Kari Kilgore 
The Garbage Belt [EPUB ebook] 

Looking for humans? Just look for the garbage.
From bones to plastic to dead electronics, people rarely manage to clean up after themselves.
Humanity takes a long time to learn how to manage limited resources, too. The rare and precious get lost with the useless and plentiful.
Meet Gayle Simmons, pilot of the Treasure Hunt.
Rare and precious, in her sights.