PARENT SESSION
Causal Relationships: Exposure & Effects in Aquatic Ecosystems Poster Session.
S. Marshall Adams, Tracy Collier
Wednesday, November 15, 2000
8:00 AM to 12:00 PM
CC West/Center Exhibit Hall
(PWA095) Characterization of toxicity associated with chemical resistance of Fundulus heteroclitus from a Superfund site.
Lienesch, Laila A.1, Meyer, Joel N.1, Burkhart, James G.2, Di Giulio, Richard T.1, 1 2
ABSTRACT- The Atlantic Wood site (AW) along Elizabeth River, VA (ER) is a Superfund site contaminated with various chemicals including PAHs, low molecular weight aromatic hydrocarbons, nitrogen and sulfur heterocycles, pentachlorophenol, and metals. It has been reported that Fundulus heteroclitus (Fh) dwelling in this region of ER have undergone genetic adaptation for resistance to high levels of chemical contaminants; the ability of populations to adapt to contaminated environments raises important regulatory issues. However, neither mechanisms of nor stressors driving adaptation have been clearly elucidated. The goal of this study is to characterize components in water and sediment that are responsible for genetic adaptation of Fh from the AW site. Wild caught Fh from a reference site ("clean") in Kings Creek, VA and the AW site were reared and bred under laboratory conditions to separate heritable from non-heritable population effects. Ten-day old first (F1) and second (F2) generation laboratory-raised Fh offspring from these wild caught parental (P) fish were randomly divided into three treatment groups and exposed to aqueous sediment extract, activated carbon treated extract, or size exclusion filtrates of extracts from the reference and AW sites. Mortality was assessed after 96h. Aqueous sediment extracts of AW sediment proved to be highly toxic to offspring of fish from the reference site, while offspring from AW site fish exhibited no mortality. These data support previous observations of resistance in the ER population of Fh. Exposure of larvae to extracts passed through an activated carbon column, which would remove organics, and filtration of extracts through 1.2, 0.8, and 0.2 um glass filters did not alter toxicity. More complete characterizations of components involved in apparent genetic selection of Fh to the AW site, e.g. metals and oxidants, are currently being performed. Determination of stressor(s) driving adaptation of the AW Fh population will help determine the mode of toxicity thereby facilitating insight into mechanisms of adaptation.
Key words: Adaptation, Resistance, Fundulus, heteroclitus