Formation and extraction of persistent fumigant residues in soils

Mingxin Guo, Sharon K. Papiernik, Wei Zheng, Scott R. Yates

Research output: Contribution to journalArticlepeer-review

Abstract

Fumigants are commonly thought to be short-lived in soil, but residues have been found in soils years following application. In this study,formation and extraction of persistent soil fumigant residues were investigated. Fumigants 1,3-dichloropropene (1,3-D), chloropicrin (CP), and methyl isothiocyanate (MITC) were spiked into Arlington, Glenelg, and Hagerstown soils and incubated for 30 d under controlled conditions. The incubated soils were evaporated for 20 h prior to extraction with a variety of organic solvents at different temperatures. Extraction with acetonitrile in sealed vials at 80 °C for 24 h was the most efficient method to recover persistent soil fumigant residues. At application rates of 1000-1700 mg (kg of soil)-1, persistent residues of 1,3-D, CP, and MITC in the three soils ranged from 5 to 67 mg kg-1. The residue content increased with application rate, correlated positively with soil silt content, decreased dramatically as indigenous organic matter (OM) was removed, and changed little with external OM addition. Adsorption to clay surfaces was not important in fumigant retention, while pulverization of soil aggregates significantly decreased persistent fumigant residues. The results suggestthat persistent fumigant residues are retained in soil intra-aggregate micropores resulting from binding clay flocs and silt particles by humic substances.

Original languageEnglish (US)
Pages (from-to)1844-1849
Number of pages6
JournalEnvironmental Science and Technology
Volume37
Issue number9
DOIs
StatePublished - May 1 2003
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry

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