A warning that it’s not just the water you have to worry about at the beach when it’s posted as unsafe for swimming.

The sand could be contaminated too.

Raj Bejankiwar is the deputy director and physical scientist of the Great Lakes regional office of the International Joint Commission. He tells CTV News when a beach is closed due to high E. coli counts in the water, the sand can pose a danger as well.

He recommends beachgoers to avoid moist places and stay in dry areas on the sand, especially the areas covered in green matter or algae.

Bejankiwar notes that beaches that are well maintained and raked often will not pose a health risk.

"If you have less coarse sand and a lot of organic debris, they multiply faster," says Bejankiwar.