MP12 Organic, Metallic, Organometallic Pollutants
Monday, 14 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(NAM-1117-742059) Longitudinal monitoring of persistent organic pollutants in UK breast milk: correlation with genotoxicity.

Nam, J. J.^{1, 2}, Hewitt, R.³, Martin, F.³, Jones, K.², ¹ Department of Environmental Science, Institute of Environmental and Natural Sciences, Lancaster University, Lancaster, UK² National Institute of Agricultural Science and Technology, Suwon, Korea³ Department of Biological Sciences, Institute of Environmental and Natural Sciences, Lancaster University, Lancaster, UK

ABSTRACT- The importance of exogenous exposures in the aetiology of breast cancer remains to be established. Through environment or diet, humans are continuously and variously in contact with fat-soluble xenobiotics that may elicit effects, often damaging, either singly or in mixtures. In order to simulate in vitro the potential effects of in vivo human exposures, we employed milk fat as a surrogate tissue; persistent organic pollutants (POPs) in adipose tissue may be excreted during lactation. Longitudinal analyses for fluctuations in POP concentrations in milk-fat extracts (n = 5 UK-resident mothers) collected over a one-month period (on six different days) were conducted. Geometric means and ranges of the sum of five PBDE congeners, DDT/DDEs, 33 PCB congeners, and HCB were 2.5 (0.4-8.3), 107 (15-9260), 59 (16-220), 8.5 (5.2-12) ng/g lipid, respectively. Although information on the exact date post-partum that samples were collected was not made available, one could assume that the first sample per series was collected within one month of the start of lactation. In light of this, a general trend where POP levels were elevated towards the middle part of the collection series and began to decline towards the end was noted. The highest to lowest ratios of PBDE, DDT, PCBs, and HCB were 21, 3, 14, and 2, respectively; similar to observed ratios in air. These low ratios for DDT, PCB, and HCB suggest that these compounds are currently not being used whereas the higher PBDE ratio might be suggestive of extensive use throughout the UK due to stringent fire regulations. In parallel experiments, "low-dose" effects of such contaminant mixtures present in milk-fat extracts were examined in MCF-7 cells using the cytokinesis-block micronucleus assay and the alkaline COMET assay. Such an approach may provide evidence as to whether such exposures modulate the susceptibility of target-cell populations to pathogenic events.

Key words: POPs, breast milk, genotoxicity, bioassay