Effects of rice straw ash amendment on Cu solubility and distribution in flooded rice paddy soils
Journal
Journal of Hazardous Materials
Journal Volume
186
Journal Volume
186
Journal Issue
2-3
Journal Issue
2-3
Pages
1801-1807
Start Page
1801
End Page
1807
ISSN
03043894
Date Issued
2011-02-28
Author(s)
Abstract
Rice straw burning is a common post-harvest practice on rice paddy land, and it leads to the accumulation of rice straw ash (RSA) in paddy soil. To understand the role of RSA in determining the mobility and bioavailability of metal contaminants, this study investigated the effects of RSA amendment on the solubility and distribution of Cu in contaminated rice paddy soils with flooding incubation. The addition of RSA to the soils suppressed the release of Cu into the soil solutions, which was primarily attributed to the metal-binding capacity of the RSA. Additionally, after the soils were flooded, the increase in soil pH and decrease in redox potential resulted in the transformation of Cu into less soluble forms. The RSA amendment appeared to enhance the changes in pH and redox potential of the flooded soils and, consequently, the immobilization of Cu in the soils. The results suggest that the RSA can retard the bioavailability and movement of the metal in contaminated soils and, thus, lower the potential environmental risk of Cu toxicity.
Subjects
Bioavailability
Black carbon
Heavy metals
Mobility
Rice paddy soils
Rice straw ash
Type
journal article