The Surfrider Foundation, along with many county and state health departments has always advised the public never to swim or surf within 72 hours after a rain. During these periods, the coastal waters are polluted with urban runoff and may also contain sewage from leaking sewer pipes or overflowing sewer manholes. In most places, and especially in heavily urbanized areas like Southern California, ocean water quality after a rain typically has high concentrations of bacteria and may also have high concentrations of pesticides, herbicides, fertilizers, heavy metals, and petroleum products.
In Southern California most counties issue a 72-hour advisory after it rains. Unfortunately, they do not necessarily post the beaches after a rain. The Orange County Health Care Agency is quoted as saying, "We just assume all surfers know that the water is polluted after it rains." Surfrider thinks increased outreach must be done to warn surfers of the risks.
If you feel you have gotten sick after exposure to polluted ocean water you can report it at Surfrider's Ocean Illness Reporting Tool.
A study cited in EPA's draft guidance document on water quality found that surfers and divers are at greater risk of illness from contact with contaminated beach water than are swimmers or waders. In addition, an epidemiological study in Santa Monica Bay found that there is an increased health risk when swimming within 400 yards of a flowing storm drain. In Southern California you will be hard pressed to find a stretch of surf that isn't near a storm drain.
Waters that are polluted may contain several different disease-causing organisms, commonly called pathogens. Enteric pathogens -- those that live in the human intestine - can carry or cause a number of infectious diseases. Swimmers in sewage-polluted water (or even just "normal" urban runoff) could contract any illness that is spread by migration and inadvertent ingestion of fecal-contaminated water. (AIDS and many other diseases are not carried by enteric pathogens.)
Viruses are believed to be a major cause of swimming-associated diseases, and are responsible for many cases of gastroenteritis, hepatitis, respiratory illness, and ear, nose, and throat problems. Gastroenteritis (commonly referred to as "stomach flu") , which can also be caused by bacteria, is a common term for a variety of diseases that can cause symptoms such as vomiting, diarrhea, stomach ache, nausea, headache, and fever. Other microbial diseases that can be contracted by swimmers include salmonellosis, shigellosis, and infection caused by E. coli (a type of enteric pathogen). Other microbial pathogens found at varying concentrations in recreational waters include amoeba and protozoa, which can cause giardiasis, amoebic dysentery, skin rashes, and pink eye.
There is also what can be referred to as a "toxic cocktail" of pesticides, herbicides, heavy metals and other pollutants that are not monitored regularly and the health effects of which are poorly understood. It is important to understand that the typical ocean water monitoring program used by most municipalities in California consists only of tests for total coliform, fecal coliform, and enterococcus bacteria. Other states typically only test for enterococcus (in salt water) or E. coli (in fresh water). No tests for viruses, hydrocarbons, pesticides, herbicides, fertilizers, metals, or other pollutants are routinely performed. This is another reason for the recommendations to stay out of the water for 72 hours after a rain and always keep away from flowing storm drains.
To learn more visit Surfrider's Clean Water articles and the Coastal blog posts on water quality.
Transworld Surf has published an article Seven Surf Sicknesses which are actually a mixture of illnesses and the pathogens that cause illnesses. Their list is: MRSA, Hepatitis A, Encephalitis and Meningitis, Gastroentiritis, Vibrio Vulnificus, Leptospirosis, and Unknown and Bizarre illnesses.
Personal examples of extreme health effects from exposure to polluted runoff and/or sewage spills include:
Sea Otters, Dolphins and other marine life are also affected by pollutants that are discharged into the ocean. In fact, because they spend all their life in the ocean and subsist entirely on food from the ocean, they are more vulnerable to pollutants and infectious agents than humans. This National Geographic article explores some of the issues and specific pollutant threats.
Some of this information was gleaned from NRDC's Testing the Waters reports.
American Rivers has created a well-written flyer discussing Health Risks of Sewage. The document includes a list of common pathogens along with the acute and chronic effects they may cause.
Balarajan, R., Soni Raleigh, V., Yuen, P., Wheeler, D., Machin, D. and Cartwright, R. 1991. Health Risks Associated with Bathing in Sea Water. Brit. Med. J., cited in USEPA's Implementation Guidance for Ambient Water Quality Criteria for Bacteria - 2004.
R. Haile, et al. An Epidemiological Study of Possible Adverse Health Effects of Swimming in Santa Monica Bay. Santa Monica Bay Restoration Project, 1996.