Magnetic approach to normalizing heavy metal concentrations for particle size effects in intertidal sediments in the Yangtze Estuary, China

In this study, mineral magnetic, particle size and geochemical analyses were conducted on intertidal sediments from the Yangtze Estuary to examine the feasibility of heavy metal concentrations normalization using magnetic techniques. Susceptibility of Anhysteretic Remanent Magnetization (χ_ARM), the ratio of χ_ARM to SIRM (Saturation Isothermal Remanent Magnetization) and susceptibility (χ_ARM/SIRM and χ_ARM/χ, respectively), and to a lesser degree, frequency dependent susceptibility (χ_fd), displayed significant correlations with the fine sediment fraction (<16 μm). The strong relationships between χ_ARM and heavy metals can be explained by the role of particle size and iron oxides in controlling metal concentrations. This study demonstrates that χ_ARM can be used to normalize for particle size effects as efficiently as common reference elements such as Al. Furthermore, the rapid and non-destructive nature of mineral magnetic measurement technique means that χ_ARM has a considerable application value in environmental quality monitoring and related studies.