If an environment card is also a target ( as in Anubis), can it be destroyed by a hero with a card that states "destroy an environment card"?
Yes it can.
Yes as it is still an environment card which is the main concern and welcome to the forums.
Thank you for the quick replies and the warm welcome!
Glad to have you! 
Enjoy blasting Anubis with Grappling Hooks!
Welcome to the forums!
Fixed this for you…