VULNERABILITY TO ACIDIFICATION OF SOILS OF THE ZLATNA AREA

In the period when the non-ferrous metallurgical plant of Zlatna was functioning, both sulfur dioxide and powder of metal sulphides and metal oxides were emitted in the air. Dioxide and trioxide sulfur in contact with rain water convert to sulfuric acid that leads to the formation of acid precipitation, which in contact with soils leads to its acidification. Soil cover in the Zlatna area is mainly represented by Eutric Cambisols (47.3%) Dystric Cambisols (29.5%) Luvisols (4.2 %), regosols (1.7 %), strongly eroded soils (3.3 %). Soil resistance to acidification depends on the soil fundamental characteristics such as reaction, texture, content and nature of humus, cation exchange capacity, etc. Based on the calculation of soil buffering capacity indicator for reaction, the vulnerability map to soil acidification in the Zlatna area, Budeni-Izvorul Ampoiului-Mets-Sard-Alba Iulia sector was drawn. Within this area, four classes of soil vulnerability to acidification were designated. Soils with high vulnerability are extended on a small area (2320 ha - 4,8%) and are represented by the following soils: Rhodic-dystric Cambisols, Leptirodic-dystric cambisols, Rhodic Cambisols, Rhodic-leptic Regosols, Albic-stagnic Luvisols, Stagnic Luvisols. The soils with high vulnerability are spread over large areas occupying 22 000 ha (45.5%). In this class, Dyistric Cambisols, Lepti-dystric Cambisols, Eutric Cambisols are included. Soils with medium vulnerability are spread over 41.4% of the area (20,000 hectares) and are represented by: Eutric Cambisols, Lepti-eutric Cambisols, Haplic Luvisols, Luvisols (eroded phase), Eutric Leptosol. Soils with low vulnerability are found only on 8.3% of the area (4,000 hectares) and are represented by: Eutric Fluvisols, Fluvi-eutric Cambisols; Haplic Phaeozems, Eutric Gleysols, Calcaric Regosols, Calcaric-rhodic Regosols. The most affected soils were found near the pollution source and the effect was stronger in the case of natural acidity of soils.