You can limit the results of your search by using Google advanced search. Enter .gov, .org or .edu in the site or domain box.
Before you use material from the Internet, evaluate the site.
WHO- is the author or sponsor ?
Is it a reliable person, site?
WHAT- information is provided ?
Does it match other information from valid sources?
WHEN- was the information posted/updated ?
Is it current?
WHERE- does the information come from?
Is it a reputable source such as .edu or .gov?
WHY- is the information there?
Is it there to inform and educate without bias?
The following websites are just suggestions, there are many different environmental sites you may find interesting.