Studies on estrogenic disrupting compounds （EDCs） occurrence and identification of main responsible compounds in river water discharged into the sea are of significance. In the present research, we screened estrogenic activities of 10 river water samples from 3 main rivers discharged into Bohai Sea in Tianjin using a recombinant two-hybrid yeast assay and chemical analysis by gas chromatography-mass spectrometry. All sample extracts induced significant estrogenic activity, with 17^-estradiol equivalents （EEQ） of raw water ranging from 5.72 to 59.06 ng/L. Six most concerned EDCs in the fiver water samples including estrone, 17（5-estradiol, 17ct-ethinylestradiol, estriol, diethylstilbestrol and estradiol valerate were determined, with their concentrations up to 50.70, 31.40, 24.40, 37.20, 2.56, and 8.47 ng/L, respectively. Through causality analysis by comparing the EEQ values of yeast assay and chemical analysis, 17ct-ethinylestradiol and 17[3-estradiol were identified as the main contributors to the estrogenic effects of the river samples, accounting for the whole estrogenic activities （62.99% to 185.66%）, and estrogen antagonistic compounds might presented in the heavy polluted water samples. The proposed approach using both chemical analysis and bioassay could be used for identification and evaluation of the estrogenic activity of EDCs in river water.
The distribution of seventeen gaseous and particle-bound 2,3,7,8-substituted chlorinated PCDD/Fs in the flue gas of different windboxes of the sintering machine was analyzed. The influence of temperature change on the PCDD/Fs emission from the sintering process and the formation mechanism of PCDD/Fs were discussed. The result has shown that among the seventeen gaseous and particle-bound PCDD/Fs in the flue gas of different windboxes, furans occupied the major place. The proportion of the gaseous PCDD/Fs in most windboxes is from 40% to 60%. The change tendencies of the concentration of both the gaseous and particle-bound PCDD/Fs were similar, with a higher level at the end of the sintering bed. The PCDD/Fs concentration＇ s change tendency in the windbox was very consistent with the change of temperature of the flue gas in the windboxes. More than 60% PCDD/Fs of the total PCDD/Fs emission amount was emitted at the end of the sintering bed. Only this part of the waste gas accounted for 12% of the total waste gas volume.
Polychlorinated biphenyls(PCBs) are chlorinated biphenyl compounds with wide applications in the industry.In spite of a ban on their production in the late 1970s,PCBs,as a group of POPs,are still persistent and widely spread in the environment,posing potential threats to human health.The role of PCBs as etiologic agents for breast cancer has been intensively explored in a variety of in vivo,animal and epidemiologic studies.Initial investigations indicated higher levels of PCBs in mammary tissues or sera corresponded to the occurrence of breast cancer,but later studies showed no positive association between PCB exposure and breast cancer development.More recent data suggested that the CYP1A1 m2 polymorphisms might add increased risk to the etiology of breast cancer in women with environmental exposure to PCBs.PCBs are implicated in advancing breast cancer progression,and our unpublished data reveals that PCBs activate the ROCK signaling to enhance breast cancer metastasis.Therefore,the correlation between PCB exposure and breast cancer risk warrants further careful investigations.
LIU SiJin ,ZHANG ShuPing,QU Chen,LIU Wei & DU YuGuo State Key Laboratory of Environmental Chemistry and Ecotoxicology
Reporter genes produce a protein product in transfected cells that can be easily measured in intact or lysed cells and they have been extensively used in numerous basic and applied research applications.Over the past 10 years,reporter gene assays have been widely accepted and used for analysis of 2,3,7,8-tetrachlorodibenzo-p-dioxin and related dioxin-like compounds in various types of matrices,such as biological,environmental,food and feed samples,given that high-resolution instrumental analysis techniques are impractical for large-scale screening analysis.The most sensitive cell-based reporter gene bioassay systems developed are the mechanism-based CALUX(Chemically Activated Luciferase Expression) and CAFLUX(Chemically Activated Fluorescent Expression) bioassays,which utilize recombinant cell lines containing stably transfected dioxin(AhR) responsive firefly luciferase or enhanced green fluorescent protein(EGFP) reporter genes,respectively.While the current CALUX and CAFLUX bioassays are very sensitive,increasing their lower limit of sensitivity,magnitude of response and dynamic range for chemical detection would significantly increase their utility,particularly for those samples that contain low levels of dioxin-like HAHs(i.e.,serum) .In this study,we report that the addition of modulators of cell signaling pathways or modification of cell culture conditions results in significant improvement in the magnitude and overall responsiveness of the existing CALUX and CAFLUX cell bioassays.
BASTON David S.KHAN ElaineSORRENTINO ClaudioDENISON Michael S.
