Wilfrid Laurier University, Waterloo, Ontario, Canada N2L 3C5.
Ecotoxicol Environ Saf. 2011 Mar;74(3):230-7. doi: 10.1016/j.ecoenv.2010.12.003. Epub 2010 Dec 23.
Copper-induced toxicity in aqueous systems depends on its speciation and bioavailability. Natural organic matter (NOM) and reduced sulphur species can complex copper, influencing speciation and decreasing bioavailability. NOM composition in estuaries can vary, depending on inputs of terrigenous, autochthonous, or wastewater source material. At a molecular level, variability in NOM quality potentially results in different extents of copper binding. The aims of this study were to measure acute copper EC(50) values in coastal marine and estuarine waters, and identify the relationships between total dissolved copper EC(50) values and measured water chemistry parameters proportional to NOM and reduced sulphur composition. This has implications on the development of marine-specific toxicity prediction models. NOM was characterised using dissolved organic carbon (DOC) concentration and fluorescence measurements, combined with spectral resolution techniques, to quantify humic-, fulvic-, tryptophan-, and tyrosine-like fractions. Reduced sulphur was measured by the chromium-reducible sulphide (CRS) technique. Acute copper toxicity tests were performed on samples expressing extreme DOC, fluorescent terrigenous, autochthonous, and CRS concentrations. The results show significant differences in NOM quality, independent of DOC concentration. CRS is variable among the samples; concentrations ranging from 4 to 40 nM. The toxicity results suggest DOC as a very good predictive measure of copper EC(50) in estuaries (r(2)=0.87) independent of NOM quality. Furthermore, for filtered samples, CRS exists at concentrations that would be saturated with copper at measured EC(50), suggesting that while CRS might bind Cu and decrease bioavailability, it does not control copper speciation at toxicologically relevant concentrations and therefore is not a good predictive measure of copper toxicity in filtered samples.
铜在水系统中的毒性取决于其形态和生物利用度。天然有机物（NOM）和还原态硫物种可以与铜络合，影响其形态并降低生物利用度。河口 NOM 的组成取决于陆源、自生或废水源物质的输入。在分子水平上，NOM 质量的可变性可能导致铜结合程度不同。本研究的目的是测量沿海海洋和河口水中的急性铜 EC（50）值，并确定总溶解铜 EC（50）值与测量的水化学参数之间的关系，这些参数与 NOM 和还原态硫组成成比例。这对开发特定于海洋的毒性预测模型具有重要意义。使用溶解有机碳（DOC）浓度和荧光测量值，结合光谱分辨率技术，对 NOM 进行了表征，以定量测定腐殖质、富里酸、色氨酸和酪氨酸样分数。采用铬还原硫化物（CRS）技术测量还原态硫。在表达极端 DOC、荧光陆地、自生和 CRS 浓度的样品上进行了急性铜毒性测试。结果表明，NOM 质量存在显著差异，与 DOC 浓度无关。CRS 在样品之间变化很大，浓度范围为 4 至 40 nM。毒性结果表明，DOC 是河口铜 EC（50）的非常好的预测指标（r（2）=0.87），与 NOM 质量无关。此外，对于过滤后的样品，CRS 的浓度处于在测量 EC（50）下铜将饱和的浓度，这表明虽然 CRS 可能与 Cu 结合并降低生物利用度，但它不能控制在毒理学相关浓度下的铜形态，因此不是过滤样品中铜毒性的良好预测指标。
