BIOLOGICAL AND ABIOLOGICAL CONTROLS ON TRACE METAL MOBILIZATION FROM SHALE GAS DRILL CUTTINGS BY LANDFILL LEACHATE

This study focused on possible metal mobilization from Marcellus Shale drill cuttings via biological and abiological processes in landfills and also in freshwater surface environments. Using drill cuttings from the Marcellus Shale as well as the overlaying Tully Limestone and the Hamilton Group we conducted several microcosm experiments. The microcosms were prepared under both oxic and anoxic conditions using the drill cuttings and either: 1) an artificial medium commonly used for culturing freshwater microorganism; 2) an artificial landfill leachate medium designed to mimic typical landfill leachate chemistry; or 3) natural landfill leachate collected from a working landfill. The results of these experiments indicate that the microbes found in this landfill leachate do not play a large role in metal release. Most of the metal release was due to abiological factors. Therefore, these chemical processes have a greater effect on the mobilization of metals from the drill cuttings in landfills than biological controls. The results of this research should provide landfill administrators with better tools to anticipate factors that influence the mobilization of metals from disposed drill cuttings from the Marcellus Shale.