State health officials on earlier today posted advisories about high bacteria levels at three Oahu shorelines: Lanikai Beach in Kailua, and Kahanamoku and Kuhio beaches in Waikiki.

Officials said potentially harmful microorganisms may be in the water and could make swimmers ill, especially children, the elderly and people with weakened immune systems.

The levels of enterococci exceeded the threshold of 130 per 100 milliliters at all three beaches — 1,652 per 100 milliliters at Kuhio Beach, 207 per 100 milliliters at Kahanamoku Beach and 207 per 100 milliliters at Lanikai Beach.

The advisories will remain in effect until water sample results no longer exceed the threshold level of 130 enterococci per 100 milliliters.

Enterococci bacteria indicates possible contamination by fecal waste that could originate from wastewater treatment plants, septic systems, stormwater runoff, sewage discharge or even animal waste.