Distribution of heavy metals in irrigated vertisol proflies in semiarid region of Turkey

Abstract

Vertisols with swell-shrink properties comprise most of the arable land in northwestern Turkey. These soils are important for agricultural activities. Seven sites were selected to represent Vertisols irrigated with polluted water from the Ayvali Canal. The soils occur on flat to gently sloping plains of the region. The soils were formed on marl parent material under thermic temperature and xeric moisture regimes in the Western Bursa plain, Turkey. Some agricultural lands in the plain were irrigated with heavily polluted water from the Ayvali Canal. This is a unique surface water source for irrigation in the studied area. The morphology, physico-chemical properties and DTPA-extractable Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn were determined in this research. The heavy metal concentrations were found in high levels in the upper horizon and decreased gradually throughout all the profiles studied. The results showed that accumulation of heavy metals in the upper horizon is due to long periods of irrigation with polluted surface water. Soil characterization was determined to provide useful information to understand the behavior of the heavy metal distribution throughout the soil profiles in the semiarid region with under intensive irrigation with polluted water.