Qualifications
Conservationists tend to be an educated bunch. While having a bachelor of science degree can get you an entry-level job, chances are that if you plan on working for the private industry or even the government, you'll be required to have at least master's degree. A PhD isn't a bad idea, either.
Getting a broad education in several areas of the physical sciences—biology, chemistry, zoology, geography, and physics to name a few—will prepare you to go on and pursue your focus of choice, such as pollution, the ecosystem, hydrology, etc.
You might also consider getting an undergraduate degree in business administration or finance and a minor in a physical science, and then going on to get a higher degree in a very specific area such as environmental legislation or even environmental law. Having such a broad range of skills will make you eminently hirable, and all those degrees will look so nice on your wall.