Monitoring of selected pharmaceuticals over 3 years in a detrital aquifer during artificial groundwater recharge

Abstract

A screening survey of 81 pharmaceuticals was carried out at a wastewater facility and in a detrital aquifer (Barcelona, Spain), where treated wastewater (TWW) was injected through wells to build up a hydraulic barrier against seawater intrusion. The monitored data correspond to the 2007–2010 period. The TWW was tertiary treated with additional treatment consisting of ultrafiltration, reverse osmosis and UV disinfection. During the monitoring period groundwater monitoring was carried out in wells located within a 1-km radius distance from the injection wells. During monitoring period 20 new pharmaceuticals were detected in the aquifer media and 11 compounds were found with concentration above 0.1 μg l−1 (selected threshold) in both TWW and wells. After 1 year of TWW injection change of redox conditions, a decrease of Cl− concentration and presence of 11 pharmaceuticals (4-AAA, 4-FAA, carbamazepine, ciprofloxacin, diazepam, diclofenac, hydrochlorothiazide, mepivacaine, sulfamethoxazole, sulfamethazine and sulfapyridine) was observed in the monitoring wells. After the studied period the sodium-chloride aquifer water type evolved to a bicarbonate-sulphate facies. Decrease of the pharmaceuticals concentration in groundwater appears to be driven by the dilution process and hydraulic characteristics of the aquifer media, with the attenuation or degradation process much less important.