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Sewage chemical information mining – development of a novel concept for the assessment of human exposure to pollutants through wastewater analysis

Periodic Reporting for period 1 - SCHEME (Sewage chemical information mining – development of a novel concept for the assessment of human exposure to pollutants through wastewater analysis)

Reporting period: 2019-10-01 to 2021-09-30

Humans are nowadays exposed to an increasing number of environmental contaminants. Our exposure to these potentially harmful substances can be assessed by human biomonitoring (HBM) studies, which involve the analysis of specific biomarkers (excreted parent compounds and/or metabolites) in urine and other biological matrices from individuals. Due to several limitations of this approach, which involves complex cohort studies, a novel concept, based on the analysis of human biomarkers in municipal wastewater (sewage), often referred to as wastewater-based epidemiology (WBE) or sewage chemical information mining (SCIM), was proposed. So far, WBE has been successfully applied to assess human exposure to pesticides, mycotoxins, phthalates, alternative plasticizers, phosphorus flame retardants/plasticizers (PFRs) and bisphenol A. However, most of these studies were exclusively focused on one specific class of compounds, while studies which would include larger number of biomarkers from different groups are still very scarce.
The aim of the SCHEME project was to develop a multiresidue analytical method for the determination of biomarkers of human exposure to chemicals from personal care and household products. To accomplish this goal, three specific objectives were established:
(i) To select an appropriate set of biomarkers of human exposure to selected chemicals;
(ii) To develop a reliable multi-class analytical methodology for their monitoring in wastewater and to demonstrate its analytical feasibility;
(iii) To demonstrate the applicability of the WBE/SCIM approach for the assessment of human exposure to selected chemical substances.
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.
The method developed in this work is one of the first that includes determination of a larger number of human biomarkers from different chemical classes in wastewater. It allows rapid determination of target compounds and eventually it could be expanded to include additional biomarkers. The results of this exploratory study could lead to implementation of this novel, relatively inexpensive and near real-time approach for the assessment of population exposure to potentially harmful chemical substances. By monitoring temporal and spatial trends, communities with the highest exposure levels could be promptly identified.
The newly developed methodology is now available to other researchers at ICRA. In fact, a new research line, focused on the link between the exposure to chemical substances and human health ("Water and Human Health") is planned to be established at ICRA. This research line could contribute to preventing human health problems related to exposure to chemical contaminants through "One Health" approach.
In addition, data on human exposure to selected harmful substances, scattered over numerous pharmacokinetic and HBM studies, were systematically reviewed for the first time, which could also help researchers in future applications of WBE in this field.
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