HydroQual, Mahwah, New Jersey, USA.
Environ Toxicol Chem. 2012 Aug;31(8):1774-80. doi: 10.1002/etc.1906. Epub 2012 Jun 14.
Cyanide can be toxic to aquatic organisms, and the U.S. Environmental Protection Agency has developed ambient water-quality criteria to protect aquatic life. Recent work suggests that considering free, rather than total, cyanide provides a more accurate measure of the biological effects of cyanides and provides a basis for water-quality criteria. Aquatic organisms are sensitive to free cyanide, although certain metals can form stable complexes and reduce the amount of free cyanide. As a result, total cyanide is less toxic when complexing metals are present. Cyanide is often present in complex effluents, which requires understanding how other components within these complex effluents can affect cyanide speciation and bioavailability. The authors have developed a model to predict the aqueous speciation of cyanide and have shown that this model can predict the toxicity of metal-cyanide complexes in terms of free cyanide in solutions with varying water chemistry. Toxicity endpoints based on total cyanide ranged over several orders of magnitude for various metal-cyanide mixtures. However, predicted free cyanide concentrations among these same tests described the observed toxicity data to within a factor of 2. Aquatic toxicity can be well-described using free cyanide, and under certain conditions the toxicity was jointly described by free cyanide and elevated levels of bioavailable metals.
氰化物对水生生物具有毒性，美国环境保护署制定了环境水质标准以保护水生生物。最近的研究表明，考虑游离氰化物（而非总氰化物）能更准确地衡量氰化物的生物效应，并为水质标准提供依据。尽管某些金属可以形成稳定的配合物，从而降低游离氰化物的含量，但水生生物对游离氰化物很敏感。当存在络合金属时，总氰化物的毒性较低。氰化物通常存在于复杂的废水中，因此需要了解这些复杂废水中的其他成分如何影响氰化物的形态和生物利用度。作者开发了一种预测氰化物水溶液形态的模型，并表明该模型可以根据水化学变化的溶液中游离氰化物预测金属氰化物配合物的毒性。对于各种金属氰化物混合物，基于总氰化物的毒性终点范围跨越了几个数量级。然而，在这些相同的测试中，预测的游离氰化物浓度在 2 倍以内描述了观察到的毒性数据。游离氰化物可很好地描述水生毒性，在某些条件下，游离氰化物和生物可利用金属水平升高共同描述了毒性。
