Colline Metallifere Research Articles

Fine structure of the midgut and Malpighian papillae in Campodea ( Monocampa) quilisi Silvestri, 1932 (Hexapoda, Diplura) with special reference to the metal composition and physiological significance of midgut intracellular electron-dense granules

The fine structure of the midgut and the Malpighian papillae in Campodea ( Monocampa) quilisi Silvestri, 1932 (Hexapoda, Diplura) specimens was described. We observed the presence of electron-dense granules (EDGs) in the midgut epithelial cells, similar in genesis, structure and aspect to the type A spherocrystals described in the midgut epithelium of Collembola and Diplopoda. Energy-dispersive X-ray microanalysis was used to detect the chemical composition of the granules and to relate it to the concentrations of some potential toxic heavy metals (Pb, Cu, Zn) in soil and litter. Chemical composition of the granules seems strongly influenced by the presence and bioavailability of heavy metals in the external environment. Specimens from a contaminated abandoned mining and smelting area (Colline Metallifere, southern Tuscany) were able to accumulate Fe, Mn, Zn, Pb and Cu in their midgut EDGs. In addition, we observed that C. ( M.) quilisi was able to excrete the metal-containing granules into the external medium by the moulting of the intestinal epithelium. This confirms that the process of ionic retention of midgut cells is particularly significant in animals lacking Malpighian tubules.

Origin of Arsenic Pollution in Southwest Tuscany: Comparison of Fluvial Sediments

The Colline Metallifere in SW Tuscany are characterized by strong anomalies in arsenic concentrations and distribution. The area is sparsely populated and largely wild, though it has been subject to human impact due to mining and metal processing since Etruscan and Roman times. In the Middle Ages it was exploited intensively for silver and copper. Until 1995, pyrite (FeS2) was mined and roasted to produce sulphuric acid and iron. Hypotheses based on geological and mineralogical factors formulated in the last 20 years have failed to explain the peculiar distribution of arsenic in the Colline Metallifere. Here we report preliminary results of widespread sampling and analysis of the fluvial sediments of rivers originating in this mining area. The data was analysed in relation to the archaeological features of the area, since the presence of ancient mining and ore processing sites can shed light on the peculiar distribution of arsenic. Comparison of data from two rivers and their respective contaminated and uncontaminated coastal lagoons also clarified the general mechanisms of arsenic mobility, pinpointing the source of arsenic contamination. The study methods also promise to be useful for discovering unknown archaeological sites.

Oak leaves as accumulators of airborne elements in an area with geochemical and geothermal anomalies

The Colline Metallifere (Tuscany) was a major Italian mining district (FeS 2, Ag, Cu, Pb, Zn) for centuries, and in the last fifty years it has become the most important area for the exploitation of geothermal resources. Leaves of the widespread oak Quercus pubescens and surface soils were collected from 90 sampling sites in the area and their elemental composition was compared. The results showed that the composition of oak leaves was not significantly affected by the presence of mineral deposits (metal sulphide ores) or soils with high concentrations of Cr, Mg, and Ni (ultramafic). Arsenic was the only element showing higher concentrations in leaves from sites with deposits of metal sulphide ores or As-polluted soils around abandoned smelting plants. Compared to the composition of epiphytic lichens and epigeic mosses from the same sites in the Colline Metallifere, the elemental composition of Q. pubescens leaves was less affected by element contributions from adsorbed soil particles. It was thus easier to evaluate atmospheric inputs of elements in oak leaves than in cryptogams.

Mosses and lichens as biomonitors of trace metals. A comparison study on Hypnum cupressiforme and Parmelia caperata in a former mining district in Italy

Samples of the moss Hypnum cupressiforme and the epiphytic lichen Parmelia caperata were collected during the summer of 1999 in an area (Colline Metallifere, central Italy) intensively exploited in the past for metals (Cu, Fe, Pb, Zn) and currently for geothermal resources. Lichens were more sensitive than mosses to emissions of S compounds near geothermal fields and abandoned sulphide ore smelting plants. Comparison of elemental compositions of the two cryptogamic species from the same sampling sites showed significantly higher concentrations of lithophile elements (Al, Cr, Fe, Mn, Ni, Ti) in the moss and atmophile elements (Hg, Cd, Pb, Cu, V, Zn) in the lichen. Patterns of bioaccumulation of elements throughout the study area were quite similar for widespread pollutants such as S, B, As, Zn, Cr and Ni, but the lichen and the moss showed different distribution patterns of Hg, Cd and other elements subject to long-range atmospheric transport. These results are due to differences in the morphology and ecophysiology of mosses and lichens and indicate that these organisms cannot be used interchangeably as biomonitors of metals in areas with mineral deposits.

