Fractionation and Batch Desorption Experiments to Understand Co-occurrence of Arsenic and Fluoride under Oxidizing Conditions

Abstract

In south America Argcntina is hotspot of arsenic and fluoride cooccun·cnce. The cl imatic rcgimc o f this region ranges between mi ld humid and semi-arid climate. Co occurrence had been investigatcd profoundly in L Pampa province, Cordoba province, Tucuman province, Buenos Aires province, and pcninsul a Valdes. Aquifers o f these areas arc mainl y composed o f quaternary loess sediments by rh yolitic volcanic glass calca reous kmna ti ons. Arscni c and fl uoride co-occurrence are observed in varying depths including not only in shallow and deep aquifers as well as in phreatic aquifers. The major GW type was noti ced as Na-HCOJ wi th high arsenic and fluoridc concentrations. Aquifers are mainly attri buted by oxidizing conditio ns in which desorption from mineral hydroxides accompanied by calcite and volcanic glass dissolution was considcred the major mcchanism of arseni c and fluoride release in GW (A lvarez & Carol, 20 19; Aqib & Rawah i, 20 16; Barra nquero, ct aI. , 20 17; Borgnino et aI., 20 13; Bundschuh ct aI., 20 12; Gimenez ct al., 20 13; Gomez et al., 2009; Nicolli, ct aI., 20 19a, 20 19b; Warren, et aI., 2005).