Arsenic bioaccessibility and speciation in the soils amended with organoarsenicals and drinking-water treatment residuals based on a long-term greenhouse study

Rachana Nagar, Dibyendu Sarkar, Konstantinos C. Makris, Rupali Datta

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

Although organoarsenical pesticides are no longer applied to agricultural fields in the US, their widespread use until recently, toxicity, and potential transformation to inorganic arsenic has raised serious concern. Drinking-water treatment residuals (WTRs) have been proposed as a low-cost amendment for remediation of organoarsenical pesticide contaminated soils. A long-term greenhouse study was initiated to evaluate the effect WTR application on bioaccessibility, geochemical partitioning, and speciation of the Dimethylarsinic acid (DMA). Two soils (Immokalee and Orelia series) were spiked with DMA (1500mgAskg-1) and amended with an Al- and Fe-based WTR at two rates (5% and 10% by wt.). Soil sampling was done immediately after spiking (time zero) and after 0.25, 0.5, 1, and 3 (time final) years of equilibration and subjected to bioaccessibility test and sequential extraction. Results showed that compared to the unamended (no WTR) control, As bioaccessibility in the WTR-amended soils significantly (p<0.001) decreased by 40-70% in 3years. The Fe-WTR was more effective than Al-WTR in decreasing soil As bioaccessibility. The in vitro and water-extracted samples were subjected to As speciation at time zero and time final. Results showed transformation of DMA into inorganic As, irrespective of WTR amendments. The Orelia soil showed significantly (p<0.001) higher transformation than the Immokalee soil.

Original languageEnglish
Pages (from-to)477-485
Number of pages9
JournalJournal of Hydrology
Volume518
Issue numberPC
DOIs
StatePublished - 1 Oct 2014

Keywords

  • Bioaccessibility
  • Dimethylarsinic acid (DMA)
  • Drinking-water treatment residual (WTR)
  • Organoarsenicals
  • Speciation

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