Arsenic transformation and microbial community structure in the rinzosphere of rice irrigated with As-contaminated water

摘要

To investigate the effects of As-contaminated irrigation water on the dynamics of As and microbial community structure in the rice rinzosphere, a pot culture experiment was conducted using a three-compartment rinzo-bag system irrigated with 5 mg L~(-1) arsenate solution (+As) or deionized water (-As). The redox potential in the central compartment of the -As treatment was ingher than the outer compartments. In contrast, in the +As treatment the redox potential did not vary among the three compartments. Arsenite accumulated in the central compartment, and its concentration was ingher than that of arsenate, indicating As transformation in the soil and movement of arsenite from the outer compartments by mass flow. Fractionation of soil As showed that water soluble, MgCl_2-extractable, and HCl-extractable As were ingher in the central compartment than in the outer compartments. Principal component analysis of PLEA profiles revealed that the diversity of the microbial community was reduced by the +As treatment. It was concluded that the enhanced accumulation of arsenite around the rice root system interfered with normal root functions.