Cent. Eur. J. Geosci. • 1-15 Proofreading version Central European Journal of Geosciences 1 53 2 54 3 55 4 56 5 Natural Contamination by As and Heavy Metals in 57 6 58 7 Soil, Their Bio-Accumulation and Potential Sources: 59 8 60 9 the Case of a Travertine Limestone Quarry, Greece 61 10 62 11 63 12 Research Article 64 13 65 14 66 15 Evdokia E. Kampouroglou1, Maria Economou-Eliopoulos1∗ 67 16 68 17 69 1 Dept. of Geology & Geoenvironment, Section of Economic Geology & Geochemistry, National University of Athens, 18 Panepistimiopolis, 15784 Athens 70 19 71 20 72 21 73 22 74 Received 7 November 2012; accepted 2 March 2013 23 75 24 76 25 Abstract: The first mineralogical and geochemical investigation of the travertine limestone, soil and corresponding plants 77 26 associated with the Neogene basin of Varnavas, NE Attica, revealed a significant enrichment in the metalloid As. 78 27 The total concentrations of As ranged from 61 to 210 ppm in limestone and 33 to 430 ppm in the associated soil 79 demonstrating a wide variation of values. Calcite is a common authigenic mineral within travertine limestone, 28 80 forming fine uniform micritic aggregates, having As and Mg concentrations lower than detection limits of EDS 29 analysis. Clastic dominated minerals are quartz (both fine- and coarse-grained), muscovite, clinochlore, illite, 81 30 pyrite, galena, arsenides, rutile, sphene, zircon, REE-minerals and albite. Goethite and Fe-Mn-oxides occur 82 31 between calcite grains. The presence of fossilized micro organisms, resembling foraminifera, in travertine 83 32 limestone combined with hydrous Fe-Mn-oxides, suggests a possible marine transgression during the evolution 84 of the basin. 33 85 The As content in plants ranges from 1.1 to 28 ppm As in shoots, and 0.8 to 114 ppm As in roots. The 34 translocation factor, which is defined as the ratio of metal concentration in the shoots to the roots, is relatively 86 35 low (average 0.33%) suggesting that the internal transport of metals from the roots to shoots was restricted. The 87 36 bioaccumulation factor, which is defined as the ratio of metal concentration in the plants to that in soil, exhibits a 88 37 wide range from relatively low (5.2 - 9.0% for As, Fe, Cr, Ni and Pb), much higher (56 - 67% for Cu and Zn) and 89 exceptionally high (160% for Mo). A significant correlation between the translocation factors for Fe and As may 38 90 confirm that Fe-Mn oxides/hydroxides represent the major sorbing agents for As in soils. The presented data, 39 due to As contamination in travertine limestone, soil and plants, suggest a potential environmental risk not only 91 40 for that part of Greece but in general for similar depositional environments. 92 41 93 Keywords: arsenic• travertine limestone• Fe-Mn oxides• Mn-Fe ore• plants• Varnavas• Greece 42 94 © Versita sp. z o.o. 43 95 44 96 45 97 46 98 47 1. Introduction 99 48 100 ∗E-mail: [email protected] 49 101 50 Arsenic (As) is a toxic and carcinogenic element, 102 51 depending on its oxidation state. Elevated arsenic 103 52 concentrations in nature may be derived by natural 104 processes, such as the occurrence of arsenic in 1 Natural Contamination by As and Heavy Metals in Soil, Their Bio-Accumulation and Potential Sources 1 groundwater related to the presence of geothermal the first assessment of the extent and intensity of their 53 2 systems or to water-rock interactions, under specific environmental impact, determine the As-hosts, metal bio- 54 3 geochemical conditions [1]. Also industrial activities accumulation (their percentage transferred from soil into 55 4 such as mining of coal and mixed sulphides, smelting, the plants) and the potential sources of contamination. 56 5 beneficiation activities and a wide variety of applications 57 6 can be responsible for the arsenic contamination [2–4]. It 58 7 is well known that hazardous wastes may be highly toxic, 2. Geotectonic outline of the 59 8 with high bioavailable fractions of heavy metals, which Varnavas basin 60 9 may be transported over long distances and contaminate 61 10 large agricultural areas [5–7]. Thus, toxic elements can be 62 The basins being investigated, i.e. the Varnavas and 11 taken up by plants and finally enter the food chain, with 63 Kalamos basins are located in NE Attica, between 12 adverse effects on human health. The European Union 64 latitudes 23◦85’ and 23◦96’, and longitudes 38◦16’ and 13 has adopted maximum levels for heavy metals as regards 65 38◦29’ (WGS84 system). The Varnavas basin covers 14 foodstuffs (Regulation 1881/2006/EK), drinking water 66 approximately 30 km2 [13] and the maximum altitude in 15 (Directive 98/83/EK), and the use of sludge (Directive 67 the basin is 600 m, while it falls to 220 m towards 16 86/278/EK), air (Directive 2008/50/EK) and tail gas 68 Lake of Marathonas. Many coastal sites in the central 17 incineration (Directive 2000/76/EK). 