Dozens of beaches close before July Fourth weekend due to fecal bacteria

Just ahead of the Independence Day long weekend, beaches across the country have closed and issued advisories due to excessive levels of harmful bacteria. The culprit is fecal waste, a common summer problem in both freshwater and oceans that can cause gastrointestinal illness and skin infections.

At least six states have issued closures or advisories for certain beaches and lakes that have tested positive for fecal bacteria above safe levels. In Massachusetts, almost two dozen beaches are closed due to excessive bacteria levels. Four beaches in New York are closed. Illinois has issued at least eight advisories in the past few weeks. Los Angeles County had released eight ocean water quality advisories as of Tuesday. Michigan has closed three beaches.

The bacteria causing havoc for summer swimmers include E.coli and Enterococcus — nasty germs often found in the feces of people and animals. The contamination can occur because of sewage, manure or storm runoff. E.coli is more likely to be found in freshwater, whereas enterococcus can form in both marine and freshwater.

Edward Dudley, director of the E. Coli Reference Center at Pennsylvania State University, said testing bodies of water used for swimming is routine and common, as are closures.

Beach closures are more likely around the summer months, when ocean surface temperatures are high and bacteria can grow more easily, said Antarpreet Jutla, associate professor of environmental engineering sciences at the University of Florida. However, a variety of factors — including human activity, temperature and water movement — can affect bacterial growth, he said.

Jutla also said that beach closures due to fecal bacteria are very common.

In North Carolina, officials warned about cyanobacteria algae blooms in Lake Norman, urging people to keep children and pets away from water that appears bright green, blue or scummy. Different from fecal bacteria, cyanobacteria are the most common cause of algae blooms in freshwater, such as lakes or rivers, according to the Centers for Disease Control and Prevention. Research suggests that climate change may be triggering cyanobacterial algae blooms more frequently.

Although the Environmental Protection Agency sets guidelines on safe levels of fecal bacteria, states can set their own water quality and monitoring standards. Some, such as Illinois, test public beaches every two weeks.

“I would say, the higher the levels, probably the higher the risk,” Dudley said.

While fecal waste can lead to many harmful diseases, experts are worried by recent increasing levels of another harmful bacteria: vibrio.

Vibrio is a potentially deadly bacteria that has caused similar beach closures in recent years. The flesh-eating bug thrives in warm, coastal waters. Jutla, who researches vibrio bacteria, has seen vibrio gradually migrate north across the United State. Testing for vibrio depends on each state as well as its concentration limits, he said.

“It’s a rare thing right now with increasing trends in the entire country, but that’s something that we are really concerned about — what is going to be present in the coastal waters,” Jutla said about vibrio.

The deadly V. vulnificus is a rare type of the bacteria, but infections have been growing in recent years as it follows warming ocean water up the eastern coast of the U.S.

This article was originally published on NBCNews.com