Radiocesium dating of sediments from lakes and reservoirs of different hydrological regimes
- Swiss Federal Inst. for Environmental Science and Technology, Duebendorf (Switzerland)
Important information on the transport and deposition of anthropogenic substances in rivers and lakes can be assessed using sediment analyses. Dating is a necessary prerequisite to calculate fluxes, to account for varying sedimentation rates, and thus to allow comparison between different localities. For sediments not older than 40 years {sup 137}Cs dating has been successfully applied to natural and artificial lakes representing a wide range in water-residence times and sediment-trapping characteristics. Sedimentation rates for the period 1986 to the time of coring vary as a function of distance to the inflowing rivers, between 0.5 and 2.5 cm yr{sup {minus}1} in Greifensee and between 1.4 and 3.5 cm yr{sup {minus}1} in Lake Biel. In reservoirs located along the major Swiss rivers Aare and Rhine, sedimentation rates are in the same range from 1.8 cm yr{sup {minus}1} in August (Rhine) to 3.4 cm hr{sup {minus}1} in Klingnau (Aare). Sedimentation rates from the period 1963--1986 are in some cases significantly lower. The dating is based on the identification of radiocesium deposition maxima in sediment cores that are related to the global deposition of radiocesium during atmospheric nuclear weapons testing and the accident of the Chernobyl nuclear reactor (April 1986). Additional markers confirm age determinations based on radiocesium.
- OSTI ID:
- 642232
- Journal Information:
- Environmental Science and Technology, Vol. 32, Issue 13; Other Information: PBD: 1 Jul 1998
- Country of Publication:
- United States
- Language:
- English
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