HR: 08:30h
AN: NB51C-01 [Abstracts]
TI: Influence of Natural and Anthropogenic Disturbance Regimes on the Fate and Transport of Metals in a Mine-Impacted River
AU: * Hornberger, M I
EM: mhornber@usgs.gov
AF: U.S. Geological Survey, 345 Middlefield Rd., MS 465, Menlo Park, CA 94025 United States
AU: Luoma, S N
EM: snluoma@usgs.gov
AF: U.S. Geological Survey, 345 Middlefield Rd., MS 465, Menlo Park, CA 94025 United States
AU: Johnson, M
EM: mbjohnson@ucdavis.edu
AF: UC Davis, 1 Shields Avenue, Davis, CA 95616 United States
AU: Holyoak, M
EM: maholyoak@ucdavis.edu
AF: UC Davis, 1 Shields Avenue, Davis, CA 95616 United States
AB:
A complex set of disturbances, including hydrology, contaminated floodplains, and remediation, impact temporal trends of
metal contamination in the Clark Fork River, MT. A 15-year dataset showed declining Cu trends in resident biota and sediment, indicating a positive remediation response in the upper 30 Km. However, identifying effects of remediation from 85-190 Km
were confounded by the significant positive correlation between bioaccumulation and stream discharge. Because remediation
focuses primarily on the upper 45 Km, spatial correlations in temporal Cu trends were used to determine how a reduction in
upstream contamination levels would influence metal concentrations at each downstream station. Site-specific influence on
metal concentrations was inferred when temporal patterns in downstream stations were significantly correlated to patterns at
an upstream station. Correlations indicated strong connections between adjacent stations; 60-75 % of adjacent stations were
significantly correlated over time, suggesting that events upstream usually affect the next downstream station. Correlations
also indicated two upstream sites that appear to be major sources of metal. For example, sediment Cu concentrations at 5 and
10 Km were significantly correlated with concentrations at five out of seven downstream stations, showing evidence of
upstream-downstream contaminant linkages along a 190 Km reach.
DE: 1803 Anthropogenic effects
DE: 1845 Limnology
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly