The number of Massachusetts beaches closed to swimming spiked to 25 on Thursday ahead of a three-day holiday weekend of summer weather.
There were nine beaches closed as of earlier this week.
Most of the beaches that close across Massachusetts each summer do so because of high bacteria levels caused by storm runoff and other means of fecal contamination. Water quality at public beaches in Massachusetts is required to be monitored by local public health departments.
When the water quality is unsafe, the beach must be "posted" with a sign indicating that swimming is unsafe and may cause illness.
Massachusetts beaches closed as of 3 p.m. on Thursday include:
The bacteria used as indicator organisms to test the waters at beaches are Enterococci and E. coli. Marine beaches are tested for the presence of Enterococci. Freshwater beaches are tested either for the presence of E. coli or Enterococci. Enteric bacteria are indicator organisms found in the intestines of warm-blooded animals and humans, often associated with fecal contamination.
An elevated presence of these organisms indicates the water may not be safe for human or animal consumption or contact, and may cause symptoms ranging from gastrointestinal pain to eye and ear discomfort to flu-like symptoms.
Most of these symptoms are minor, but occasionally a more serious illness may occur. Children, the elderly, and those with weakened immune systems are at greater risk of developing serious symptoms.
Some beach areas may remain open for recreational activities, though any contact with the water is strongly discouraged.
Sign up for free local newsletters and alerts for the
Across Massachusetts Patch
Patch.com is the nationwide leader in hyperlocal news.
Visit Patch.com to find your town today.