Effect of Incubation Time and Kiwi Skin on Mobility of Heavy Metals in Contaminated Sandy Soil

Contamination of soils with heavy metals is caused either in a natural manner or by human activities such as industrial and mining activities. Decontamination is especially important for the environment. Today, natural absorbents are used to remove heavy metals. This study aimed to study the effect of incubation time of natural absorbent (kiwi skin) on the mobility decrease of some heavy metals such as cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn), in contaminated sandy soils. The soil was synthetically contaminated in the laboratory with multi-component solutions. The experiments were performed in two replicates and two treatments (soil without adding kiwi skin (control) and soil contain kiwi skin). The samples were kept at fixed temperature of 28ºC for 3 hours, 1, 3, 7, 14, 21 and 28 days. Then, concentration of Cd, Cu, Pb and Zn were studied in soil components using sequential extraction. The results showed that The descending trend of distribution percentage of the heavy metals competing with each other in exchangeable phase in the sandy soil sample along with the kiwi skin was as follows: Cu>Zn>Pb>Cd. after 28 days (soil with kiwi skin), (Cd) distribution in manganese and iron oxide phase was higher than other phase, (Cu) distribution in organic phase was higher than other phase, (Pb) distribution in manganese and iron oxide phase was higher than other and distribution of (Zn) was high in manganese and iron Phase.