Hanauma Bay will be closed Thursday after testing showed elevated levels of bacteria in the water.

It’s one of six separate areas of Oahu where high bacteria levels were found. 

According to the Department of Health, testing showed levels of 137 enterocci per 100 mL at Hanauma Bay, the acceptable threshold being 130 per 100 mL.

At two areas of Queen’s Beach in Waikiki, the levels were roughly ten times higher than the threshold.

Pokai Bay, Ala Moana Regional Park and the lagoon fronting Disney Aulani also showed elevated levels. 

According to health officials, enterococci indicate that potentially harmful microorganisms such as bacteria, viruses, protozoa, or parasites may be present in the water.

Children, the elderly, and people with weakened immune systems are the most likely populations to develop illnesses or infections after coming into contact with polluted water, usually while swimming. 

The most common illnesses is gastroenteritis. Symptoms include nausea, vomiting, stomachache, diarrhea, headache or fever. 

Other minor illnesses include ear, eye, nose and throat infections. 

In highly polluted water, swimmers may occasionally be exposed to more serious diseases.

It’s unclear what’s causing the high bacteria levels, but further testing will be done. 

Warning signs have been posted in all affected areas.