Environmental risk assessment of selected organic chemicals based on TOC test and QSAR estimation models

Environmental risks of organic chemicals have been greatly determined by their persistence,bioaccumulation, and toxicity(PBT) and physicochemical properties. Major regulations in different countries and regions identify chemicals according to their bioconcentration factor(BCF) and octanol–water partition coefficient(Kow), which frequently displays a substantial correlation with the sediment sorption coefficient(Koc). Half-life or degradability is crucial for the persistence evaluation of chemicals. Quantitative structure activity relationship(QSAR) estimation models are indispensable for predicting environmental fate and health effects in the absence of field-or laboratory-based data. In this study, 39 chemicals of high concern were chosen for half-life testing based on total organic carbon(TOC) degradation,and two widely accepted and highly used QSAR estimation models(i.e., EPI Suite and PBT Profiler) were adopted for environmental risk evaluation. The experimental results and estimated data, as well as the two model-based results were compared, based on the water solubility, Kow, Koc, BCF and half-life. Environmental risk assessment of the selected compounds was achieved by combining experimental data and estimation models. It was concluded that both EPI Suite and PBT Profiler were fairly accurate in measuring the physicochemical properties and degradation half-lives for water, soil, and sediment.However, the half-lives between the experimental and the estimated results were still not absolutely consistent. This suggests deficiencies of the prediction models in some ways, and the necessity to combine the experimental data and predicted results for the evaluation of environmental fate and risks of pollutants.     

有机磷农药对海洋扁藻毒性构效关系的密度泛涵理论研究

采用密度泛函理论方法,在B3LYP/6-311G**水平上,计算了11个有机磷农药化合物的结构参数,将结构参数作为理论描述符,导出了有机磷类化合物的分子结构参数与2种盐度(S=20,S=30)下扁藻毒性(-lgEC50)的定量关系式(式(3)和(6)),并用交叉验证法验证,相关系数R分别为0.923 2和0.893 3,交叉验证相关系数q2分别为0.527 0和0.540 5.在此基础上,预测了11种有机磷农药的毒性.研究表明,所得预测方程有较好的稳定性和较强的预测能力.可用于有机磷化合物的-lgEC50预测.     

α-二羰基化合物的结构-致突活性关系

采用ＡＭ１方法计算了６个α－二羰基化合物与ＤＮＡ碱基岛嘌呤环外Ｎ＾２发生紊电加成反应的速率控制步骤的活化能及分子结构和电子结构。研究其结构－知必凶线性回归结果表明;可用烷化反应活化能、ＬＵＭＯ能量、分子量表面积比和羰基面原子的正电性表示化合物的致突活性指数,获得很好的回归效果（Ｌ顺归系数Ｒ＝０．９９９８）。以本文提出的方程对这些化合物的估性进行计算,秘得到的结果与实验结果吻合得很好。     

应用次最低空轨道能研究硝基芳烃的生物活性

采用半经验分子轨道ＡＭ１方法计算了１８种硝基芳烃化合物的分子轨道能ＥＨＯＭＯ、ＥＬＵＭＯ、ＥＵＬＵＭＯＥＮＨＯＭＯ,生成热△Ｈｂ,偶极矩μ等量化参数;结合一阶价分子连接性指数Ｘ和正辛醇／水分配系数ｌｏｇＫｏｗ与发光菌的３０ｍｉｎ－半数活性浓度（ＥＣ５０）,黑呆头鱼９６ｈ－急性毒性值建立了包括ＥＮＬＵＭＯ在内的ＱＳＡＲ模式,探讨了硝基芳烃化全物的毒性作用机制,研究表明,硝基芳烃化合物的生物活性不仅与     

基于QSAR模型预测有机污染物在XAD与空气中的分配系数

基于定量构效关系(QSAR),运用线性(逐步多元回归MLR)和非线性(支持向量机SVM)两种计算方法开发了两种可靠且高效预测聚苯乙烯二乙烯基苯树脂(XAD)和空气之间分配系数(K_XAD-A)的模型.构建模型的数据包含醇类(Alcohols),苯类(Benzenes),多氯联苯(PCBs)和多环芳香烃(PAHs)等,共计70种有机污染物.两个模型的决定系数R²_adj和外部验证系数Q²_ext均在0.930以上,同时所有物质均在定义的应用域内,结果表明两种QSAR模型有较高的拟合度、稳健性和较为优秀的预测能力,且非线性(SVM)模型比线性(MLR)模型的拟合效果更好.     

