Impacts of aging on in vivo and in vitro measurements of soil-bound polycyclic aromatic hydrocarbon availability

Ingestion of contaminated soil is an exposure pathway at approximately one- half of the Superfund sites in the United States. This study was designed t o evaluate the impacts of aging in soil on the availability of polycyclic a romatic hydrocarbons (PAHs). Two coal tar (CT)-amended soils were prepared. One was aged for 270 days and the other was not aged. Both of these treatm ents were incorporated into pellets and fed to male Fischer 344 rats. Excre tion of l-hydroxypyrene (1-OHP) in urine and PAH concentrations in the live r were monitored as end points. Additionally, soil:water partitioning and d esorption were measured as comparisons to the in vivo results. After 5 days of ingesting their respective treatments, rats in the aged soil group excr eted 4.41 +/- 1.67 ppm 1-OHP/mg of pyrene ingested while rats in the unaged soil group excreted 5.27 +/- 1.37 ppm/mg of pyrene ingested. Animals fed a ged CT soil had 0.051 +/- 0.011 ppm carcinogenic PAHs in livers/mg ingested while rats fed unaged CT soil had 0.063 +/- 0.037 ppm carcinogenic PAHs in livers/mg ingested. Partitioning and desorption results revealed a similar results. These results indicate that, at high application rates, soil cont act time may not play as significant a role in determining availability as simple dispersion and sorption on soil.