Heavy Metals in Indonesian Paddy Soils

Abstract

Long-term cultivation of paddy soils has resulted in Pb and Cd accumulation that exceeds the WHO tolerance levels of 2 mg kg−1 and 0.24 mg kg−1 in food. In Musi Rawas, South Sumatra, Indonesia, the paddy soils with the greatest levels of Pb and Cd were those that had been intensively farmed for 80 years, reaching the concentrations of 20.56 mg kg−1 Pb and 0.72 mg kg−1 Cd for soil, and 3.11 mg kg−1 Pb and 0.29 mg kg−1 Cd for rice. The lowest concentrations were obtained with 20 years of cultivation at 17.82 mg kg−1 and 0.26 mg kg−1, for Pb and Cd in soils, respectively. The Pb content in the paddy fields in Pati, Central Java, ranged from 0.23 to 2.55 mg kg−1, while the Pb content in the lowland watershed of Solo Hilir ranged from 0.20 to 2.94 mg kg−1. The highest concentration of Pb and Cd in rice was found at 80 years old in paddy soils with the value of 3.11 mg kg−1 and 0.29 mg kg−1, respectively. The lowest concentrations were found at 20 years old of soils with a value of 2.35 mg kg−1 Pb and 0.15 mg kg−1 Cd, respectively.