Vijayram K, Geraldine P
Research Department of Zoology, Periyar E.V.R. College, Tiruchirappalli, India.
Bull Environ Contam Toxicol. 1996 Feb;56(2):335-42. doi: 10.1007/s001289900049.
Despite the low concentrations of heavy metals in the surrounding medium, aquatic organisms take them up and accumulate them in their soft tissues to concentrations several fold higher than those of ambient levels (Bryan 1979; Rainbow et al. 1990). Knowledge of accumulation patterns of a particular trace metal is a prerequisite for understanding the significance of an observed metal concentration in a particular animal, especially from the aspect of biomonitoring. Many marine invertebrates accumulate heavy metals without any regulation and the accumulation necessarily being associated with mechanisms to store the metals in a detoxified form. Two detoxification mechanisms have been described, both of which may occur in one specimen. Heavy metals can either be bound up in insoluble metalliferous 'granules' (Mason and Nott 1981), or are bound to soluble metal-binding ligands, such as metallothioneins (Roesijadi 1992). Some marine decapod crustaceans have an innate ability to regulate the internal concentrations of essential but potentially toxic metals within a constant level, presumably to meet their metabolic demands (Rainbow 1985, 1992). However, at present, there is no such information relating to freshwater decapod crustaceans, especially shrimps which occupy a totally different environment. Macrobrachium malcolmsonii (Milne Edwards), a potential aquaculture species for freshwater is found in abundance in one of the major Indian rivers, the Cauvery. In the present study, an attempt was made to determine whether the freshwater prawn, M. malcolmsonii, is able to regulate the three essential elements, copper, chromium and zinc, over a wide range of dissolved concentrations. These three metals were chosen because the Cauvery River receives pollutants containing these metals (Vijayram et al. 1990).
尽管周围介质中重金属浓度较低，但水生生物仍会摄取并在其软组织中积累这些重金属，使其浓度比环境水平高出几倍（布莱恩，1979年；雷恩博等人，1990年）。了解特定微量金属的积累模式是理解在特定动物中观察到的金属浓度意义的先决条件，特别是从生物监测的角度来看。许多海洋无脊椎动物无节制地积累重金属，且这种积累必然与以解毒形式储存金属的机制有关。已经描述了两种解毒机制，这两种机制可能在一个样本中同时出现。重金属要么被结合在不溶性的含金属“颗粒”中（梅森和诺特，1981年），要么与可溶性金属结合配体结合，如金属硫蛋白（罗西贾迪，1992年）。一些海洋十足目甲壳类动物具有先天能力，可将必需但潜在有毒的金属的内部浓度调节在恒定水平，大概是为了满足其代谢需求（雷恩博，1985年、1992年）。然而，目前尚无关于淡水十足目甲壳类动物的此类信息，尤其是占据完全不同环境的虾类。印度主要河流之一的高韦里河中大量存在淡水虾类马氏沼虾（米尔恩·爱德华兹），它是一种有潜力的淡水养殖品种。在本研究中，试图确定淡水虾马氏沼虾是否能够在广泛的溶解浓度范围内调节三种必需元素铜、铬和锌。选择这三种金属是因为高韦里河受到含有这些金属的污染物污染（维贾伊拉姆等人，1990年）。
