Plant Uptake and Distribution of Endosulfan and Its Sulfate Metabolite Persisted in Soil.

Jeong-In Hwang,Jang-Eok Kim,Sung-Eun Lee,Pankaj Kumar Arora

doi:10.1371/journal.pone.0141728

Abstract

The distributions of endosulfan (ED) residues (α-, β-isomers, and sulfate-metabolite) in cucumbers grown in soils treated with ED at concentrations of 20 and 40 mg kg-1 were assessed using indoor and outdoor experiments. In all treatments, degradation rates of the α-isomer in soils were higher than that of the β-isomer. In the indoor tests, uptake amounts of total ED by cucumbers, after 15 d of growth, were 7.8 and 14.5 mg kg-1 in 20 and 40 mg kg-1-treated pots, respectively. For growth time from 15 to 30 d, uptake amounts in 20 and 40 mg kg-1-treated pots were 3.8 and 7.9 mg kg-1, respectively. Outdoor tests resulted in smaller ED residues in cucumbers than those in indoor tests. In both indoor and outdoor tests, ED residues absorbed were highest in roots, and the α-isomer was the more frequently absorbed isomer. These results will be useful for determining management criteria for soil persistent pesticides.

Highlights

Several recent studies have reported pesticide residues in organic agricultural products [1,2]
Total ion chromatogram and mass spectra of α, β-isomers, and sulfate-metabolite of ED identified by gas chromatography-mass spectrometer (GC-MS) are shown in S1 Fig Fragment ions of each compound present in the mass spectra corresponded to the mass spectral library data provided by the National Institute of Standards and Technology (NITS), having similarities > 92%
Target ions used for the selected ion monitoring (SIM) analysis were the most intensive and free from fragment ions that appeared in blank samples of soil and cucumber compartments

Summary

Introduction

Several recent studies have reported pesticide residues in organic agricultural products [1,2]. Uptake studies were conducted under both indoor and outdoor conditions, and residual amounts of the ED were analyzed in four plant compartments, including roots, stems, leaves, and fruits. In the 20 mg kg-1-treated pots, the uptake rates of the isomers in cucumbers sampled after 15 d of growth were 0.6% of the initial soil residue for the α-isomer, and 0.9% for the β-isomer (Fig 1a).

Results

Conclusion