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Beaches and Your Health

How Does Water Quality Relate to Public Health?

  • Microorganisms are naturally present in all ecosystems.
  • Many of them are beneficial for digestion of food, decomposition, as food sources for animals and essential components of biochemical cycle of nutrients.
  • Microorganisms that cause illness in the human body are referred to as human pathogens. Typically, human or animal feces are possible sources for the pathogens. Waterborne disease- causing pathogens may be bacteria, protozoa, or viruses.
  • Bacteria are microscopic, unicellular organisms. Many types of bacteria, such as coliforms and enterococci, may be found on beaches. Not all bacteria are pathogenic.
  • Protozoa are also unicellular organisms. They exist in the environment as cysts that hatch, grow and multiply after ingestion and cause illness. Giardia lamblia and Cryptosporidium parvum are the most common protozoan of concern.
  • Viruses are submicroscopic infectious agents that require a host to live in. Animal feces are a common source for transmission.
  • Human health concerns arise from exposure to disease-causing organisms. This may occur during swimming or other recreational activities through accidental ingestion, inhalation, or direct contact with polluted water.
  • Gastroenteritis is the most common illness caused by ingestion of contaminated recreational water.
  • The eye, ear, skin and upper respiratory tract may also be affected if microorganisms contact breaks or tears in skin or eye, ear or nose membranes.

Why Do Microbial Populations Increase?

Potential sources of microbiological contamination of beach waters are:

  • Failures in municipal wastewater treatment facilities
  • Leaking sewer lines
  • Storm water and runoff, releases from boat holding tanks
  • Animal waste (including waste from water fowl)
  • Leachate from poorly maintained or flooding septic systems

For instance, significant rainfall events or water from garden hoses and sprinklers can cause elevated levels of pathogen indicators as the water flows over streets and yards and into the storm drains washing pollutants such as motor oil, pesticides, paints, grass clippings, and pet waste. In most places, whatever goes down a storm drain flows directly into local creeks, rivers, lakes, and eventually into the ocean, threatening water quality for humans and wildlife.

The most common causes for elevated bacteria counts at Madison beaches are:

  • Large populations of waterfowl
  • Recent heavy rainfall which flushed the storm sewer system
  • Lack of water movement in the beach area
  • Very occasionally, a broken sewer main will pollute the beaches with sanitary sewage