What was the central idea in Alphabet by Naomi Shinab Nye?

I've never read this book, but from what I have been able to gather the central idea in Nye's book, Alphabet, is pollution.... specifically carelessness and the way we treat what we perceive to be garbage..... trash to throw away, whether it be bottles and straws or people. This poem collection addresses the environment, immigration, politics, the community, and the planet.