The applications of various soil conditioners have been used to reduce mobility and availability of heavy metals in soils.Relative studies usually focused on mobile metal elements such as Cu,Zn,and Cd while relative information of Pb,Cr,and Ni is insufficient.This study examined the effects of several soil conditioners on the mobility and availability of Pb,Cr,and Ni in six different levels of contaminated soils of Taiwan.Three soils were enriched in Pb(63-340 mg/kg)and the other three soils were enriched in Cr(44-94 mg/kg)and Ni(35-143 mg/kg).Calcium carbonate(CAC; 1%),compost(COM; 3%),CAC combined with COM(CAC+COM),Fe oxide(FO; 1%),and calcium phosphate(CAP; 0.5%)were added as soil conditioners in the pot experiments cultivated in the rotation system of rice and Chinese cabbage with no any addition of soil conditioner as control treatment.The soil pH value,organic matter content,and DTPA and aqua regia extractable amount of Cr,Ni,and Pb in soils were determined.Cr,Ni,and Pb concentrations of brown rice and Chinese cabbage were also analyzed.The results indicated that Pb concentration of brown rice grown in the Pb-contaminated soils(125-500 mg/kg)were below 0.5 mg/kg and not affected by different soil conditioners,but those in Chinese cabbage were 2-7 mg/kg and were slightly decreased by COM and CAP treatments.In the soils contaminated with Cr and Ni,the concentration of Cr in brown rice and Chinese cabbage were below 2.5 and 2-4 mg/kg,respectively,while the effects of different soil conditioner additions were not observed.The Ni concentrations of brown rice and Chinese cabbage were below 2.2 and 2-53 mg/kg while those were decreased only by the application of compost(COM).For all the treatments,the concentrations of DTPA extractable Ni in soils were significantly correlated to the Ni concentrations in brown rice and Chinese cabbage.The DTPA extractable amounts of soil Pb or Cr were not significantly correlated with Pb and Cr concentration in plants.These results indicated that both Pb and Cr availability were relative low even their total concentration in soils reached 94 and 340 mg/kg.In comparison,Ni availability in soils were relative high and DTPA extractable method can be as a good soil testing method to predict the bioavailability.Compost can be selected as an efficient soil conditioner to reduce the Pb and Ni concentration in brown rice and Chinese cabbage.