Accurate and precise determination of lead isotope composition in selected geochemical reference materials

Lead (Pb) isotopes have been extensively employed in tracing sources of Pb and its transport pathways through the environment. However, Pb isotopic ratios in related geochemical reference materials are scarce. Here, we report high-precision Pb isotopic ratios measured by Nu Plasma II MC-ICP-MS using calibrated Tl-205/Tl-203 = 2.38865 (NIST SRM 997) for mass discrimination correction. The long-term external precision (2SD) for NIST SRM 981 of Pb, BCR-2, and BHVO-2 are 0.31 parts per thousand (n = 105), 0.42 parts per thousand (n = 11), and 0.25 parts per thousand (n = 5) for Pb-208/Pb-206 and 0.16 parts per thousand, 0.53 parts per thousand, and 0.07 parts per thousand for Pb-206/Pb-207, both respectively, and their Pb isotopic ratios are in excellent agreement with the recommended values. Using this method, we report for the first time Pb isotopic compositions in shale SGR-1b (USGS); coal CLB-1 (USGS); stream sediments GSD-17, -21, and -23 (IGGE); soils GSS-12, -13, -14, -15, and -16 (IGGE); plants GSV-1, -2, and -3 (IGGE); and human hair GSH-1(IGGE).