A recent study by Washington, D.C.-based Environmental Water Group found that 75 percent of the U.S. drinking water supply(affecting about 200 million people) is high in the chemical chromium six. The chemical, also known as hexavalent chromium, is the very contaminant made infamous in the film “Erin Brockovich” for poisoning some California residents with the cancer-causing agent.
In Northeast Texas, chromium six levels are in most areas higher than the California safe standard of .02 parts per billion. Hexavalent in even miniscule quantities has been linked to cancer.
In Hunt, Fannin, Collin, Rains, and Rockwall counties, levels of hexavalent chromium in the water supply were, according to the EWG report, generally around 0.2 parts per billion. Grayson County had the highest concentrations in the KETR listening area, at 0.55 parts per billion. Lamar, Hopkins, and Delta counties reported no trace of chromium six in the water supply.
The North Texas Municipal Water District, which serves 10 counties in Northeast Texas responded to questions it has received about the EWG report by saying the water it distributes is treated and, therefore, safe to drink. The district said that it conducts 250,000 tests annually and that total chromium in its water is well below EPA-accepted guidelines of 100 parts per billion.
Total chromium in the water is comprised of chromium six and chromium three. The difference is that while chromium three is largely harmless, hexavalent chromium is entirely not. Chromium six occurs naturally from the erosion of natural chromium deposits and from industrial processes. It is more often found in wells than surface water supplies, such as lakes.
Interestingly, consumers in the three counties without chromium six in the water get their water from lakes. NTMWD water supplies are all from surface water sources.