Comparison of mathematically-predicted toxic equivalents (TEQs) and bioassay-derived dioxin-equivalents (TCDD-EQs) in heron embryos

Conference · Sun Dec 31 00:00:00 EST 1995

OSTI ID:242314

Rattner, B; Hatfield, J; Melancon, M; Custer, T; Tillitt, D ^[1]

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1. National Biological Service, Laurel, MD (United States)

Pipping black-crowned night-heron (Nycticorax nycticorax) embryos were collected from an uncontaminated site (Chincoteague National Wildlife Refuge, VA) and three polluted sites (Cat Island, Green Bay, WI; Bair and West Marin Islands, San Francisco Bay, CA). Hepatic microsomal monooxygenases were induced up to 85-fold relative to the reference site, and was associated with concentrations of total PCBs and 11 PCB congeners that are presumed to express toxicity through the Ah receptor. TEQs [mathematically predicted; summed product of PCB congener concentrations using 5 different sets of toxic equivalency factors (TEFs)] were compared to TCDD-EQS [derived by bioassay; ethoxyresorufin-O-dealkylase activity of treated H4IIE rat hepatoma cells]. Although TEQs were up to 15-fold greater than TCDD-EQs, the pattern among sites was consistent and TEQs were highly correlated with TCDD-EQS. TEFs based on single congener mammalian studies yielded TEQs that greatly exceeded values from the H4IIE bioassay of field sample. TEFs generated from avian egg injection studies yielded TEQs that most closely approximated bioassay-derived TCDD-EQS. Cytochrome P450 parameters were related to TEQs and TCDD-EQS; adjusted r{sup 2} often exceeded 0.5 for the relation among mathematically predicted TEQs and cytochrome P450 measurements. These data document the general predictive value of TEQs and TCDD-EQs for P450 induction in field collected samples, but also indicate the need for development of TEFs for the species and biological end point of concern.

• OSTI ID: 242314
• Report Number(s): CONF-9511137-; ISBN 1-880611-03-1; TRN: IM9626%%142
• Resource Relation: Conference: 2. Society of Environmental Toxicology and Chemistry (SETAC) world conference, Vancouver (Canada), 5-9 Nov 1995; Other Information: PBD: 1995; Related Information: Is Part Of Second SETAC world congress (16. annual meeting): Abstract book. Global environmental protection: Science, politics, and common sense; PB: 378 p.
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
56 BIOLOGY AND MEDICINE
APPLIED STUDIES
NATURE RESERVES
LAND POLLUTION
VIRGINIA
WISCONSIN
WATER POLLUTION
SAN FRANCISCO BAY
POLYCHLORINATED BIPHENYLS
TOXICITY
DIOXIN
BIRDS
SENSITIVITY
BIOLOGICAL INDICATORS
LIVER
ENZYME INDUCTION
ENZYME ACTIVITY
BIOLOGICAL MARKERS
COMPARATIVE EVALUATIONS
FORECASTING
MATHEMATICAL MODELS