Seasonal occurrence and distribution of a group of ECs in the water resources of Granada city metropolitan areas (South of Spain): Pollution of raw drinking water

This piece of research deals with the monitoring of a group of emerging contaminants (ECs) in the metropolitan area of Granada, a city representative of the South of Spain, in order to evaluate the environmental management of the wastewater system. With that aim, the spatial and seasonal occurrence and distribution of a group of ECs in groundwater, surface and irrigation water resources from the aquifer "Vega de Granada" (VG) have been investigated for the first time. A set of the most prescribed drugs in Spain (ibuprofen, loratadine, pantoprazole and paracetamol), a pesticide widely used in agriculture (atrazine) and a typical anthropogenic contaminant (caffeine) were included in the study. Water samples were taken from the metropolitan area of the city of Granada inside of the zone of the aquifer, from the downstream of two waste water treatment plants (WWTPs) and from the two main irrigation channels where surface and wastewater are mixed before distribution for irrigation purposes in the crops of the study area. A total of 153 water samples were analyzed through liquid chromatography coupled with mass spectrometry (LC-MS/MS) throughout the study that took place over a period of two years, from July 2011 to July 2013. Results demonstrated the occurrence of four of the six target pollutants. Ibuprofen was detected several times, always in both channels with concentration ranges from 5.3 to 20.8 μg/L. The occurrence of paracetamol was detected in rivers and channels up to 34.3 μg/L. Caffeine was detected in all the water resources up to 39.3 μg/L. Pantoprazole was detected twice in the surface water source near to a WWPT ranging from 0.02 to 0.05 μg/L. The pesticide atrazine and the drug loratadine were not detected in any of the water samples analyzed. These results show evidence of poor environmental management of the wastewater concerning the water quality of the aquifer studied. The groundwater sources seem to receive a very continuous input of wastewater due to leaks from the drainage and sewerage system. This input may increase during rainy periods when it joins the recharge flow. The relationship between ECs and surface waters can be observed by comparing the averages for the rainy period with those for the driest. The highest concentration of ECs in irrigation water sources were detected in irrigation period times, between March and July. In general, concentration of the ECs uncovered in this study are similar to those reported in water sources from developed countries and environmental interpretation suggests that waste water management should be improved in order to reverse the current situation.