Effect-directed Analysis Of Key Organic Toxicants In Different Environmental Samples

With the rapid development of industry and agriculture, a great deal of pollutants were discharged into the environment. Many pollutants have been found in different environmental samples by instrumental analysis. However, the number of pollutants in the environmental samples was too large to detect all of them by use of instrumental analysis. Moreover, the potential toxic effects could not determined by use of instrumental analysis. Many different methods were developed to detect the toxicity of the environmental samples in recent years. Although the potential risks could be evaluated by use of bioassays, it is different to identify the key pollutants contributed to the toxicity. Therefore, it is necessary to combine the instrumental analysis and bioassays to determine the toxic effects and identify the key pollutants. Effect-directed analysis (EDA), combining fractionation, bioanalytical techniques and instrumental analyses, is an useful tool to examine the toxicity and identify the potential key organic pollutants.In the present study, EDA was improved to determine the toxicity and identify their potential key organic pollutants of different environmental samples with different pollution levels. Different bioanalytical methods, fractionation methods, toxicity assessment methods, instrumental analysis and confirmation approaches were developed and selected for different environmental samples to overcome the insufficient of the present EDA. Firstly, EDA was improved, including different bioassays, key pollutants identification and confirmation approaches. Then, EDA was used for examining the toxicity and identifing the key organic pollutants in source water samples, water and sediment samples from Tai Lake, and sludge samples from different chemical industry parks in Jiangsu Province. The main original conclusions are shown as follows.(1) Daphnia magna acute toxicity test, green alga(Scenedesmus obliquus) acute toxicity test and reporter gene assay were developed. Their corresponding data base were also established based on previous literatures. Toxic units (TUs) were selected to evaluate the potential toxic effects based on Daphnia magna acute toxicity test and alga(Scenedesmus obliquus) acute toxicity test. Toxic Equivalent Quangtity (TEQ) was selected to evaluate the androgenic activity. Three confirmation approaches were used to confirm putative toxic agents, including correlation analysis, addition of putative causative agents and addition of a synergist.(2) EDA was used to determine the androgenic activity and identify the key pollutants in source water samples. None of the thirteen source water samples from Jiangsu Province showed androgen receptor (AR) agonistic activity. Ten of the thirteen source water samples exhibited significantly AR antagonistic activities with Ant-AR-EQs ranging from 9.9 to 1.4×102μg flutamide/L. Potential health risks might be posed to aquatic organisms and residents in this region. DIBP and DNBP were responsible for the AR antagonistic activities of the tested source water. Because DIBP is frequently detected and has notable concentrations in China, more attentions should be paid to its toxic effects and addition into the emission standards in China for further management and control.In order to assess the potential risk to residents in this region, the androgenic activities of the finished water from waterworks, tap water, boiled water and poured boiled water were examined. All the finished water from waterworks, tap water, boiled water and poured boiled water showed no AR antagonistic activity. The metabolites of phthalate esters showed no AR agonistic nor antagonistic activity and could not increase the AR agonistic or antagonistic activities of phthalate esters when they coexit in mixtures.(3) EDA was used to determine the acute toxicity to Daphnia magna and identify the key organic pollutants in water and sediment samples from Tai Lake. Organic extracts of five samples of water caused significant toxicity to Daphnia magna with OTUs ranging from 1.0×10-2 to 3.7×10-1, and extracts of all 12 sediments showed significant toxicity to Daphnia magna with OTUs ranging from 6.0×10-2 to 7.9×10-1 mL/mg dw. The greatest toxic potency was observed in July for water and in October for sediment. The toxicity of both water and sediment samples from one site at the edge of Tai Lake were greater than that at other sites. Organophosphate and pyrethroid insecticides were the major contributors to toxicity of water and sediments, with chlorpyrifos and cyfluthrin being the predominant causes of toxic potency of water and sediments. However, no water quality standards have been promulgated in China for chlorpyrifos and cyfluthrin. Three confirmatory manipulations confirmed that chlorpyrifos and cyfluthrin were the primary constituents contributing to toxicity of samples.(4) EDA was used to determine the acute toxicity to green alga and androgenic activity and identify the key organic pollutants in sludge samples from different chemical industry parks in Jiangsu Province. Six extracts of eighteen sludge samples showed toxic effect to green alga with the 72h-TUs as 1.1×10-1 to 6.2. None of the eighteen sludge samples exhibited AR agonistic activity. The extracts of twelve sludge samples showed significantly AR antagonistic activity with the Ant-AR-EQs ranging from 1.2×10-1 to 1.8×101μg flutamide/g sludge dry weight (dw). The greatest AR antagonistic potency was observed in site LS economic development zone with the Ant-AR-EQs as 1.8×101 μg flutamide/g sludge dw. The reporter gene assay is more sensitive than green alga acute toxicity test. It was found that the key pollutants were various in different sites. The chemicals, such as bisphenol A, octylphenol, nonylphenol, some pesticides and some polycyclic aromatic hydrocarbons, were the key organic pollutants contributed to the AR antagonistic activities in different sludge samples.