PARENT SESSION

2P Modelling ecotoxic effects
Poster Hall
8:30 AM - Monday, 28 April 2003

(MOP/143) Effects of Paper Mill Effluents and Mill Process Modifications on Anal Fin Morphology of Mosquito Fish (gambusia).

Gross, Timothy^{1, 2}, Noggle, Jessica¹, Holm, Stewart³, ¹ University of Florida, Gainesville, FL, US² USGS-FISC, Gainesville, FL, US³ Georgia Pacific Corporation, Atlanta, GA, US

ABSTRACT- Results from our laboratory have demonstrated altered anal fin morphology, elongation, for gambusia downstream from a papermill in Florida, as well as for gambusia exposed to other mills in Florida. Male gambusia normally have an elongated anal fin, termed the gonopodium, which is a copulatory structure in this species. Anal fin elngation has been termed a masulinization effect, however, fin elongation in female gambusia rarely developes to a male-like gonopodium. Chemical characterization of mill effluents indicate expsoure to both chlorinated and naturally derived components. The current study evaluated gambusia exposed under laboratory and natural conditions, pre (2000-2001) and post (2002) mill process modifications. The GP Palatka mill converted to elemental-chlorine-free bleaching sequences during 2001, as well as concurrent modifcations to secondary treatment during 2001-2002. Fish were exposed to 0%, 10%, 20%, 40% and 80% effluents in the laboratory and to natural levels within Rice Creek, the effluent receiving stream for the mill. Fish (20 male and 20 female) were sacrificed following 30 days of expsoure in the laboratory and from field sites during 2000, 2001 and 2002. Fish were processed to include measures of anal fin length and morphology. Water and bile were analyzed for selected chlorinated compounds, resin acids and phytosterols. In general, results pre-process modifications, were at effluent concentrations of 80% and greater and indicated increased anal fin length. Effects post-process modifications, were diminished, and also at concentrations of 80% and greater. Naturally exposed gambusia exhibited similar effects but at increased magnitude than under laboratory conditions. Chemical analyses demonstrated non-detectable chlorinated prodcuts as well as a 60% reduction in naturally derived components. These results demonstrate significant alterations in anal fin length/masculinization effects for gambusia exposed to effluents post-process as compared to pre-process modifications. The results continue to sugegst naturally derived chemical components in these effects. Results do not support the utilization of gambusia as a screeing and testing procedures to evaluate mill-process modifications. (Funding provided by Georgia Pacific Corp.)

Key words: papermill effluent, gambusia, process modifications, anal fin morphology