By Gary Polakovic
Los Angeles Times
May 23, 2006
Polluted water isn't the only health threat for Southern
California beachgoers: The sand at some of the region's most
popular beaches can be laced with bacteria even when the water
is clean.
A UCLA study to be released today of Santa Monica Bay beaches
from Malibu to Redondo shows that, although water bacteria
levels may meet state health standards, sand acts as an
incubator in which microbes can flourish and contaminate water
used by swimmers and surfers.
"It can actually grow in the sand," said Jennifer
Jay, UCLA professor of environmental engineering who headed
the study. "Even on days when the water is very clean,
bacteria is still in the sand for a week. We feel it can be an
important exposure route" for contamination.
Researchers found the worst offenders were the sheltered side
of Cabrillo Beach in San Pedro, Mother's Beach in Marina del
Rey, Santa Monica Beach near the pier and Topanga Beach in
Malibu. Sheltered or enclosed beaches showed persistent
elevated levels of bacteria.
Health standards for beach sediment have not been developed,
however, so it is difficult to evaluate how much of a health
risk these bacteria pose, Jay said.
Health officials have long known that microbes, mainly E.
coli and enterococci bacteria found in fecal material, can
reach harmful levels in ocean water. Urban runoff from city
streets, farms and industries carries a witches' brew of
pollutants that are concentrated to unhealthful levels around
storm drains and river mouths. The new study, to be published
in the forthcoming issue of the journal Water Research, adds
to a growing body of evidence that health risks extend to the
shore.
"People haven't looked at the sand until recently,"
said Alexis Strauss, director of the water division for the
U.S. Environmental Protection Agency. "Our urban
existence yields bacteria year-round."
Of greatest concern is that scientists discovered the highest
sand bacteria concentrations at beaches favored by parents
with toddlers. Mothers take children to sheltered sites
because they are protected from high surf and dangerous
undercurrents. But Jay said those conditions may contribute to
more bacteria because the still waters do not agitate sand and
flush it clean.
"This is particularly relevant when we're talking about
sheltered beaches such as Mother's Beach and the enclosed part
of Cabrillo Beach, for example, which appear to be more
conducive to the persistence of these bacteria," Jay
said. "The levels of enterococci were approximately 1,000
times higher than the levels observed at the beaches open to
the ocean."
Mark Gold, executive director of the Santa Monica-based
advocacy group Heal the Bay, said the study adds urgency to
beach cleanup efforts and could lead to additional warnings
posted along the shore. He said the problem underscores how
difficult it will be for beaches to meet new water quality
standards set to take effect July 15. Heal the Bay plans to
release a list of the most polluted California beaches at a
news conference Wednesday.
Jay and graduate researcher Christine Lee tested three beaches
— Surfrider Beach in Malibu; Santa Monica Beach; and
Mother's Beach in Marina del Rey — during a storm in
February 2003. They also took samples of water and sand to
test in the lab. And they surveyed sand at 13 beaches in Santa
Monica Bay during summer.
Researchers focused on wet sand near the water's edge; the
bleached, dry sand farther inland does not show significant
levels of bacteria. Also, the sand pollution is more
pronounced during and after storms. Beachgoers can reduce
their risk by not ingesting polluted water or sand, exposing
open wounds or cuts, and washing with soap and water after
contact with sand or water.
Jay, a mother of twins, said her children enjoy splashing in
the ocean, though she avoids the placid, enclosed beaches that
are popular with youngsters and their parents.
"My kids play in the sand at the open beaches all the
time. I wouldn't worry much about that," she said.
Jay said the presence of fecal bacteria is not definitive
proof that dangerous pathogens are present.
She said the next phase of the study would examine whether
viruses are present in the sand.
Jay will discuss the findings at 7 p.m. Wednesday at UCLA. For
details, visit www.engineer.ucla.edu/events/jay.html
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