The Effect of Water Management on Arsenic Accumulated in Rice
Growing in Two Arsenic Contaminated Soils
Tai-Hsian Huang, Hao-Yen Chang and Zueng-Sang Chen*
Department of Agricultural Chemistry, National Taiwan University
No. 1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan
*
soilchen@ntu.edu.tw
Extended abstract
Water management has been demonstrated effective to reduce arsenic accumulation in paddy rice. In
this study, four water management strategies were conducted to compare the effect on reducing arsenic
accumulation in brown rice, they were: (1) Aerobic treatment for 10 days after 35 days of rice seedling
(CK); (2) aerobic treatment for 3 weeks before rice heading (A); (3) aerobic treatment for 3 weeks
after rice heading (B); and (4) aerobic treatment for 3 weeks before rice heading and continue for
another 3 weeks after rice heading(C). Two soil series, Erlin (Eh) and Pinchen (Pc) were used in this
experiment with two arsenic spiking levels for each. Soil redox potential raised about 60-400 mV
during the aerobic treatment period. At the same time, As, Fe, and Mn concentrations of soil solution
decreased significantly in Erlin soil, but not obviously in Pinchen soil. During the flooding period, As
concentration of soil solution was not increased significantly in Pinchen soil. Considering the effects
on reducing As concentration in brown rice, there was no significant difference among four water
treatments in Erlin soil. In Pinchen soil with 40 mg/kg As spiked, As concentration of brown rice
cultivated under strategy A (0.29 mg.kg) was significantly lower than those under strategy CK (0.42
mg/kg). Total As uptake of rice plant increased with the increasing As concentration in Pinchen soil.
For rice cultivated in the As-spiked Erlin soil, As uptake decreased with the increasing soil As
concentration. In addition to arsenic stress, a physiological mechanism may regulate the arsenic
transport in rice plant. For rice cultivated in the Pinchen soil with 40 mg/kg arsenic spiked, available
arsenic will enhance the As content of brown rice without inducing toxic effect on growing, and
strategy A was practicable to reduce the risk of arsenic contamination in brown rice.
Keywords: Arsenic (As), water management, soil aerobic treatment, rice (Oryza sativa L.)
Table. ANOVA of brown rice arsenic concentration
Soil
Erlin
Pinchen
#
Conc.
N.S.
***
N.S.
**
Method§
N.S.
N.S.
Conc. × Method
#: Soil arsenic spiking concentration; §: Water management strategies (CK, A, B, and C); N.S.: no
significant; *p<0.05; **p<0.01; ***p<0.001.
Figure 1. Brown rice arsenic concentration of
different treatments in this pot experiment.
Results followed by the same letter are not
significantly different at p<0.05 using Fisher’s
LSD method.