Gas-Phase Distribution and Emission of Chloropicrin Applied in Gelatin Capsules to Soil Columns
- Qiuxia Wanga,
- Dong Wangb,
- Jueting Tanga,
- Dongdong Yana,
- Hongjun Zhangc,
- Fangyan Wanga,
- Meixia Guoa and
- Aocheng Cao *a
- a Key Laboratory of Pesticide Chemistry and Application, Ministry of Agriculture, Dep. of Pesticide, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
b USDA–ARS, Water Management Research Unit, San Joaquin Valley Agricultural Sciences Center, Parlier, CA 93648
c Institute for the Control of Agrochemicals, Ministry of Agriculture, Beijing 100125, China. Assigned to Associate Editor Mingxin Guo
Chloropicrin (CP) is highly volatile and may pose strong exposure risks for humans and the environment. A gelatin capsule formulation was developed to reduce atmospheric CP emissions and to improve application safety. The objective of this study was to determine the distribution, atmospheric emissions, and soil residual of CP after application in gelatin capsules to soil columns. Two treatments were studied: (i) CP liquid injection with polyethylene film and (ii) CP gelatin capsules with polyethylene film. For the CP liquid injection treatment, the concentration of CP peaked (120.7 μg cm−3) at the 20-cm depth 1 h after fumigant injection and decreased with time; at other depths, the CP concentration increased initially and decreased after a typical diffusion-dispersion process. For the gelatin capsule treatment, concentrations of CP at 20 cm depth increased slowly and peaked at 30.04 μg cm−3 264 h after application, indicating a slow CP release through the gelatin capsule shells. The results indicate that a rapid breakdown of gelatin capsules occurred between 11 and 12 d after application. The application of CP gelatin capsules reduced total CP emission by approximately 3 times compared with liquid injection with film cover. Similar residual soil CP was found between the liquid injection and the two gelatin capsule treatments. Chloropicrin gelatin capsules could be a promising new technology for reducing environmental emissions and potential human exposure.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 2010.