生物配体模型(biotic ligand model,BLM)能够用于重金属生物有效性和毒性的预测,为了考察水质参数作用下重金属Cd对大型潘的生物有效性和毒性,引入均匀实验设计方法对水质参数(Ca2+、Mg2+、Na+、K+、pH)的不同水平进行优化组合.结果表明:7个不同均匀实验设计组中Cd对大型溢的LC50有较大差异,LC50变化范围为352.46～ 10 626.59 μg·L-1.毒性试验中Ca2+、Mg2+和pH对Cd的毒性有较强的抑制作用.由生物配体模型结合Cd对大型潘毒性试验数据得出半致死累积量(LA50)后,分别求得7个均匀设计组中阳离子(Cd2+、Ca2+、Mg2+、Na+和H+)与大型潘生物配体结合的平衡常数,其中lgKBL-Ca(Cd与生物配体结合的平衡常数)变化范围为8.34 ～ 8.47 L·mol-1.利用BLM预测Cd对大型溞的LC5o,LC5o预测值与实测值之比在1.04 ～ 1.27,预测结果与试验结果有较好的一致性.%Biotic ligand model can be used to predict bioavailability and toxicity of heavy metals.In order to examine the toxic effect of Cd to Daphnia magna based on water quality parameters(Ca2+,Mg2+,Na +,K +,pH),uniform design method was introduced to optimize the combination of different levels of water quality parameters.The results showed that LC50 of Cd to Daphnia magna in seven different uniform design groups existed difference significantly and LC5o is in the range of 352.46μg · L-1to 10 626.59μg · L-1.Ca2+,Mg2+ and pH have strong inhibition effect for the toxicity.After LA50 (lethal accumulation occurring 50％ toxic effect) of Cd on Daphnia magna was obtained by combining toxic results with biotic ligand model (BLM),stability constant of Cd,Ca,Mg,Na and H combined by biotic ligand was calculated.lg KBL-cd is in the range of 8.34-8.47 L · mol-1.The ratio of predicted LC50 by BLM to experimental LC50 is in the range of 1.04-1.27 and in good agreement.
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