Chapter 16 A greenhouse study on soil-arsenic forms and their bioaccessibility in two chemically variant Florida soils amended with sodium arsenate pesticide: Preliminary results

Shahida Quazi, Dibyendu Sarkar, Rupali Datta, Saurabh Sharma

Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review

1 Scopus citations

Abstract

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.

Original languageEnglish
Title of host publicationConcepts and Applications in Environmental Geochemistry
EditorsDibyendu Sarkar, Rupali Datta, Robyn Hannigan
Pages345-362
Number of pages18
DOIs
StatePublished - 2007

Publication series

NameDevelopments in Environmental Science
Volume5
ISSN (Print)1474-8177

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