3 - SOUTHERN TUSCANY - B - COLLINE METALLIFERE

In the last decades the geology of Southern Tuscany (Giannini et al., 1971; Boccaletti et al., 1982, cum bibl.) has been greatly improved by lithostratigraphic, biostratigraphic and geophysic studies, and by deep geothermal drillings (with a depth down to 3000 m b.g.l.) (Bertini et al., 1991; 1994; Elter and Pandeli, 1996, cum bibl.). The geological setting of this area is composed, from top to bottom, of the following tectono-stratigraphic units (Figs. 1 and 2): a. Neo-autochthon (post-orogenic). It is formed by the sediments filling the extensional basins, generally oriented along to the Apenninic chain. They unconformably lie on the stack of Ligurian and Tuscan Units, and are represented by lacustrine-marine (late Tortonian-Messinian), marine (Pliocene) and lacustrine-fluvial (early Villafranchian-Quaternary) sediments. b. Ligurian, sub-Ligurian and epi-Ligurian Units. They are composed of five tectonic units: 1- Upper Ophiolitic Unit (Late Jurassic-Early Cretaceous: Vara Supergroup), largely represented by Palombini Shales with some ophiolitic outcrops. 2- Lower Ophiolitic Unit, (Jurassic-Early Cretaceous: Vara Supergroup), including thick ophiolitic successions. This unit is stratigraphically capped by: 3- The syn-orogenic Upper Paleocene- Middle Eocene epi-Ligurian Lanciaia Fm. (ophiolitic breccias and sandstones, grading upward to a mainly carbonate-siliciclastic flysch). 4- Monteverdi Marittimo Unit (Southern Tuscany Elminthoid Flysch Group): consisting of a calcareousmarly- arenaceous flysch of Late Cretaceous- Early Paleocene age. 5- Canetolo Unit (Paleocene- Middle/Late Eocene), made up of shales with limestone, calcarenite and graywacke intercalations. This unit belongs to the sub-Ligurian paleogeographic Domain (close to the Adria margin). c. Tuscan Nappe. It is composed, from top to bottom, of the following non-metamorphic formations: Macigno (Late Oligocene-Early Miocene), “Scisti Policromi” (Early Cretaceous- Oligocene), Tuscan Cherts (Malm), Posidonia Marlstones (Dogger), “Rosso Ammonitico” and Limano Cherty Limestones (Middle-Late Liassic), “Calcare Massiccio” (Late Triassic?-Early Liassic), Spezia Fm. (Rhaetian), Burano Anhydrites (Norian-Rhaetian). In this succession lateralvertical facies changes and sedimentary unconformities are present, mainly in Middle-Late Jurassic times. Furthermore, the Tuscan Nappe is often tectonically laminated or locally lacks (“Serie Toscana Ridotta” = Reduced Tuscan Series Auctt.) by low-angle extensional faulting with flat-ramp-flat geometry (Fig. 3). The Tuscan Nappe lies on the Tuscan Metamorphic succession (Monticiano-Roccastrada Unit) which is quoted below. d. Monticiano-Roccastrada Unit. The upper part of this unit is a complex pile of tectonic slices made up of epimetamorphic Lower to Upper Paleozoic formations, Triassic “Verrucano”, Tocchi Fm. and non-metamorphic Upper Triassic anhydrite-carbonate successions. The lower part is made up of ?Upper Cambrian-?Lower Ordovician siliciclastics and metabasites (Phyllitic-quartzitic Complex), which include relics of Hercynian schistosity. In the subsurface of Larderello geothermal area, the Phyllitic-quartzitic Complex overlies ?Lower Paleozoic/?pre-Paleozoic Micaschist Complex (see Stop 5). The Colline Metallifere area is characterised by high heat flow (>650 mWm-2 in the Larderello geothermal field), by lithosphere thinning (Moho at a depth of about 22 km in the Grosseto area), by the uplift of the metasomatised and partially melted mantle, and by anatectic crustal magmatism (Boccaletti et al., 1985; Mongelli et al., 1991).

A new site for Sphagnum in Tuscany in the Belagaio forest

Summary Sphagnum subnitens Russ. & Warnst, and Sphagnum subsecundum Nees are reported from a new site in Tuscany. The two species were found in a recently described Betula pendula stand, located in the Belagaio forest, Colline Metallifere, southern Tuscany. Fifty-two bryological taxa (19 liverworts and 33 mosses) were recorded in this area. The forest of Belagaio is the southernmost site known for Sphagnum subnitens and Sphagnum subsecundum in Tuscany. Plagiomnium ellipticum is another new species for Tuscany.