Determination of Arsenic Species in Soil Solution under
B. M. Onken* and L. R. Hossner
Greenhouse experiments were conducted to evaluate the relationships between
the species and concentrations of As in the soil solution of flooded soils with other
parameters including soil pe, pH, Fe, Mn, and type and amount of As added.
Two soils were treated with 0, 5, 15, 25, 35, and 45 mg As kg-1 soil added as
either Na-arsenate or Na-arsenite and planted with rice (Oryza saliva L.). Soil
solution samples were collected during a period of 60 d and analyzed for As.
Selective hydride generation was employed to evaluate both type and quantity of
As present in the samples. Inorganic As in the form of arsenate and arsenite was
found in the soil solution of both soils. The conversion of added arsenite to
arsenate occurred within the first 10 d of the experiment when the pe/pH of the
soil was not conducive to arsenite stability. Added arsenate was converted to
arsenite during the course of the experiment as the pe/pH of the soil declined due
to flooding. Arsenate reached a maximum in soil solution at 10 to 20 d after
flooding while maximum arsenite concentrations occurred at 20 to 30 d after
flooding. The total concentration of As in soil solution generally reached a
maximum at 20 to 30 d after flooding, after which time precipitous losses of As
from soil solution occurred in all but the highest As treatments. Soil solution As
concentrations were not statistically different between planted and unplanted
B.M. Onken, Dep. of Plant Science, 149 Townsend Hall, Univ. of Delaware,
Newark, DE 19717-1303; and L.R. Hossner, Dep. of Soil and Crop Sciences,
Texas A&M Univ., College Station, TX 77843.
*Corresponding author (firstname.lastname@example.org).
SREL Reprint #2122
Onken, B.M. and L.R. Hossner. 1996. Determination of arsenic species in soil
solution under flooded conditions. Soil Science Society of America Journal
To request a reprint