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Impacts of toxic thresholds of sediment-associated contaminants to robust redhorse (Moxostoma robustum) in the Lower Oconee River

Society of Environmental Toxicology and Chemistry, annual meeting abstract book

Environmental Sciences in the 21st Century: Paradigms, opportunities, and challenges, Nashville, Tennessee, November 12-16.
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Abstract

The robust redhorse is a ?Species-at-Risk? in the lower Oconee River, GA. The population is composed of aging adults with little natural recruitment. Factors contributing to the loss of early-life stages are unknown, but contaminants associated with fine sediments may play a role. The objectives of this study were to determine toxicities of sediments and pore waters from the Oconee River to early-life stages of robust redhorse and to establish toxic thresholds of metals (Cd, Cu, Mn, Zn) and ammonia, elements potentially threatening this species. Depositional sediments were collected from the only known spawning site and three sites downstream of major tributaries. Sediment pore waters were extracted in the laboratory from all sites and in situ at two sites. Toxicity tests with sediments, pore waters and metal solutions were initiated with eggs, yolk-sac fry and swim-up fry to determine effects on the life stage initially exposed as well as effects manifested in later developmental stages. Survival and growth were test endpoints, and toxicity was observed in both sediments and pore waters. Although the yolk- sac stage was the most sensitive across all tests, sediment toxicity was elicited only in tests initiated with eggs that developed through the yolk-sac stage. Toxicity appeared to be due to Mn in sediment and pore water exposures, but was more prevalent in pore waters. Sediment handling and the associated effects on redox potential contributed to the elevated concentrations of Mn in pore waters. Pore waters extracted in situ had significantly less Mn and were less toxic than laboratory-extracted pore waters. These data suggest that sediment-associated Mn may impact early-life stages of robust redhorse in the Oconee River.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Impacts of toxic thresholds of sediment-associated contaminants to robust redhorse (Moxostoma robustum) in the Lower Oconee River
Series title:
Society of Environmental Toxicology and Chemistry, annual meeting abstract book
Volume
21
Year Published:
2000
Language:
English
Contributing office(s):
Patuxent Wildlife Research Center
Description:
213 (abstract PTP111)
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
213 (abstr