可离子化有机污染物对大型溞的毒性及QSAR研究

取代苯酚、苯胺和苯甲酸类化合物是在环境水体中具有较强生物毒性的芳香族可离子化有机化合物,它们在水体中对水生生物和水生生态系统都有较大危害。测定此类化合物在p H值为6、7.8和9的条件下对大型溞的24 h急性毒性,计算化合物在不同p H值条件下的中性态分子所占比例F0。研究毒性与F0的相关性,结果表明F0对取代苯酚和苯甲酸类化合物的毒性的影响较大而对取代苯胺毒性的影响很小。对于卤代苯甲酸类化合物,毒性与疏水性的相关性较好,但是羟基苯甲酸类化合物的毒性与疏水性参数的相关性很差,引入量子化学参数EHOMO和取代羟基个数NOH,可以改进苯甲酸类化合物的模型的质量。

The Toxicities of Ionized Organic Compounds to Daphnia magna and QSAR Study

The ionization organic compounds of substituted phenols, anilines and benzoic acids are ubiquitous with strong biotoxicity in environmental water and quite harmful to aquatic organisms and aquatic ecosystems. The 24 h acute immobilization toxicity of the three kinds of compounds was determined for the freshwater crustacean Daphnia magna under the condition of pH equal to 6, 7.8 and 9 respectively. The proportion of neutral form (F0) was consequently calculated for the three kinds of compounds at three different pH conditions. Based on the correlation between toxicity and F0, the results showed that it was an important influencing factor of ionization for the toxicity of phenols; and neutral form was accounts for absolute advantage, so the effect of ionization to anilines was smaller than phenols. The correlation between the toxicity for halogenated benzoic acids and hydrophobicity parameter was strong, while, the correlation between the toxicity for hydroxyl benzoic acids and hydrophobicity parameter was much weaker. Moreover, the results suggested that inclusion of EHOMO and the number of hydroxyl (NOH) with log KOW can improve the determinate coefficient of the models.