title: Arsenic and lead (beudantite) contamination of agricultural rice soils in the Guandu Plain of northern Taiwan.
abstract: This study investigates the species of As and Pb (beudantite) residues present in the seriously contaminated agricultural rice soils of the Guandu Plain. Two pedons in the Guandu Plain agricultural soils, each pedon separated into five horizons (each of 20 cm) were collected for this study. Soil samples were packed into a column for leaching with simulated acid rains. Soil pH ranged from 5.1 to 7.1 with high base saturation. Soils can be classified as clay loam, mixed, thermic, Typic or Umbric Albaqualfs. The XRD analysis indicated the beudantite particles are present in clay fractions, showing high concentrations of As and Pb. This is because of 50-100 years ago irrigation water was introduced from Huang Gang Creek of hot springs containing high concentrations of As and Pb. Only low concentrations of As and Pb can be leached out with simulated acid rains (i.e., pHs 2 and 4), even through 40 pore volumes of leaching experiments. The sequential extraction experiments resulted in the high portions of As and Pb remaining in the amorphous, Fe and Al oxyhydroxides and residual fractions. Thus, the remediation of As and Pb in this agricultural rice paddy soils merits further study.
authors.affiliation: Department of Agricultural Chemistry, National Taiwan University, Taipei, Taiwan.
authors.forename: Kai Ying
authors.initials: KY
authors.lastname: Chiang
authors.forename: Kuo Chuan
authors.initials: KC
authors.lastname: Lin
authors.forename: Sheng Chi
authors.initials: SC
authors.lastname: Lin
authors.forename: Tsun-Kuo
authors.initials: TK
authors.lastname: Chang
authors.forename: Ming Kuang
authors.initials: MK
authors.lastname: Wang
mesh_terms: D001151:Arsenic / Q000032:analysis*; D018556:Crops, Agricultural; D052918:Environmental Restoration and Remediation; D007854:Lead / Q000032:analysis*; D012275:Oryza; D012989:Soil Pollutants / Q000032:analysis*; D013624:Taiwan; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; D007854:Lead; D001151:Arsenic