We all know that sharks and jellyfish and the occasional undertow can harm ocean goers, but how much thought have you given to pollution? According to a recent report from NRDC, you really should pay more attention to the water-quality than anything.  Here's a quick list of the best beaches around, pollution-wise: California, Stinson Beach, Marin County (0%) California, Newport Beach, Orange County (0%) Delaware, Rehoboth Beach,...