Distribution of Heavy Metals in Radishes: A Time Dependent Approach.

Waste products from zinc smelting plants have contaminated the residential soils of Spelter, WV and Palmerton, PA with lead, cadmium, zinc and copper.  This has led to growing concerns about how these elements might accumulate in lawn and garden plants grown in these soils.  Pot experiments were designed with 6 different levels of heavy metal concentration in soil to determine the uptake of these metals by radish (Raphanus sativus) over a 12 week period.  The time dependent variation in metal accumulation demonstrated that the uptake of heavy metals by radish differed at various growth phases.  Maximum uptake was during the 7^th to 8^th week after which plants started showing prominent signs of chlorosis.  The amount of heavy metal accumulation in different parts of radish followed the order of root>leaves>stem.  These results suggest that vegetables grown on these soils may be an important exposure pathway and could pose a human health risk.