The city of Ceres is notifying residents this week that uranium levels in excess of state standards were detected in the municipal water supply last year. The city has capped the troublesome well and said the situation "is not an immediate health risk" but issued a set of recommendations.
Like all cities, Ceres routinely monitors the water supply for drinking water contaminants. Sample results taken from one of the city's 15 active wells on Feb. 10, May 5, Aug. 27 and Oct. 30 in 2015 showed a four-quarter average uranium level of 30 picocuries per litre (pCi/L). The state says the maximum contaminant level is 20 pCi/L.
Pico is equal to one trillion, 1 pCi/L is equal to one trillionth of a curie (a unit of radioactivity) per liter of water.
The city sent a notice out Tuesday that says residents "do not need to use an alternative water supply" such as bottled water. The statement also indicated "This is not an immediate health risk. If it had been, you would have been notified immediately. However, some people who drink water containing uranium in excess of the MCL over many years may have kidney problems or an increased risk of getting cancer. If you have other health issues concerning the consumption of this water, you may wish to consult your doctor."
The state directed the city in February 2015 to monitor the single contaminated well for four consecutive quarters due to above average uranium traces at that time. The city completed the testing each quarter and the average of 30 pCi/L exceeded the state cap of 20 pCi/L. City staff has shut the well off and have removed piping from the well to disconnect the well from the domestic water system and are relying on other wells in the area to maintain pressures within the water system.
"We are working with the State Water Board to evaluate the water supply and research options to correct the problem," said a statement issued by Director of Public Works Jeremy Damas. "These options may include treating the water to remove the uranium, drilling a new well, rehabilitating the existing well, abandoning the well, or using the well for irrigation purposes."
Uranium is naturally present in most rocks and soils and can be released into the environment through wind and water erosion. Uranium can commonly be found in drinking water wells due to the nature of a well being drilled into rock formations through the earth.
"We anticipate resolving the problem and or providing the state with a plan within the next five months to meet the states deadline of April 1."