I did my BS and MS in Biology with particular attention to aquatic ecology. As a graduate student, I got to do field work, lab work, publish research, and present at conferences. I would say that depending on your job, the day-to-day could be going out in the field and collecting data and lots of time in the lab doing data analysis. For me, it was a lot of time spent identifying and counting diatoms (a type of microscopic algae) under the microscope, analyzing the results. I imagine that any environmental studies field you choose will have elements of conducting scientific research. I have friends who studied fields related to environmental studies and now work for government agencies such as Georgia Environmental Protection Agency to the Environmental Protection Agency in DC. Much of the work consists of the same responsibilities as I mentioned above. Doing scientific research allows them to use the data to inform land management decisions to environmental policies.
Good luck on selecting your major!