Distribution of Cadmium in Soil around Zinc Mining Area

Abstract

Cadmium distribution was studied in four creeks of Mae Sot district, Tak province. Huai Mae Tao, a reputed creek, was shown to have low cadmium level at the upstream (8.45 mg/kg soil) and increased to 22.5 mg/kg soil at Ban Mae Tao Mai. Huai Mae Ku, the creek on the other side of the mountain with zinc mining, also showed high cadmium levels (7.55-34.95 mg/kg soil). Huai Mae Tao Ngae Sai, a creek in the north-eastern highland of the zinc mining, which was supposed to have no relation to zinc mining area showed cadmium level of 3.05 mg/kg soil. Huai Nong Khiao, a creek of the south-western highland showed cadmium level of only 1.1 mg/kg soil. From the data, it is suggested that cadmium source is at the upstream of Huai Mae Tao then causing the cadmium accumulation downstream. The cadmium source is unclear. Cadmium levels in the creek of two highlands were similar to the EU Maximum Permissible (MP) level of 3.0 mg/kg soil.