Los Osos CSD unsure of source of harmful chemical at well site, exploring treatment options

The Los Osos Community Services District found high levels of hexavalent chromium in its water. This image is an example of what the substance looks like.
The Los Osos Community Services District found high levels of hexavalent chromium in its water. This image is an example of what the substance looks like.

The Los Osos Community Services District isn’t sure what caused one of its wells to exceed state standards for Chromium 6, also known as hexavalent chromium, which can be a carcinogen at high exposure levels.

The district’s board of directors is expected to consider in future meetings whether to treat and rehabilitate the well, install a new well, or keep it shut down. The district said it has stopped using the well.

The Los Osos CSD posted a notice on its website Friday that Chromium 6 levels at one of its six wells were 11 micrograms per liter in a test taken Dec. 7.

The standard for the chemical is 10 micrograms per liter, a California regulation adopted in July 2014.

Protecting the water supply is first and foremost for the district.

Jon-Erik Storm, Los Osos CSD director

The test results for the 3rd Street well came back Dec. 17 and notices by mail were sent to the district’s water customers Jan. 11, said Margaret Falkner, the district’s acting general manager.

“This is a material that can come from natural sources, or sometimes certain industrial practices can produce this substance,” Falkner said. “I don’t know what industry we have that could cause this. … We don’t know where it’s coming from.”

Falkner said the State Water Resources Control Board allowed the district to average its test results between December 2014 and December 2015, which showed two tests at the well site at 10 micrograms per liter and two tests at 11 micrograms per liter. A test on June 6 also showed 11 micrograms per liter.

The state requires public notification of a violation of chemical contamination standards within 30 days of the discovery if it does not pose an immediate health risk, unless directed otherwise by the state. Water agencies also must either publish a notice in the local newspaper, deliver the notice to community organizations or post it in conspicuous places or online.

“We were following their protocol,” Falkner said. “We notified the public according to their latest regulations.”

Chromium 6 is the same substance that was brought to public attention by Erin Brockovich, who championed the legal case against PG&E’s contamination of drinking water in the town of Hinkley.

The district notice said some people who drink water containing Chromium 6 in excess of the maximum contamination level over many years may have an increased risk of getting cancer.

However, the district believes the contamination poses no immediate risk to consumers of its water because it blends water from its wells. The product delivered to customers hasn’t exceeded any state standards for the chemical, Falkner said.

People can be exposed to chromium by inhaling or ingesting it, or through skin contact, according to the Centers for Disease Control and Prevention’s Agency for Toxic Substances and Disease Registry. That would include drinking or bathing in the tainted water.

The Los Osos CSD serves about 2,750 customers, or about half the community.

We were following their protocol. We notified the public according to their latest regulations.

Margaret Falkner, Los Osos CSD acting general manager

Falkner said the district will consult with its engineer, Rob Miller, about whether to try to rehabilitate the well.

Los Osos CSD director Jon-Erik Storm said he expects the board to discuss the financial viability of keeping the 3rd Street well shut down or restoring it to safe standards.

“Protecting the water supply is first and foremost for the district,” Storm said. “We want to make sure it’s absolutely safe.”

Storm said it raises the question about the district having another water source to rely upon.

“There’s no real backup plan, and that kind of concerns me,” Storm said. “We’re only one toxic problem away from having no water.”

Storm said the 3rd Street well draws from an upper aquifer, and the district will need to make sure its contamination levels meet state standards at the lower levels.

“Our staff is on this, and we know that this hasn’t been an ongoing issue, but just what the latest tests showed,” Storm said. “I’m somewhat comforted that it’s just a bit over the limit and our state standards are very high.”