4 reasons for the 72-hour beach advisory
“Surfers know that they should stay out of the water for at least 72 hours after it rains to avoid getting sick.
This is especially true after a “first flush” storm, the first heavy rain of the season, when an accumulation of grit, grime and pathogens built up during the dry season are carried in runoff, storm drains and rivers to the beach, and perhaps your favorite surf spot.
“We’ve done the monitoring and we know bacteria counts spike after it rains and go back to normal, in general, in 72 hours,” said Keith Kezer, an environmental health specialist with San Diego County’s Beach and Bay Monitoring Program.
But what exactly happens in this 72-hour period that magically turns water that can give you diarrhea, an eye infection, bronchitis or worse into water safe for human contact?
Kezer listed four processes that naturally reduce “fecal indicator” bacteria counts, which when elevated trigger beach closures. We thought we’d share, as an interesting FYI, since the rainy season and the good surf will soon be upon us.”
Keep reading at: http://caseagrantnews.org/2013/11/13/4-reasons-for-the-72-hour-beach-advisory/