烃基酚类化合物结构与毒性关系研究

有机化合物通常由电性各异的氢、碳、氮、氧、硫及卤素等原子以共价键结合而成,从分子的三维空间结构出发,按照不同类型原子之间电性相互作用得到一种分子结构表达方法--三维分子电性相互作用矢量(three dimensional molecular electronegativity interaction vector,3D...     

苯砜基环烷酸酯类化合物的结构与急性毒性关系的密度泛函理论研究

用密度泛函理论方法,在B3LYP／LANL2DZ水平上,计算了28个苯砜基环烷酸酯类化合物的结构参数;将结构参数作为理论描述符,导出苯砜基环烷酸酯类化合物的分子结构参数(α、εa、q^-和μ)与对发光菌毒性(EC50和LC50)的定量关系方程,并用交叉验证法验证,r^2分别为0.9509和0.9320,q^2分别为0．9318和0．9025,其结果优于AM1、CoMFA和CoMSIA方法的计算结果．     

基于基团贡献法的有机化合物好氧生物降解预测模型研究

从MITI-Ⅰ试验中筛选出587种不同类型有机化合物的可用数据,通过对这些物质的结构进行拆分,随机选择其中50种化合物作为验证集,另外537种作为训练集,利用多元线性回归(MLR)和支持向量机(SVM)2种计算方法分别建立模型。结果表明,芳香酸、醛、芳香碘和叔胺等功能基团对有机化合物的好氧生物降解性影响较大;MLR模型总体预测正确率为81.43%,验证集正确率为82%,SVM模型总体预测正确率为87.90%,验证集正确率为86%。所建立的2种定量结构与生物降解性关系(QSBR)模型有效,可用于化学品的好氧生物降解性评价。     

过氧化物酶催化去除水体中酚类内分泌干扰物的研究进展

内分泌干扰物(EDCs)会干扰生物体的内分泌系统从而对人类、野生动物以及水生生物产生负面影响,这一问题已经引起了人们的广泛关注.广泛分布于自然环境中的辣根过氧化物酶(HRP)和木质素过氧化物酶(LiP),具有较强的催化氧化能力,能够催化去除雌激素、双酚A等多种具有内分泌干扰效应的污染物.本文在介绍辣根过氧化物酶(HRP)和木质素过氧化物酶(LiP)两种过氧化物酶的相关性质和催化氧化机理的基础上,从污染物结构与其催化去除效率关系的角度综述了过氧化物酶去除具有内分泌干扰效应的污染物的研究进展.为污水处理过程中过氧化物酶用于去除内分泌干扰物提供依据,并展望了其未来的发展方向.     

Comparative quantitative structure–activity relationship (QSAR) study on acute toxicity of triazole fungicides to zebrafish

We employed two-dimensional quantitative structure–activity relationship (2D-QSAR) and hologram QSAR (HQSAR) methods to quantitatively investigate the mechanism and active site of toxicity for Danio rerio exposed to triazole fungicides. Our results showed that 2D-QSAR models constructed using the energy of the lowest unoccupied molecular orbit, the net C atom charges, the octanol–water partition coefficient and the molecular shape factor had higher predictive abilities. HQSAR models containing the fragment distinctions atoms (As), bonds (Bs), chirality (Ch) and donors and acceptors (D&A) had higher reliability. It was found that 2D-QSAR results explaining the toxicity mechanism were consistent with HQSAR. In summary, the hydrophobicity and shape/size of the molecule were the important factors influencing the toxic effect of these chemicals against D. rerio. In addition, electron exchange may occur between these fungicides and the target. The study provided a method to evaluate the environmental risk of chemicals with a similar structure, based on the QSAR models obtained.