ABSTRACT
Despite the significant differences in regional geology and climate as a function of latitude in Chile, environmental regulations for arsenic (As) concentrations in water are based on a constant international value (WHO) and do not consider potentially high (natural) background values. Furthermore, there are no sediment and soil reference guidelines. This study presents the analysis of newly-collected surface water and sediment data along three E-W transects of distinct regions of Chile in order to evaluate the relationship between As content and the regional geological units, crustal thickness, and climate. Analyzed samples indicate that average As values vary substantially from the south (0.37 µg/L in water and 9 mg/kg in sediments) to the north (2873 µg/L in water and 153 mg/kg in sediments), and there exists a correlation between high arsenic values, low precipitation, increased crustal thickness, and specific volcanic rocks such as Neogene volcanics of the Central Volcanic Zone. Regionally-based limits for As concentrations will therefore be recommended and discussed.
