The Suffolk County Health Department warned residents Monday to avoid contact with waters in the tidal area of the Peconic River east of Grangebel Park as high rates of chlorination at the Riverhead sewage treatment plant have led to “a visible plume of cloudy water.”

Children and pets should also be kept away from the area, but if contact with water is made, rinse off immediately, officials said.

If symptoms occur, including “nausea, vomiting or diarrhea; skin, eye or throat irritation; or allergic reactions or breathing difficulties,” health officials advised to see a physician.

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On Dec. 15, health officials warned against water contact in the river area due to the potential impact of “inadequately treated wastewater” discharged from the treatment plant, which has been undergoing an upgrade that disrupted operations.

The situation has improved, health department officials said, with effluent now meeting state Department of Environmental Conservation limits.