69 Aegean region, including Attica, have followed the long- 18 70 The present study is focussed on the first assessment of term subsidence trend of the Aegean Sea from the 19 71 the arsenic content in a multicolour travertine limestone Middle to Upper Pleistocene and are characterized by 20 72 quarry, that may be a "risk lithology" for increased an extensional tectonic regime [14]. A spatial distribution 21 73 natural As concentrations in soils and plants, due to of uplift and subsidence in the coastal areas of the Aegean 22 74 the vicinity with an abandoned Fe-Mn mine. The Sea has been demonstrated, as well as a relationÂňship 23 75 term travertine is commonly used in a broader sense, between this distribution and tectonic and sedimentary 24 76 including all non-marine limestones formed under climatic processes operating within the Aegean region [15]. 25 77 controls in streams, lakes and springs. A great variety East Attica is composed by two major units: (a) 26 78 of travertine deposits have been described, depending The lower group of the NE Attica comprising the 27 79 on many variables, such as physical and biological autochthonous unit or crystalline basement, forming 28 80 processes [8]. Travertine, consisting of calcite or aragonite a large anticline with the axis oriented in the 29 81 of low to moderate porosity, is generally defined as NNE-SSW direction, composed of metamorphic rocks 30 82 a chemically-precipitated continental limestone formed (Triassic schists, metabasic, quartz-feldspathic rocks) 31 83 around seepages, springs and along streams, rivers and and (b) an overlying carbonate sequence, ranging from 32 84 occasionally in lakes [9] has been located at the Varnavas upper Triassic to Upper Cretaceous and Neogene- 33 85 basin, Attica, of Greece [10, 11]. This Neotectonic Quaternary deposits [11] (Fig. 1). More specifically, 34 86 basin, composed of post-Alpine sediments including the upper group, known as allochthonous metamorphic 35 87 Late Miocene-Pliocene continental deposits and minor unit of Aghios Georgios, consists of glaucophane- 36 88 outcrops of Pleistocene and Holocene alluvial travertine bearing metasediments, metasandstones, calc-schists and 37 89 limestones [10], is well known as an open quarry producing mica blueschist intercalated with marble (Fig. 1) [11]. 38 90 multicolored (yellow-orange-brown) travertine limestone, The Neogene formations, comprising Late Miocene- 39 91 which is used as building material (Fig. 2). Preliminary Pliocene continental deposits and minor Pleistocene 40 92 investigation of the mineralogical, geochemical and and Holocene alluvial deposits, can be classified as 41 93 mineral chemistry data on the Varnavas limestone basin follows: 1) continental deposits of clays, sandstones 42 94 revealed the presence of 2-4 hundreds of ppm arsenic (As) and conglomerates 2) lacustrine deposits of travertine 43 95 and significant heavy metal contents, such as copper (Cu), limestones, located in the Varnavas and Kalamos basins 44 96 lead (Pb), mercury (Hg), nickel (Ni), zinc (Zn) in soil and 3) Continental deposits of conglomerates containing 45 97 the associated travertine limestone [12]. boulders. A large part of the Varnavas basin is covered 46 98 by ririverine flood deposits [10]. 47 In this study the investigation of the As, Mo, Cu, Pb, Zn, 99 48 Mn, Fe, Sb and Hg contents in travertine limestone from The composition of the travertine limestone in the 100 49 the Varnavas quarry was extended to the wider area of Varnavas basin may have been affected by transportation 101 50 the Kalamos basin (Fig. 1). A compilation of rock data, and deposition of the weathered material from the 102 51 as well as the distribution of the above elements around Grammatiko Fe-Mn mineralization. Although any 103 52 the Varnavas travertine limestone quarry in soil and continuity between the famous ancient mines of 104 corresponding plants are presented, in order to provide Grammatiko and Lavrio is not obvious, underground 2 E. E. Kampouroglou and M. Economou-Eliopoulos 1 53 2 54 3 55 4 56 5 57 6 58 7 59 8 60 9 61 10 62 11 63 12 64 13 65 14 66 15 67 16 68 17 69 18 70 19 71 20 72 21 73 22 74 23 75 24 76 25 77 26 78 27 79 28 80 29 81 30 82 31 83 32 Figure 1. Simplified geotectonic map of NE Attica showing the localities of sampling. 84 33 85 34 86 35 the "ferromanganese formation" [16] or gossan [17] that 87 36 resemble those located at the Lavrio mine. 88 37 89 38 90 39 3.