Evaluating variation of estrogenic effect by drinking water chlorination with the MVLN assay

It is important to evaluate the estrogenic effect of disinfection by-produc ts in drinking water in addition to typical possible endocrine disrupting c hemicals. The estrogenic effect was measured by the MVLN assay as an estrog en receptor transcriptional activation assay. The results suggested that th e isolation procedure of aquatic humic substances using XAD7HP resin can be recommended to detect the estrogenic effect of natural water and its chlor inated drinking water by the MVLN assay. Sample volume necessary for the as say would be 1.2 L and required concentration factor would be 100 times. Th e relative importance of organic substances in Lake Biwa water and the chlo rinated one concentrated using XAD7HP resin is large in terms of estrogenic effect. it was also suggested that 4-nonyl phenol and 17 beta -estradiol w ould be important chemicals in investigating the estrogenic effect of natur al water. The estrogenic effect of Lake Biwa water increased by chlorinatio n. The estrogenic effect of chlorinated water was approximately 2.3 times a s strong as that of Lake Biwa water itself.