Ecotoxicology Program, Environmental Research Institute of Supervising Scientist, Darwin, Northern Territory, Australia.
Environ Toxicol Chem. 2012 Feb;31(2):427-36. doi: 10.1002/etc.1704.
The influence of dissolved organic carbon (DOC) on the toxicity of aluminum (Al) at pH 5 (relevant to acid mine drainage conditions), to the tropical green hydra (Hydra viridissima), green alga (Chlorella sp.), and cladoceran (Moinodaphnia macleayi) was assessed. Two DOC sources, a natural in situ DOC in soft billabong water (SBW) and Suwannee River fulvic acid (SRFA) standard, were compared. The order of sensitivity of the test organisms to dissolved Al (0.1 µm fraction) was Hydra viridissima > Moinodaphnia macleayi > Chlorella sp. with DOC reducing dissolved Al toxicity most for Hydra viridissima. However, colloidal or precipitated Al may contribute indirectly to the toxicity for M. macleayi and Chlorella sp. The toxicity of dissolved Al was up to six times lower in test waters containing 10 mg L(-1) DOC (in the form of SRFA), relative to toxicity observed at 1 mg L(-1) DOC. In contrast, the toxicity of Al was up to two times lower in SBW containing 10 mg L(-1) DOC, relative to water containing 1 mg L(-1) DOC. The increased ability of SRFA in reducing Al toxicity was linked to its greater affinity for complexing Al compared with the in situ DOC. This has important implications for studies that use commercial standards of humic substances to predict Al toxicity in local environments. Speciation modeling demonstrated that Al(3+) and AlOH(2+) provided a strong relationship with toxicity. An empirical relationship is provided for each organism that can be used to predict Al toxicity at a given Al and DOC concentration.
在 pH 5 下（与酸性矿山排水条件有关），评估了溶解有机碳 (DOC) 对铝 (Al) 毒性的影响，供试生物为热带绿水螅 (Hydra viridissima)、绿藻 (Chlorella sp.) 和枝角类 (Moinodaphnia macleayi)。比较了两种 DOC 来源，即软泻湖水中的天然原位 DOC (SBW) 和苏万尼河富里酸 (SRFA) 标准品。测试生物对溶解 Al (0.1 µm 级) 的敏感性顺序为绿水螅>大型溞>绿藻，DOC 降低溶解 Al 毒性对绿水螅的影响最大。然而，胶体或沉淀 Al 可能会间接导致大型溞和绿藻的毒性。在含有 10 mg L(-1)DOC（以 SRFA 形式存在）的测试水中，溶解 Al 的毒性比在 1 mg L(-1)DOC 时降低了六倍。相比之下，在含有 10 mg L(-1)DOC 的 SBW 中，Al 的毒性比在含有 1 mg L(-1)DOC 的水中降低了两倍。SRFA 降低 Al 毒性的能力增强与其与 Al 络合的亲和力较大有关，这对使用商业标准腐殖质物质来预测当地环境中 Al 毒性的研究具有重要意义。形态建模表明，Al(3+)和 AlOH(2+)与毒性具有很强的相关性。为每个生物体提供了一个经验关系，可以用来预测在给定 Al 和 DOC 浓度下的 Al 毒性。
