Effect of Concentration on Sorption of Dissolved Organics by Well Castings

摘要

This report examines sorption of low ppb levels of organic solutions bypolytetrafluoroethylene (PTFE), rigid polyvinyl chloride (PVC) and stainless steel 304 and 316 well casings. Nineteen organics that were either on the EPA priority pollutant list or of concern to the U.S. Army were selected, including several munitions and chlorinated solvents. These compounds were selected to give a range in physical properties such as solubility in water, octanol-water partition coefficient and molecular structure. When these results were compared with the results from a similar study conducted at ppm levels, the rate and extent of sorption by PTFE and PVC was the same for almost all analyses. There were no losses of any compounds associated with stainless steel. At these low levels (ppm and ppb) the rate of diffusion within the polymer (PVC and PTFE) is independent of concentration. Only with PTFE are the rates rapid enough to be of concern when monitoring for some compounds in groundwater. Tetrachloroethylene was the compound sorbed by PTFE the most rapidly. The study showed that PVC well casings are suitable for monitoring low levels (ppm and ppb) of organics. Groundwater monitoring, Organic solutions, Groundwater sampling, Well casings.