Hey, you have a possibility of getting a job in the environmental science field after you have done your M.Sc in environmental science. Because they deal with some similarities we see the possibility but the first preference will always go with people who have done their graduation in Environment Engineering or any type of engineering. Other Career options you can look out for M.Sc Environment Science are

Environmental Scientist

Environmental Lawyer

Zoologist

Conservation Scientist

Hydrologist

Teacher