Contents lists available at ScienceDirect Catena journal homepage: www.elsevier.com/locate/catena Suitability of magnetic proxies to reflect complex anthropogenic spatial and historical soil heavy metal pollution in the southeast Nile delta A.M. Guda a, ⁎ , I.A. El-Hemaly a , E.M. Abdel Aal a , H. Odah a , E. Appel b , A.M. El Kammar c , A.M. Abu Khatita d , H.S. Abu Salem c , A. Awad a a Earth’s Geomagnetism Lab, National Research Institute of Astronomy and Geophysics (NRIAG), Helwan, Egypt b Geosciences Department, Centre of Applied Geosciences, Tübingen University, Germany c Geology Department, Faculty of Sciences, Cairo University, Egypt d Geology Department, Faculty of Sciences, Azhar University, Egypt ARTICLE INFO Keywords: Soil pollution Magnetic proxy Heavy metals Nile delta ABSTRACT Magnetic proxy methods are effective tools for detecting anthropogenic heavy metal pollution of the environ- ment. In this study we investigated the viability of using this method in an area of a complex setting where natural geogenic input, interfering land-use, and multiple different industries affect the magnetic signal. For this purpose, we took surface (N = 70) and core (N = 18) samples from an ~80 km 2 area in the south-eastern Nile delta that was partly flooded before construction of a major dam, with overlapping agricultural, residential (urbanization and land reclamation), and multiple industrial activities. Using ICP-MS we characterized the spatial pollution pattern and found enrichments in seven potentially toxic heavy metals; Cu, Zn, Pb, As, Sb, Cd, and Hg, located near industrial hotspots, with highly varying pollution levels, high concentrations in the upper soil and clear depletion with depth. Magnetic susceptibility (ϰ) was measured in-situ at 170 sites, and on all samples. Thermomagnetic runs reveal that magnetite and Ti-rich titanomagnetite control the magnetic signal. Despite industrial activities are predominantly located in more sandy areas, and ϰ is found to be strongly related to spatial lithological variation, the magnetic results reasonably outline the industrial areas and show elevated ϰ levels around drains where pollutants are discharged and redistributed by irrigation. In most of these locations, ϰ decreases with depth in parallel with the pollution level, and there is a moderate correlation of ϰ with the pollution load index for the topsoil values of the core samples normalized to their bottom values. Despite the area's complexity, the spatial ϰ pattern matches reasonably well with the chemistry data of cores located in the vicinity of the main industrial spots. Therefore, also for this complex setting, time-efficient ϰ mapping provides a helpful tool as a qualitative approach for detecting key features of the spatial distribution of pollutants, which will be useful for supporting a better-targeted chemical sampling. 1. Introduction During the last few decades, the worldwide death rate due to pol- lution increased to be at least- 1 million case/year (WHO, 2016). The Environmental magnetism, concerned in this study, was formally in- troduced by Thompson et al. (1980) suggesting magnetic properties as a proxy for heavy metal pollution. As the Fe-bearing minerals are sensi- tive to a range of environmental processes they are thought to be useful for detecting signals related to environmental processes (Liu et al., 2012). Magnetic measurements are efficient, non-destructive and sen- sitive (Verosub and Roberts, 1995). They provide a successful metho- dology in the qualitative or semi-quantitative delineation of pollution sources and affected areas prior to the quantitative chemical analysis. Despite the relation between magnetic parameters and heavy metal pollutants differs according to the nature of pollution and the en- vironmental setting, many researchers achieved significant results. For example, Ma et al. (2015) found a very strong correlation between magnetic concentration parameters (χ, ARM, SIRM) with heavy metals concentrations in a study on sediments from a water reservoir. Cao et al. (2015) related different magnetic parameters measured for leaf and topsoil samples to the known severe pollution in Shanxi Province, China. They also found that it is possible to separate natural and an- thropogenic sources. Maher et al. (2008) identified vehicle-derived heavy metal pollution and found a moderate to strong correlation with https://doi.org/10.1016/j.catena.2020.104552 Received 20 September 2019; Received in revised form 18 February 2020; Accepted 10 March 2020 ⁎ Corresponding author. E-mail addresses: alshymaa@nriag.sci.eg, shimaaguda@yahoo.com (A.M. Guda). Catena 191 (2020) 104552 0341-8162/ © 2020 Published by Elsevier B.V. T