engleski

Trace Element Distribution in Surface Sediments of Lake Vrana and Topsoil of Cres Island, Croatia

This paper presents a study of major and trace element distribution and evaluation of their environmental geochemical aspects in surface sediments of Vrana Lake and the topsoil within its catchment. The concentrations of 22 elements were determined in 30 lake sediment samples and 60 topsoil samples covering the lake catchment and the whole Island of Cres. The element to Al ratios fall into three main groups, the group of elements that show no difference in ratios in soils and lake sediments: Ni, Co, Mn, Th, Zn, Ba, Ti, K, V, Na, and Hg, the elements that are enriched in the sediments ; Ca, Sr, Cd, Pb, Ba and Mg, and the elements that can be considered as depleted in the lake sediments are Cu, P, Fe, Cr, and La. Long-range air pollution is probably main reason why the content of metals, especially lead, is increased in the lake sediments, although a local source from road transport as indicated by soil data from the catchment could also be an important source of the Pb. Some pollutants in catchment soils, such as Cu and Hg from agro-chemical sources were not determined in elevated concentrations in the lake sediments. Comparison of element/Al indexes from this study with the other studies of surface materials in the region show mutually similar sources, with loess and flysch as two geochemical end-members.

trace element distribution; lake sediments; soils; lead; normalization; atmospheric deposition

nije evidentirano