Chromium 6 Rules: Comments Due Aug. 4

By Jondi Gumz

Rulemaking is in progress for state limits on chromium 6 in drinking water.

• A hearing is scheduled on Aug. 2.
• Written comments are due Aug. 4.
• Proposed Maximum Contaminant Level: 10 parts per billion (ppb) (0.01 mg/L)
• Proposed Detection Limit for Reporting: 0.1 ppb (0.0001 mg/L)
• The current California MCL standard is 50 ppb.
• The current federal standard for total chromium is 0.1 mg/l mg/l milligrams per liter or 100 ppb.

The source of chromium 6 can be a discharge of chemical used in industry. It also occurs naturally in the environment from the erosion of natural chromium deposits, which in the case in Soquel Creek Water District.

Asked to comment, the Soquel Creek Water District provided this statement: “We have and will continue to be tracking and monitoring the State’s progress with the rulemaking of Chromium6 and the requirements for compliance once in effect. As such, the District has an anticipated a treatment project (both design and construction) to address the State’s potential WQ objective for Chrom-6 within our 10-year Capital Improvement Plan (CIP) budget. We currently do not use reverse osmosis technology. We will be using that for the Pure Water Soquel project.”

You may have heard of chromium 6 if you saw the film, “Erin Brockovich,” which told the story of groundwater contaminated in Hinkley by PG&E dumping and residents complaining of chronic illnesses. Monitoring the 1996 settlement for $333 million may take 30 to 50 years.

Studies show that Cr6 in drinking water may cause an increased risk of stomach cancer and reproductive harm, according to state regulators.

The proposed regulations include estimates of the theoretical number of cancer cases avoided per year, based on the connections and where the maximum contaminant level is set.

The cost of monitoring, treatment and preparing compliance plans depends the number of connections.

Filtration pitchers and common fridge filters do not filter chromium-6 from water.

Ion exchange and reverse osmosis filtration are ways to remove chromium-6 from a water supply.

In 2010, the Environmental Working Group found chromium 6 in 31 of 35 cities tested, and at levels that exceeded public health goal of .02 parts per billion adopted by California regulators in 2011. To view a map of Cr6 testing, see www.ewg.org/interactive-maps/chromium6_contamination/map/

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For more information, see www.waterboards.ca.gov/drinking_water/certlic/drinkingwater/SWRCBDDW-21-003_hexavalent_chromium.html

For questions, contact Bethany Robinson (Bethany.Robinson@waterboards.ca.gov) or Melissa Hall (Melissa.Hall@waterboards.ca.gov).