Chromium III vs. Chromium VI in Water: What You Need to Know

Child Drinking WaterRecent reports have indicated the presence of chromium vi, also known as hexavalent chromium, in the municipal water supplies of 31 cities across the U.S. This toxic compound is an industrial pollutant and is known to be carcinogenic. Currently, the most effective way to remove chromium-6 from water is reverse osmosis filtration.

However, yearly water quality reports fail to distinguish between chromium vi and chromium iii. While the former is toxic and cancer-causing, the latter is an essential nutrient that is biologically active and found in everyday foods. Chromium-3 or trivalent chromium, is known to enhance the action of insulin, a hormone needed to metabolize and store carbohydrate, fat and protein in the body. Researchers have investigated the effect of chromium-3 supplements on preventing the onset of type-2 diabetes, and though these studies are inconclusive, there is no doubt that trivalent chromium is an essential and healthy compound. Failing to distinguish between hexavalent chromium and trivalent chromium is, as one report notes, like “lump[ing] a known carcinogen in with a vitamin.”

The moral of the story? Make sure you test your water for hexavalent chromium, specifically. Since chromium iii is found in so many foods, removing it from your water, along with chromium vi, is likely inconsequential. Most water filters that remove hexavalent chromium are likely to remove trivalent chromium as well, and it’s worth removing both in order to reduce your exposure to chromium-6. But simply buying a water filter that claims to remove “chromium,” but does not specify which type, may end up doing you no good, if your goal is to reduce the toxic variety.

The good news is, since the discovery of chromium-6 in water supplies across the U.S., health officials have recognized the importance of specifying these details on yearly water reports and will likely do so, in order to ensure a higher level of reliability in the future.