There are a number of ways that beaches can become contaminated with bacteria. Storm water runoff, combined with sewer overflows, sewage treatment plant bypasses, agricultural runoff, faulty septic systems, and large populations of waterfowl like geese all contribute to water pollution which can result in beach postings.

Beach postings are most likely to occur after rain storms or prolonged hot weather. Rain water washes fecal material from cats, dogs, birds and other wildlife into storm sewers which flow directly into nearby rivers and lakes. Prolonged hot weather conditions promote the growth of the bacteria in the water.

Water temperature also has a significant effect on bacterial levels. Shallow beaches will have warmer water and a higher potential for bacterial growth.

You can play a role in making local beaches safer to use. Here are some suggestions on how to reduce water contamination:

• Pet owners should observe the “stoop and scoop” bylaws as domestic pet waste is a major source of bacteria in storm water.
• Allow water from eavestroughs to discharge onto lawns. This reduces the amount of rainwater going directly into the sewer system.
• Reduce household water use. This avoids capacity problems at sewage treatment plants that could result in untreated sewage entering lakes and rivers.
• Fence livestock away from streams and provide them with an alternative source of water. This will benefit both the health of the herd and the environment.
• Ensure that runoff from feedlots and manure piles are properly contained.
• Upgrade septic systems and keep them in good working order.

Bacteria and viruses are some of the most common contaminants found in beach water. Local beach waters are tested for E. coli bacteria, which is an indicator that there is fecal contamination present from animals, humans, or both. E. coli, as well as other disease-causing organisms, can cause intestinal illness or infections of the eyes, ears, nose, or throat.

To protect yourself and your family from the health hazards of contaminated beach water, it is important to be aware of water quality conditions and avoid swimming when the water quality is poor. It is also important to take precautions such as showering after swimming, and avoiding swallowing or coming into contact with the water. If you do experience any health symptoms after swimming in beach water, please seek medical attention.

Swimmer’s itch, also called cercarial dermatitis, appears as a skin rash caused by an allergic reaction to certain microscopic parasites that infect some birds and mammals. These parasites are released from infected snails into fresh and salt water (such as lakes, ponds, and oceans). While the parasite’s preferred host is the specific bird or mammal, if the parasite comes into contact with a swimmer, it burrows into the skin causing an allergic reaction and rash. Swimmer’s itch is found throughout the world and is more frequent during summer months.

Learn more about the symptoms, risk and treatment of Swimmer's Itch.

Yellow Scum (Pine Pollen)

The mustard yellow scum which may be seen in early summer on the surface of lakes and along their shorelines is a product of Mother Nature, not industry.

Environment Ontario’s Water Resources staff explain that the yellow scum, most prevalent in the month of June, floats on the surface of water or accumulates along shorelines and beaches. It is due to the presence of pine pollen or pollen from other trees and should not be mistaken for algae or an industrial waste.

In most instances, pine pollen will not be a health hazard. It will probably be blown or washed away when the wind changes direction and will eventually break down or become trapped in the sediment at the bottom of a watercourse. The condition is seasonal, and should begin to taper off in early July of any year in which it appears as a problem.

Foam

The foaming of surface waters on lakes is not a new phenomenon. It is a natural process that has been going on for a long time. All lakes contain organic matter, such as algae, rooted aquatic plants and leaves. When this organic matter decomposes, it releases cellular products to the water, which form a surfactant, or surface agent. A surfactant simply lessens the surface tension of water, making it susceptible to foaming. When the wind blows, the waves on the lake agitate this surface agent, thus transforming it into sudsy white foam.

Natural foam is most noticeable along beaches exposed to the prevailing wind direction. When the foam reaches the shoreline, it tends to form a loose line where it mixes with tiny pieces of organic matter, which act as a binding agent and give it stability.

Foam on the surface waters is a harmless by-product of our lakes. Its chemical makeup is 99% air and water, combined with 1% or less surfactant.