California regulators have voted to establish a drinking water limit on hexavalent chromium, a toxic compound known as chromium-6. This new rule is the first in the nation to specifically target this heavy metal and is expected to reduce the number of cancer and kidney disease cases resulting from long-term ingestion. The standard, which sets the limit at 10 parts per billion, is estimated to impact more than 200 million Americans who currently have chromium-6 in their drinking water. While the proposal was unanimously passed by the State Water Resources Control Board, it still needs approval from the Office of Administrative Law to take effect.
While the new limit on chromium-6 is seen as a step in the right direction by state officials, community members and health advocates are concerned that it doesn’t go far enough to protect public health. They are advocating for a lower drinking water limit closer to the public health goal of 0.02 parts per billion, which scientists have determined does not pose significant health risks. Some public water providers have raised concerns about the financial burden associated with meeting the new standard, which could potentially lead to higher water bills for customers, especially in disadvantaged communities. Critics from the chemical industry have also argued that the limit is not based on the most recent scientific evidence.
Water providers will now need to start testing for chromium-6 within six months of the rule taking effect, which is anticipated in October. If water tests above the limit, providers will be required to submit a compliance plan within 90 days and come into compliance within two to four years, depending on the number of customers served. Chromium, including chromium-6, is a naturally occurring substance that can leach into groundwater from soil. While scientists have long known that inhaling chromium-6 can cause lung cancer, recent studies have shown that ingestion of the compound can also lead to cancer, particularly intestinal and oral cancer in rodents exposed to high levels of chromium-6 in their water.
The new limit set by California is 500 times greater than the public health goal, with a significantly increased risk of cancer for those exposed to drinking water containing 10 parts per billion of chromium-6 over a period of 70 years. While studies on the health impacts of ingesting chromium-6 through drinking water are limited, experts believe that the 10 parts per billion limit is a starting point that should be adjusted periodically based on new research. The state water staff plans to review these standards every five years, but they are constantly monitoring and reviewing the regulations to ensure they are effective. The regulation of chromium-6 has been a long-standing issue, famously brought to light by the movie “Erin Brockovich,” which highlighted a community in Southern California that was contaminated with chromium-6. Residents eventually won a settlement with the responsible company for contaminating their water.
