The frequency of sample collection ranges from at least weekly to five times per week along the Orange County coastline, depending upon the requirements of the agency collecting the samples. When the results of testing indicate a contamination problem exists, the sampling frequency and locations around the original sample location may increase until the sample results are within standards and/or the source of the problem is determined.

Water samples are analyzed for indicator bacteria – total coliform, fecal coliform and enterococcus – which indicate possible pollution from numerous sources including fecal waste. They are called indicator bacteria because they are relatively easy to collect and analyze, and may show the presence of harmful viruses, bacteria or protozoa (also known as pathogens). Collecting and measuring the disease-causing organisms directly is difficult. Sources of indicator bacteria may be:

• Environmental – soils, decaying vegetation
• Animal wastes – birds, dogs, cats or rabbits
• Humans – sewage, kids with diapers, shedding from body
• Storm water or urban runoff

There are three ways that water samples are analyzed for indicator bacteria. The results of each of these techniques are considered to be equivalent.

Membrane Filtration Technique – Uses extremely fine paper filters through which the water sample is passed. These filters are then placed on bacteriological growth media that contain food specific to the indicator bacteria (total coliforms, fecal coliforms and enterococci). If these bacteria are present, they will grow on the filter and form colonies. These colonies are counted and the number of the original bacteria present in the water sample calculated. Results for the membrane filtration technique are reported as the number of colony forming units (CFU) per 100 milliliters of water sample or CFU/100ml. All three of the agencies collecting and analyzing ocean and bay samples in Orange County (the Health Care Agency and two local sanitation agencies – Orange County Sanitation District and South Orange County Wastewater Authority) use the membrane filtration method.

Multiple Tube Fermentation Technique – Uses test tubes containing nutrient broth or food (media) specific to the indicator bacteria. These tubes are inoculated with several dilutions of the original water sample. The presence of indicator bacteria is evidenced by the production of carbon dioxide gas, an end product of lactose fermentation. After the positive tubes are tallied, a statistical technique is used to determine the concentration of bacteria in the sample. Results for this technique are reported as Most Probable Number (MPN) of bacteria per 100 milliliters of water sample or MPN/100 ml.

Defined Substrate Technology Technique – Uses a multiple well tray test kit to detect the presence or absence of indicator bacteria. The detection of indicator bacteria is based on a color change of the media in the wells to yellow or yellow with fluorescence. Results for this technique are reported as Most Probable Number (MPN) of bacteria per 100 milliliters of water sample or MPN/100 ml.

The results of shoreline bacteriological testing are reviewed on a daily basis. The status of ocean and bay waters can include:

The California Ocean Water-Contact Sports Standards are found in the California Code of Regulations – Title 17 and the California Health and Safety Code.

Single Sample Standards:

30-day geometric log mean standards of 5 weekly samples:

Polluted runoff and untreated sewage released into bathing waters may result in swimmer exposure to pathogenic bacteria, viruses and protozoans. These disease-causing organisms may be present at or near the site where the polluted discharge enters the water. The following table lists the types of organisms and the diseases (or symptoms) they may cause.

The levels of bacteria, viruses and protozoa decrease over time due to the following reasons:

• Die off due to sun (ultraviolet exposure), salt water or age;
• Predation by other organisms; and
• Dilution.

Everyone can help improve water quality at the beach no matter where they live, work or play. Runoff from anywhere in Orange County eventually ends up at the beach and with the runoff, all the bacteria, litter, oil or grease it picks up along the way. Many of the storm drains lead to the beach, not to a treatment plant. Some easy things we can do to help include:

Tar balls are little, dark-colored pieces of oil that can sometimes stick to your feet when you go to the beach. They can be from natural occurring seeps, places where oil slowly escapes from the earth surface above petroleum reservoirs, or are remnants of oil spills. Tar balls have been found to form naturally from seeps located in Southern California, including in Orange County.

For most people, an occasional brief contact with a small amount of oil, while not recommended, will do no harm. However, some people are especially sensitive to chemicals, including the hydrocarbons found in crude oil and petroleum products. They may have an allergic reaction or develop rashes even from brief contact with oil. In general, we recommend that contact with oil be avoided. If contact occurs, wash the area with soap and water, baby oil, or a widely used, safe cleaning compound such as the cleaning paste sold at auto parts stores. Avoid using solvents, gasoline, kerosene, diesel fuel, or similar products on the skin. These products, when applied to skin, present a greater health hazard than the tarball itself.

If you notice unusual numbers of tar balls on the beaches, call the U.S. Coast Guard any time at 800.424.8802. Click here for more information on tar balls.