Contents lists available at ScienceDirect Marine Pollution Bulletin journal homepage: www.elsevier.com/locate/marpolbul The marine sedimentary record of natural and anthropogenic contribution from the Sulcis-Iglesiente mining district (Sardinia, Italy) Elena Romano a,⁎ , Giovanni De Giudici b , Luisa Bergamin a , Stefano Andreucci b , Chiara Maggi a , Giancarlo Pierfranceschi a , Maria Celia Magno a , Antonella Ausili a a ISPRA, National Institute for Environmental Protection and Research, Via Vitaliano Brancati 60, 00144 Rome, Italy b Università di Cagliari, Department of Chemical and Geological Sciences, Via Trentino 51, 09127 Cagliari, Italy ARTICLE INFO Keywords: Local background Enrichment factor Mineralogy Mine exploitation Metals and trace elements Sulcis-Iglesiente ABSTRACT Intensive exploitation of base metal deposits in the Sulcis-Iglesiente district (Sardinia, Italy), lasted from the 1850s to the 1990s, determined a high environmental impact on the coastal area, but the effects on marine environment have never been investigated. A marine sediment core, dated with 14 C, was characterized for grain size, chemical and mineralogical composition, in order to reconstruct the sedimentary history of the area and to assess the environmental impact of mining. The comparison of chemical and mineralogical characteristics of recent sediments with those of pre-industrial age allowed discriminating the real anthropogenic impact from the natural metal enrichment. The correspondence, in the upper core, of anthropogenic trace metal enrichment with the presence of mine waste minerals is attributed to the exploiting over industrial scale; the still high metal enrichment in sediment surface levels suggests a still existing impact due to mine dumps and tailings weathering. 1. Introduction The operations carried out in mining districts, including exploiting, treatments and storage, have strong consequences on the surrounding territory, not only during the period of the activities, but also after their end. Consequently, studies about soil, stream sediment/water, and groundwater are commonly carried out to evaluate the environmental degradation on the mainland (Cidu and Fanfani, 2002; Garcia-Ordiales et al., 2017). Differently, the effects of mining activities on marine environment are scarcely investigated and often considered only in case of submarine tailings disposal (Elberling et al., 2003; Blackwood and Edinger, 2007), or after disastrous events (Hudson-Edwards, 2016). Since marine sediments are the final destination of metals and trace elements, both derived from the natural erosion of the upstream basins and from anthropogenic supply, they can be considered as an archive where temporal changes of these contributions are recorded (Apitz et al., 2009). For this reason, the study of sediment cores is a suitable method to investigate the impact of human activities on marine en- vironment and to compare impacted conditions with the reference ones recorded in the ancient levels, ascribable to pre-industrial times. In marine areas impacted by mining activities, the study of vertical dis- tribution of trace metal concentrations along sediment cores, as done by Shumilin et al. (2013), can help to discriminate contaminated intervals from pristine layers with concentrations lower than natural background. For a reliable assessment of metal enrichment due to an- thropogenic contribution, the local background concentrations should be considered, especially in areas affected by natural geochemical anomalies (Ligero et al., 2002; Wang et al., 2008; Liu et al., 2010; Romano et al., 2015, 2017). In this study, marine sediment cores were collected in a coastal zone of Sulcis-Iglesiente (West Sardinia, Italy), impacted by pre-industrial and industrial-time past mining activities (Cidu, 2011; Medas et al., 2012; De Giudici et al., 2014, 2017). The analytical work was focused to characterize the sediment core by means of chemical and physical composition and to identify the primary and secondary mineral phases. The study of pre-industrial uncontaminated levels offered the possibi- lity to determine the degree of enrichment for some elements by means of the determination of local background values. 2. Geological setting and study area Sardinia is the second biggest island of the West Mediterranean Sea and represents the eastern margin of the Balearic Basin. It is mainly characterized by Paleozoic (Lower Cambrian to Lower Permian) rocks deformed during the Hercynian orogenesis (Carmignani et al., 2001). The style of deformation and metamorphic grade within the orogen change systematically from South to North, producing distinctive tec- tonic zones: (i) parautochthonous tectonic unit of the foreland zone in http://dx.doi.org/10.1016/j.marpolbul.2017.06.070 Received 10 May 2017; Received in revised form 22 June 2017; Accepted 23 June 2017 ⁎ Corresponding author. E-mail address: elena.romano@isprambiente.it (E. Romano). Marine Pollution Bulletin xxx (xxxx) xxx–xxx 0025-326X/ © 2017 Elsevier Ltd. All rights reserved. Please cite this article as: Romano, E., Marine Pollution Bulletin (2017), http://dx.doi.org/10.1016/j.marpolbul.2017.06.070