Geochemical modelling application for a 1-d arsenic reactive transport study in alluvial aquifers, Matlab Upazila, Bangladesh
2009 (English)In: Rendiconti Online Societa Geologica Italiana, ISSN 2035-8008, Vol. 6, 364-365 p.Article in journal (Refereed) Published
Mechanistic modelling was used to investigate the hydrochemical evolution along a vertical column, should cross-contamination occur. 1-D reactive transport was carried out to assess sorption effects on aqueous/solid arsenic distribution in Matlab Upazila, Bangladesh. Thermodynamic relationships between aqueous ions and aquifer materials have been investigated: comparison between redox couples shows electrochemical disequilibrium; sorption mainly occurs on weak and strong Hydrous Ferric-Oxides, described by the Surface Complexation Mode. The basis for reactive transport calculations is given by a static model, that evaluates the competing ions net effect: they reduce by ca. 50% arsenic bounding. Desorption process alone can give unacceptable As (aq) concentrations, starting from only a few mg/kg As (sorb). Redox zonation was the starting point for the model conception, which allowed calculating the contamination evolution in an oxidising As-low aquifer. Groundwater analysis is worked out for a 20 cells column of aquifer material, whose top represents the upper reducing aquifer, the bottom the oxidising aquifer; contamination takes place through an As-rich solution percolating into the column. Results are a function of the flow velocity, that needs to be carefully defined before further modelling.
Place, publisher, year, edition, pages
2009. Vol. 6, 364-365 p.
Arsenic, Bengal basin, Geochemical modelling, Reactive transport
IdentifiersURN: urn:nbn:se:kth:diva-151982ScopusID: 2-s2.0-84863505256OAI: oai:DiVA.org:kth-151982DiVA: diva2:749410
[Applicazioni di modelli geochimici per la formulazione di un trasporto reattivo dell'arsenico in acquiferi alluvionali, Matlab Upazila, Bangladesh]2014-09-242014-09-232014-09-24Bibliographically approved