Use of human placenta for environmental biomonitoring. Preliminary observations on multi-elemental analysis of placental tissue in a Delhi hospital

The recent increase in the hazards of environmental pollution has led to the search for adequate methods of biomonitoring of aquatic/terrestrial animal and human tissues in a prospective and retrospective manner. Environmental specimen banking is a natural corollary for these purposes in view of the limitation of human autopsy material. In the search for an alternative approach, the choice of the ubiquitous placental tissue appears promising from several aspects. Hence, a feasibility study was undertaken for the estimation of important non-toxic as well as toxic inorganic elements. After sampling of the tissues the analytes were prepared in 'Suprapur' HNO3 and digested in a 'Parr bomb' in a domestic microwave oven. Simultaneous multi-elemental analysis for 21 elements was carried out with inductively coupled plasma-mass spectrometry (ICP-MS). Out of 101 analytes originally planned, the estimation of 26 samples has been completed so far. The results demonstrated operational ease and internal consistency in terms of the standard reference material (SRM) (SRM-1643b or SRM-1643c) of the National Institute of Standards and Technology, which was run concurrently with the samples. The values of 5.48 ± 1.94 ppm for Cu, 0.02 ± 0.02 ppm for Co, 1.64 ± 0.92 ppm for Se and 0. 14 ± 0.14 ppm for Mb are in close agreement with the published literature apart from some variation in the values of heavy metallic elements Zn, Fe, Cd and Pb. Although the average levels of Cd and Pb were less than the reported values, the corresponding finding of higher values for toxic elements As, Cd and Pb in some of the samples is noteworthy. (author)