The aim of this study is to trace possible sources of metal pollutions in the aquatic environment. In the first year of the project, we focus on the method developments for accurate and high-precision metal isotopic compositions in a variety of environmental water samples using MC-ICP-MS. By combining elemental concentrations and metal isotopes, we expect that the source tracings of environmental pollutions in the industrial parks and/or surrounding areas can be achieved. For the analytical techniques of the metal isotopic determinations, we have successfully established accurate and high-precision analytical techniques for Sr, Nd, Pb, Fe and Mo isotopes in water and solid samples. Several international isotopic standards, including IAPSO, SLRS-5 and SLRS-6, were determined using our new analytical protocols, and the measured isotopic values are in excellent agreement with the recommended values. We have measured metal concentrations and the Sr-Pb isotope ratios of the water samples, including treated and untreated wastewater, collected from the five selected industries (two factories for each industry) in the industrial park. Based on the elemental concentrations alone, we cannot find any useful tracers for the source apportionment in the industrial park. With the additional Sr-Pb isotopic data, we are able to distinguish the signals from different industries (and even different factories from the same industries). The preliminary results of Fe and Mo isotopes analyses also show distinguishable isotopic signatures among different factories, suggesting a great potential of using isotope compositions as a powerful tracer for studying the sources of wastewater pollutions. More detailed investigations on the isotopic variations for the factories are still required in order to further verify the utility of Sr-Pb (and Fe-Mo) isotopes as a reliable tracer for metal pollutions in the aquatic environment.

MC-ICP-MS, aquatic environment, metal pollution