Heavy metals in bottom sediments of great slave lake (Canada): A reconnaissance |
| |
| Authors: | R J Allan |
| |
| Institution: | (1) National Water Research Institute Inland Waters Directorate Western and Northern Region, 501 University Crescent, Winnipeg, Manitoba, Canada |
| |
| Abstract: | Near the shores of Great Slave Lake, natural sources of heavy metals include gold and base metal deposits, mineralized greenstone
belts and sedimentary bedrock, and uraniferous granites. Potential anthropogenic sources of heavy metals (As, Zn, Pb) include
large gold and base metal extraction -processing facilities on the shores of the lake. Six sediment cores were collected on
a traverse of the lake. Heavy metal concentrations and distributions are related to the regional bedrock geochemistry in the
drainage basin. Higher uranium concentrations in the northernmost core are attributed to extensive uraniferous areas north
of the lake. More subtle variations of concentration are related to sedimentologic characteristics and processes in the lake.
The west basin is a natural sink for most of the heavy metals determined. Two centrally located west basin cores had mean
zinc concentrations of 145 ppm, whereas cores closer to the north and south shores had mean concentrations of 80–110 ppm.
Mn, Ni, and Pb were enriched in some of the cores from the area of shallower water near the MacKenzie River outlet, rather
than in the central west basin. The enrichment is related to Mn-, Ni-, and Pb-rich amorphous coatings on quartz grains. Elevated
zinc or lead levels from anthropogenic activities were not detected but elevated levels are suspected for arsenic. In the
two cores from the center of the west basin, surface sediment contains up to 12 ppm arsenic, not high in comparison with noncontaminated
freshwater lakes elsewhere in Canada but considerably elevated relative to concentrations of 1 ppm found deeper in the same
cores.
Contribution from the National Water Research Institute, Western and Northern Region. Presented at the 10th International
Sedimentological Congress, Jerusalem, Israel, 1978. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
