Bioavailability of PCDD/F from contaminated soil in young Goettingen minipigs.
For the general population the intake of food of animal origin is the main route of human exposure to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F). Besides this the ingestion of contaminated soil might be an important exposure path for small children. For risk assessment the knowledge of the bioavailable fraction of soil bound contaminants is important. In a balance study with young Goettingen minipigs the oral bioavailability of PCDD/F from contaminated soil was estimated by determination of the retention of PCDD/F from soil in different organs and tissues. Relative bioavailability was estimated by comparing the retention from soil to the retention of PCDD/F in organs and tissues after oral administration of a PCDD/F mixture extracted from the same soil by solvent. The soil had a PCDD/F-contamination of 5.3 microg I-TEq/kg and originated from a former arable land that had been treated with sludge from the port of Hamburg some years ago. Two groups of each four animals were exposed daily for 28 days via their diet either to 0.5 g soil per kg body weight and day (2.63 ng I-TEq/(kg(bw).d)) or to a daily dose of 1.58 ng I-TEq/(kg(bw).d) given to the diet by solvent. Five unexposed animals were used as a control group. Liver, adipose tissue, muscle, brain and blood were analyzed for their PCDD/F content. Accumulation of PCDD/F from soil or solvent in comparison to control animals was only observed for congeners with 2378-chlorosubstitution and predominantly took place in the liver. Bioavailability of 2378-chlorosubstituted congeners was in the range of 0.64%-21.9% (mean: 10.1%) from soil and 2.8%-59.8% (mean: 31.5%) when administered by solvent. The soil matrix reduced the bioavailability by about 70%. Expressed as I-TEq only 13.8% of the PCDD/F contamination were bioavailable from soil. The relative bioavailability of 2378-chlorosubstituted congeners from soil in relation to administration by solvent was in the range of 2%-42.2% (mean: 28.4%). When not considering the bioavailability, the risk by oral uptake of PCDD/F contaminated soil might be overestimated.
Wittsiepe
Jürgen
J
Ruhr-University Bochum, Department of Hygiene, Social and Environmental Medicine, Universitätsstrasse 150, 44801 Bochum, Germany. wittsiepe@hygiene.rub.de
Erlenkämper
Bibiane
B
Welge
Peter
P
Hack
Alfons
A
Wilhelm
Michael
M
D000273:Adipose Tissue / Q000187:drug effects* / Q000378:metabolism; D000284:Administration, Oral; D000367:Age Factors; D000821:Animal Feed; D000818:Animals; D001572:Benzofurans / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000633:toxicity; D001682:Biological Availability; D001769:Blood / Q000187:drug effects* / Q000378:metabolism; D001835:Body Weight / Q000187:drug effects* / Q000502:physiology; D002947:Cities; D005858:Germany; D000072317:Polychlorinated Dibenzodioxins / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000633:toxicity; D018570:Risk Assessment; D012989:Soil Pollutants / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000633:toxicity; D012997:Solvents / Q000737:chemistry; D013552:Swine; D013556:Swine, Miniature; D013997:Time Factors; D014018:Tissue Distribution / Q000187:drug effects* / Q000502:physiology
D001572:Benzofurans; D000072317:Polychlorinated Dibenzodioxins; D012989:Soil Pollutants; D012997:Solvents; C023614:dibenzofuran