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Dermal bioavailability of benzo[ a ]pyrene on lampblack: Implications for risk assessment
Author(s) -
Stroo Hans F.,
Roy Timothy A.,
Liban Cris B.,
Kreitinger Joseph P.
Publication year - 2005
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/04-240r.1
Subject(s) - pyrene , chemistry , environmental chemistry , bioavailability , contamination , hydrocarbon , soil water , polycyclic aromatic hydrocarbon , absorption (acoustics) , environmental science , organic chemistry , soil science , ecology , bioinformatics , biology , physics , acoustics
Lampblack is the principal source of contamination in soils at manufactured gas plant (MGP) sites where oil was used as the feedstock. Risks and cleanup criteria at these sites are determined primarily by the total carcinogenic polynuclear aromatic hydrocarbon (PAH) content, particularly the concentration of benzo[ a ]pyrene (B a P). Dermal contact with soils at oil‐gas MGP sites is a significant component of the overall risks. Seven samples were collected from oil‐gas MGP sites and the steady‐state dermal fluxes were measured over 96 h in vitro. The standard dermal bioassay technique (in which 3 H‐B a P is added to the soil matrix) was modified to allow direct measurement of the dermal absorption of the native B a P in the samples. The experimentally derived dermal absorption factors for B a P were 14 to 107 times lower than the default assumption of 15% over 24 h (55‐fold lower on average). The dermal fluxes were correlated positively to the total B a P and total carbon concentrations. The measured dermal absorption factors were compared to the default risk‐assessment calculations for all seven samples. The calculated excess cancer risk was reduced as a result of using the measured absorption factors by 97% on average (with reductions ranging from 93 to 99%). This work indicates the risks at oil‐gas MGP sites currently are overestimated by one to two orders of magnitude, and provides a protocol for the testing and data analysis needed to generate site‐specific cleanup levels.