TY - CHAP
T1 - Chapter 16 A greenhouse study on soil-arsenic forms and their bioaccessibility in two chemically variant Florida soils amended with sodium arsenate pesticide
T2 - Preliminary results
AU - Quazi, Shahida
AU - Sarkar, Dibyendu
AU - Datta, Rupali
AU - Sharma, Saurabh
PY - 2007
Y1 - 2007
N2 - Long-term application of arsenical pesticides in agricultural lands has resulted in high levels of arsenic (As) in certain soils. Conversion of former agricultural lands to residential areas has increased human contact with soil-As. Soil ingestion from incidental hand-to-mouth activity by children is now a very important issue in assessing human health risk associated with exposure to arsenical pesticide-applied former agricultural soils. Human health risk from exposure to soil-As is restricted only to those fractions of As in the soil that are available to the human gastrointestinal system. This study followed up on a static incubation experiment aimed at addressing the issue of soil variability on As bioaccessibility as a function of soil chemical properties, but in a greenhouse column system accounting for dynamic interactions between soils, water, plants, and pesticides. Two chemically variant soil types were chosen based on their potential differences with respect to As reactivity. The soils were amended with sodium arsenate pesticide at two high rates. Rice (Oryza sativa) was used as the test crop. A sequential extraction scheme was employed to identify the geochemical forms of As in soils (soluble, exchangeable, organic, Fe/Al-bound, Ca/Mg-bound, residual) immediately after spiking and after six months of equilibration. Concentrations of these As forms were correlated with the in-vitro fractions of As to identify those As species that are most likely to be bioaccessible in the human gastrointestinal system. Results from this study verified those obtained from the static incubation experiment, and demonstrated that As bioaccessibility is a function of soil speciation of As and that soil-As forms are a function of soil chemical properties.
AB - Long-term application of arsenical pesticides in agricultural lands has resulted in high levels of arsenic (As) in certain soils. Conversion of former agricultural lands to residential areas has increased human contact with soil-As. Soil ingestion from incidental hand-to-mouth activity by children is now a very important issue in assessing human health risk associated with exposure to arsenical pesticide-applied former agricultural soils. Human health risk from exposure to soil-As is restricted only to those fractions of As in the soil that are available to the human gastrointestinal system. This study followed up on a static incubation experiment aimed at addressing the issue of soil variability on As bioaccessibility as a function of soil chemical properties, but in a greenhouse column system accounting for dynamic interactions between soils, water, plants, and pesticides. Two chemically variant soil types were chosen based on their potential differences with respect to As reactivity. The soils were amended with sodium arsenate pesticide at two high rates. Rice (Oryza sativa) was used as the test crop. A sequential extraction scheme was employed to identify the geochemical forms of As in soils (soluble, exchangeable, organic, Fe/Al-bound, Ca/Mg-bound, residual) immediately after spiking and after six months of equilibration. Concentrations of these As forms were correlated with the in-vitro fractions of As to identify those As species that are most likely to be bioaccessible in the human gastrointestinal system. Results from this study verified those obtained from the static incubation experiment, and demonstrated that As bioaccessibility is a function of soil speciation of As and that soil-As forms are a function of soil chemical properties.
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U2 - 10.1016/S1474-8177(07)05016-4
DO - 10.1016/S1474-8177(07)05016-4
M3 - Chapter
AN - SCOPUS:44349180919
SN - 9780080465227
T3 - Developments in Environmental Science
SP - 345
EP - 362
BT - Concepts and Applications in Environmental Geochemistry
A2 - Sarkar, Dibyendu
A2 - Datta, Rupali
A2 - Hannigan, Robyn
ER -