Pharmaceuticals and transformation products in coastal waters of the Iberian Peninsula

Abstract

Approximately one-third of the earth's population lives in the near-coastal zone. Wastewater treatment in these areas tends to be less efficient than in their in-land counterparts due to increased reliance on dilution. This increases the likelihood of drugs and their transformation products reaching the environment. Other sources, such as aquatic recreative activities, also contribute to coastal pollution. In this study, we aimed to provide a descriptive analysis of the presence of pharmaceuticals and TPs during summer and spring at 46 beaches of the Iberian Peninsula. Beaches from Lisbon to the south of the peninsula, and the region of Murcia (Mar Menor) were sampled. A risk assessment was performed by calculating a Risk Quotient (RQ) for each substance and a Hazard Index (HI) for the mixture of pharmaceuticals from each pharmacotherapeutic group. Of all the 36 different pharmaceuticals and TPs monitored in this study, 31 were detected above their own limit of detection in at least one sample. The highest concentration of any pharmaceutical was found for diclofenac in summer at Los Arcos beach (1916 ng/L), followed by paracetamol (203 ng/L) in Valdegrana beach. Every sampled location presented at least one substance with a RQ above 0.1. The highest risk was attributed to diclofenac with a RQ of 479 at Paço de Arcos beach (Portugal). This study shows that pharmaceutical pollution is widespread in coastal waters across the west and southern parts of the Iberian Peninsula. Furthermore, we report the first detection of flecainide and 7 metabolites-TPs in coastal-marine environments