http://www.motherjones.com/blue-marble/2012/07/dirtiest-beaches-nrdc
It doesn't matter how expansive the ocean is, the beaches aren't always pristine!
I was happy to see that the NC beaches were generally on the "cleaner" end. This was based on coliform bacteria present. Interesting factoid - beaches that meet minimum federal standards would still sicken 1 in 28 swimmers. Not sure how that was calculated but impressive if true.
South Padre Island in Texas was also listed as one of the cleanest - nice to hear given how many students flock down there each Spring