ENZYMOLOGICAL AND MICROBIOLOGICAL STUDY OF THE EVOLUTION OF A TECHNOGENIC SOIL SUBMITTED TO BIOLOGICAL RECULTIVATION AT THE LEAD AND ZINC MINE IN RODNA (ROMANIA)

The technogenic soil containing Pb and Zn impurities at the Rodna mine (Bistrita-Nasaud county, Romania) was submitted to a bioremediation t echnology. In the 1987(1988)-1996 period, 16 plots and 8 controls were systematically sampled for determination of the enzymatic and bacteri al indicators of spoil quality. The evolution of the enzymatic and bac terial potential showed that the best results were obtained with compl ex treatment (covering with soil+NPK fertilization and sowing a grass- legume mixture or seeds of plants belonging to the native flora of the region). A favourable outcome of the complex treatments is reflected in a gradual colonisation by nematodes and their increased specifical and trophical diversity. (C) 1998 Elsevier Science B.V. All rights res erved.