The objectives of this project are (1) to revise the regulation of heavy metals in contaminated soils or in monitoring system, (2) to establish the relationships between metal concentration in soil and metals uptake in the food crop, (3) to propose a regulation of heavy metals in contaminated soils for different land uses, and (4) to study the status of lead accumulation along the super freeway in Taiwan. After collecting the databases and references and making the analysis, we recommend that the regulation of total contents of heavy metals in Taiwan rural soils should be revised as Cd 4 mg/kg, Cu 600 mg/kg, Zn 800 mg/kg, and Pb 1000 mg/kg. The other elements are proposed not to be changed. For non-rural soils in Taiwan, the total Cu concentration should be revised as 1000 mg/kg. We also propose three chemical extraction methods including 0.1M HCl, 0.01M EDTA, and 0.005M DTPA to identify the bioavailability of heavy metals in contaminated soils. The regulation of bioavailable concentration of contaminated soils is also proposed. We propose that the regulation of the concentration of heavy metals in resident and park region should be higher than those of rural soils region, and the concentration of heavy metals in soils of industrial and commercial region should be higher than those of soils of resident and park region. Lead is almost distributed in the 30 cm soil depth around 3 to 30 meters along Taiwan No. 1 Super Freeway. Until now, the total deposition of lead is estimated as more than 450,000 tons. Some recommendations are proposed that the government agencies should (1) request the compensation to the farmers paid from the soil contamination producer, (2) establish the regulation of bioavailability of heavy metals in the contaminated soils for monitoring the soil and crop quality, and (3) make a detail survey on the heavy metals in the rural soils along the main roads of Taiwan.

Regulation of heavy metals in contaminated soils,Soil heavy metal,As,Cd,Cr,Hg,Cu,Ni,Pb,Zn,Soil bioavailabile concentration