A lead isotope distribution study in swine tissue using ICP-MS

In the United States lead is an ubiquitous environmental pollutant that is a serious human health hazard especially for women of childbearing age, dev eloping fetuses, and young children. Information concerning the uptake and distribution of lead to maternal and fetal tissues during pregnancy is poor ly documented. A study was designed using domestic swine and lead isotope e nrichment methodology to focus on maternal absorption and distribution of l ead into bone and soft tissues, including the fetal compartment, under vary ing conditions of oral lead exposure and during altered physiological state s (pregnant vs unbred). Total lead levels and Pb-207/Pb-206 ratios in bone (femur and vertebra), blood, and soft tissues (liver, kidney , brain) were determined by ICP-MS. Lead in fetal tissues derived from maternal bone coul d be differentiated from that derived from exogenous dosing. Unbred swine a bsorbed much less lead than pregnant females receiving the same dose. The a ccuracy and precision of ICP-MS at the instrumental level and for the entir e method (sample collection digestion, and analysis) were evaluated for bot h Pb-207/Pb-206 ratios and total lead. Several changes were suggested in me thod design to improve both instrumental and total method precision.