Long-term application of organic and inorganic fertilizers increases the possibility of contamination of greenhouse soils with heavy metals. This study investigated heavy metals (Cd, Co, Cu, and Zn) adsorptiondesorption under mono and competitive systems in 10 soils from agricultural and greenhouse soils in western Iran. In most of the studied soils, the values of the Freundlich distribution coefficient (Kf) of Cu were higher than other heavy metals, indicating that Cu is maintained by the soils stronger than Cd, Co, and Zn. Based on the average Kf, the selectivity sequence of heavy metals in agricultural and greenhouse soils was ordered as Cu > Zn > Cd > Co in both mono and competitive systems. In general, greenhouse soils had lower Kf for heavy metals compared with agricultural soils, indicating the vulnerability of greenhouse soils to heavy metals leaching. In desorption experiments, the percentage of heavy metal desorption increased as the concentration of added heavy metals increased in both systems (except Cu in the mono-heavy metal system). The findings revealed that continuous vegetable production and the application of organic and inorganic fertilizers in these greenhouse soils may cause changes in soil properties and heavy metal mobility, posing hazards to human health and groundwater quality.
