De Schamphelaere Karel A, Vasconcelos Flavio M, Heijerick Dagobert G, Tack Filip M, Delbeke Katrien, Allen Herbert E, Janssen Colin R
Laboratory of Environmental Toxicology and Aquatic Ecology, Ghent University, Jozef Plateaustraat 22, B-9000 Ghent, Belgium.
Environ Toxicol Chem. 2003 Oct;22(10):2454-65. doi: 10.1897/02-499.
In this study, the combined effects of pH, water hardness, and dissolved organic carbon (DOC) concentration and type on the chronic (72-h) effect of copper on growth inhibition of the green alga Pseudokirchneriella subcapitata were investigated. Natural dissolved organic matter (DOM) was collected at three sites in Belgium and The Netherlands using reverse osmosis. A full central composite test design was used for one DOM and a subset of the full design for the two other DOMs. For a total number of 35 toxicity tests performed, 72-h effect concentration resulting in 10% growth inhibition (EbC10s) ranged from 14.2 to 175.9 micrograms Cu/L (factor 12) and 72-h EbC50s from 26.9 to 506.8 micrograms Cu/L (factor 20). Statistical analysis demonstrated that DOC concentration, DOM type, and pH had a significant effect on copper toxicity; hardness did not affect toxicity at the levels tested. In general, an increase in pH resulted in increased toxicity, whereas an increase of the DOC concentration resulted in decreased copper toxicity. When expressed as dissolved copper, significant differences of toxicity reduction capacity were noted across the three DOM types tested (up to factor 2.5). When expressed as Cu2+ activity, effect levels were only significantly affected by pH; linear relationships were observed between pH and the logarithm of the effect concentrations expressed as free copper ion activity, that is, log(EbC50Cu2+) and log(EbC10Cu2+): (1) log(EbC50Cu2+)= - 1.431 pH + 2.050 (r2 = 0.95), and (2) log(EbC10cu2+) = -1.140 pH -0.812 (r2 = 0.91). A copper toxicity model was developed by linking these equations to the WHAM V geochemical speciation model. This model predicted 97% of the EbC50dissolved and EbC10dissolved values within a factor of two of the observed values. Further validation using toxicity test results that were obtained previously with copper-spiked European surface waters demonstrated that for 81% of tested waters, effect concentrations were predicted within a factor of two of the observed. The developed model is considered to be an important step forward in accounting for copper bioavailability in natural systems.
在本研究中，调查了pH值、水硬度、溶解有机碳（DOC）浓度及类型对铜对绿藻羊角月牙藻生长抑制的慢性（72小时）效应的综合影响。使用反渗透法在比利时和荷兰的三个地点采集天然溶解有机物（DOM）。对一种DOM采用完全中心复合试验设计，对另外两种DOM采用该完全设计的一个子集。在总共进行的35次毒性试验中，导致10%生长抑制的72小时效应浓度（EbC10s）范围为14.2至175.9微克铜/升（相差12倍），72小时半数效应浓度（EbC50s）范围为26.9至506.8微克铜/升（相差20倍）。统计分析表明，DOC浓度、DOM类型和pH值对铜毒性有显著影响；在所测试的硬度水平下，硬度不影响毒性。一般来说，pH值升高会导致毒性增加，而DOC浓度增加会导致铜毒性降低。以溶解态铜表示时，在所测试的三种DOM类型中，毒性降低能力存在显著差异（相差达2.5倍）。以Cu2+活性表示时，效应水平仅受pH值显著影响；观察到pH值与以游离铜离子活性表示的效应浓度的对数之间存在线性关系，即log（EbC50Cu2+）和log（EbC10Cu2+）：（1）log（EbC50Cu2+） = -1.431pH + 2.050（r2 = 0.95），以及（2）log（EbC10cu2+） = -1.140pH - 0.812（r2 = 0.91）。通过将这些方程与WHAM V地球化学形态模型相联系，建立了一个铜毒性模型。该模型预测的溶解态EbC50和EbC10值中有97%在观测值的两倍范围内。使用先前用加标铜的欧洲地表水获得的毒性试验结果进行的进一步验证表明，对于81%的测试水体，预测的效应浓度在观测值的两倍范围内。所建立的模型被认为是在考虑自然系统中铜生物可利用性方面向前迈出的重要一步。
