HR: 16:30h
AN: NB44A-05    [Abstracts]
TI: Trace Metal Concentrations and Macroinvertebrate Assemblages in Black Shale-Draining Streams
AU: * OGENDI, G M
EM: gogendi@astate.edu
AF: ARKANSAS STATE UNIVERSITY, PROGRAM OF ENVIRONMENTAL SCIENCES, P.O. BOX 767, STATE UNIVERSITY, AR 72467 United States
AB: Natural and anthropogenic release of metals into surface waters and sediments may alter benthic community structure. To better understand the effect of trace metals on aquatic communities of black shale-draining streams in Arkansas, we collected water, sediment and macroinvertebrates at 12 sites on black shale-draining streams (BLS) and four sites on a limestone-draining stream (LMS). Trace metal analysis of streamwater and sediments and rapid bioassessment of the macroinvertebrate communities followed US EPA methods and protocols. Concentrations of zinc, cadmium, copper, lead and nickel in BLS water and sediments were significantly (p<0.05) higher than in LMS water and sediments. Concentrations of copper, cadmium, arsenic and nickel in the BLS water exceeded slightly the acute aquatic-life standards. Similarly, concentrations of cadmium, arsenic, lead, zinc, and mercury in BLS sediments exceeded the Effect Range-Low values of the sediment quality guidelines. Total abundance, taxa richness, and percent EPT taxa, were significantly (p< 0.05) lower in the BLS than the LMS. The absence of pollution-sensitive Heptageniidae and Chloroperlidae in the BLS samples was associated with elevated metal concentrations in these sites, but not apart from observed hydrologic and habitat differences. Biological condition scores for BLS and LMS sites categorized the streams as slightly impaired and unimpaired, respectively. This study shows that trace metals released from natural sources such as black shales can cause structural alterations to benthic communities.
UR: http://www.benthos.org
DE: 0614 Biological effects
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly