There was no lead-weighting used in the molded plastic, nor lead in the stainless steel coin. If you are suggesting that the area should be escavated to elminate ground water pollution in order to free the rest of the chips, it would probably be at a cost of several million dollars... and the chips would be ground up and buried in a hazardous materials site. We would not see any more chips as a result.
Maybe you left a out of your post? [g]