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.