ROGERS, Ark. -- A summertime sizzle has settled over the area and a popular pastime during the hottest season of year is to take a splash in a local swimming hole.

Public swim beaches on local lakes and rivers are packed every day with people having fun and cooling off.

But if you think you're only sharing the water with fish, think again.

Microscopic bacteria are also part of aquatic life. It's part of the natural environment of lakes and streams. When you take a dive, you're swimming with bacteria that could make you sick.

40/29 News took water samples at 6 area swim beaches and a microbiologist tested the samples for bacteria. The samples were from four beaches on Beaver Lake: Prairie Creek, Hickory Creek, Rocky Branch, and War Eagle.

We also tested two sites on the White River, a popular fishing and wading site near the twin bridges in Goshen and at the city park in West Fork.

"Coliform bacteria can make people sick," said microbiologist Gordon Whitbeck.

At Whitbeck's lab, he tested the water for tiny organisms called coli form.

"Those organisms are organisms that inhabit the intestinal tract of warm blooded-animals. Humans and animals. Those are indicating organisms we use along with that can come hepatitis and salmonella. Anything associated with fecal matter," said Whitbeck.

The presence of coliform is an indication of fecal contamination and Whitbeck says all of the samples had levels of coliform.

"You have to consider the situation around Beaver Lake. There are a lot of septic systems and housing pressure on the lake," said Whitbeck.

Lake levels are still high from the spring floods and more lake water is in contact with the shoreline.

The other things that effect contamination levels are how often the swim beaches are used, and also the weather.

Rain causes runoff and run off will increase levels of coliform.

It rained two days before our samples were taken.

The swim beaches with the fewest contaminants were Rocky Branch and War Eagle on Beaver Lake.

The samples from the rivers had bacteria that was too numerous to count.

"Hickory Creek and Prairie Creek were the worst,” said Whitbeck.

After the findings a second round of samples were taken from the dirtiest beaches: Prairie Creek and Hickory Creek on Beaver Lake. Those samples were specifically tested for E. coli and fecal coliform. Both tested positive.

“You can get a good case of diarrhea from high counts of it," said Whitbeck.

Contamination can happen if you swallow the water. Swimming in water bubbling with bacteria doesn't necessarily mean you'll get sick and it doesn't mean you should be worried about swimming.

It's not chlorinated treated water like you're going to have in your back yard or in a public pool. You're going have coliform present, you're going to have coliform, fecal coliform and E. coli present just by the nature of the environment."

The Arkansas Health Department does test and regulate public swim beaches They test them 4-times during the summer and the most recent testing on beaver lake was done the last week in June. Officials said all of the beaches contained levels of E. coli, but the levels were low enough not to be considered a serious health risk.