engleski

Heavy Metals in Forest Soils in the Mediterranean Karst of Croatia

The forest ecosystem in central Europe has been exposed to pollution for decades, some forest stands have even been exposed for more than a century. Gases such as SO_2 and NO_x not only pollute the leaves but also acidify the soil. At the same time, acid in the soil immobilises heavy metals that have accumulated through atmospheric accumulation. Less mobile heavy metals such as lead and to a certain extent copper accumulate through a long period od time in the upper layers of the soil. Depending on the distance from the pollution´s source heavy metals pollution can be measured in lower or higher concentrations. 55 localities of calci-mollic Cambisols in the Croatian karst were analysed. On average 1 kg of soil was collected from each locality for analysis. Heavy metals were ascertained by an atomic absorption spectophotometre AAS Perkin Elmer 3001 S, using the extracting method with a 2N HCl. The heavy metal content (lead, copper, zinc and cadmium) per mg kg^-1 was analysed. Research was undertaken in the karst forest ecosystem area in the Mediterranean region of Croatia. From the results obtained, it can be concluded that there is a higher level of lead, and especially cadmium, in the upper layers of the soil (0-3 cm), while in the mineral layer (5-25 cm) this level is comewhat lower. The amount of cadmium is close to the boundary value of 2, 0 mg kg^-1. The mean value for lead in the upper layer is 43, 1 mg Pb kg^-1 while for the mineral area of the soil it is 29, 8 mg Pb kg^-1, for cadmium the mean value in the upper layer is 1, 7 mg Cd kg^-1 while for the mineral layer it is 1, 8 mg Cd kg^-1.According data from literature, this is the boundary limit of cadmium content in soils. As such, the soil is polluted with cadmium. The mean values for copper are 9, 9 mg Cu kg^-1 for the upper layer and 10, 1 mg Cu kg^-1 for the mineral layer of the soil, while for zinc they are 19, 0 mg Zn kg^-1 for the upper layer and 7, 6 mg Zn kg^-1 for the mineral area of the soil. Copper and zinc can be found in low concentrations in the karst area of the Mediterranean region of Croatia.

heavy metals; Croatian karst; forest soils; Calci-mollic Cambisols

nije evidentirano