engleski

Leaching of some heavy metals into drainage water in Croatia

This study was aimed: at determining the concentration and total leaching of heavy metals (Pb, Zn and Cd) in drainage water and their contents in soil (until 0.30 m) at four different variants of pipe drainage spacing (15 m, 20 m, 25 m and 30 m) and at determining the yield of crop maize for each variants. The study was conduced on reclamation test field on hydroameliorated Gleyic Podzoluvisol, during five years. The crop maize was grown and the same agricultural practices were applied in all pipe drainage variants in each trial year. Drainage discharge was measured continually by means of automatic limnimeters. Sampling of drainage water were done three times each month during the discharge period and sampling of soil were done each month. Heavy metals were determined by AAS. The total annual quantity leached of heavy metals were estimated on the basis of average yearly concentration and yearly quantity of drainage discharge. Data were statistically processed by means of the analysis of variance. Based on the results, it can be confirmed that the concentrations of heavy metals in drainage water and in soil at all variants and in all years were below from limited values. The results of concentrations and their leaching depended on variant to variant and from year year to year. The highest concentrations (and leaching) of all heavy metals in drainage water and at all variants were recorded soon after appled of fertilizer and after higer precipitation (t.i. drainage discharge). There were no statistically significant differences between the tested variants and heavy metals in drainage water and in soil in a particular year. As a rule, the highest yields were achieved in the drainpipe spacing variant of 15 m and the lowest in variant of 30 m. The yields are fluctuated from 88 dt.ha-1 (15 m) ap to 43.48 dt.ha-1 (30 m).

drainage; water; leaching; metals

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