Evaluation of Passive Sampling Devices as Potential Surrogates of Perchlorate Uptake into Soybean

摘要

Anion exchange membrane (AEM), Nation~® tubing, and strong anion exchange cartridges (SAX) were evaluated as passive sampling devices for perchlorate uptake in soybean (Glycine max). Plant uptake studies and AEM studies were conducted in three soil textures: Ottawa sand, silt loam soil, and sandy loam soil. Nafion~® tubing and SAX experiments were only conducted in Ottawa sand. AEMs were sampled every hour for the first 12 h, then every 12 h until 72 h. Perchlorate concentrations in plant tissues, SAX, and water solution in Nafion~® tubing were determined weekly for 4 weeks. In sand, the amount of perchlorate accumulated in AEM increased linearly with time. Perchlorate uptake by soybean plants was poorly described by linear regressions with perchlorate concentrations on membranes. The only significant relationship between soybean uptake and membrane uptake occurred for data from membranes buried 6-12 h in sand. Significant differences (p < 0.0001) were observed for the amount of perchlorate exchanged on AEM in the three soil textures. There were no differences in perchlorate concentrations in soybean leaves among the three soil textures. Regression analysis of perchlorate concentrations in water within Nafion~® tubing and in sand solution indicted that there was a significant linear relationship between them (r~2=0.5132, p=0.0006). Perchlorate was not detected in eluent of SAX. AEM demonstrated its potential to accumulate perchlorate. Nafion~® tubing is not a good surrogate for plant uptake, but may be a promising PSD for soil solution. SAX may not be used as a PSD by itself.