PROGRAMME

Due to their economic advantages, landfills are the primary repository of municipal solid wastes, receiving everyday by-products such as food wastes, plastic containers and product packaging materials, unused pharmaceuticals, textile and other products. As a result of the higher demand and better quality of consumer products, the profile of chemicals in solid wastes has changed during the last decades. Landfill leachates are produced during the precipitation and percolation of water through waste, biochemical processes in wastes cells and the inherent water content of wastes themselves (Eggen et al., 2010). Emerging Contaminants (ECs) from landfill leachates can transport in the subsurface and leachate-affected aquifers surrounding landfills, contaminating groundwater. Their fate is high affected by the soil type and availability of aqueous electron acceptors (e.g., constituent concentrations) in the aquifer, temporal variations in the configuration of redox zones down-gradient, biogeochemical and microbial processes affecting contaminant transport, and hydrodynamic framework (e.g., groundwater recharge events and seasonal water-table fluctuations) (Ramakrishnan et al., 2015). Moreover, transformation products (TPs) of ECs may be produced during abiotic or biodegradation processing, with unknown ecotoxicological behavior. Therefore, the contamination of freshwater reservoirs with leachates from deposition sites could pose a serious threat to the environment and human health and needs further investigation. The aim of this study was the determination of ECs and their TPs in landfill leachates and groundwater from the surrounding area, to investigate the potential impact of landfill contaminants on the aquifer. For this purpose, both raw and treated landfill leachates and groundwater samples were collected in 2021 in Greece. For the determination of emerging contaminants, Solid-Phase Extraction using mixed-mode cartridges with 4 sorbents was used for the extraction and pre-concentration of the anlyes with different physicochemical properties. The samples were analysed by LC-ESI-QTOFMS and the HRMS chromatograms were screened with an in-house wide-scope database of more than 2,300 organic pollutants including compounds of different classes (such as pharmaceuticals, personal care products, drugs of abuse, pesticides, stimulants, sweeteners, perfluorinated compounds, benzotriazoles, benzothiazoles, phthalates and surfactants), as long as their TPs and metabolites (Nika et. al, 2020). The concentrations of the contaminants in leachates were calculated based on the standard addition method. Preliminary results indicate the presence of pharmaceuticals such as lidocaine, niflumic acid, paracetamol and ketoprofen, the stimulant nicotine and several industrial chemicals including benzotriazole, 2-OH-benzothiazole, 2-amino-benzothiazole, bisphenol A and S, and perfluorinated substances such as PFBuS, PFOA and PFHpA, in the raw leachates.