Disinfection By‐Products Bind the Human Estrogen Receptor‐Alpha

ABSTRACT

Disinfection by‐products (DBPs) are formed during most drinking water treatment and number over 800 to date, some of which are implicated in human health outcomes including bladder cancer and infertility. Their mechanisms of action in these instances, however, are unknown. In particular, it is not yet understood whether these compounds can disrupt the estrogen‐signaling pathway through binding to the human estrogen receptor. In this study 21 DBPs, selected for their predicted involvement in endocrine‐related diseases and their structural diversity, were individually evaluated for their binding affinity to the human estrogen receptor and in silico, and then a subset of these chemicals was studied in binary mixtures with the known weak estrogen, 4‐n‐nonylphenol. Individually, 9 of the 21 DBPs were able to weakly bind to the estrogen receptor, with affinities ranging from log[IC50] values of −3.83 M to −2.19 M. In binary mixtures, the chemicals followed concentration addition, with their weak binding affinities having little contribution to the overall mixture affinity. These results demonstrate the variety of small molecule DBP structures that are capable of binding to the estrogen receptor, and that their weak binding can still be of importance when considering overall human exposure to mixtures of DBPs in disinfected drinking water. This article is protected by copyright. All rights reserved

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