| Autor: |
Baeyens, W., Dehandschutter, B., Leermakers, M., Bobrov, V. A., Hus, R., Baeyens-Volant, D. |
| Předmět: |
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| Zdroj: |
Water, Air & Soil Pollution; Jan2003, Vol. 142 Issue 1-4, p375-393, 19p |
| Abstrakt: |
Natural geological Hg deposits control the Hg levels in the upper Katun river. Very high levels of total Hg are observed in the watercolumn (up to 20 ng L-1) and the sediments (up to 244 μg g-1) close to the deposit area, but almost normal levels (1.8 ng L-1 in the water column and 0.14 μg g-1 in the sediments) are reached 60 km downstream of that zone. In general, low dissolved methylmercury (MMHg) concentrations were found (0.04–0.05 ng L-1) due to unfavourable methylation conditions. The MMHg concentrations in the sediments vary from 23.3 ng g-1, in the vicinity of the geological Hg deposits, to 0.17 ng g-1 60 km downstream. Total Hg levels in Lake Teletskoye (a geological active area) are slightly increased (1.1–1.8 ng L-1) compared to Lake Baikal and fairly constant alover the Lake, suggesting multiple sources. High mercury concentrations in springs and soils coincide with high radon concentrations in the same compartments as well as high soil exhalation fluxes. These results in combination with the fact that Lake Teletskoye is located in an active fault zone suggest that the Rn and Hg sources may be fault aligned spring waters and deep seated gases escaping through open cracks. Methylmercury concentrations in the Lake (0.03–0.1 ng L-1) were comparable to the concentrations found in Katun river but relative to the total Hg burden this means a higher percentage. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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