Transfer of elements and soluble salts is controlled by the depth and dynamics of the active layer as well as by the cyclicity and intensity of the processes of cryogenic denudation. The activation of slope processes essentially influences the amount of the suspended solids, the mineralization, and the chemical composition of the run-off. Eventually those processes affect the composition and quality of the drinking water derived from the surface sources.

Yamal Peninsula (North of West Siberia) is characterized by the widely spread perennially frozen saline deposits. They were not washed through their history, only the active layer was subjected to washing by atmospheric precipitation.

The chemical testing of slopes showed that:

1. The active layer deposits within the undisturbed sites contain a relatively small amount of water soluble salts with a chemical composition similar to that in the atmospheric water. At the landslides' shearing surface, which in fact is more or less recently exposed permafrost, the active layer contains several times larger concentration of soluble salts and elements, comparable to that found in underlaying permafrost and of similar composition.
2. The difference is found between the chemical composition of the run-off originating from the sites with the active layer detachments (exposing frozen ice-bearing deposits) and slumps (exposing massive ice). Water soluble salts from the ice-bearing deposits increase the mineralization of the active-layer ground water in hundreds of times. The thawing of the massive ice doesn't greatly affect the total mineralization of the run-off, but relatively high concentration of heavy metals and other elements in the massive ice may change the composition of the run-off.
3. Migration of the elements within the active layer, that is newly formed at the exposed permafrost surface, brings to the following distribution. Solutions partially ascend to the surface along the capillaries and evaporate. The salts crystallize on the surface forming a seasonal saline. Solutions also accumulate on the acquifuge - the new permafrost upper limit. The horizons of the heightened concentration are separated by the horizon of low concentration from which the salts migrated upwards and downwards.
4. Comparison of the mineralization and chemical composition of the surface water from year to year demonstrates the peak-like rise of the element and ion concentration, including heavy metals and other pollutants in the surface run-off due to the natural activation of the slope processes. Similar phenomena may be observed also if the sliding or excavations in the active layer appear resulting from human activity. However in this case the rise will be more gradual than catastrophic.

Marina O. Leibman
Earth Cryosphere Institute SB RAS
Vavilov str.30/6, room 74a
Russia, 117982 Moscow,
Phone: 7-095-2158666
Fax: 7-095-1356582
E-mail: mleibman@glas.apc.org