Air & Waste Management Association (Allegheny section): This group offers scholarships in the range of $1000 to $2000 to undergraduates pursing degrees in environmental geology /environmental science. The purpose of the A&WMA is to promote a "better understanding of problems in the fields of air and water pollution and waste management and providing a means for exchanging information towards resolving those problems".
Annie's Homegrown Environmental Studies Scholarship Program
Annie's Homegrown (they make organic foods) is offering 25 $1000 scholarships each year (no application deadline) to undergraduates who are in a program of study related to preserving the environment. Pitt environmental studies and environmental geology majors would be well-suited to apply for this scholarship. Under "Our Programs" information is provided on other scholarship programs plus things like ways to get cheap or free food from the company (site content seems to vary, so check it out!).
The (Bill) Gates Millenium Scholarship Program If you are an undergraduate who is African American, American Indian/Alaska Native, Asian Pacific American, or Hispanic and you've got a GPA > 3.3, you could get full support for the remainder of your undergraduate career or for graduate school!