Concentrations of toxic metals and radionuclides in Kazakhstani breast milk

Numerous reports have highlighted the profound health and economic consequences of environmental degradation in the former USSR. The potential consequences of contamination for breast milk safety are of concern to health authorities. The paper presents data on concentrations of toxic metals and radionuclides in breast milk samples collected in Kazakhstan. The data are from a larger study designed to provide a scientific basis for the development of a national infant feeding policy. Breast milk samples were collected in eight sites (including the former Soviet nuclear site of Semipalatinsk) in 1995. Between 12 and 17 samples per site were collected for a total of 115 samples. At the time of collection, within-clinic compositing of breast milk samples was completed for radionuclide analysis for a total of 22 composite samples. Rigorous collection protocols were followed to ensure that samples were not contaminated during collection. Breast milk was hand expressed into 2 oz (60 mL) plastic containers through plastic funnels, acid washed to be free of the contaminants under study. Two independent analytical techniques, inductively coupled plasma-mass spectrometry (ICP-MS) and neutron activation analysis (NAA), were used to facilitate verification of results. The ICP-MS laboratory also used inductively coupled plasma-atomic emission spectrometry (ICP-AES) for the determination of the major elements zinc and iron. Minor elements were measured by ICP-MS. 137Cs was determined by a high sensitivity and high resolution Ge detector. Results by NAA and ICP-AES or NAA and ICP-MS indicate excellent agreement between the two methods. For the toxic elements, the median concentrations in breast milk are within the range of median concentrations in other countries. 137Cs was not detected in any of the samples. All the major minerals and electrolytes showed breast milk levels within reference values. Likewise, levels of all essential trace elements were comparable to the median concentrations in other countries. Based in part on the results of this study, the Ministry of Health of Kazakhstan is promoting breast feeding. (author)