Investigating the impact of chronic atrazine exposure on sexual development in zebrafish.

TitleInvestigating the impact of chronic atrazine exposure on sexual development in zebrafish.
Publication TypeJournal Article
Year of Publication2012
AuthorsCorvi MM, Stanley KA, Peterson TS, Kent ML, Feist SW, La Du JK, Volz DC, Hosmer AJ, Tanguay RL
JournalBirth defects research. Part B, Developmental and reproductive toxicology
Volume95
Issue4
Pagination276-88
Date Published2012 Aug
ISSN1542-9741
KeywordsAnimals, Atrazine, Embryo, Nonmammalian, Environmental Exposure, Female, Gonads, Male, Sexual Development, Zebrafish
Abstract

Atrazine (ATZ) is a selective triazine herbicide used primarily for preemergent weed control in corn, sorghum, and sugar cane production. It is one of the most widely used herbicides in North America. Some research published over the last decade suggests that chronic exposure to environmentally relevant ATZ concentrations can adversely impact gonadal development and/or sexual differentiation in amphibians and fish, while other studies report no effect, or moderate effects. As a result, contrasting conclusions have been published regarding the potential effects of the herbicide ATZ on aquatic species. Two near-identical 4-month studies in 2009 (Study I) and 2010 (Study II) were performed investigating the potential for chronic ATZ exposure to affect zebrafish (Danio rerio) sexual development and differentiation. Zebrafish were chronically exposed to 0, 0.1, 1, 10 μM ATZ or 1 nM 17β-estradiol (E2). Fish were histologically examined to assign gender and to evaluate potential impacts of E2 or ATZ on gonadal development. Exposure to E2 consistently resulted in a significantly higher proportion of female fish to normal male fish when compared to unexposed fish (both studies). In both studies, ATZ exposure did not significantly influence the percentage of female or male fish when compared to unexposed fish. A greater percentage of abnormally developed male fish and fish lacking differentiated gonadal tissue was observed in Study II E2 exposures but not in ATZ exposures. Together, these studies indicate that long-term exposure to ATZ at or above environmentally relevant concentrations does not significantly impact zebrafish gonadal development or sexual differentiation.

DOI10.1002/bdrb.21016
Alternate JournalBirth Defects Res. B Dev. Reprod. Toxicol.