title: Evidence of estrogenic mixture effects on the reproductive performance of fish.
abstract: Recent research into the effects of mixtures of estrogenic chemicals has revealed the capacity for similarly acting chemicals to act in combination, according to the principles of concentration addition. This means that, collectively, they may pose a significant environmental risk, even when each component is present at a low and individually ineffective concentration. The aim of this study was to investigate the ecological significance of mixture effects at low-effect concentrations by assessing the combined effect of estrogenic chemicals on the reproductive performance of fish. Pairs of fathead minnows were exposed to five estrogenic chemicals. Endpoints analyzed included fecundity, the expression of male secondary sexual characteristics, somatic indices, and vitellogenin induction. In the first phase of the study, a concentration-response analysis was performed to investigate the relative sensitivity of these endpoints. In the second phase, mixture effects at low-effect concentrations were explored by exposing fish to each of the mixture components, individually and in combination. Data from these experiments provide evidence of mixture effects on fitness and fecundity, demonstrating the capacity for chemicals to act together to affect reproductive performance, even when each component is present belowthe threshold of detectable effects. This has important implications for hazard assessment and contributes to our understanding of mixture effects at increasing levels of biological complexity.
authors.affiliation: Institute for the Environment, Brunel University, Uxbridge, Middlesex, UB8 3PH, United Kingdom. jayne.brian@brunel.ac.uk
authors.forename: Jayne V
authors.initials: JV
authors.lastname: Brian
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Harris
authors.forename: Martin
authors.initials: M
authors.lastname: Scholze
authors.forename: Andreas
authors.initials: A
authors.lastname: Kortenkamp
authors.forename: Petra
authors.initials: P
authors.lastname: Booy
authors.forename: Maria
authors.initials: M
authors.lastname: Lamoree
authors.forename: Giulio
authors.initials: G
authors.lastname: Pojana
authors.forename: Niels
authors.initials: N
authors.lastname: Jonkers
authors.forename: Antonio
authors.initials: A
authors.lastname: Marcomini
authors.forename: John P
authors.initials: JP
authors.lastname: Sumpter
mesh_terms: D000818:Animals; D045424:Complex Mixtures / Q000633:toxicity*; D003530:Cyprinidae; D004305:Dose-Response Relationship, Drug; D052244:Endocrine Disruptors / Q000633:toxicity*; D023381:Endpoint Determination; D004967:Estrogens / Q000633:toxicity*; D005260:Female; D016014:Linear Models; D008297:Male; D012098:Reproduction / Q000187:drug effects*; D018570:Risk Assessment; D014818:Vitellogenesis / Q000187:drug effects
chemical_list: D045424:Complex Mixtures; D052244:Endocrine Disruptors; D004967:Estrogens