A multi-residue analytical method for extraction and analysis of pharmaceuticals and other selected emerging contaminants in sewage sludge

Abstract

Sewage sludge is a by-product of wastewater treatment processes, and may be employed in agriculture as a fertilizer or in forestry for land reclamation. It is an important source of nutrients but its reuse can arouse concern on account of the wide range of contaminants that are retained and may persist during treatments. Information on the emerging contaminants (ECs) in sewage sludge in Italy is limited. The present study developed and applied a reliable analytical method for the analysis of 44 ECs in sewage sludge. ECs were extracted by accelerated solvent extraction followed by a clean-up step on solid-phase cartridges. High performance liquid chromatography coupled to mass spectrometry was used for analysis. The ECs, selected on the basis of their use and documented presence in the environment, were 42 pharmaceuticals belonging to 12 therapeutic categories and 2 perfluorinated substances. The method performance was good, with recoveries higher than 70%, good repeatability (<20%) and sensitivity in the low ng g⁻¹ range, allowing measurement of the analytes selected. The method was applied for analysis of sludge from 12 wastewater treatment plants in Italy. The most abundant compounds were antibiotics, anti-inflammatories and antihypertensives and ranged up to 5 μg g⁻¹ (ciprofloxacin). Seasonal differences were found for some antibiotics and anti-inflammatory drugs as well as some differences – in terms of concentration – with other European countries. This is the first Italian study to investigate the presence of a large number of ECs in sewage sludge and the results may be useful to drive future regulatory actions.