Mineral magnetic measurements as a pollution proxy for canal sediments (Birmingham Canal Navigation Main Line)

The use of mineral magnetic measurements (XLF, XARM and saturation isothermal remanent magnetization (SIRM)) as a potential particle size - pollution proxy for sediment samples collected from the Birmingham Mainline canal (UK) is explored as an alternative means of monitoring pollution. Comparison of sediment-related analytical data by correlation analyses between each magnetic parameter and individual particle size classes (i.e. sand, silt and clay), and more discrete intervals within classes (e.g. fine sand or medium silt) are reported. XLF, XARM and SIRM parameters reveal few significant (p < .05; n = 60), weak (rs = .443), associations with clay content. Specific areas of historic anthropogenic activity are investigated and reveal improved correlations with )XLF vs. clay (r = .739, p < .001; n = 60), silt (r = -.612, p < .001; n = 60), and discrete fractions of sediment (r = .700-.868; p < .001). Comparison of mineral magnetic concentration and geochemistry are also reported with moderate to strong relationships between XLF, XARM, Fe, Pb and Co. Contrary to earlier research findings, the results for the Birmingham Canal Navigations Main Line indicate that magnetic measurements cannot always provide a predictable particle size proxy and it is only certain environments and/or specific settings that are appropriate for granulometric normalization by this technique.