Historical mercury trends recorded in sediments from the Laguna del Plata, Córdoba, Argentina. Chemie der Erde-Geochemistry

STUPAR YOAHANA; JÖRG SCHÄFER; GABRIELA GARCÍA; SABINE SCHMIDT; EDUARDO L PIOVANO; BLANC GERARD; FRÉDÉRIC HUNEAU; PHILIP LE COSTUMEAU

CHEMIE DER ERDE

ELSEVIER GMBH, URBAN & FISCHER VERLAG

Lugar: ALEMANIA; Año: 2014 vol. 74 p. 353 - 363

0009-2819

tThe main carrying phases of mercury (Hg) were analyzed in a 120 cm sediment core taken at the Lagunadel Plata (LP), a small lake connected to the main water body of Laguna Mar Chiquita (LMC) during high-stands. LMC is considered to be one of the largest saline lakes in the world representing a sensitive climaticindicator due to its frequent lake level variations at millennial and interdecadal scale like the last onesthat started early in the 1970s and after 2004. Total particulate Hg (HgTP) concentrations vary between∼13 and ∼131 g kg−1indicating a system with low pollution. Selective extractions with ascorbate, HCland H2O2were performed in the sediments and they revealed that Hg is associated mainly to reactivesulphides in the base of the core, while in the middle and upper part the organic matter seems to bethe main Hg-bearing phase. The highest and most important peak was found in sediments accumulatedbetween 1991 and 1995. More than a punctual source of pollution, this peak is likely related to two erup-tive events occurred in the Andean Cordillera in this period: the eruption of Hudson volcano in southernPatagonia that occurred in 1991 and the one of the Láscar volcano in northern Chile that occurred in 1993.In both cases, the respective ash plumes were documented to have reached the Laguna del Plata region.© 2013 Elsevier GmbH. All rights reserved.