Successful application of lead isotopes in source apportionment, legal proceedings, remediation and monitoring

Abstract

In late 2006,the seaside community in Esperance Western Australia was alerted to thousands of nativebird species dying.The source of the lead(Pb) was determined by Pb isotopes to derive from thehandling of Pb carbonate concentrate through the Port, which began in July 2005. Concern wasexpressed for the impact of this on the community. Our objectives were to employ Pb isotope ratios toevaluate the source of Pb in environmental samples for use in legal proceedings,and for use inremediation and monitoring. Isotope measurements were undertaken of bird livers, plants,drinkingwater, soil,harbour sediments,air,bulk ceiling dust,gutter sludge,surface swabs and blood.The uniquelead isotopic signature of the contaminating Pb carbonate enabled diagnostic apportionment of lead insamples.Apart from some soil and water samples, the proportion of contaminating Pb was > 95% in theenvironmental samples. Lead isotopes were critical inr esolving legal proceedings, are being used in theremediation of premises, were used in monitoring of workers involved in the decontamination of thestorage facility,and monitoring transport of the concentrate through another port facility. Air samplesshow the continued presence of contaminant Pb,more than one year after shipping of concentrateceased,probably arising from dust resuspension. Brief details of the comprehensive testing and cleanupof the Esperance community are provided along with the role of the Community. Leadisotopic analysescan provide significant benefits to regulatory agencies, interested parties,and the community wherethe signature is able to be characterised with a high degree of certainty.