Sampling is an important step of every analytical procedure for the determination environmental pollutants. Traditional monitoring programmes have many shortcomings when we need the information about average concentration of analytes. Passive sampling offers an attractive alternative. Passive sampling combines sampling, selective isolation of analytes and preconcentration in one step. As a result, passive samplers give us a time-weighted average (TWA) concentration in exposure time. The purpose of this study was to assess time weighed average (TWA) concentrations for some common pharmaceutical residues (diclofenac, ibuprofen, ketoprofen, naproxen, carbamazepine, diazepam and clofibric acid, a stable metabolite of clofibrate) in surface and ground water. Use of the passive samplers in field experiments requires a prior laboratory calibration of the sampling rates. Within this study we chose the most suitable sorbent for the target analytes and then the best method for transferring the sorbent from a membrane into an empty SPE cartridge and elution, which followed. Then we checked the repeatability and tried to define the time when the sorbent was saturated. Afterwards we determined the sampling rates for all the selected analytes under various conditions (changing the flow and the concentration) and finally exposed the passive samplers in surface and ground water to assess TWA concentrations of the selected pharmaceuticals. For the calibration curves, determinations of the limits of detection, extraction efficiency and concentrations in grab samples we used solid-phase extraction (SPE). All the samples were derivatized and analysed with GC-MSD. Results showed that the most effective sorbent was Oasis® HLB and the most suitable way to transfer sorbent from the membrane into an empty SPE cartridges was to wash with acidified water, followed by elution with 1 mL of ethyl acetate four times. In 12 days the saturation of sorbent had not been reached. Relative standard deviation of the rate of peak area for analyte and peak area for internal standard in laboratory experiments did not exceed 24 %, which means that the repeatability was quite good. We determined sampling rates under various conditions (constant flow and concentration, changing the flow at the constant concentration and changing the concentration at the constant flow) and we did not notice major changes of the sampling rates. For the calculation of environmental concentration we used the main value of the RS. The samplers were exposed to environment in the Stržen stream, the Ljubljanica, the Gradaščica and the Drava river and in the groundwaters on Dravsko polje. In all waters we determined at least one of the investigated pharmaceuticals. We also determined at least one of the investigated pharmaceutical in all grab samples except in some of the ground water samples.
E.01 National awards
COBISS.SI-ID: 1536180931In 2011 a critical review (Kosjek in Heath, TrAC, 2011) was published on the existing literature regarding the analysis of pharmaceutically derived cytostatic compounds in the environment. Cytostatics are a broad group of mostly organic compounds possessing a diverse range of physico-chemical parameters. These differences and that they are present in the environment in trace amounts makes their determination in complex matrices a major challenge. Despite the firm scientific foundation prepared by those in the field, it is apparent that the focus prior to 2011 was on analysing hospital effluents rather than actual environmental samples. Importantly, no study has looked at environmental transformation products that along with human metabolites could contribute to overall toxicity. At the outset of the EU FP7 CytoThreat project, which began in 2011 we promised to research the chemodynamics of cytostatics in natural waters and to deliver more data on the occurrence and fate of these compounds, including their human metabolites and environmental transformation products. This has required the development and use of advanced sampling techniques and the application of state-of-the-art analytical tools including the latest separation methods and cutting edge analytical instrumentation, which has been available within the project. The presentation will show an overview of CytoThreat contribution (www.cytothreat.eu) in the field of analysis of cytostatic compounds in environmental samples.
B.04 Guest lecture
COBISS.SI-ID: 28194087Ester Heath is an active editor of international journal Environmental Science and Pollution Research (Springer, IF 2,5)
C.04 Editorial board of an international magazine