The research will be presented at the 223rd national meeting of the American Chemical Society, April 7-11 in Orlando.

The interaction of toxic metals in water with mineral surfaces in soils and rocks plays a major role in the quality of the world's fresh water and the mobility, bioavailability, persistence, and ultimate fate of dangerous environmental pollutants.

Lead (Pb), which is toxic, is one of the most common of the heavy metals in the earth's crust and therefore a common pollutant. But it can bind to several minerals, effectively reducing its availability to plants and animals.

S. Erin O'Reilly, a doctoral student in geological sciences at Virginia Tech is examining the lead sorption efficiency of several manganese (Mn) and iron (Fe) oxides. The aim is to clarify the understanding of which phases of Mn and Fe and which mineral properties of those phases are most influential in controlling lead availability in the environment. "We also hope to increase the understanding of the mineral surface properties that determine the lead absorption efficiency of a solid," says O'Reilly.

Iron oxide minerals are common in soils, so plentiful that they are responsible for the orange or red rusty color of many soils. Manganese oxide minerals are also common, but not all forms are easily studied. Birnessite, for instance, is "poorly crystalline" andis often mixed with other soil components and difficult to isolate for laboratory study.

The comparisons are based upon the amount of lead per surface area that the minerals "sorb" or remove from solution. The minerals are reduced to particles and placed in solution, which is injected into a filter chamber called a "reactor" -- one reactor per mineral type. The same amount of lead
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Contact: S. Erin O'Reilly
soreilly@vt.edu
540-231-3358
Virginia Tech
10-Apr-2002