Accumulation of cadmium in sunflowers from calcium- and zinc-loaded hydroponic solutions

CHED 1059

Emily G. Frost, efrost@chatham.edu, Department of Chemistry, Chatham University, Woodland Road, Pittsburgh, PA 15228 and Joseph MacNeil, macneil@chatham.edu, Department of Chemistry, Chatham College, Woodland Road, Pittsburgh, PA 15232.
Heavy metals, including cadmium, accumulate in soil from many sources, including car exhaust, airborne particles, paints, acid mine drainage, and pesticide and fertilizer run-off. One of the most promising methods of removing these pollutants from soil involves phytoremediation via phytoextraction, where a plant absorbs the toxins and is harvested, reducing the concentration left in the soil. Previous research has shown that sunflowers are efficient at accumulating cadmium (Cd2+) from soil, especially when EDTA, a chelating agent, is added to make the Cd2+ more mobile. It is not yet fully understood how the Cd2+ crosses the plant membranes at the root. This study investigated this process by studying how Cd2+ absorption is affected by the presence of calcium (Ca2+) or zinc (Zn2+) ions, both of which are essential to the plant's development. Sunflowers grown hydroponically were treated with Cd2+, EDTA, and varying levels of Ca2+ or Zn2+. Results show that an interaction does exist, suggesting that Cd2+ may enter cells through the same channels as Ca2+ and/or Zn2+.