Contamination of vegetation by tetraethyl lead
Tetraethyl lead is a normal constituent of vegetation growing along our highways. Washed grass near Denver contained 3000 ppm (in ash) near major intersections and > 50 ppm for 500 feet downwind. Vegetables grown within 25 feet of a road in upstate New York and western Maryland averaged 80 to 115 ppm.
Maryland, New York↗