Groundwater contamination is rife — there's the chromium in the Erin Brokovitch case, there's MTBE in groundwater all across the state
of California, and other areas have rocket
fuel residues like perchlorate, commonly found in
small amounts in much lettuce grown in the U.S. Agricultural drainage is also full
of fertilizers, pesticides and herbicides, which ends up in rivers and lakes that
feed into municipal water supplies.