Accelerator Mass Spectrometry (AMS) and Inductively Coupled Plasma Mass spectrometry (ICP-MS) are rapidly growing techniques for the ultra-trace analytical determination of stable and long-lived isotopes. Both methods have a wide potential within environm ental science, including ecosystem tracers and radioecological studies. For AMS, the proposed project will involve investigations on both heavy and light element analysis. AMS has only recently been applied to the determination of heavy elements (Pu-isoto pes, U-isotopes, Np-237, Ra-isotopes, Th), and method optimisation and validation, particularly for environmental samples, needs to be documented. AMS determination of Cl-36 and Ni-59 has been carried out within geological studies. Together with Tc-99, th ese long-lived radionuclides are also important, yet little studied, components of radioactive waste management. Hence the project will investigate potential applications of AMS to their analysis in contaminated areas, focusing on improvement of Environmental Impact Assessment and Ecological Risk Assessment. ICP-MS is a more widespread technique compared to AMS, but still offers advantages over routine counting methods. In addition to intercomparison of AMS and ICP-MS (IPM has already developed methods for Pu-isotopes and Tc-99), ICP-MS will be applied for sc reening of samples for AMS determination, and documentation of matrix interferences. The project builds on a five year collaboration between NLH/IPM and the Australian National University on the development and application of advanced MS techniques for the analysis of long-lived radionuclides, with the intention of extending this collabor ation to include other exotic radionuclides, instigating collaborations with other AMS facilities (Zurich) and demonstrating novel applications within environmental studies.