Find me four common themes in these articles, “Delivering freshwater critical infrastructure, environmental justice in Flint, Michigan”, by Michael R Greenberg, Mauna Kea: “The Fight to preserve culture”, the article “Choking the oceans with plastic” by Charles J Moore, “Banning plastic bags is great for the world right” by Ben Adler, the the article “Elevated Blood Lead Levels in Children Associated with the Flint Drinking Water Crisis” by Mona Hanna-Attisha, Jenny Lachance, Richard Casey Sadler, And Allison Champney Schnepp.