MONITORING SOIL COLUMN MOBILITY OF CROSS-LINKED AND SOLUBLE POLYACRYLATES USING GEL-PERMEATION CHROMATOGRAPHY

The potential fate of polymeric materials in soils is important to env ironmental safety. This study validated highperformance gel permeation chromatography (HPGPC) to assess elution behavior of a commercially a vailable, crosslinked, high molecular weight polyacrylate absorbent (P A) and a soluble low molecular mass (4500 Da), linear poly(acrylic aci d) (LPA) in three types of columns prepared from sandy and loamy soils . HPGPC was used to monitor the elution of the soluble PA and LPA from the columns. The LPA represents the fraction (<4%) of the PA that is typically extractable in commercial PA material. Over 99% of the PA sa mple was found to be retained on a Borden sand test column. The amount that moved is probably related to the extractable polymer. A total of 92% of the non-cross-linked LPA was retained on a Borden sand column. Virtually all of the LPA was retained on the Fox loam column. PA mobi lity could not be studied bn the Fox loam soil; however, the high clay content of this soil is expected to make the PA less mobile than in B orden sand. Londo loam soil yielded high levels of background interfer ents for PA and LPA, preventing acquisition of definitive mobility dat a. However, LPA and PA are expected to be less mobile on Londo loam th an on Borden sand due to the higher organic matter/clay contents. Thes e results indicate that typical consumer product-grade PAs would not m ove appreciably through common soil types in or near landfills. The re sults also support the use of LPA as a model for studying movement of the soluble portion of commercially available PA through soils and dem onstrate that HPGPC is suitable for quantifying soluble polyacrylates in synthetic groundwater effluents.