Noront Resources

It's not the only industrial application for hexavalent chrome, but chrome plating uses a lot of it. The reason they use hexavalent chrome is because it's soluble in water. You put a negative charge on the object you want the chrome to plate out on, and the chrome ions move through the water and get reduced to chrome metal on the surface of the charged object.

The spent plating solution (still with a lot of hexavalent chrome in it) used to have a strange way of finding its way into the environment. Monitoring of waste chrome solution just wasn't happening, years ago. That's where Erin Brokovich (spelling?) got involved.

The problem arising in discussions of e.g. risk is that the same substance can have vastly different properties depending on its oxidation state and molecular structure. Chlorine gas has different properties than hydrochloric acid (hydrogen chloride) and table salt (sodium chloride). The properties are specific to the chemical structure.

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