An integrated approach to the determination of trace metal distribution within Lahontan Reservoir, Nevada

Conference · Thu Apr 01 04:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5138892

Miller, J R; Rowland, J; Ritter, D F ^[1]; Lechler, P J; Desilets, M; Hsu, L C; Price, J G ^[2]

---

1. Desert Research Inst., Reno, NV (United States). Quaternary Sciences Center
2. Univ. of Nevada, Reno, NV (United States)

Milling and mining of the gold and silver rich Comstock ore during the late 1800's released substantial quantities of Hg, Au, and Ag to the Carson River system of west-central Nevada. As a result, Lahontan Reservoir, built in 1915 along the Carson River, has become a trace metal sink. Below normal precipitation since 1986 resulted in some of the lowest water stages on record for Lahontan Reservoir. Low water allowed for the delineation and mapping of stratigraphic units that underlie the reservoir. Eleven stratigraphic units have been defined and mapped, seven of which post-date dam construction. The post-1915 units represent sedimentation in coastal, deep-water, and deltaic environments. More than 80 samples collected from the post-dam units have been analyzed for Hg, Au, and Ag. The chemical data indicate that trace metal concentrations vary between stratigraphic units. However, Hg, Au, and Ag concentrations are relatively uniform within the individual deposits. These geologic/geochemical relations allow for a more detailed understanding of contaminant distribution than can be obtained from commonly invoked methods of random geochemical sampling. For example, only two units, representing deposition in deltaic and deep-water zones, exhibit high levels of Hg, Au, and Ag in Lahontan Reservoir. Developed geologic maps not only show the distribution of these units, but indicate the percentage of the reservoir significantly contaminated. In addition, combining geologic and geochemical data allows the quantity and loading rates of non-conservative trace elements to be estimated.

• OSTI ID: 5138892
• Report Number(s): CONF-9305259--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 25:5
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540220* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (1990-)
540320 -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (1990-)
58 GEOSCIENCES
580000 -- Geosciences
CHEMICAL COMPOSITION
DEPOSITION
DEVELOPED COUNTRIES
DISPERSIONS
DISSOLUTION
DISTRIBUTION
ECOLOGICAL CONCENTRATION
ELEMENTS
GEOCHEMICAL SURVEYS
GEOLOGIC DEPOSITS
GEOLOGY
GOLD
GOLD ORES
LAKES
LAND POLLUTION
LEACHATES
LEACHING
LIMNOLOGY
MERCURY
METALS
MIXTURES
NEVADA
NORTH AMERICA
ORES
POLLUTION
SEDIMENTS
SEPARATION PROCESSES
SILVER
SILVER ORES
SOLUTIONS
SPATIAL DISTRIBUTION
STRATIGRAPHY
SURFACE WATERS
SURVEYS
TRACE AMOUNTS
TRANSITION ELEMENTS
USA
WATER POLLUTION
WATER RESERVOIRS