Water advisories

Advisories sent to residents in the Stent area include the following information about nitrates exposure and arsenic exposure:

Do not give the water to infants. Infants below the age of 6 months who drink water containing nitrates in excess of the maximum contaminant level may quickly become seriously ill and, if untreated, may die because high nitrate levels can interfere with the capacity of the infant’s blood to carry oxygen. Symptoms include shortness of breath and blueness of the skin. Symptoms in infants can develop rapidly, with health deteriorating over a period of days. If symptoms occur, seek medical attention immediately.

Pregnant women should not consume the water. High nitrate levels may also affect oxygen-carrying ability of blood of pregnant women.

Water, juice, and formula for children under 6 months of age should not be prepared with tap water. Bottled water or other water low in nitrates should be used for infants until further notice.

Do not boil the water. Boiling, freezing, filtering or letting water stand does not reduce nitrate levels. Excessive boiling can make nitrates more concentrated, because nitrates remain behind when the water evaporates.

• Arsenic exposure in most water sources tends to be inorganic. Inorganic arsenic in drinking water can exert toxic effects after short-term or long-term exposure. Acute effects can include vomiting, abdominal pain and diarrhea. Long-term effects can include skin changes, and in long-term and high-level exposures there may be increased risks of skin, bladder and lung cancers.

PUBLIC FORUM: 6 p.m. Thursday, Jamestown Elementary School, 18299 Fifth Ave., Jamestown.


The Union Democrat

Elevated levels of nitrates and arsenic have been found in some private wells in the Stent area of Jamestown, and 12 residents have been warned to use bottled water for drinking and cooking and brushing their teeth, Tuolumne County health officials said Monday.

Nitrates and arsenic are naturally occurring elements in geology of the Mother Lode and Central Sierra Nevada, said Rob Kostlivy, the county’s environmental health director.

The federal Environmental Protection Agency defines the threshold of concern for arsenic as 10 parts per billion, and for nitrates the EPA standard is 10 parts per million, said Liza Ortiz, the county’s public health officer.

No acute illnesses had been reported as of Monday, Ortiz said, emphasizing that county health staff are in the process of reaching out to the 100 people who live in the area. A public forum has been scheduled at 6 p.m. Thursday at Jamestown Elementary School.

“The people who we know are affected have been notified,” Ortiz said. “We don’t want to cause a panic. We want to keep people informed and continue figuring this out.”

Symptoms from nitrates can include difficult breathing for infants, Ortiz said. Symptoms from arsenic may include abdominal pains and other gastrointestinal problems including vomiting and diarrhea.

County health staff who were investigating failing wells first heard from a homeowner that nitrates and/or arsenic could be a concern in the Stent area in August. Owners of private wells are responsible for testing their wells and should do so annually or every two years, Kostlivy said.

The Stent area includes Stent Cut Off Road, Dutch Mine Road and Quartz Street.

A homeowner in the Stent area presented his own testing to Kostlivy, and county health staff conducted testing on about 15 homes in August. The second round of samples from 21 wells was collected March 3, and test results came back to the county on March 24.

Ortiz said that 12 of the 21 wells came back with “high” or “abnormal” readings. Some wells tested normal, some tested positive for nitrates, some tested positive for arsenic, and some tested positive for both, Ortiz and Kostlivy said.

Tests of the March 3 samples of drinking water from private wells were conducted by the California Department of Public Health’s Radiation and Sanitary Laboratory.

More testing is planned, and some residents can expect to hear from county health officials in the next two weeks, Ortiz said.

“We appreciate the public’s willingness to allow the testing, as this will assist the county in establishing a database of water quality in the area and may help to expedite a public water extension project,” Ortiz and Kostlivy said in a statement.

The Thursday forum is being hosted by Tuolumne County’s Environmental Health Department and Public Health Department. Representatives from Tuolumne Utilities District will also be on hand. Jamestown Elementary School is at 18299 Fifth Ave.

Drought-related domestic well failures in Tuolumne County affected more than 225 wells and 11 springs through September, leaving more than 330 homes without running water. Reporting of well failure slowed by then, but county emergency and health people remain unsure if Mother Lode wells will rebound in the wake of the region’s wettest winter since 2010-2011.

An earlier version of this article has been edited to correct the number of people who have been told to use bottled water. Twelve residents have been asked to refrain from using their well water for drinking, cooking and brushing teeth.