Chemical characterization of sediments and pore water from the upper Clark Fork River and Milltown Reservoir, Montana
- National Biological Survey, Columbia, MO (United States). Midwest Science Center
The upper Clark Fork River basin in western Montana is widely contaminated by metals from past mining, milling, and smelting activities. As part of a comprehensive ecological risk assessment for the upper Clark Fork River, the authors measured physical and chemical characteristics of surficial sediment samples that were collected from depositional zones for subsequent toxicity evaluations. Sampling stations included five locations along the upper 200 km of the river, six locations in or near Milltown Reservoir and two tributary references. Concentrations of As, Cd, Cu, Mn, Pb, and Zn decreased from the upper stations to the downstream stations in the Clark Fork River but then increased in all Milltown Reservoir stations to levels similar to uppermost river stations. Large percentages of the total Cd, Cu, Pb, and Zn were extractable by dilute HCL for all samples. Copper and zinc accounted for greater than 95% of extractable metals on a molar basis. Acid-volatile sulfide (AVS) concentrations were typically moderate in grab sediment samples and appeared to regulate dissolved concentrations of Cd, Cu, and Zn in sediment pore waters. Acid-volatile sulfide is important in controlling metal solubility in the depositional areas of the Clark Fork River and should be monitored in any future studies. Spatial variability within a sampling station was high for Cu, Zn, and AVS; therefore, the potential for toxicity to sediment-dwelling organisms may be highly localized.
- OSTI ID:
- 6527946
- Journal Information:
- Environmental Toxicology and Chemistry; (United States), Vol. 13:12; Other Information: Presented at the Symposium on Integrated Ecological Assessment of a Superfund Site: Milltown Reservoir, Clark Fork River, Montana, 13th Annual Meeting, Society of Environmental Toxicology and Chemistry, Cincinnati, Ohio, November 8--12, 1992; ISSN 0730-7268
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ARSENIC
ECOLOGICAL CONCENTRATION
CADMIUM
COPPER
INTERSTITIAL WATER
CHEMICAL COMPOSITION
LEAD
MANGANESE
MONTANA
RIVERS
WATER RESERVOIRS
WATER POLLUTION
SEDIMENTS
ZINC
DEVELOPED COUNTRIES
ELEMENTS
GROUND WATER
HYDROGEN COMPOUNDS
METALS
NORTH AMERICA
OXYGEN COMPOUNDS
POLLUTION
SEMIMETALS
STREAMS
SURFACE WATERS
TRANSITION ELEMENTS
USA
WATER
540320* - Environment
Aquatic- Chemicals Monitoring & Transport- (1990-)