title: Enantiomeric ratios as an indicator of exposure processes for persistent pollutants in human placentas.
abstract: The enantiomeric ratios (ER) of alpha-HCH and o,p'-DDT ((+)-isomer concentration/(-)-isomer concentration) and o,p'-DDD (first eluting enantiomer/second enantiomer) were investigated in 112 human placentas from Finnish boys collected 1997-2001. Both o,p'-DDD and alpha-HCH showed changes in their ER depending on the total concentration of the compound in the sample. Their ERs are approaching a value close to racemic mixture (ER=1) at high concentrations. At low concentrations they often differ from 1. The relationship between concentration and ER is clearly identified and it has been shown that it is not affected by analytical uncertainty. This relationship appears to be important for assessing tissue- and species-specific exposure and risk and it may indicate whether net uptake or metabolic activity is dominant in exposure for the resulting exposure of the enantiomers.
authors: Institute of Ecological Chemistry, GSF-National Research Center for Environment and Health, Ingolstädter Landstrasse 1, D-85764, Neuherberg, Germany. shen@gsf.de
authors: Heqing
authors: H
authors: Shen
authors: H E
authors: HE
authors: Virtanen
authors: Katharina M
authors: KM
authors: Main
authors: M
authors: M
authors: Kaleva
authors: A M
authors: AM
authors: Andersson
authors: Niels E
authors: NE
authors: Skakkebaek
authors: Jorma
authors: J
authors: Toppari
authors: Karl-Werner
authors: KW
authors: Schramm
mesh_terms: D003634:DDT / Q000032:analysis*; D004781:Environmental Exposure / Q000032:analysis*; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000032:analysis*; D005387:Finland; D001556:Hexachlorocyclohexane / Q000032:analysis*; D006801:Humans; D066298:In Vitro Techniques; D008137:Longitudinal Studies; D010920:Placenta / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D004785:Environmental Pollutants; D001556:Hexachlorocyclohexane; D003634:DDT