College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Key Laboratory of Health Risk Factors for Seafood of Zhejiang Province, Zhoushan 316022, China.
College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
Sci Total Environ. 2017 Feb 15;580:1078-1084. doi: 10.1016/j.scitotenv.2016.12.062. Epub 2016 Dec 16.
Phthalate esters (PAEs) are widely used as plasticizers and have become one of the emerging contaminants with an increasing public concern. The residues of PAEs frequently co-exist with heavy metals such as cadmium (Cd) in waters; however, their joint ecotoxicity remains largely unknown. We herein investigated the single and joint toxicity of commonly used PAEs and Cd using freshwater luminescent bacteria Vibrio qinghaiensis sp.-Q67. The median effective concentration (EC) of benzyl butyl phthalate (BBP), dibutyl phthalate (DBP), diethyl phthalate (DEP), dimethyl phthalate (DMP), diisooctyl phthalate (DIOP) and di-n-octyl phthalate (DOP) were determined to be in the range from 134.4mg/L to as high as 1000mg/L, indicating very weak toxicity to Vibrio qinghaiensis sp.-Q67. The toxicity of single PAEs showed a significant linear relationship with Log K, indicating the dependence of the elevated toxicity on the increasing hydrophilicity. The toxicity of binary mixture of PAEs was further evaluated in silico using the independent action (IA) model and concentration addition (CA) model. DMP-DEP, DEP-DBP or DMP-DBP exhibited antagonistic effects with the toxic unit value higher than 1.2. The CA and IA models poorly predicted the joint toxicity of DMP-DEP, DEP-DBP or DMP-DBP. The joint toxicity of the binary mixtures of DMP, DEP or DBP with Cd was simple additive as predicted by the CA and IA models. Our results indicated the potentially higher risk of PAEs in the presence of Cd, emphasizing the importance of determining the impact of their joint effects on aquatic organisms. The integrated in vitro and in silico methods employed in this study will be beneficial to study the joint toxicity and better assess the aquatic ecological risk of PAEs.
邻苯二甲酸酯（PAEs）被广泛用作增塑剂，已成为公众日益关注的新兴污染物之一。PAEs 的残留物经常与水中的重金属如镉（Cd）共存；然而，它们的联合生态毒性在很大程度上仍然未知。本研究采用淡水发光菌青海弧菌 Q67 对常用 PAEs 和 Cd 的单一和联合毒性进行了研究。邻苯二甲酸苄丁酯（BBP）、邻苯二甲酸二丁酯（DBP）、邻苯二甲酸二乙酯（DEP）、邻苯二甲酸二甲酯（DMP）、邻苯二甲酸二异辛酯（DIOP）和邻苯二甲酸二正辛酯（DOP）的半数有效浓度（EC）范围为 134.4mg/L 至 1000mg/L，表明对青海弧菌 Q67 的毒性非常弱。单一 PAEs 的毒性与 Log K 呈显著线性关系，表明毒性的升高取决于亲水性的增加。进一步使用独立作用（IA）模型和浓度加和（CA）模型对 PAEs 二元混合物的毒性进行了计算机模拟评估。DMP-DEP、DEP-DBP 或 DMP-DBP 表现出拮抗作用，毒性单位值高于 1.2。CA 和 IA 模型均不能很好地预测 DMP-DEP、DEP-DBP 或 DMP-DBP 的联合毒性。CA 和 IA 模型预测 DMP、DEP 或 DBP 与 Cd 的二元混合物的联合毒性为简单相加。我们的研究结果表明，在存在 Cd 的情况下，PAEs 可能具有更高的风险，这强调了确定其联合效应对水生生物的影响的重要性。本研究采用的体外和计算机模拟相结合的方法将有助于研究联合毒性，并更好地评估 PAEs 的水生生态风险。
