@ Aplenty- you definitely have a reason to not to swim or surf in that stuff. My buddy grew up in Santa Monica, and surfed the Cali coast line since he was really young. He would go out on days when there were pollution alerts on the beach...just to catch the epic swells. These were also the days that were really foamy.
Long story short, he ended up with a growth in his breast by the time he was 25. The doctor told him it was a non-malignant tumor or growth of some sort that was caused by surfing polluted waters around L.A.; crazy, right!