- Copyright © 2002 Society of Exploration Geophysicists
Environmental geophysics deals with issues ranging from local-scale fluid-rock changes to large-scale climatic changes caused by anthropogenic activities and natural processes. It is enjoying rapid growth for two reasons: (1) the present sociopolitical climate of increasing awareness of the effect of man's past activities on the environment; and (2) new technological and multidimensional modeling advances that may have brought geophysical methods close to their theoretical resolving power.
However, there are some outstanding problems: Realistic whole-site multidimensional imaging of contam-inated land, understanding fluid-rock interactions, optimal data integration, and remote prediction of flow and subsoil compositions are currently the most pressing scientific issues.
This article stresses that due to increasingly stringent statutory requirements, the road ahead will call for more than purely physical models of the subsurface. Integrated investigative approaches need to become routine, especially when there may be postsurvey legal connotations. Thus, more work needs to be done on integration of disparate data types, prediction of hydrochemistry from noninvasive profiling, and time-lapse characterization for monitoring natural attenuation or remediation processes (Table 1).
Land and groundwater contamination
The decline in heavy industrial activities, past waste disposal practices and accidental spills, military decommissioning activities, and past legislative inadequacies have left a legacy of closed and/or abandoned mines and quarries, military bases, oil and gas fields, petroleum refineries, etc. Many derelict sites are contaminated by petroleum liquids—such as light nonaqueous phase liquids (gasoline-based benzene, toluene, or xylene) or dense nonaqueous phase liquids (cleaning solvents such as trichloroethylene or heavy oils such as crankcase oils), mine spoils, and other inorganic pollutants. Accidental spills or poor disposal practice at these sites would result in significant concentrations of numerous types of both organic and inorganic contamination and would pose a severe threat to groundwater aquifers. Petroleum liquids occur in the subsurface as pure-phase organic liquids, …