An historical assessment of trace metal accumulation in Lake Champlain, Vermont
- Univ. of Rhode Island, Narragansett, RI (United States). Graduate School of Oceanography
The Lake Champlain watershed, with its increased land use, shoreline development, and population, is being threatened by pollutants in the water column and bottom sediments. A comprehensive study is currently being conducted to characterize the bottom sediments of the lake for toxicity and to reconstruct the history of pollutant inputs. Surface sediment samples were collected from 30 stations and analyzed for metal (Cu, Zn, Cr, Pb, Ni, Mn, Fe, Cd, Al, and Ag) concentrations to determine the contaminated regions of the lake. Once the contaminated regions were determined, a Nemesis corer was used to retrieve sediments cores averaging 1 meter in length from 10 sites within Lake Champlain. Grain size and metal analyses were conducted at one and two cm intervals down the cores. Grain size data, in combination with metal and radiometric stratigraphy, can serve as an indicator of changing land use in the watershed. The grain size in some cores has a fining upward trend indicating increased land use and soil erosion. Downcore variations in metal concentrations reveal two different regimes. The concentration at depth remain consistently low and are inferred to correspond with the natural background levels. In contrast, the upper section of the cores show abrupt increases in metal concentrations which are attributed to increased anthropogenic inputs. Radiometric ([sup 210] and [sup 137]Cs) and pollen chronostratigraphy of these cores indicates that the increased metal concentrations and the changes in grain size recorded in the upper most sediments is related to increased human disturbance beginning in the late 18th and early 19th centuries. This study demonstrates that the historical record of pollution inputs to Lake Champlain can be reconstructed from the sediment sequences.
- OSTI ID:
- 5508455
- Report Number(s):
- CONF-9303211--
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Journal Name: Geological Society of America, Abstracts with Programs; (United States) Vol. 25:2; ISSN GAAPBC; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
540230 -- Environment
Terrestrial-- Radioactive Materials Monitoring & Transport-- (1990-)
540250* -- Environment
Terrestrial-- Site Resource & Use Studies-- (1990-)
540330 -- Environment
Aquatic-- Radioactive Materials Monitoring & Transport-- (1990-)
540350 -- Environment
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CHEMICAL COMPOSITION
DEVELOPED COUNTRIES
ECOLOGICAL CONCENTRATION
ELEMENTS
ENVIRONMENTAL TRANSPORT
HISTORICAL ASPECTS
LAKES
LAND USE
MASS TRANSFER
METALS
NORTH AMERICA
POLLUTANTS
POLLUTION
SEDIMENTS
SURFACE WATERS
TRACE AMOUNTS
TRANSITION ELEMENTS
USA
VERMONT
WATER POLLUTION
WATERSHEDS