Assessment of metals, emerging contaminants, and physicochemical characteristics in the drinking water and wastewater of Cuenca, Ecuador

Background: Traditional drinking water and wastewater treatments used in Latin-American and Caribbean coun- tries are meant to improve the organoleptic, and microbiological characteristics and to remove nutrients. How- ever, to be effective, treatments need to process potential threats from natural or anthropogenic origins. Objective: to evaluate emerging contaminants and metals in drinking water and wastewater from traditional water treatment systems, in the city of Cuenca, in the Ecuadorian Andes. Methods: samples were taken from the water plants of Cuenca, from its wastewater treatment plant, and from domestic houses. The physical-chemical characteristics and 15 metals (ICP-OES) were analyzed in samples from the drinking water plant and from the houses. A heavy metal pollution index (HPI) was calculated. The wastewater samples were also analyzed for 7 emerging contaminants (ECs) (GC-MS). Results: Our results show that the treated water depends on the quality of the incoming water, and that the available treatments are not capable of removing unexpected pollution, such as aluminium, which could be due to natural sources, such as ashes from the Sangay volcano might contaminate Cuenca’s water sources. The HPI varied from 0.44 to 0.59, which indicates that water distribution systems have low metal contamination. The wastewater plant was not capable of removing emerging contaminants such as caffeine. Conclusions: Natural and anthropogenic contamination in the water must be considered in the treatments due to the potential risk that they represent