CHEMICAL COMPOSITION OF RECENT SEDIMENTS FROM LAKE COMO
Lake Como, one of the great subalpine Italian lakes, covers 146 sq.km and has a volume of 22.5 cubic km. Its drainage basin (4572 sq.km) has a mean altitude of 1569 m (a.s.l.) and shows a dominance of igneous rocks in the northern part, whereas limestones and dolomites prevail in the southern region. The origin of the lake dates back to Messinian time (end of Miocene), when the isolation of Mediterranean basin induced a sudden drop of water level, so that River Adda started incising a valley: after that, glaciers reshaped and dammed (by frontal moraines) the valley, now filled with water. More than 800 m of sediments presently cover the bedrock, and the current sedimentation rate ranges from 0.9 to 1.4 cm/year. In the framework of a wider research on L. Como hydrobiogeochemistry, top sediments (first 10-15 cm) were sampled in 101 stations, along with 18 major tributaries; in addition, six cores were collected in the deepest parts of the various sub-basins. All samples were then analyzed for the following elements: P, Zn, Ni, Mn, Fe, Cr, V, Cu, Ti (by Inductively Coupled Plasma); C, N (CHN Elemental Analyser); Pb, Cd (Anodic Stripping Voltammetry); Hg (Hydrid AAS); As (Zeeman Graphite Furnace AAS). Maps of distribution and discussion about relevant data are reported in the paper.
Bibliographic Reference: INTERNATIONAL CONFERENCE "HEAVY METALS IN THE ENVIRONMENT", ATHENS (GREECE), SEPT. 10-13, 1985 WRITE TO CEC LUXEMBOURG, DG XIII/A2, POB 1907 MENTIONING PAPER E 32069 ORA
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Record Number: 1989125002200 / Last updated on: 1987-01-01
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