Swimming in Santa Monica Bay

How Safe is it to Swim
in Santa Monica Bay_

SMBRP Epidemiology Study Assesses Health Risks

Concerned beachgoers and other advocates for Santa Monica Bay now know more than ever before about how safe it is to swim in Santa Monica Bay, thanks to a landmark epidemiology study conducted by the Santa Monica Bay Restoration Project (SMBRP).

The results, announced in May before a diverse audience of government agencies, environmental organizations, local dignitaries and media representatives, confirmed what health experts have long suspected but lacked the supporting data to definitively proclaim: To stay healthy, Bay swimmers should steer clear of flowing storm drains.

Study findings revealed that individuals who swim in front of flowing storm drains are 50 percent more likely to develop a variety of symptoms than those who swim 400 yards away from the same drains.

Introduction | The Study | Findings | Action Agenda

Introduction

The epidemiology study, commissioned and co-designed by the SMBRP and conducted by epidemiologist Dr. Robert Haile of the University of Southern California School of Medicine, is the first in the country to examine whether there are adverse health effects associated with swimming in marine waters contaminated by urban runoff.

According to study participants, the findings could also apply to any urban area in the country with recreational areas that are impacted by urban runoff.

As a $750,000 cooperative venture partially funded through the non-profit Santa Monica Bay Restoration Foundation, the epi study included significant contributions of cash, grants, and in-kind services from a variety of federal, state and local agencies, private organizations and community groups.

The epidemiology study is one of 74 priority actions included in the Bay Restoration Plan, a blueprint to guide the recovery of Santa Monica Bay which was created by the SMBRP, and approved by Governor Pete Wilson in 1994 and by US EPA Administrator Carol Browner in 1995.

"One of the reasons the Santa Monica Bay Restoration Project was created in the first place was because people were concerned about the possible health risks of swimming in the Bay," said SMBRP Director Catherine Tyrrell. "For years, swimmers and surfers have complained about eye, ear, skin and stomach problems which they believe stem from their contact with the Bay. But we lacked the proof to make the connection. With this study, we finally know that people can get sick from swimming in front of flowing Bay storm drains."

The study is a follow-up to an earlier multi-phase research project conducted by the SMBRP between 1989 and 1992. That effort found enteric viruses in runoff at three widely separated Bay storm drain locations, indicating that human fecal waste was present in the storm drain system. Because of the findings, signs have been posted since 1992 near storm drain outlets on beaches along the Bay, cautioning bathers to swim at least 100 yards from flowing drain outlets.

The Study

During the course of the study, which was conducted from June through September 1995, a team of bi-lingual interviewers questioned 15,492 beachgoers of all ages who swam at three Santa Monica Bay beaches located near flowing storm drain outlets. They contacted the swimmers again 9-14 days after their initial questioning to inquire as to the presence of a variety of symptoms, including: fever, chills, earache, skin rash, nausea, stomach pain, coughing, sore throat, a group of symptoms indicative of "highly credible gastrointestinal illness" (HCGI), and "significant respiratory disease" (SRD).

In addition, daily water samples were collected at and near the studied storm drain locations and analyzed for total and fecal coliforms, enterrococci, and E. coli. Water samples were also collected at storm drain sites and analyzed for enteric viruses.

Findings

According to Dr. Haile, swimmers who do not follow the advice to steer clear of flowing drains could experience an increased risk for a broad range of adverse health effects including fever, nausea, and gastroenteritis, as well as cold and flu-like symptoms such as nasal congestion, sore throat, fever and/or cough.

"Some 373 people out of every 10,000 can develop any of these symptoms if they swim in front of a flowing storm drain," said Dr. Haile.

Increased health risks were also associated with swimming in areas with high bacterial indicator counts, and on days when water samples tested positive for enteric viruses.

Epi Study Action Agenda

The SMBRP outlined a list of actions that agencies have agreed to implement as a result of the study's findings. Designed to better inform and further protect the public on several fronts, these actions will be carried out by a variety of government agencies.

Prominently featured in the Epi Study Action Agenda are tasks which expand on efforts to educate and advise the public regarding safe swimming choices.

Strikingly colored new bilingual warning signs have been created which read "WARNING! STORM DRAIN WATER MAY CAUSE ILLNESS. NO SWIMMING." They will be posted on either side of all flowing storm drains in Los Angeles County, and will also be accompanied by crossed warning flags. In addition, lifeguards will actively warn swimmers away from areas directly in front of storm drain outlets when swimming.

Other actions that will be carried out by local agencies include implementing source control measures to reduce the input of pathogens (organisms that cause disease in humans) and other contaminants into storm water runoff. Diverting dry-weather flows from problem storm drains to wastewater treatment facilities, investigating and correcting malfunctioning septic systems, and improved response to and control of sewage spills are among the tasks to be undertaken.

The Epi Study Action Agenda also calls upon regulatory agencies to incorporate epi study findings into monitoring programs, and for revising recreational water quality standards/criteria if appropriate.

In addition, members of the public are being asked to practice "good housekeeping" at their homes and workplaces to help prevent Bay pollution.

For further information on the epidemiology study, please request a copy of the full technical document or the 13-page Public Summary by e-mailing us at SMBRP@earthlink.net or writing us at 101 Centre Plaza Drive, Monterey Park, CA 91754.