The WHAM-F_TOX model quantifies cation toxicity towards freshwater organisms, assuming an additive toxic response to the amounts of protons and metals accumulated by an organism. We combined a parameterization of the model, using data from multi-species laboratory toxicity tests, with a fitted field species sensitivity distribution, to simulate the species richness (n_sp) of crustacean zooplankton in acid- and metal-contaminated lakes near Sudbury, Ontario over several decades, and also in reference (uncontaminated) lakes. A good description of variation in toxic response among the zooplankton species was achieved with a log-normal distribution of a new parameter, β, which characterizes an organism’s intrinsic sensitivity towards toxic cations; the greater is β, the more sensitive is the species. The use of β assumes that while species vary in their sensitivity, the relative toxicities of different metals are the same for each species (common relative sensitivity). Unbiased agreements between simulated and observed n_sp were obtained with a high correlation (r² = 0.81, p < 0.0001, n = 217). Variations in zooplankton species richness in the Sudbury lakes are calculated to be dominated by toxic responses to H, Al, Cu and Ni, with a small contribution from Zn, and negligible effects of Cd, Hg and Pb. According to the model, some of the Sudbury lakes were affected predominantly by acidification (H and Al), while others were most influenced by toxic heavy metals (Ni, Cu, Zn); for lakes in the latter category, the relative importance of heavy metals, compared to H and Al, has increased over time. The results suggest that, if common relative sensitivity operates, n_sp can be modelled on the basis of a single set of parameters characterizing the average toxic effects of different cations, together with a species sensitivity distribution.

WHAM- F _TOX模型假设阳离子对生物体积累的质子和金属有附加的毒性反应，从而量化了阳离子对淡水生物的毒性。我们使用来自多个物种的实验室毒性测试的数据以及拟合的物种敏感度分布，对模型的参数化进行了组合，以模拟安大略省萨德伯里附近被酸和金属污染的湖泊中甲壳类浮游动物的物种丰富度（n _sp）。几十年来，还涉及到参考湖泊（未受污染）。利用新参数β的对数正态分布很好地描述了浮游动物物种之间毒性反应的变化。，表征生物体对有毒阳离子的内在敏感性；β越大，物种越敏感。β的使用假设物种的敏感性不同，但每种物种的不同金属的相对毒性相同（共同的相对敏感性）。模拟和观察到的n _sp之间的无偏协议具有高度相关性（r ² = 0.81，p <0.0001，n= 217）。据计算，萨德伯里湖中浮游动物物种丰富度的变化主要由对H，Al，Cu和Ni的毒性反应控制，而锌的贡献很小，而Cd，Hg和Pb的影响可忽略不计。根据该模型，萨德伯里的一些湖泊主要受到酸化作用（H和Al）的影响，而另一些则受有毒重金属（Ni，Cu，Zn）的影响最大。对于后一类湖泊，与H和Al相比，重金属的相对重要性随着时间的推移而增加。结果表明，如果操作通用的相对灵敏度，则可以基于表征不同阳离子的平均毒性作用的单一参数集以及物种灵敏度分布，对n _sp进行建模。