Arsenic in groundwater is a dramatic global problem due to the high incidence of arsenicosis or HACRE (Chronic Endemic Regional Hydro-arsenicism, Hidroarsenicismo Crónico Regional Endémico in Spanish), a severe illness causing skin lesions and cancer in extended regions of the world. For this reason, research on low-cost technologies for As removal to be applied in isolated, poor, rural locations is mandatory. This seminar will present a brief overview of arsenic pollution issues and mitigation needs in Latin America. It will also present results on As(V) removal using photochemical processes like the zerovalent iron technology with commercial iron nanoparticles (NZVI) and heterogeneous photocatalysis with TiO2. In the case of NZVI, factors such as mass of iron, effect of UV light and addition of humic acids are analyzed. In the second case, oxidative processes transforming As(III) to As(V) and reductive processes are discussed. Preliminary results with natural groundwater of the Chacopampean Plain of Argentina (Santiago del Estero and Tucumán Provinces) are also reported.