Guideline values and human risk assessment for the presence of anti-inflammatory drugs remaining in drinking water after lab scale treatment

Abstract This study aimed to determine whether the anti-inflammatory drugs that are most commonly consumed in Brazil, including diclofenac, ketoprofen, naproxen, indomethacin, ibuprofen and acetaminophen, are present in drinking water and to derive guideline values to characterize the human risk. These pharmaceuticals were quantified in surface waters by LC-MS/MS with solid phase extraction, both before and after conventional treatment on a laboratory scale, using a jar test assay. The methods used to quantify these drugs showed good results: the chromatographic analysis obtained correlation coefficients between 0.9952 and 0.9991, with limits of quantification of 0.5 ng.mL-1 - 50 ng.mL-1 and precision standard deviations (0.08 - 2.08). Only ketoprofen and ibuprofen were not completely removed through the jar test. Environmental samples were collected and handled by the same method; the values for ketoprofen and ibuprofen after treatment were 18.67 - 19.65 ng.L-1 (±17%) and 166.70 - 244.73 ng.L-1 (±14%), respectively. Human risk was assessed by comparing the guideline values for each compound to the concentrations obtained in the environmental samples, considering the toxicological backgrounds, following WHO (2011) method. The results suggest that the concentrations of ketoprofen and ibuprofen found in drinking water do not pose a risk to human health, even with chronic consumption.