In the present paper, comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) were applied to investigate two 3D-QSAR models for the cytotoxicity of chlorophenols. These models have evaluated the intensity of chlorophenols. toxicity on HepG2 cells in vitro. The CoMFA model has both high consistency and predictability. The contribution of the electrostatic field to biological activity is greater than that of the steric field. The CoMSIA model used in this study includes two fields, one is hydrophobic field, and the other is electrostatic field. The relative contribution of them is 0.789:0.211. Consisted with the CoMFA model, the CoMSIA electrostatic filed also plays a dominant role. The CoMFA and CoMSIA contour maps significantly elucidated that the electrostatic field is more important than the other fields and might be one of the reasons resulting in potential reactive mechanism involved in cell proliferation inhibition.

A comparison of influent and effluent wastewater toxicities to Daphnia magna was undertaken to determine the most representative aqueous fraction for future toxicity identification evaluation (TIE) studies. Wastewater samples originated from a wastewater treatment plant which receives mainly domestic wastewater and industrial effluents. The TIE results reveal that the key toxicant contained in the influent was 2-propylbezaldehyde oxime. Results suggest that greater attention needs to be given to the receiving influent containing 2-propylbezaldehyde oxime to avoid damaging the bacterial populations in the primary activated sludge process. In addition, in order to evaluate the applicability of the reuse of activated sludge as a fertilizer in agriculture, TIE studies were also performed on water extracts from surplus sludge.

A cloud-point extraction (CPE) technique for the determination of a cyanobacterial hepatotoxin, nodularin-R, in aqueous media using a cationic surfactant, tricaprylmethylammonium chloride (Aliquat-336), was developed. Cloud-point phase separation of Aliquat-336 at ambient temperature was induced by the addition of sodium sulfate. The Aliquat-336/Na2SO4 CPE system displayed large preconcentration factor, FC, for nodularin-R. At the operational CPE conditions, FC of 709.2 was achieved. Distribution constant, KD, of the distribution of nodularin-R between the surfactant-rich and aqueous phases of the CPE system was estimated to be (4.94

The integrated method combining chemistry and toxicology, toxicity identification evaluation (TIE), was conducted to identify key toxicants in an effluent from a nitrogen fertilizer plant in China. Toxicity characterization, phase I of TIE, revealed that the suspected toxicant in the effluent was an anion that could be changed into a volatile acid. The results of toxicity identification and confirmation procedures indicated potassium cyanide to be the primary toxicant in the effluent.

Based on the C18 EmporeTM disk/water partition coelficient of a mixture, quantitative structure-activity relationships (QSARs) are presented, which are used to predict the toxicity of mixed halogenated benzenes to P. phosphoreum. The predicted toxicity of 10 other related mixtures based on the QSAR model, agree well with the observed data with r2=0.973, SE=0.113 and F=287.785 at a level of significance P<0.0001. The joint effect of these chemicals is simple similar action and the toxicity of the mixtures can be predicted from total hydrophobicity and is independent of hydrophobicity of the components or the ratio of the individual chemicals.

目的：预测麻醉型化合物卤代苯混合体系的毒性。方法：采用发光细菌对卤代苯的单一体系和混合体系进行毒性试验；利用特定的公式计算了混合物的分配系数；建立了混合体系的定量村效关系。结果：（1）建立了单一化合物的正辛醇/水分配系数与毒性的关系。（2）建立了二元混合体系的分配系数与毒性之间的定量结构模型。（3）用二元混合体系的QSAR模型预测了其它不同组份和不同毒性比例的混合体系毒性。结论：QSAR能很好地预测麻醉型化合物卤代苯混台体系的毒性，并且有助于该类化合物的混合体系毒性作用的评价。

Whole effluent toxicity (WET) tests are increasingly used to monitor compliance of consented discharges, but few studies have related toxicity measured using WET tests to receiving water impacts. Here we adopt a four-stage procedure to investigate the toxicity and biological impact of a point source discharge and to identify the major toxicants. In stage 1, standard WET tests were employed to determine the toxicity of the effluent. This was then followed by an assessment of receiving water toxicity using in situ deployment of indigenous (Gammarus pulex) and standard (Daphnia magna) test species. The third stage involved the use of biological survey techniques to assess the impact of the discharge on the structure and functioning of the benthic macroinvertebrate community. In stage 4, toxicity identification evaluations (TIE) were used to identify toxic components in the effluent. Receiving-water toxicity and ecological impact detected downstream of the discharge were consistent with the results of WET tests performed on the effluent. Downstream of the discharge, there was a reduction in D. magna survival, in G. pulex survival and feeding rate, in detritus processing, and in biotic indices based on macroinvertebrate community structure. The TIE studies suggested that chlorine was the principal toxicant in the effluent.

The n-octanol/water partitioning coefficients (logKow) of three snlfonylurea herbicides, metsulfuron methyl, chlorsulfuron and bensulfuron methyl, and five of the degradation products were determined by the shake-flask method. The capacity factors (logK') were determined by RP-HPLC with ODS column and methanol-water eluent. Correlations between logKow and, logK' and molecular connectivity index were studied. Acute toxicity to the bacterium Photobacterium phosphoreum (15-min-logEC50) and the green alga Chlorella pyrenoidosa (96-h-logEC50) were determined and correhted with logKow and logK'. The quantitative structure-activity-relationship equations showed that logKow and logK' are linearly correhted with toxicity, and both logKow and logK' can be used in the prediction. No significant acute toxicity of the tested compounds to the chdocera Daphnia magna was observed in the laboratory tests, and this was explained by ionic forms of the compounds in neutral aqueous solution.

Toxicity of a Chemical Works effluent from the Southeast China to the Daphnia magna was compared to determine the most representative aqueous fraction for simplified toxicity identification evaluation (TIE) studies. Toxicity characterization procedures revealed that the primary toxicant(s) was a nonpolar organic compound. Toxicity was recovered through C18 solid-Phase extraction and concentration steps. Gas chromatography-mass spectroscopy of these concentrates revealed the presence of chlorobenzene, nitrobenzene, naphthalene, l-chloro-3-nitrobenzene, l-ehloro-4-nitrobenzene, 2-naphthol and aniline. The mass balance approach of TIE implicated the seven chemicals as the primary toxicants. The simplified TIE procedures can save our cost and time. The significance of the TIE results may indicate a more widespread problem what chemical(s) has priority to be controlled when being discharged.