Copper and Zinc Fractionation in Apple Orchard Soil in the Village of Bukevje (Croatia) Using the Revised Four-Step BCR Extraction Procedure

Abstract

The aim of this study was to establish the fractionation of copper and zinc in a small apple orchard using the revised (four-step) Bureau Communautaire de Référence (BCR) sequential extraction procedure and assess their potential mobility in soil. Soil samples were collected at the depth of 10 cm to 25 cm, sixteen from the orchard and fi ve control samples from a meadow located some 200 m away from the orchard. As the distribution of trace-element concentrations in the control samples was normal, they were used for comparison as background levels. We also determined soil mineralogical composition, carbonate content, soil pH, cation exchange capacity, and soil organic matter. The extraction yields of Cu and Zn from the control soil were lower than from the orchard soil (25 % vs. 34 % and 47 % vs. 52 %, respectively), which pointed to natural processes behind metal bonding in the control soil and greater infl uence of man-made activities in the orchard soil. Compared to control, the orchard soil had signifi cantly higher concentrations of total Cu (P=0.0009), possibly due to the application of Cu-based fungicides. This assumption was further supported by greater speciation variability of Cu than of zinc, which points to different origins of the two, Cu from pesticides and Zn from the parent bedrock. Copper levels signifi cantly better (P=0.01) correlated with the oxidisable fraction of the orchard soil than of control soil. Residual and organically bound copper and zinc constituted the most important fractions in the studied soils. However, the use of Cu-based fungicides in the apple orchard did not impose environmental and health risk from Cu exposure.

Possible Influence of Agriculture on an Unsaturated Zone in Croatia

“…3). Medunić et al [4]; Dabiri et al [29]; Ružičić et al [25]; Bakircioglu et al [30]; and Liu et al [31] found the same orders of Zn fractioning in Cambisol. In soil, zinc forms complexes with organic matter quite quickly, and this has a holding- back effect on the activity of Zn in the soil solution [32].…”

“…Many previous studies were made to get information about soil accumulation of potentially toxic metals from agriculture. Medunić et al [4] studied the fractionation of copper and zinc in apple orchard soil using sequential extraction procedure. They concluded that copper and zinc are bounded to residual and reducible fractions and their total values do not exceed maximal permissible concentrations (MAC) in agricultural land.…”