The assessment of the environmental and public health risks due to pharmaceutical residues, is a main issue particularly in the light of water cycle management and water resources. Hospitals are supposed to be a main source of pollution and the assessment of their contribution to the overall pharmaceutical pollution is necessary. Monitoring the pharmaceutical loads in hospital sewage is a great challenge because of the difficulties which have to be overcome to obtain representative samples: high organic content and suspended solids, wastewater flow variations, difficult access to sampling sites, variations of pharmaceutical release throughout the day resulting from hospital activities. An interesting alternative way is to use passive samplers, which allow for the measurement of Time Weighted Average (TWA) concentrations, overcoming many shortcomings of the spot sampling techniques. The aim of this work is to evaluate the applicability of POCIS for the monitoring of pharmaceuticals in hospital wastewater. This tool is mainly used for surface water or WWTP effluent and its application for wastewater sampling remains scarce. This study was conducted on six compounds already selected as representative of some of the main class of pharmaceuticals used at the hospital (Atenolol, Prednisolone, Methylprednisolone, Sulfamethoxazole, Ofloxacin, Ketoprofen). POCIS were calibrated for the analytes of interest in tap water and wastewater in laboratory conditions close to relevant environmental conditions (temperature, flow velocity, fouling). Sampling rates (Rs) were determined and we observed a significant increase with flow velocity and temperature. Whatever the compound, the Rs value was lower in wastewater and the linear phase of uptake was shorter than in tap water. A five-day period was defined as the optimal duration for POCIS exposition in wastewater.POCIS were then deployed in a hospital sewage pipe during four days and the estimated water concentrations were close to those measured in twenty-four hour composite samples, carried out with an autosampler.This work gives encouraging results for the deployment of POCIS in wastewater that could be a useful tool for pharmaceutical pollution management.
