Low-cost automatic geochemical scanning of sediment cores using pXRF, XZ-axial translation stages, and the PyCoreX software

Current environmental changes are increasing the demand for analytical tools and procedures that are affordable, reliable, and time-efficient for use in various academic research projects as well as civil engineering applications. In this context, sediments are a major source of subsurface environmental data, and the accelerating growth of sediment core libraries has motivated the use of fast, low-cost, and quasi-continuous geochemical investigations of sediment sequences. Portable handheld X-ray fluorescence spectrometers (pXRF) serve as practical, efficient, and economical tools for elemental assessment of sediment samples and have therefore become popular in numerous sediment laboratories and environmental consultancies worldwide. Here, we present a setup for low-cost automatic pXRF elemental scanning of sediment cores using a motorized XZ-axis translation stage, controlled with the Python-based open-source PyCoreX desktop software featuring an easy-to-use graphical user interface. We demonstrate the applicability of the setup by analyzing a 10-m heterogeneous sediment core with varying grain sizes and organic matter content. The reliability of the analyses was evaluated by comparing in situ pXRF measurements on the raw sediment core surface with analyses on dried and ground samples as well as measurements obtained using conventional elemental analytical techniques. The advantages of automatic pXRF elemental scanning of sediment cores are discussed in terms of convenience, scientific relevance, cost, speed, and radiation safety. The effects of grain size, moisture, organic matter content, and porosity of the sediment core surface are also discussed to shed light on potential sources of uncertainty in elemental assessment.