Effects of application municipal effluent on heavy metal (Cr and Ni) accumulation in Olea europaea L. trees and soil

The aim of the study was to determine the accumulation of heavy metals (Cr and Ni) in different layers of soil, leaves and fruits of Olea europaea. In this investigation, irrigation of olive trees were done with both water of well (control) and sewage, for seven years in Rey town, south of Tehran. In each treatment (well water and municipal effluent), three samples were selected systematic randomly. In each sample, leaves and fruits of olive trees and soil (from 0-15, 15-30 and 30-60 cm depths), were collected for analyses in three replications. Samples were analyzed with standard methods and used atomic absorption based on flame (PU9400X). For comparison of concentrations of heavy metals in layers of soil, leaves and fruits and in order to normalizing of data, independent sample t-test was used. Results of this study show that irrigation with municipal effluent increase concentration of Ni and Cr in soil. Concentration of Ni and Cr were statistically greater in leaves of trees irrigated with municipal effluent than those of the leaves of trees irrigated with well water. There was no significant difference in spite of accumulation of heavy metals (Ni and Cr) in Olive fruits.