Millions of people visit Santa Monica beaches each year, but if you swim near the pier area, be warned that the water is the most polluted in the state, according to Heal the Bay’s research.

Heal the Bay’s Santa Monica Pier Aquarium will celebrate Earth Day on Saturday, April 21, opening early and hosting special eco-friendly activities from 11 a.m. to 5 p.m.

Heal the Bay released its 26th annual beach report card last week, and along with it came the environmental group’s top-10 “Beach Bummer” list. Heal the Bay analysts assigned A-to-F letter ...