), examined in ten species, shows higher levels in the muscle tissue (1.49+/-0.47mgkg(-1), ww), which accounted for between 59% and 82% of the total body burden of mercury and in the kidney (0.93+/-0.14mgkg(-1), ww) and liver (0.61+/-0.25mgkg(-1), ww) with lower levels observed in the skin (0.12+/-0.06mgkg(-1), ww). Additional THg determinations were performed in the muscle tissue of five other species allowing geographical and inter-specific comparisons. Speciation analysis demonstrated that more than 90% mercury was bound in muscle tissue as MMHg with higher percentages (>95%) observed in sharks species occupying deeper environments. Species differences were observed. Highest THg levels in the muscle tissue (up to 6.64mgkg(-1) wet weight, ww) were recorded in Proscymnodon plunketi and Centrophorus zeehaani (mean values; 4.47+/-1.20 and 3.52+/-0.07mgkg(-1), ww, respectively). Consistent with the ongoing paradigm on mercury bioaccumulation, we systematically observed THg concentrations increasing with animal size from the embryos to the larger sharks. Embryos of Etmopterus baxteri and Centroselachus crepidater had average levels 0.28 and 0.06mgkg(-1) (ww), while adult specimens reached 3.3 and 2.3mgkg(-1) (ww), respectively. THg concentrations in Australian sharks were compared with the same genus collected in other world regions. Levels were closer to data reported for East Atlantic than for the epicontinental Mediterranean margins. At a smaller geographical scale, the habitat effect on mercury concentration in sharks seems less clear. Squalid sharks occupying shelf waters showed higher mean mercury levels relative to their size (body weight, bw) than mid-slope species (0.4-6.7mgkg(-1) bw and 0.3-2.2mgkg(-1) bw, respectively). However, local regional differences (East and South Tasmania vs. Victoria) in Hg levels were not detected for the majority of taxa examined. All species, with the exception of Figaro boardmani showed values greater than 0.5mgkg(-1) (ww) and all but four were above many international regulatory thresholds (1.0mgkg(-1), ww).
总汞（THg）和甲基汞（MMHg）浓度在澳大利亚东南大陆架和斜坡水域的底栖鲨鱼（Order Squaliformes 和 Families：Scyliorhinidae、Hexanchidae）和 Chimera 物种（Families：Chimaeridae 和 Rhinochimaeridae）的组织中进行了测定，包括胚胎、幼体和成体。在十种物种中检查了 THg 在各种组织（肌肉、肝脏、肾脏和皮肤）中的分布，结果表明肌肉组织中的含量更高（1.49+/-0.47mgkg(-1)，ww），占汞总量的 59%至 82%，肾脏（0.93+/-0.14mgkg(-1)，ww）和肝脏（0.61+/-0.25mgkg(-1)，ww）中的含量较低，皮肤（0.12+/-0.06mgkg(-1)，ww）中的含量较低。在另外五种物种的肌肉组织中进行了额外的 THg 测定，以进行地理和种间比较。形态分析表明，超过 90%的汞在肌肉组织中以 MMHg 的形式结合，在栖息在较深环境中的鲨鱼物种中观察到的百分比更高（>95%）。观察到物种差异。肌肉组织中的最高 THg 水平（高达 6.64mgkg(-1)湿重，ww）记录在 Proscymnodon plunketi 和 Centrophorus zeehaani 中（平均值；4.47+/-1.20 和 3.52+/-0.07mgkg(-1)，ww，分别）。与汞生物积累的现有范式一致，我们系统地观察到从胚胎到较大鲨鱼的动物大小与 THg 浓度的增加有关。Etmopterus baxteri 和 Centroselachus crepidater 的胚胎平均水平分别为 0.28 和 0.06mgkg(-1)（ww），而成年标本分别达到 3.3 和 2.3mgkg(-1)（ww）。与其他世界地区同一属的鲨鱼进行了比较。水平更接近东大西洋报道的数据，而不是大陆边缘的地中海。在较小的地理范围内，鲨鱼栖息地对汞浓度的影响似乎不太清楚。栖息在大陆架水域的肮脏鲨鱼相对于其体型（体重，bw）表现出更高的平均汞水平（0.4-6.7mgkg(-1) bw 和 0.3-2.2mgkg(-1) bw，分别）。然而，对于大多数检查的分类群，没有检测到东塔斯马尼亚和南塔斯马尼亚与维多利亚之间的 Hg 水平的本地区域差异。除了 Figaro boardmani 之外，所有物种（0.5mgkg(-1)（ww））的含量均大于 0.5mgkg(-1)，除了四种以外，所有物种均高于许多国际监管阈值（1.0mgkg(-1)，ww）。
