M4 PM Endocrine Disruption in Fish (Part 2)
Monday, 14 November 2005: 1:50 PM - 5:30 PM in Ballroom 4

(PAR-1118-086490) Lifecycle exposure to municipal wastewater effluents decreases egg production and male sex characteristics of fathead minnows.

Parrott, J¹, Blunt, B¹, Sullivan, C, Bennie, D¹, ¹ National Water Research Institute, Environment Canada, Burlington, ON, Canada

ABSTRACT- Assessing the effects of municipal wastewater effluents (MWWEs) on fish poses a challenge, as the effluents are complex mixtures of nutrients, hormones and pharmaceutical drugs. Some pharmaceuticals discharged in MWWEs can have profound endocrine disrupting effects on fish. Assessment of the effects of very low concentrations (1-10 ng/L) of pure endocrine disrupting substances (estrogens and androgens) allows the development of sensitive and predictive fish tests that can assess the potential reproductive effects of complex mixed municipal effluents. Male fathead minnows exposed in situ to 100 % model scale MWWE for a lifecycle had increased liver-somatic indices and decreased male secondary sex characteristics (smaller dorsal fatpads and fewer nuptial tubercles). Laboratory lifecycle exposure to an Ontario MWWE (100 %) caused a decrease in egg production and decreases in male secondary sex characteristics of fathead minnows, although fish grew as well as or better than control fish. For assessing the endocrine disrupting potential of pharmaceuticals, long term fish tests of real MWWEs provide clues that will link to the health and reproductive performance of wild fish.

Key words: fathead minnow, lifecycle, municipal wastewater, pharmaceuticals