Heavy metal uptake by balloon flower together with investigating soil properties and heavy metal concentrations in the cultivated soils

Abstract

Soil properties and heavy metal (HM) concentrations in the field soils where balloon flowers (Platycodongrandiflorum, BF) were cultivated, were investigated together with HM (Cd, Cu, Pb, and Zn) accumulation bythe BF roots. Basically, in most soils examined (51-97% among 65 samples), the chemical propertiesincluding soil pH, organic matter, available-P, and exchangeable cation contents appeared to be lower than theoptimal ranges for balloon flower cultivation. There were no samples exceeding the standard limits for HM insoils. Instead, the total HM concentration levels in soils appeared to be maintained at around backgroundlevels for general soil in Korea. This implied that elevated HM accumulation in the soils caused by anypossible input sources was unlikely. Even though the BF cultivated soils were not contaminated by HM, it wasappeared that substantial amount of Cd was accumulated in BF roots with 1.5% and 35% roots samplesexceeding the standard limits legislated for BF root (0.81 mg kg-1 DW) and herbal plants (0.3 mg kg-1 DW),respectively. This implied that the soil HM standard limits based on the total concentration does not reflectwell the metal accumulation by plants and also it is likely that the Cd standard limits for BF and herbal plantsis too restrict.