--An environmental geologist knows how to look at the underlying soil and rock, understands how the ground water moves, and figures out where those chemicals have gone to help find the best way to cleanup the spill. County, state, and/or federal regulatory agencies require that reports documenting the geology, ground water, and contamination of such areas be submitted.
Now communities properly site and design landfills, but what if your community used an old gravel pit as its garbage dump many years ago and now the garbage is polluting the ground water and threatening the community drinking water supply? An environmental geologist can figure out how far the contaminated ground water plume has moved through the earth and pick the best location for wells to control the contamination and prevent further degradation of the environment. Meanwhile, an environmental geologist (or engineering geologist) can help find the best location for the new landfill, placed in a geologic setting with the lowest risk of polluting ground water. Environmental geologists are also called upon to evaluate the migration of landfill gas that is generated in solid waste landfills as it decomposes. They help assure that unsafe or explosive levels of methane do not migrate off the landfill property and into nearby homes.
Environmental geology, like hydrogeology, is a multidisciplinary field of applied science and is closely related to engineering geology and somewhat related to environmental geography. They all involve the study of the interaction of humans with the geologic environment including the biosphere, the lithosphere, the hydrosphere, and to some extent the atmosphere. It includes:
managing geological and hydrogeological resources such as fossil fuels, minerals, water (surface and ground water), and land use.
defining and mitigating exposure of natural hazards on humans
managing industrial and domestic waste disposal and minimizing or eliminating effects of pollution, and
performing associated activities, often involving litigation. http://en.wikipedia.org/wiki/Environmental_geology