Hexavalent Chromium Contamination
In 1952, Pacific Gas & Electric (PG&E) started adding hexavalent chromium (Cr6+) to cooling water in order to suppress rust in a Hinkley, California compressor station. The toxic metal was stored in unlined pools, allowed to percolate into the ground and contaminate the water supply. Unexplained illnesses (including respiratory cancer and organ damage) in the town sparked an investigation (as dramatized in the film Erin Brockovich), ultimately resulting in a blockbuster settlement of $333M in 1996.
The Cr6+ levels in Hinkley groundwater were reported at 0.58 ppm in 1993, high above the 0.1 ppm legal limit of the time; due to widespread violations exposed since the Hinkley case, some states are planning to implement Cr6+limits as low as 0.06 ppb. A 2010 study found that 21 US cities suffered from chromium-contaminated groundwater. There is currently no enforced contamination limit for Cr6+ in drinking water, but legislation for this purpose is in progress. Continue reading “Why Measure Chromium Concentration in Liquids?”