Bioavailability and cytochrome P-450 induction from 2,3,7,8-tetrachlorodibenzo-P-dioxin contaminated soils from Times Beach, Missouri, and Newark, New Jersey.

Bioavailability of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) from contaminated soils from Times Beach, Missouri and Newark, New Jersey, was examined using liver concentrations and toxicity in guinea pigs observed up to 60 days following a single oral administration, and induction of cytochrome P-450 in rats sacrificed 24 hours after a single oral dose as endpoints. Both soils are contaminated with several chlorinated dioxins and numerous other compounds. Times Beach soil resulted in greater TCDD concentration in liver and TCDD was considerably more bioavailable from Times Beach soil than from Newark soil. However, both soils induced cytochrome P-450 activity to approximately the same extent. Moreover, similar banding patterns of microsomal proteins were seen on polyacrylamide electrophoretic gels. The many other compounds present in the soils, particularly in Newark, may account for the similar protein bands and levels of cytochrome P-450 observed.