Occurrence and spatial distribution of pharmaceuticals in Mediterranean intermittent river basins

Abstract

Most river basins are subjected to several anthropogenic inputs, including wastewater treatment plant (WWTPs) discharges and urban and storm runoff waters, affecting water quality. Even though WWTPs are used to manage and treat wastewater, the WWTP effluent may still contain several wastewater borne pollutants including several contaminants of emerging concern (CECs), as conventional WWTP do not fully elimate these. In these cases, pharmaceuticals and personal care products (PPCPs) are often prevailing, as they are continuously introduced in surface water and hence are seen as pseudo-persistant contaminants in the aquatic environment where their contamination profiles are often quite constant in concentration [1]. In this study the presence of several CECs was analysed in five countries; Spain, France and Italy, located in Southern Europe and Algeria and Tunisia, located in Northern Africa. In Tunisia and Algeria, WWTPs are sometimes over-exploited and many industries directly release their wastewater to the river basins. In addition to this, the lack of regulations regarding CECs concentration in surface water and the limited monitoring makes it interesting to investigate their presence and impact. Hence, different intermittent rivers from each site were sampled and possible differences between Southern Europe and Northern Africa were investigated. Samples were extracted by means of a solid phase extraction procedure using a homemade multilayer mixed-bed cartridge containing a mixture of four different sorbents with different selectivity to cover a wide range of polarities. A total of 81 target CECs, selected based on their occurrence and ubiquity in the aquatic environment were screened and quantified using high-resolution mass spectrometry Q-Exactive Orbitrap. For the separation of the analytes, liquid chromatography was performed using Acquity UPLC HSS T3 column [2]. The presence and potential differences in contamination levels across the five countries was investigated. The studied river basins from France and Algeria reported lowest concentrations and statistical analysis were performed to study the potential differences per CECs class between countries, and the most remarkable class were the industrial compounds where significant differences between Tunisia and the other four countries were observed. Regarding specific contaminants, caffeine concentrations were outstanding in Tunisia compared to the rest of countries, and Italy presented remarkable concentrations of antihypertensives, with ibersartan and valsartan acid concentrations being statistically different from the rest of the studied countries.