Comparison of different predictors of exposure for modeling impacts of metal mixtures on macroinvertebrates in stream microcosms
Comparison of different predictors of exposure for modeling impacts of metal mixtures on macroinvertebrates in stream microcosms
复制标题
DOI：
10.1016/j.aquatox.2013.02.007
复制
发表时间：
2013-05-15
影响因子：
4.5
通讯作者：
Clements, William H.
中科院分区：
文献类型：
--
作者：
Iwasaki, Yuichi;Cadmus, Pete;Clements, William H.
知识的金属接触的预测是最好的模型金属混合物对河流大型无脊椎动物的影响仍然不确定。一个新的预测的基础上结合到腐殖酸，这是假定为一个代理的非特异性生物配位体网站的金属的量，已被提出。该量可以使用温德米尔腐殖酸水模型（WHAM）计算，我们将其称为WHAM-HA方法。在这里，我们测试的假设，预测的基础上的WHAM-HA方法提供了一个更好的估计，在微观实验中观察到的金属效应比其他三个措施：总金属浓度，游离金属离子浓度，和累积标准单位（CCU），这是一个衡量的比例测量的金属浓度相对于美国环境保护署硬度调整的标准值。对于这个评估，我们使用了9个大型无脊椎动物的丰度和丰富度的指标进行金属混合物（锌单独，锌+镉，锌+镉+铜）的微观实验。对于四个预测因子中的每一个，我们用对应于三种金属浓度或CCU的变量进行了多元线性回归，并根据Akaike的小样本量校正信息标准选择了最佳模型。对于所有受金属影响的大型无脊椎动物指标，WHAM-HA方法被选为四个预测因子中最好的，其次是总金属浓度模型。在大多数最好的模型，锌和铜或铜单独负责减少无脊椎动物指标，即使镉的最高浓度超过100倍的硬度调整标准值。自由金属离子浓度模型和CCU模型均为第三位模型。我们的研究结果表明，结合腐殖酸的金属的估计量是一个更好的预测宏观无脊椎动物的丰富度和丰度的影响，在微观实验中观察到的总或游离离子浓度的金属和CCU。(C)2013爱思唯尔有限公司版权所有。
Knowledge about which predictors of metal exposure are best to model the impacts of metal mixtures on river macroinvertebrates remains uncertain. A new predictor based on the amount of metals binding to humic acid, which is assumed to be a proxy of non-specific biotic ligand sites, has been proposed. The amount can be calculated using Windermere Humic Aqueous Model (WHAM), which we will refer to as the WHAM-HA approach. Here, we tested the hypothesis that the predictor based on the WHAM-HA approach provided a better estimate of metal effects observed in microcosm experiments than three other measures: total metal concentrations, free metal ion concentrations, and the cumulative criterion unit (CCU) which is a measure of the ratios of measured metal concentrations relative to the U.S. Environmental Protection Agency hardness adjusted criterion values. For this evaluation, we used nine macroinvertebrate metrics of abundance and richness obtained from microcosm experiments conducted with metal mixtures (Zn alone, Zn + Cd, and Zn + Cd + Cu). For each of the four predictors, we performed multiple linear regression with variables corresponding to the three metal concentrations or CCU and selected the best model based on Akaike's information criterion corrected for small sample sizes. For all of the macroinvertebrate metrics affected by metals, the WHAM-HA approach was selected as the best among the four predictors, followed by the model with total metal concentration. In most of best models, Zn and Cu or Cu alone was responsible for reductions in invertebrate metrics, even though the highest concentrations of Cd exceeded 100 times the hardness-adjusted criterion value. Either of the models with free metal ion concentration and CCU was the third ranked model. Our results suggest that the estimated amount of metals binding to humic acid is a better predictor for the effects on macroinvertebrate richness and abundance observed in microcosm experiments than total or free ion concentrations of metals and CCU. (C) 2013 Elsevier B.V. All rights reserved.