Arsenic and associated trace elements in the solid phase and their interrelationships with the aqueous phase in loessic aquifers of the Southern Pampa, Argentina

DÍAZ, SILVANA; SCHMIDT, ERICA; BLANCO, MARIA DEL CARMEN; ESPÓSITO, MARTÍN; AMIOTTI, NILDA; SEQUEIRA, MARIO; PAOLONI, JUAN DARÍO; NICOLLI, HUGO

Buenos Aires

Congreso; 5º Congreso Internacional sobre el Arsénico en el Medio Ambiente; 2014

International Society of groundwater for sustainable development

In the Southern Pampa, excess levels of As are due to its geoavailability within loess sediments-soils sequences hosting the phreatic aquifers. We analyzed total contents of As and associated trace elements in the loess solid phase, including spatial distribution of As, F, B and V in hydric resources. The interrelationships between solid and aqueous As contents were studied in El Divisorio Creek Basin applying statistics (Principal Components Analysis, PCA). Total As in soils ranges 5.1-20.7 mg?kg -1, being lower in the valley slopes and appeared irregularly distributed in the alluvial plain. Alluvial activity determines intrabasin distribution of As-bearing minerals as reflected in As contents in the solid phase. Variability of As in waters is explained by the local factors controlling water residence time in the aquifers, by processes of silicate hydrolysis, oxido-reduction, sorption-desorption and formation of complex ions in the fine fraction (