In the area of 540 km2 belonging to the County of Zagreb, 280 samples of surface soil layer were taken on agricultural land intended for different purposes and under different utilization intensity. After aqua regia extraction, samples were analyzed for the contents of lead, cadmium, zinc and copper. More then 13,000 ha of agricultural land are situated in a specially sensitive water protection area. According to the geomorphological characteristics and participation of soil types, three regions were separated: 1. Tertiary terrace and metamorphites of Mt. Medvednica; 2. Pleistocene zone with pseudogley and generally acid soils; and 3. Sava river valley with brook valleys and small river valleys in the investigated region. More expressly than all other metals studied, lead content follows the course of the Sava river. The highest average lead content per groups of 43.43 mg/kg Pb was determined in fluvisols along the Sava, while anomalous values occurred on several locations. These locations can be allotted to the class of highly contaminated soils, requiring intensive protection and control of emission sources.
The highest average cadmium content of 0.93 mg/kg Cd per designated regions was recorded in the youngest river valley along the Sava. Anomalous values were also encountered in the youngest valley along the Sava watercourse, where the average zinc content amounted to 87.08 mg/kg Zn, which are classified as highly contaminated soils. Higher copper values were determined in the hilly area of Mt. Medvednica and Pleistocene of sloping terrains, which seems to be related to the manner of land use (vineyards, gardens at private holdings).

heavy metals; aqua regia extraction; agricultural soils; spatial distribution; soil pollution

Published by University of Zagreb, Faculty of Agriculture, Zagreb, CROATIA
Sponsored by Ministry Science and Education of the Republic of Croatia