Submitted to: Proceedings of International Research Conference on Methyl Bromide Alternatives
Publication Type: Proceedings
Publication Acceptance Date: 9/1/2006
Publication Date: 11/6/2006
Citation: Gao, S., Pflaum, T.J. 2006. Trapping efficiency of cis-1,3-dichloropropene by xas-4 sorbent tubes for emission studies. 2006 Proceedings of International Research Conference on Methyl Bromide Alternatives, pages 121-1 - 121-4. Interpretive Summary:
Technical Abstract: Monitoring fumigant emissions often requires the use of sampling tubes filled with organic polymer sorbents to trap fumigants from gas samples. 1,3-Dichloropropene (1,3-D) and chloropicrin (CP) are being increasingly used as alternative fumigants to methyl bromide and are often used in combinations for soil fumigation. XAD-4 is considered effective for trapping CP, but the trapping efficiency of XAD-4 for 1,3-D has been questioned. The amount of work in sample collection and processing can be significantly reduced if one sampling tube can be used for trapping 1,3-D and CP. In this study, we tested the efficiency of XAD-4 sorbent tubes for trapping cis-1,3-D from gas samples under different flow rates and sampling times. The trapping efficiencies of 1,3-D by Charcoal and CP by XAD-4 were used for comparisons. The tested amount of 1,3-D and CP for small and large tubes were approximately 0.3 and 0.7 mg, respectively. At the low flow rate (100-200 mL/min), a single XAD-4 can trap 92-99% of the 1,3-D. At the high flow rate (1000 mL/min), several tests showed that a single XAD-4 tube recovered 87-96% (average 92%) of the 1,3-D at a sampling time of 10 min. However, substantially lower recovery was obtained from the 1st tube if flushed for 3 h regardless of fumigants (20% loss for 1,3-D and 10% for CP). These tests indicate that XAD-4 sampling tubes can be used for trapping 1,3-D from gas samples with greater than 90% recovery at both low and high flow rates for short sampling time (< 30 min). Longer sampling time (3 h) may lead to significant loss of fumigants from the XAD-4 sampling tubes. Thus, short sampling intervals or a series of sampling tubes may be used to achieve high trapping efficiency of 1,3-D and CP. It should be noted that the tested amount of fumigants used in this study may be higher than normal field monitoring conditions.