EFFECTS OF ORGANIC LIQUIDS ON THE PERMEABILITY OF SELMA CHALK

The permeability of monolithic specimens of Selma chalk to six pure or ganic liquids - acetone, ethylene glycol, heptane, acetic acid, xylene , and aniline - representing some of the classes of organic compounds stored in hazardous waste repositories and to water. was measured in t he laboratory. Specimens were core-drilled from large blocks of chalk obtained from the formation in western Alabama and in central Alabama, 150 km to the cast. Specimens of both ''virgin chalk'' and of chalk t aken from naturally re-cemented crack zones were studied. In order to prevent viscosity effects from masking the changes in chalk structure brought on by contact with the permeant, intrinsic permeabilities rath er than hydraulic conductivities are reported. Compared to data for wa ter (intrinsic permeability of 1.5 x 10(-13) cm(2)) the mean values of the experimentally measured permeabilities to the organic liquids wer e found to be higher, but not by more than a factor often. The only ex ception was the permeability to ethylene glycol, which had a mean valu e about thirty times that to water. Higher mean values were significan t at the 90% level of confidence only for ethylene glycol and aniline. There was not much difference found in permeability between specimens from the western and central Alabama locations or between ''virgin ch alk'' and chalk taken from re-cemented crack zones.