Analyses of selected groundwater databases provide insight into the abiotic reaction conditions that occur in subsurface ecosystems. With this information it is possible to impose boundaries on the activity of selected chemical species in porous media and narrow the ranges of reactivities to be studied in quantifying abiotic transformation processes. The groundwater parameters that are addressed here are, pH, oxygen levels, and organic carbon content. These data suggest that neutral or pH independent hydrolysis would be the more important process for many organic compounds in groundwater systems than would alkaline of acid hydrolysis pathways. Also the data suggest that, for abiotic redox transformation reactions of organic compounds, reductive processes would be more important. Based on the knowledge of the kinetics of abiotic hydrolysis of selected organic compounds in soil and aquifer samples, it appears that sorption affects the observed hydrolysis rate constant depending on the hydrolytic pathway.