Magnetic particle characterization in the Seine river system: Implications for the determination of natural versus anthropogenic input

Abstract

[1] This study presents an innovative application of well-established environmental magnetic proxy parameters on fluvial sediments, with the aim to trace geological and human-induced processes in the complex Seine river drainage system in northern France. We seek to identify environmental fingerprints of mechanical and chemical weathering processes, the regional distribution of the suspended material, and changes in the balance of natural input versus anthropogenic pollution. In order to reach these goals, we applied a combination of rock magnetic and advanced scanning electron microscopic techniques on a large number of sediment trap samples. Generally, we observe an increase in magnetic concentration coupled with a coarsening in magnetic grain size downstream of the Seine river system. Furthermore, the dominant magnetomineralogy changes from high-coercivity minerals upstream in more rural areas to magnetitedominated assemblages downstream. Each river (segment) shows its specific trend line depending on regional initial input, weathering conditions, drainage area, and potential pollution sources. One major outcome of this study is the observed significant correlation between anthropogenic antimony-rich iron oxide particles and the magnetic concentration. This shows the potential of magnetic remanence measurements as proxy parameters for specific heavy metal pollution concentrations. Hence, the environmental magnetic study presented herein serves to identify major trends as well as local particularities and leads to quantitative analyses of the contributions of individual tributaries in the Seine river system.Components: 9513 words, 9 figures, 4 tables.

Magnetic minerals in three Asian rivers draining into the South China Sea: Pearl, Red, and Mekong Rivers

“…The magnetic mineralogy reflects the geology and the hydrology in the catchment of the three studied rivers although we cannot exclude that part of the magnetites might also be of anthropic origin because the floodplains are highly populated, urbanized, and industrialized [ Franke et al ., ]. The processes by which sediments are transported by the rivers from the eroded regions downstream are complex and not fully understood.…”

Magnetic, chemical and radionuclide studies of river sediments and their variation with different physiographic regions of Bharathapuzha river, southwestern India

“…Magnetic iii parameters have been widely used in environmental magnetism and some of them have been proven to be good proxies for environmental changes and contamination. Thus, magnetic proxies allow rivers to be assessed for reduced or wide extensions using the bed sediments (e.g., Scholger, 1998;Magiera et al, 2002;Jordanova et al, 2004;Desenfant et al, 2004;Chaparro et al, 2004Chaparro et al, , 2008Chaparro et al, , 2013Knab et al, 2006;Yang et al, 2007;Franke et al, 2009;Zhang et al, 2011;Sandeep et al, 2011).…”

Monitoring of dredged-dumped sediment dispersal off the Bay of the Seine (northern France) using environmental magnetism

“…Thus, over the last decade, dredge dumping at sea has been monitored by several innovative approaches using natural radionucleides (Venema and de Meijer, 2001), acoustic techniques (Wienberg and Bartholomä , 2005), and particle-size distributions combined with metal concentration analyses (Okada et al, 2009). Besides, environmental magnetism techniques have been used for monitoring heavy metals (Akinyemi et al, 2012;Franke et al, 2009;Pozza et al, 2004), inputs of anthropogenic magnetic spherules (Horng et al, 2009), artificial alpha-radioactivity (McCubbin et al, 2000), as well as petroleum hydrocarbons (Venkatachalapathy et al, 2011) in human-impacted sedimentary systems. However, to our knowledge, no dispersal monitoring of In this study, we developed a novel approach for fingerprinting dredged-dumped sediments at sea using magnetic susceptibility.…”