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Popular Massachusetts beaches and lakes are closing as a heat wave sweeps across the state.

Dozens of popular beaches and lakes across Massachusetts are closed amidst a fierce heat wave.

The Massachusetts Department of Public Health's Interactive Beach Water Quality Dashboard shows that 16 state beaches were closed  Wednesday morning due to harmful levels of bacteria.

The state said test results take about 24 hours, so the beaches could to stay closed for one or two days after a high-bacterial sample is gathered, reported local news station WFXT-TV.

Water quality can be significantly impacted by rainfall and the runoff of sewer and pet waste. 

Swimming in contaminated waters can lead to health problems such as gastrointestinal and respiratory problems.

The state conducts water quality testing at the beginning of each week, from Memorial Day through Labor Day.

The dashboard is updated twice a day, once at 9:30 a.m. and again at 12:30 p.m., providing a list of active closures.