Maternal and cord serum exposure to PCB and DDE methyl sulfone metabolites in eastern Slovakia

Abstract

Polychlorinated biphenyls (PCBs) were commercially produced between 1959 and 1984 in eastern Slovakia. Improper handling led to a highly contaminated local environment and high levels of PCBs in humans and wildlife in the Michalovce area. The aim of this study was to analyse serum for methylsulfonyl metabolites of PCB (MeSO 2 -PCBs) and DDE (3-MeSO 2 -DDE) in serum samples from pregnant women and in a selected number of paired cord blood samples to assess maternal sulfone levels and patterns, and transplacental transfer of these metabolites. The donating women were from two districts in eastern Slovakia. A liquid-liquid extraction method together with separation of substance groups and further clean up on silica gel columns were applied prior to analysis by gas chromatography/mass spectrometry. 3-MeSO 2 -DDE was the major methyl sulfone in most of the samples followed by a yet not identified MeSO 2 -hexaCB, 4′-MeSO 2 -CB101, 4′-MeSO 2 -CB87 and 4-MeSO 2 -CB149. The women from the contaminated area had three times higher concentrations of the MeSO 2 -PCBs than women from the reference area. This is the first report on methyl sulfone metabolites of PCB and DDE in human cord serum. It is shown that these metabolites are transported through the placenta. The levels of MeSO 2 -PCBs in the maternal serum were about 1.5 times higher than in the corresponding cord serum on a lipid weight basis. For 3-MeSO 2 -DDE, the levels were about the same in maternal and cord serum. The difference in the maternal:cord ratio, comparing MeSO 2 -PCBs with 3-MeSO 2 -DDE might be due to differences in transport through the placenta caused by their different affinities for lipoproteins and plasma proteins.

Polychlorinated biphenyls and their hydroxylated metabolites in placenta from Madrid mothers

“…The OH-PCB fraction was methylated using diazomethane to obtain MeO-PCB derivates (Hovander et al 2000) for their subsequent GC analysis. The clean-up of the two fractions (methylated OHPCBs and PCBs) was carried out using multilayer columns filled with different amounts of neutral activated silica gel and activated silica gel modified with potassium hydroxide and sulphuric acid as described elsewhere (Hovander et al 2000;Linderholm et al 2007). The final fractions were evaporated under a gentle stream of nitrogen before the addition of the injection, standards previously mentioned, and the injection of the extracts in the different GC systems.…”

Ratio of cord to maternal serum PCB concentrations in relation to their congener-specific physicochemical properties

“…To reach the fetus they must cross the placenta. PCBs, as a group, easily pass the placental barrier (Park et al, 2008; Linderholm et al, 2007; Correia Carreira et al, 2011; Bergonzi et al, 2009) by simple diffusion due to their electronegativity, high lipophilicity and moderate molecular weight. However PCBs in the environment are a mixture of congeners, each of which is characterized by its own physicochemical properties and toxicity.…”

The spatial distribution of human exposure to PCBs around a former production site in Slovakia

“…The scope and extent of environmental contamination and the associated impacts on health have been documented in a series of studies (Kočan et al 1994; Kočan et al 2001; Kočan et al 2008; Jusko et al 2014; Langer et al 2014; Hertz-Picciotto et al 2008; Ghosh et al 2013; Patayová et al 2013; Trnovec et al 2013; Verner et al 2013; Jusko et al 2012; Mitra et al 2012; Trnovec et al 2011; Horváthová et al 2011; Dutta et al 2012; Jusko et al 2010; Park et al 2010; Park et al 2007; Park et al 2009; Park et al 2008a; Park et al 2008b; Sonneborn et al 2008a; Trnovec et al 2008; Yu et al 2007; Park et al 2007; Linderholm et al 2007). …”