Exposure Chamber Measurements of Mass Transfer and Partitioning at the Plant/Air Interface
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- 作者：Randy L. Maddalena ; Thomas E. McKone ; and Norman Y. Kado
- 刊名：Environmental Science & Technology
- 出版年：2002
- 出版时间：August 15, 2002
- 年：2002
- 卷：36
- 期：16
- 页码：3577 - 3585
- 全文大小：155K
- 年卷期：v.36,no.16(August 15, 2002)
- ISSN：1520-5851
文摘
Dynamic measures of air and vegetation concentrationsin an exposure chamber and a two-box mass balance modelare used to quantify factors that control the rate andextent of chemical partitioning between vegetation andthe atmosphere. A continuous stirred flow-through exposurechamber was used to investigate the gas-phase transferof pollutants between air and plants. A probabilistic two-compartment mass balance model of plant/air exchange withinthe exposure chamber was developed and used withmeasured concentrations from the chamber to simultaneouslyevaluate partitioning (Kpa), overall mass transfer acrossthe plant/air interface (Upa), and loss rates in the atmosphere(Ra) and aboveground vegetation (Rp). The approach isdemonstrated using mature Capsicum annuum (bell pepper)plants exposed to phenanthrene (PH), anthracene (AN),fluoranthene (FL) and pyrene (PY). Measured values of logKpa (V[air]/V[fresh plant]) were 5.7, 5.7, 6.0, and 6.2 for PH,AN, FL, and PY, respectively. Values of Upa (m d-1) underthe conditions of this study ranged from 42 for PH to119 for FL. After correcting for wall effects, the estimatedreaction half-lives in air were 3, 9, and 25 h for AN, FL,and PY. Reaction half-lives in the plant compartment were17, 6, 17, and 5 d for PH, AN, FL, and PY, respectively.The combined use of exposure chamber measurementsand models provides a robust tool for simultaneouslymeasuring several different transfer factors that are importantfor modeling the uptake of pollutants into vegetation.