TECHNOGENIC WATERFLOWS GENERATED BY OIL SHALE MINING: IMPACT ON PURTSE CATCHMENT RIVERS
A. RÄTSEP
V. LIBLIK
Tallinn University of Educational Sciences,
Institute of Ecology
North-East Estonian Department
15 Pargi St., Jõhvi
41537 Estonia
| The correlation between natural (meteorological, hydrological) and technogenic (mining-technological, hydrogeological, hydrochemical) factors caused by oil shale mining in the Purtse catchment region in northeastern Estonia during 1990–1998 has been studied. As a result of a complex effect of these factors (correlation coefficients r = 0.60–0.86), a so-called hydrogeological circulation of water has been formed in the catchment area. It totals 25–40 % from the whole amount of mine water pumped out at the present, but in the near future it will reach even up to 50–55 %. On the ground of average data, a conceptual balance scheme of water circulation (cycles) for the Purtse catchment landscape has been worked out. It shows that under the influence of technogenic waterflows a new, anthropogenic biogeochemical matter cycling from geological environment into hydrological one has been formed in this catchment area. Transition of the macro- and microelements existing in the composition of oil shale into the aqueous solution and their distribution in mine water are in a good harmony with the so-called arrangement of the elements by the electrode potentials. The technogenic hydrochemical conditions arising in the catchment rivers will not disappear even after finishing oil shale mining. |