High levels of chromium-6 still found in city’s water

Water samples from wells serving the city of Los Banos continue to show high levels of a toxic chemical, according to a quarterly report being sent to consumers.

While levels of hexavalent chromium-6 in Los Banos’ city wells are within federal allowances, they have exceeded tighter limits that were adopted by California in July 2014, said Mark Fachin, Los Banos’ public works director and city engineer.

“The chromium-6 level has been consistent for a long time,” he said Thursday. “It’s not the water that changed, it’s the standard.”

According to sample results received in December, levels of chromium-6 in the city’s 13 wells ranged from 13 parts per billion to 46 parts per billion.

California limits levels of chromium-6, the more toxic form of chromium, to 10 parts per billion.

The U.S. Environmental Protection Agency in 1991 raised its allowable standard for total chromium from 50 parts per billion to 100 parts per billion, according to the state Water Resources Control Board. California did not follow the federal move.

Levels of hexavalent chromium-6 in Los Banos’ water first were recorded in January 2001, when tests found between 13 parts per billion and 31 parts per billion, Fachin said.

Hexavelent chromium-6, a known carcinogen, can target the respiratory system, kidneys, liver, skin and eyes, according to the U.S. Occupational Safety & Health Administration.

A notice being sent to Los Banos water users this month says there is no immediate health risk, and consumers may continue to use the city’s water.

“However, some people who drink water containing hexavalent chromium in excess of the (maximum contaminant level) over many years may have an increased risk of getting cancer,” the notice said.

Los Banos is conducting studies to try to determine the source of its contamination, which can be produced from industrial and agricultural processes as well as occur naturally, Fachin said. Other cities in the area, including Patterson, also have found high levels of chromium-6, he said.

The city submitted a corrective action plan that has been approved by the state, and it is working with several parties to try to find a long-term solution that isn’t cost prohibitive, Fachin said. One solution might be to dig deeper wells, but that would run into the issue of ground subsidence, he noted.

The city also is looking into pilot studies. It is working with North American Hoganas Inc., the Pennsylvania-based arm of a Swedish firm, that is hoping to prove it has technology that could help Los Banos and other cities rid their water supplies of chromium-6.

The city of Los Banos serves about 10,000 water accounts representing about 37,000 people, Fachin said.

Anyone who has concerns about consuming the city’s water should consult with his or her doctor.

Asked if he is drinking the city’s water, Fachin said: “Yes.”

“My family differs on it, but it’s more of a taste issue than a health concern.”

This story was originally published January 21, 2016 at 4:21 PM with the headline "High levels of chromium-6 still found in city’s water."