The Study On The Leaching Of Endocrine Disruptors In Materials Used For Drinking Water Supply System

Organic polymeric materials are widely used in water supply system because of their low cost, ease of installation, high chemical resistance and excellent mechanical performance. A number of the substances that are used as additives or in the manufacture of additives which are used in organic polymeric materials such as phthalate and bisphenols, have been implicated as endocrine disruptors(EDCs), and these substances may leach from the materials when they contact with drinking water for a long time. EDCs may lead to adverse health outcomes by interfering with metabolic, reproductive, developmental, homeostatic or other essential biological processes. The leaching of EDCs from water supply system becomes an important area of research.Three quantitative methods were developed for the analysis of 20 EDCs (including 9 phthalates,3 bisphenols and 8 bisphenol diglycidyl ether derivatives) in the materials for the drinking water supply system using reversed-phase high-performance liquid chromatography with electrospray tandem mass(LC/MS/MS).50 materials used for drinking water supply system,30 exposure water samples and 7 water purifier water samples were analyzed. Finally, the leaching of the 20 EDCs from several drinking water contact products to the exposure water at different exposure temperature and cycles were studied. The main results are as follows:1. Three quantitative methods were developed for the analysis of 20 EDCs in materials for drinking water supply system by LC/MS/MS. Ultrasonic extraction with 2.00ml methanol for 40 min was applied and 1ml of the extract was used for LC/MS/MS analysis. The spiked recoveries ranged from 84.0%-125% with the relative standard deviations less than 16%. The limits of quantification (LOQ) were between 0.7μg/kg～62μg/kg. The pipes and water treatment materials contain more DBP and DEHP with the contents ranged from 0.02μg/g to 1.69×105μg/g. Coatings contain more BPA and its diglycidyl ether derivatives with the contents ranged from 0.64μg/g to 3.03×104μg/g. 2. Three quantitative methods were developed for the analysis of 20 EDCs in exposure water by solid phase extraction (SPE) and LC/MS/MS. The leachates were concentrated from exposure water samples using a C18 solid-phase extraction cartridge and eluted by 3.00ml methanol. lml of the eluent was analysed by LC/MS/MS. The spiked recoveries ranged from 70.2%-117% with the relative standard deviations less than 18%. The LOQ were between 7ng/L-299 ng/L. Leaching levels of BPA and DBP in the 37 water samples were higher than other leachates, ranged from 0.09μg/L to 4.69×103μg/L.3. The leaching of the 20 EDCs from several water contact products to the exposure water at different exposure temperature and cycles were studied. For the low molecular weight leachates such as DBP, DMP and BPA, the results showed that the higher of the water temperature, the larger the amount leached. During the 5 cycles, the amount leached was largely decreased after the fifth cycle for the most leachates. However, the leachates at a high level at the first cycle, still higher than others after the fifth cycle.