The Department of Environmental Conservation is warning of potentially harmful levels of bacteria found in the water at Kenai North Beach.

Water samples taken from that location Tuesday revealed elevated levels of enterococci bacteria and fecal coliform, according to an advisory the agency issued Thursday.

The samples contained 139 units per 100 ml of enterococci bacteria, almost four times higher than what is considered safe for direct contact. The threshold for seafood is even lower — for water to be considered safe enough to harvest fish and shellfish for raw consumption, it must average no more than 14 units per ml, according to the DEC.

Exposure to water contaminated by the bacteria can cause stomachaches, diarrhea and ear, eye and skin infections, the DEC said.

The agency warned against swimming in the water at Kenai North Beach until the advisory is lifted and encouraged beachgoers to rinse off with clean, fresh water if they’re exposed to marine water.

Seafood harvested from the area should be rinsed with clean water, as well, and cooked to a minimum internal temperature of 145 degrees, the DEC said.

Officials said they believe the most likely source of the enterococci bacteria is birds, but it can come from any warm-blooded animal, including humans and pets.

Water samples were also taken from nearby South Kenai Beach, Kenai River Gull Rookeries 1 and 2, and Warren Ames Bridge. Bacteria levels in those waters were normal, the DEC said.