The Effect of Clays and Soil Properties on the Bioremediation of Soils Contaminated with Pentachlorophenols

Don-Pedro, Esther and Annabelle Foos
Geology Department, University of Akron, Akron, OH

There are over 400 old wood preservative sites scattered all over the USA with established pentachlorophenol (PCP) contamination of soils, ground and surface water. PCP is a high molecular weight chlorinated organic compound. It is very toxic and carcinogenic and ranks amongst the top ten toxic contaminants on the EPA's toxicology list. The role of organic matter, and clay mineralogy on the bioremediation of chlorinated high molecular weight organics were investigated.

Although soil excavation and incineration has been the most commonly used remediation method for PCP contaminated sites, the EPA is carrying out studies on the applicability of bioremediation. When compared to soil excavation and incineration, bioremediation, the breakdown of contaminants by bacteria, is a cost effective, less intrusive remediation method. However this method is limited by our inability to predict its’ effectiveness in the field because biodegradation efficiency is site specific and dependent on local hydrology, soil characteristics and indigenous microbes.

This project investigated the adsorption and bioavailability of pentachlorophenol on different types of clay and organic matter. The objective was to determine which soil characteristics play a dominant role in contaminant bioavailability, which ultimately controls biodegradation efficiency.

The results obtained from this project will help the Environmental Engineer and Geologist when making a decision on the applicability of bioremediation of a pentachlorophenol contaminated site based on the soil characteristics and clay mineralogy of that particular site.

AAPG Search and Discovery Article #90031©2004 AAPG Eastern Section Meeting, Columbus, Ohio, October 3-5, 2004