Sysm�j�rvi ? a lake polluted by mining waste-water

Abstract

Lake Sysmljirvi is located inside the municipal boundary of Outokumpu in North Karelia, Finland. Since 1928 metalliferous, and at a later stage highly acid waste-water, has been discharged into the lake. Neutralization of the lake water by liming was introduced, and by the end of 1966 the pH of the water had become neutral to alkaline.Two sediment cores (0.5 m and 5 m long, respectively) were analyzed for pollen, diatoms, loss-on-ignition, organic carbon, Fe, Cu, Ni, Pb, Zn and Hg. The maximum concentrations of organic matter and heavy metal content occur 30 cm below the sediment surface. Evidence of the liming and of accelerated eutrophication appear close to the surface of the sediment (0-10 cm), indicated by an increase in Nitzschia plana.

Sorption Properties of the Bottom Sediment of a Lake Restored by Phosphorus Inactivation Method 15 Years after the Termination of Lake Restoration Procedures

“…Two grams of fresh sediment aliquots (in triplicates) were placed in the 50 cm 3 Falcon type centrifuge tubes and phosphate solutions (25 cm 3 ) were added (P concentrations of 0.00; 0.15; 0.30; 0.60; 1.20; 2.40 mg dm −3 ). Two drops of chloroform were added to inhibit bacteria activity [30][31][32].…”

“…Two grams of fresh sediment aliquots (in triplicates) were placed in the 50 cm 3 Falcon type centrifuge tubes and phosphate solutions (25 cm 3 ) were added (P concentrations of 0.00; 0.15; 0.30;…”

“…Water bodies located in the direct vicinity of human settlements have very often been the victims of avalanche degradation resulting from the discharge of untreated municipal or industrial sewage. There have been many cases in the world of urban lakes transforming into hypertrophic and even saprotrophic water bodies [3][4][5][6][7].…”