Predicting animal cadmium concentrations in lakes
Predicting animal cadmium concentrations in lakes
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DOI：
10.1038/380430a0
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发表时间：
1996-04-04
期刊：
影响因子：
64.8
通讯作者：
Tessier, A
中科院分区：
文献类型：
--
作者：
Hare, L;Tessier, A
人类活动大大增加了许多潜在有毒金属流入水生生态系统的通量（1）。制定和实施有效的补救措施取决于我们预测这些系统中金属的命运和影响的能力。基于合理的物理化学和生物学原理的模型，如自由离子活性模型（2-5），已显示出作为预测工具的巨大潜力。该模型有效地解释了自由离子浓度（或活性）作为金属和水生生物之间相互作用（吸收、毒性）调节器的核心作用（2、3）。它假定金属的生物效应最好通过游离金属离子的活性来预测，而不是通过总金属浓度。由于该模型是在非自然实验条件下在实验室中开发的，因此在自然界中广泛使用之前必须在现场情况下进行验证（3）。我们在这里报告，镉浓度在土著水生昆虫幼虫，Chaoborus punctipennis，最好的自由离子活性模型描述，提供的生物吸收位点之间的竞争氢离子和游离镉离子，以及镉络合天然有机物，明确考虑。我们的研究结果表明，自由离子模型将提供一个有效的理论框架，使用动物作为指示剂的金属污染的性质。
HUMAN activities have greatly increased the flux of many potentially toxic metals to aquatic ecosystems(1). The development and implementation of effective remedial measures depend on our ability to predict the fate and effects of metals in these systems. Models based on sound physical-chemical and biological principles, such as the free-ion activity model(2-5), have shown great potential as predictive tools. This model has been effective in explaining the central role of the free-ion concentration (or activity) as a regulator of interactions (uptake, toxicity) between metals and aquatic organisms(2,3). It postulates that the biological effects of metals are best predicted by the activity of the free metal ion, rather than by total metal concentration. Because this model was developed in the laboratory under unnatural experimental conditions, it must be validated in field situations before being generally used in nature(3). We report here that Cd concentrations in an indigenous aquatic insect larva, Chaoborus punctipennis, are best described by the free-ion activity model, provided that competition for biological uptake sites between hydrogen ions and free cadmium ions, as well as cadmium complexation by natural organic matter, are explicitly taken into account. Our results suggest that the free-ion model would provide an effective theoretical framework for the use of animals as indicators of metal contamination in nature.