heal.abstract |
Intensive mining and ore processing activities concerning phosphate and polymetallic sulphidic ores and concentrates have generated throughout Europe millions of tonnes of hazardous wastes which contain high residual concentrations of heavy elements and radionuclides in mobile forms. Under the action of several physicochemical mechanisms, toxic and radioactive elements contained in the wastes are mobilised, migrate to the surroundings and cause severe and widespread contamination of soils, surface and ground waters. In order to assess the risk posed by each source of pollution at each affected area and to select a viable remedial action, a risk assessment study based on a source-pathway-target basis is considered necessary. This study utilises all available data concerning wastes, probable transfer routes and target groups affected and defines the magnitude of risk for each case. In this paper, two areas of Eastern-Europe, Vromos Bay in Bulgaria and Navodari in Romania are used as case studies.At Vromos Bay, several million tonnes of flotation tailings containing heavy and radioactive elements have been disposed at a tailings dam and by the Black Sea coast. At Navodari, several million tonnes of phosphogypsum tailings and pyritic cinders also containing heavy and radioactive elements have been disposed at tailing dumps. Besides, in the latter case, decant waters often without neutralisation are discharged with a pipeline to the Black Sea. For both areas, and in order to define a viable remediation scheme, a risk assessment study was undertaken, based on a complete environmental characterisation of the pollution sources. Finally, the rehabilitation schemes being developed are briefly presented and discussed. © 1999 Elsevier B.V. All rights reserved. |
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