The object of this study was to determine the sources of lead contamination in the soil of the Dutch town Graft-De Rijp by means of trace element concentrations and stable lead isotopes. The old town centre of Graft-De Rijp (founded in the 17th century) is largely build on a mixture of slush, manure and town refuse, which was dumped to fertilize and raise the soil. In addition the town has a long industrial history (ship-building industries, sail-lofts and oil mills in the mid
17th century and gasworks, coal storage, printing-works and tanneries more recently). Therefore many sources of lead can be expected. Samples were taken from forty soil profiles (at least 2 samples per profile) of assumed polluted and unpolluted locations. In addition, old lead containing artefacts (leaden pipes, ceramics, paint and coal ashes) found in the vicinity of the studied area were analysed. Major elements and 18 minor elements of the samples were measured with XRF. Lead isotopic compositions and concentrations of most samples and artefacts were determined with ICP-MS (2s<0.8% for all ratios). Lead analyses were corrected for fractionation by repeated analysis of the NBS 981 standard.
According to the results of the XRF analyses, lead concentrations of the polluted soils vary between 100 and 5300 ppm. The unpolluted soils, predominantly consisting of clay and peat, show average lead concentrations of 20 and 50 ppm respectively. Trace element concentrations indicate that two different sources of lead contamination can be distinguished, Pb pollution in combination with increased Cu, Zn and As concentrations and Pb pollution with exclusively high Pb concentrations. The lead isotopic ratios of the samples also indicate that we deal with (at least) two sources of lead contamination. The main source of the Pb, Zn, Cu and As pollution is presumably coal ash. Another source of pollution can be assigned to domestic remnants and remains of the old town.
This study shows that stable lead isotopes in combination with trace element concentrations are useful tools to distinguish between sources of lead contamination.