Waste from oil exploration can carry mercury, chromium, selenium, and a variety of other environmentally detrimental chemicals.

If you put a shovel in the ground, scoop a load of dirt, and fling it over your shoulder, you haven’t done a whole lot to modify the environment.  If, however, you take that load of dirt from hundreds or thousands of feet beneath the surface, you’re making a bit more significant change to the environment.  That’s pretty much what happens during oil exploration and production, which is why the state of Louisiana has developed laboratory procedures for analyzing waste samples generated during those operations.  The procedure tests for a variety of contaminants, such as heavy metals.  To ensure the measurements are accurate, the first step is to weigh the sample using an analytical balance.