A posted warning about potential health risks tied to high bacteria levels in Keehi Lagoon’s waters has prompted several canoe clubs to withdraw from competing in the Hawaiian Canoe Racing Association State Championship regatta on Saturday.

In addition to the lagoon, the state Department of Health on Thursday posted warning signs at Kauai’s Waiopili Stream. While the DOH did not close the areas to recreational use, it is advising people to take precautionary measures to avoid bacteria-related illness or infection.

Faith Craycroft, a representative of the Manu o ke Kai canoe club of Haleiwa, described the presence of bacteria slightly exceeding public health standards as “a very serious concern.”

Twenty-two of Manu o ke Kai’s crews that had qualified to participate have pulled out of the regatta because of health worries.

Also, the Outrigger Canoe Club of Waikiki announced Thursday afternoon that it will not compete in the state championship race.

Fred Noa, speaking on behalf of Outrigger, said the club planned to have about 180 members paddling in the competition but decided against it, in light of worries about bacterial contamination.

State Health Department spokeswoman Janice Okubo said the advisory does not restrict the use of the waters, but recommends that people with cuts and wounds refrain from entering the ocean at both sites and for others to wash off thoroughly after getting out of the waters.

She said bacterial levels were high during Tropical Storm Darby but had returned to what the Health Department maintains is slightly elevated in the range of normal levels.

According to the Health Department, children, seniors and people with weakened immune systems or open wounds are the most likely populations to develop illnesses or infections after coming into contact with polluted water, usually while swimming.

The event’s organizer, the Hawaiian Canoe Racing Association, said the state has lifted the brown-water advisory that remained in effect after Tropical Storm Darby swept across Oahu two weeks ago, and that the bacterial levels are close to normal.

“We’re encouraged with the drop in the numbers,” said Walter Vierra, the association’s president. Vierra said Thursday’s elevated readings were probably caused by runoff from the rain Wednesday night.

Vierra said the association is encouraging people who have compromised health conditions not to participate in the race. The association’s website recommends that those who compete in the regatta should wear waterproof booties.