Chlorinated paraffins (CPs) are high
production volume synthetic
chemicals, found ubiquitously in various environmental matrices. However,
little information is available on CP contamination in mothers’
milk. In this study, 1370 urban mothers’ milk samples were
collected from 12 Chinese provinces in 2007 and 16 provinces in 2011.
CP geographical distribution and congener group profiles were studied
to assess the CP levels and figure out the source of exposure in humans.
Twenty-eight pooled samples were analyzed for 48 short-chain CP (SCCP)
and medium-chain CP (MCCP) congener groups using the GC × GC-ECNI-HRTOFMS
method. The median concentrations of SCCPs were 681 and 733 ng/g lipid
in 2007 and 2011, respectively; median concentrations of MCCPs were
60.4 and 64.3 ng/g lipid in 2007 and 2011, respectively. Variations
of more than 2 orders of magnitude in CP exposure levels were found
between different provinces. The levels of CPs increased from 2007
to 2011, which indicates that CP production and use may be an important
exposure source. This is the first global comprehensive and large-scale
investigation of CPs in mothers’ milk, and it lays foundations
for improving our understanding of the metabolism of CPs in humans.
The high CP concentrations found in Chinese mothers’ milk should
raise concern about potential toxic effects in both mothers and breastfeeding
infants.