It is important to evaluate the estrogenic effect of disinfection by-products in drinking water in addition to typical possible endocrine disrupting chemicals. The estrogenic effect was measured by the MVLN assay as an estrogen receptor transcriptional activation assay. The results suggested that the isolation procedure of aquatic humic substances using XAD7HP resin can be recommended to detect the estrogenic effect of natural water and its chlorinated drinking water by the MVLN assay. Sample volume necessary for the assay would be 1.2 L and required concentation factor would be 100 times. The relative importance of organic substances in Lake Biwa water and the chlorinated one concentrated using XAD7HP resin is large in terms of estrogenic effect. It was also suggested that 4-nonyl phenol and 17 β-estradiol would be important chemicals in investigating the estrogenic effect of natural water. The estrogenic effect of Lake Biwa water increased by chlorination. The estrogenic effect of chlorinated water was approximately 2.3 times as strong as that of Lake Biwa water itself.
2-Methylisoborneol (MIB) and geosmin produced by blue-green algae were successfully removed in a new gravel filter plant. Small amounts of sludge were sampled from the filter layer and the bacteria able to decompose MIB were isolated from the sludge samples. By-products of the MIB degradation by these bacteria were also investigated. Among these bacteria, efforts were mainly focused on Pseudomonas fluorescens. The components of cell free extracts of this bacterium were studied in order to verify the biological reactions in vitro. 2-Methylenebornane, 2-methyl-2-bornene and isomers of these compounds were found to be a part of the by-products of the MIB degradation in the gravel filter.
Several microorganisms which can decompose 2-methylisoborneol (MIB) were isolated from a slow sand filter. A yeast of the Candidasp. (Candida), which has rather limited ability to decompose MIB, was used as an effective microorganism, because of its safety and convenience of handling in the laboratory. After measuring the ability of the yeast to decompose MIB in a liquid medium, it was immobilized in a gel produced from 10% polyvinyl alcohol (PVA). Several materials, such as plastic and glass, were coated with the immobilized yeast, and were used in experiments on the decomposition of MIB.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.