Iranian Journal of

Background and Objective:  Polltion of food chain components such as vegetables to heavy metals is one of the important environmental problems. Remediation management of these metals especially Cd is very important. Thus, this research was done to investigate the effect of Arak municipal waste compost enriched with tire rubber ash on decreasing spinach Cd concentration in a Cd polluted soil.
Materials and Methods: Treatments consisted of applying (0, 200 kg/ha) Arak municipal waste compost enriched with tire rubber ash and Cd pollution at the rates of 0, 10, 20 and 30 mg Cd (kg soil)^-1. The plant used in this experiments was spinach.
Results: Increasing application rate Arak municipal waste compost from 0 to 20 and 40 ton/ha in a Cd polluted soil (mg Cd (kg soil)^-1) caused a significant reduction in DTPA extractable-Cd by16 and 45 %, respectively. Similar to this result, shoot Cd concentration was decreased. Applying tire rubber ash also had an important role on decreasing Cd concentration.
Conclusion: The results of this study showed that applying Arak municipal waste compost had an important role on decreasing Cd concentration. This was due to the application of the organic amendment on increasing soil sorption properties that it in turn decreased soil and plant Cd concentration. However, the role of plant type and soil physico-chemical properties on changes in Cd availability cannot be ignored.
 

Background and Objective: Lead is a dangerous heavy metal for human health. This research was conducted to study the potential of a new Iranian corn (Maxima CV.) and white clover in monoculture and mixed culture for phytoremediation of Pb in a Pb polluted soil.
Materials and Methods: The experimental treatments consisted of corn and white clover in a mixed culture (with 10 and 20 plant density) and either corn or white clover in a monoculture system (with 10 and 20 plant density) in a Pb polluted soil (800 mg Pb (kg soil)^‌-1) at 60 and 90 days of  experiment. Plant and soil Pb concentration were measured using atomic absorption spectroscopy.
Results: Root and shoot Pb concentration of corn and white clover were significantly increased in a mixed culture system relative to mono culture system. In addition, the increase of white clover density from 10 to 20 in a mixed culture system caused a significant increased Pb concentration in root and shoot of corn and white clover. The highest Pb translocation factor (TF) and shoot Pb concentration were observed in white clover in a mixed culture of corn and white clover (with 20 plants density).
Conclusion: The results of this study showed that the Pb concentration of corns shoot in a mixed culture system with corn and white clover (20 densities) was three times higher than that of the monoculture system.
 

Background and Objective: Today, landfill management of municipal waste and soil pollution with heavy metals are major environmental problems. This research was conducted to evaluate the effect of Shazand municipal waste compost and Saveh pomegranate peel biochar on decreasing Pb availability in soil and sorghum plant.
Materials and Methods: Treatments consisted of applying Shazand municipal waste compost (0, 10 and 20 ton/‌ha^‌) and Saveh pomegranate peel biochar (0 and 15 g/‌kg^‌) in a Pb polluted soil (0, 600, 800 and 1000 mg Pb/‌kg soil). After 8 weeks of sorghum planting (Kimya CV.), the soil physio-chemical properties and soil and plant Pb concentration were measured. 
Results: Applying 20 ton/ha‌ municipal waste compost with 15 g/‌kg^‌ biochar increased soil pH by 0.4 units and decreased soil Pb availability by 11%. The similar results were observed for the root and shoot Pb concentrations, when the same amount of  manure in a Pb polluted soil was applied (1000mg Pb/‌kg soil) that decreased the root and shoot Pb concentration by 1.8 and 2.2 times, respectively.
Conclusion: The result of this experiment showed that applying Shazand municipal waste compost and biochar can increase soil sorption properties and decrease soil or plant Pb concentration. However, the role of these organic amendments on supplying plant nutritional needs cannot be ignored.