University Park, Pa. --- A group of Penn State-led researchers has shown that, for some fossil fuel-based pollutants, increasing the humus content of the soil increases, rather than decreases, the likelihood that the contaminant will move to ground water.

Dr. Jon Chorover, assistant professor of environmental soil chemistry, says, "The general belief is that, as you increase the organic matter in soil, you increase the retention of contaminants. We found that that is not always the case. It depends on the nature of the compound."

Chorover and his colleagues at Penn State's Environmental Resources Research Institute and Ohio State University looked at quinoline, a nitrogen heterocyclic compound (NHC), that has been little studied to date. Quinoline belongs to the broad group of environmental contaminants, termed ionizable PACs (polycyclic aromatic compounds), often found in sites polluted by fossil fuels, solvents, greases, creosote and coal tar.

They found that if a soil is low in organic matter, quinoline is more likely to become strongly bound to the soil and less likely to move to ground water. However, in its strongly bound state, the pollutant is also less likely to be broken down by microrganisms.

The researchers detail their results in the just released current issue of the Soil Science Society of America Journal in a paper, "Quinoline Sorption on Kaolinite-Humic Acid Complexes."

Chorover's co-authors are Mary Kay Amistadi, research support associate in Penn State's Department of Agronomy; Dr. William D. Burgos, Penn State assistant professor of civil and environmental engineering; and Dr. Patrick G. Hatcher, professor of environmental chemistry, Ohio State University.

The study also shows that mineral interactions with humus were key to whether quinoline was retained in soil. When humic substances coated the mineral phase, quinoline was less likely to adhere. However, when the min
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Contact: Barbara Hale
bah@psu.edu
814-865-9481
Penn State
27-Sep-1999