Impact Of Aging Time On The Risk From Dermal Exposure To Soil Contaminated With Phenanthrene

The health risk from exposure to contaminated soil is related to the fraction of chemical absorbed by the body (bioavailability), rather than to the total concentration of chemical in soil. Chemical bioavailability data are necessary to improve the accuracy of risk assessment following exposure to contaminated soil and to allow more realistic soil remediation goals. One of the factors that may influence chemical bioavailability and ultimately health risk from exposure is the residence time or “aging” of chemical in soil. Skin is a primary route of exposure to phenanthrene, a polycyclic aromatic hydrocarbon found in soil at former manufactured gas plant sites. This study was conducted to determine the extent to which soil alters the dermal bioavailability of phenanthrene with respect to soil aging and soil type. Bioavailabilty was assessed by measuring the penetration of phenanthrene through dermatomed male pig skin via an in vitro approach consisting of radiotracer and flow-through diffusion cell methodology. After 3 months aging, dermal penetration was significantly decreased by 83% in Atsion soil (high sand and high organic matter content) and by 69% in Keyport soil (high clay but low organic matter content) versus pure phenanthrene (without soil). Extending the aging time to 6 months, reduced penetration through skin by 94% in Atsion soil and 86% in Keyport soil. The results indicate that because human risk from exposure to soil contaminated with phenanthrene would be reduced by aging, less soil cleanup would be needed