Potential endocrine disruptor activity of drinking water samples

Abstract

Conventional water treatment plants (WTP) do not completely remove contaminants with endocrine activity which may then be present in drinking water (DW). The potential for endocrine disruption of 2 DW samples collected in 2010 and 2012 from a conventional WTP in São Paulo, Brazil was investigated. In vivo assays were conducted with 21-day old female rats exposed to DW extracts for 3- (uterotrophic assay) or 20-days (pubertal assay). The exposure represented a daily ingestion of 2 L, 10 L and 20 L of DW per 60 kg-body weight. Caffeine (5.8 – 21 ug/L), estrone (1 ng/L), atrazine (2.2 – 11.2 ng/L), carbendazim (0.22 ng/L), azoxystrobin (0.23 ng/L), tebuconazole (0.19 ng/L) and imidacloprid (0.88 ng/L) were detected in DW extracts by LC-MS/MS. No increase in uterus wet weight in the uterotrophic assay, and no alteration of vaginal opening in the pubertal assay were observed. However, there were increased absolute blotted uterus weights in animals treated for 3-days with the 3 doses of both DW samples. LH and FSH levels showed significant dose-response increases in the uterotrophic assay using the 2010 DW sample, in association with a significantly increased incidence of vaginal keratinization after the 3-day exposure. The pubertal animals exposed to the 2010 DW had a significant body weight gain and decreased LH at the highest dose. Results suggest that DW samples tested exerted estrogenic and hypothalamic-hypophysis activity alterations in vivo.

Keywords:

• emerging contaminants
• endocrine disruption
• pesticides
• pubertal female rat development
• uterotrophic assay

Disclosure of Potential Conflicts of Interest

No potential conflicts of interest were disclosed.

Acknowledgments

The authors also thank Mary Rosa Rodrigues de Marchi (Institute of Chemistry, UNESP Araraquara/SP), Igor Cardoso Pescara (Institute of Chemistry, UNICAMP), Flávio de Oliveira Lima, Paulo Roberto Cardoso, Paulo César Georgette and Maria Luísa Ardanaz (UNESP, Botucatu/SP Brazil) for technical support.

Supplemental Material

Supplemental data for this article can be accessed on the publisher's website.

Funding

This study was supported by the Center for the Evaluation of the Environmental Impact of Human Health (TOXICAM), at UNESP, the School of Dentistry, at USP, the State of São Paulo Agency for Support of Research (FAPESP) and by the National Council for Technological and Scientific Development (CNPq), Brazil.