The focus of the SCHEME project was on exogenous biomarkers, namely human metabolites of exposure to different classes of chemicals from personal care and household products, such as parabens, UV filters, phthalates and alternative plasticizers, phosphorus flame retardants/plasticizers, and bisphenols, as well as oxidative stress biomarkers. Potential biomarkers were selected through a review of pharmacokinetic, HBM and WBE literature. The final list included 29 biomarkers – 12 parent compounds, 15 human metabolites and 2 oxidative stress biomarkers. A method based on online solid-phase extraction (SPE) and ultra-high performance liquid chromatography – tandem mass spectrometry (UHPLC–MS/MS) was developed for their analysis in raw wastewater. The method includes rather simple pre-treatment and direct injection of wastewater samples. During the method development, several model experiments were conducted to investigate possible filtration loses, stability in wastewater, and contribution of the conjugated forms of target compounds. Method validation included linearity, instrumental detection limits, intraday and interday repeatability, relative recovery of the online SPE method, process efficiency, trueness, precision, as well as method detection and quantification limits. The developed method was successfully applied to analyze biomarkers of human exposure to selected chemicals in 6 European cities: Girona, Barcelona, Jerez de la Frontera (Spain), Brussels, Antwerp (Belgium), and Zagreb (Croatia). After the analyses, mass loads of the selected compounds were determined and for the substances which quantitative excretion data are known, human exposure was assessed. This was the first time that human exposure to chemical substances from personal care and household products was estimated using WBE approach in the selected cities. Generally, mass loads in all cities were comparable, however some differences were observed for several biomarkers, indicating different exposure levels to selected chemicals.
Project results were disseminated through different communication channels. The review paper entitled "Wastewater-based epidemiology to assess human exposure to personal care and household products – A review of biomarkers, analytical methods, and applications" was published in Trends in Environmental Analytical Chemistry. Two additional papers, related to the development and application of the analytical method, are currently under preparation. Project results were also presented to the scientific community at three international conferences, including Marie Curie Alumni Association Annual conference. The major objectives of the SCHEME project were also presented to researchers, stakeholders, and the general public at the 10th ICRA anniversary conference “Water research in perspective: beyond 2020”, through the ICRA's annual newsletters, websites and the blog of Jordi Fàbregas Garriga.
