Evaluation of passive sampling devices as potential surrogates of preschorate or heavy metal uptake in terrestrial plants. Dissertation in Environmental Toxicology
Yu, L.. 2004. Texas Tech University
Abstract
As the significance of bioavailability in ecotoxicological studies has increased, the use of surrogates to monitor contaminant exposure and uptake into biological systems has gained attention among scientists. Contaminates can be taken up into vegetation, which often serves as a pathway of exposure from soil/sediment to higher-level organisms. Anion Exchange Membrane (AEM), Chelating Anion Exchange Membrane (CAEM), Nation® tubing, and Strong Anion/Cation Exchange Cartridges (SAX/SCX) were evaluated as potential surrogates of perchlorate or heavy metal uptake into soybeans (Glycine max) grown in Ottawa sand, silt loam soil, and sandy loam soil. The heavy metals tested in this study were cadmium, copper, and lead. Chemical concentrations in plant tissues. Nation® tubing, and SAX/SCX were determined weekly. AEM/CAEM exchanged chemicals were determined hourly for 12 hours and statistically related to chemical concentrations in soybean leaves. In this study, perchlorate and heavy metals were taken up into soybean leaves in the experiments conducted in different soil textures. AEM/CAEM also demonstrated their potential to accumulate perchlorate and heavy metals from various types of soils. The amount of perchlorate, Cd, and Pb accumulated on membranes increased linearly overtime in sand. Perchlorate and heavy metal uptake by soybean leaves were poorly defined by linear regressions with membrane accumulation. Soil texture had a significant effect on the amount of chemicals exchanged on the membrane. Significant differences were observed among the membrane experiments conducted in different soil textures for all chemicals. There were no significant differences in membrane-exchanged chemicals between experiments conducted in silt loam soil and sandy loam soil for perchlorate, Cd, and Pb. Significant effects of texture were observed for heavy metal uptake in soybean. Linear regressions between chemical concentrations or log transformed chemical concentrations in water solutions within Nation® tubing and soil solution were significant for perchlorate, Cd, and Pb. Chemicals were not detected in the desorption solutions of SAX/SCX. These results indicate that AEM/CAEM may not be a good surrogate for chemical concentrations in soybean leaves at different growth stages. Nation® tubing may be used as a passive sampling device for soil solution to assess bioavailability of chemicals to plants.
