Assessing Indices Tracking Changes in River Geochemistry and Implications for Monitoring

Abstract In geochemical data analysis, assessing the potential of new techniques to identify compositional time–space changes is great interest for monitoring purposes. This work aims evaluate, in light analysis perspective, performance different statistical indices tracing evolution a composition and relationships among its parts. To reach this goal, source-to-sink chemical water stream sediment Tiber river (central Italy) are analyzed using three indices: (i) cumulative sum unclosed perturbation factors each (row sum) with respect reference composition; (ii) robust Mahalanobis distance, describing differences from same and, (iii) geometric mean as measure able capture interactions The results highlight major downriver, allowing explore footprints’ propagation their natural or anthropogenic origin. tested consistent most cases, particularly if high-variability species treated separately low values rare. Under latter condition, shows close connection factors. indicates that both inherit complex history changes, well capturing parts under influence environmental drivers. With awareness, application these methods applied studies could offer insights into inner workings systems resilience pressures.