Evaluation of passive sampling devices as potential surrogates of metal uptake into soybean.

Chelating anion exchange membrane (CAEM), Nafion® tubing, and Strong cation exchange cartridges (SCX) were evaluated as passive sampling devices for cadmium (Cd), copper (Cu), and lead (Pb) uptake in soybean (Glycine max). The CAEMs were sampled every hour for 12 h. Metal concentrations in plant tissues, SCX, and water solution in Nafion® tubing were determined weekly for 4 weeks. The amount of Cd and Pb on CAEM increased linearly with time in the sand experiment. Cadmium, Cu, and Pb uptake by soybean leaves was poorly correlated with metal concentration on CAEM. Regression analysis between log transformed Cd and Pb concentrations in water within Nafion® tubing and in sand solution extracted by water indicated that there was a significant linear relationship between them. Metals were not consistently detected in elution solution of SCX. Nafion® tubing may be a promising passive sampler for heavy metals in soil solution.