School of Medical and Applied Sciences, Central Queensland University, Rockhampton, Queensland, Australia.
Environ Toxicol Chem. 2014 Mar;33(3):567-72. doi: 10.1002/etc.2459. Epub 2014 Jan 24.
Humic substances (HS) have been shown to decrease the toxicity of environmental stressors, but knowledge of their ability to influence the toxicity of multiple stressors such as metal mixtures and low pH associated with acid mine drainage (AMD) is still limited. The present study investigated the ability of HS to decrease toxicity of AMD to mayflies (Atalophlebia spp.). The AMD was collected from the Mount Morgan (Mount Morgan, Queensland, Australia) open pit. Mayflies were exposed to concentrations of AMD at 0%, 1%, 2%, 3%, and 4% in the presence of 0 mg/L, 10 mg/L, and 20 mg/L Aldrich humic acid (AHA). A U-shaped response was noted in all AHA treatments, with higher rates of mortality recorded in the 2% and 3% dilutions compared with 4%. This result was linked with increased precipitates in the lower concentrations. A follow-up trial showed significantly higher concentrations of precipitates in the 2% and 3% AMD dilutions in the 0 mg/L AHA treatment and higher precipitates in the 2% AMD, 10 mg/L and 20 mg/L AHA, treatments. Humic substances were shown to significantly increase survival of mayflies exposed to AMD by up to 50% in the 20 mg/L AHA treatment. Humic substances may have led to increased survival after AMD exposure through its ability to influence animal physiology and complex heavy metals. These results are valuable in understanding the ability of HS to influence the toxicity of multiple stressors.
腐殖质（HS）已被证明可以降低环境胁迫物的毒性，但关于它们影响多种胁迫物（如金属混合物和与酸性矿山排水（AMD）相关的低 pH 值）毒性的能力的知识仍然有限。本研究调查了 HS 降低 AMD 对蜉蝣（Atalophlebia spp.）毒性的能力。AMD 是从 Mount Morgan（昆士兰州 Mount Morgan，澳大利亚）露天矿收集的。在 0 mg/L、10 mg/L 和 20 mg/L Aldrich 腐殖酸（AHA）存在的情况下，将蜉蝣暴露于 0%、1%、2%、3%和 4%的 AMD 浓度中。在所有 AHA 处理中都观察到 U 形反应，与 4%相比，2%和 3%稀释度的死亡率更高。这一结果与较低浓度下沉淀物增加有关。后续试验表明，在 0 mg/L AHA 处理中，2%和 3% AMD 稀释度的沉淀物浓度明显更高，而在 2% AMD、10 mg/L 和 20 mg/L AHA 处理中沉淀物浓度更高。腐殖质被证明可以显著提高暴露于 AMD 的蜉蝣的存活率，在 20 mg/L AHA 处理中高达 50%。腐殖质可能通过影响动物生理学和复杂重金属，导致 AMD 暴露后存活率增加。这些结果对于理解 HS 影响多种胁迫物毒性的能力很有价值。
