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In order to reduce the accumulation of toxic metals (As, Cd and Pb) in the chives, various immobilizing agents such as a soil pH change-inducing immobilizing agent (lime), sorption agent (compost, spent mushroom compost), soil pH change and sorption agent (biochar) and, dissolved organic carbon (DOC) coagulator (gypsum) and uncontaminated soil were applied to the contaminated soils in isolation and in combination. Then chives were grown and determined for As, Cd and Pb concentrations accumulated in the edible part at harvest. The Cd and Pb concentrations of the chive plant grown in the contaminated soil (no treatment) exceeded the legislated Korean guideline values (Cd: 0.05 mg kg ) was 1,000 times higher than chives plant grown in uncontaminated environment in Korea. Application of lime and gypsum significantly reduced As, Cd and Pb concentrations in all chives examined, due to the increased soil pH and decreased soil DOC. Also, application of combination treatments involving DOC coagulator such as gypsum together with lime decreased As, Cd and Pb concentrations from 21, 1.3 and 9.7 mg kg -1 to 2.1, 0.1 and 1.1 mg kg -1, respectively. Consequently, it was concluded that pH change-inducing immobilizing agent (lime) which was already well known and DOC coagulator such as gypsum could be used as a promising immobilizing agent for safer chives plant production.

In Korea, 90% of the population lives in urban areas, so urban agriculture is commonly carried out. However, research on the safety of urban soils for growing food still needs to be done. Thus, this study was conducted to evaluate the suitability of urban soil for crop cultivation by investigating the heavy metal concentration of soil and plant from urban gardens in Jinju. Soils and crop leaves were collected from 23 urban gardens, and the concentrations of As, Cd, Cr, Cu, Ni, Pb, and Zn were analyzed. The average concentrations of garden soils in Jinju were As 5.31, Cd 0.59, Cr 30.09, Cu 33.05, Ni 21.14, Pb 23.28, and Zn 121.68 mg kg -1 , which did not exceed the Korean guidelines except for Zn in one study site. Geoaccumulation Index, calculated using the background values of heavy metals in Korean soil, showed that contamination of Cd, Cu, Pb, and Zn was in progress. The inflow of Cu and Zn into the garden soils would be from the atmosphere and direct entry into the soil by adding livestock manure. Differently, the other elements were more predominantly introduced from the atmosphere. Particularly, a significant amount of Pb was introduced into the soils from the atmosphere in a couple of gardens. Overall, the results from this study indicated that continuous monitoring for heavy metals in urban garden soils is required for food safety.

Due to rapid urbanization, urban lands have been expanded into existing agricultural areas. With such spatial changes, agricultural lands in the expanding cities or peri-urban areas are easily exposed to contaminants generated by anthropogenic activities such as traffic. Therefore, this study aimed to investigate heavy metal concentrations in major roadside agricultural soils by distance in medium-sized cities, Jinju and Changwon, and to identify the influence of roadside dust on metal contamination. The roadside arable soils of paddy and upland, roadside tree soil, and roadside dust were sampled. In paddy, the heavy metal concentration changes by the distance from the road were not observed because of soil puddling and waterlogging. However, in upland, Cu and Zn concentrations gradually decreased with the increased distance from the road. In roadside dust, Cu and Zn concentrations were very high, exceeding Korean guidelines, which indicates roadside dust could be a primary source of Cu and Zn contamination in agricultural soils. Moreover, the roadside tree soil, which is not disturbed by agricultural activities, showed higher heavy metal concentrations in topsoil rather than subsoil, even though the soil was newly introduced for tree planting. This implies that road dust containing the metal contaminants may accumulate in the nearby soils. Many scientists have thought that eco-friendly compost is the main reason for increasing Cu and Zn in urban agricultural soils. However, roadside dust needs to be more focused on as a principal source of contamination.