This study is the first year of the project “Tracing metal soures in polluted soils using multiple metal isotopes (1/2)” We aim to develop an accurate and high-precision multi-isotope (Cu-Zn-Pb) technique for a variety of environmental samples, such as soils, bedload sediments, and water samples, as well as further evaluate the potential use of Cu-Zn-Pb isotopes as a tracer for metal pollutions in contaminated soils. In this project, we have (1) reviewed/summarized the literature regarding the method developments and applications of multi-isotopes for tracing metal sources in contaminated soils; (2) successfully developed a high-precision Cu-Zn-Pb isotopic technique on a variety of environmental samples and drafted the protocol for Cu-Zn-Pb isotope analysis in soils; (3) applied the soil Cu-Zn-Pb isotope systems in the polluted soils in Changhua County; and (4) trained the NERA staffs for the analytical techniques developed in this project on 24th and 31rd October, 2023. For the soil samples collected from Changhua County, the farmland soils were polluted by local industrial sources (mainly Cu and Zn). We investigated the samples after farmland remediation, including soils, sediments, and potential sources of metals from the two factories. The preliminary results show that three sources of Cu can be identified with the implementation of Cu and Pb isotope ratios, suggesting that the stable Cu isotope ratio can be used as a powerful tool for metal source tracing in the polluted soils. Furthermore, the two factories (with the same industry) are characterized by distinct Zn isotope data, indicating that the Zn isotopes may serve as a potential tracer for further distinguishing the metal pollutions from the same industry.

MC-ICP-MS, soil contamination, metal isotopes