Riverbank filtration is a cost-effective and efficient method for drinking water production, using the natural filtration capacity of the river gravelbed. Removal efficiency for organic micropollutants (OMP) in field studies is generally calculated by comparing the concentrations measured in surface water and in the wells either on the same day or with a shift of fixed time interval, neither of which can account for the variability of surface water quality and travel time in the aquifer. The present study proposes a novel method based on travel time distribution determined by a numerical transport model with a hypothesis that it will provide more reliable estimate for OMP removal. The model was developed for two production sites of Budapest Waterworks, Hungary on Danube River. River water and riverbank filtered well water were sampled regularly for one year (158 samples each) and analysed for 41 OMPs (pesticides, pharmaceutical residues and industrial pollutants). Nineteen pollutants were detected in >50 % of the well water samples. Median removal rates were 4-97 %, while the concentration of five compounds increased in some wells. Removal rates of telmisartan, tramadol, sulfamethoxazole, 4-methyl-benzotriazole, 5-methyl-benzotriazole and desethyl-terbuthylazine correlated negatively to redox potential (|r|=0.456-0.805). Median travel time increased after high flow events resulting in reduced removal of telmisartan, tramadol, 4-methyl-benzotriazole and desethyl-terbuthylazine (|r|= 0.435-0.661). Removal of diatrizoate, iopamidol, tramadol and benzotriazole increased with distance from the shore (148 vs 395 m) by 25 %, 28 %, 8 %, 16 %, respectively. Background groundwater contamination increased pesticide concentration in the wells located in agricultural areas 1.5-5-fold compared to river water. The model-based method gave more consistent results compared to traditional calculations for OMP removal efficiency during the sampling campaign and allowed for estimating the impact of various environmental factors.

Source water quality is a key determinant of drinking water quality. The recast European Union 2020/2184 Drinking Water Directive (DWD) introduced the obligation for comprehensive risk assessment in drinking water supplies, including hazard assessment of the water source. The DWD also requires further elements of natural origin to be monitored, including U, Ca, Mg and K. The current study is the first comprehensive assessment of 15 natural elements (B, Ba, Be, Ca, Co, K, Li, Mg, Mo, Na, Se, Sr, Ti, U and V) in 1155 (82%) Hungarian drinking water sources, including surface water, bank filtered and groundwater sources. Parameters posing a risk to health (Se, V and U) were typically below the limit of quantification (LOQ), but higher concentrations (max. 7.0, 17 and 41 µg/L, respectively) may occur in confined locations. U exceeded the DWD parametric value in one water supply. Mg and Ca in the majority of the water supplies and Li in a small geographic area reached the concentration range assumed to be protective to health. Water sources were grouped in six clusters based on their elemental distribution, some of them also showing clear geographical patterns. Surface and groundwater sources were not differentiated by composition, with the exception of karstic waters (dominated by Ca and Mg). None of the investigated parameters are expected to be a source of public health concern on a national level, but local occurrences of U and Se should be investigated and managed on a case-by-case basis.

Levoglucosan and its isomers, mannosan and galactosan, are widely used atmospheric tracers of biomass combustion, and levoglucosan has been previously proposed as a potential biomarker of wood smoke exposure. This study evaluated their applicability under real-world conditions. During 14-day monitoring campaigns in both heating and non-heating seasons, daily PM_2.5 and paired urine samples were collected from adults and children in two Hungarian settlements with different heating practices. Monosaccharide anhydrides in PM_2.5 and urine were quantified by gas chromatography–mass spectrometry, while demographic, dietary, and lifestyle data were obtained via questionnaires. Ambient concentrations were substantially higher during the heating season and at the rural site, confirming the significant contribution of residential wood burning to air pollution. While urinary levoglucosan was quantifiable in >90% of samples, its isomers were often below the limit of quantification. Urinary levoglucosan concentrations did not exhibit consistent seasonal or spatial patterns and were not associated with ambient levels. Instead, an unexplained background more likely influenced by certain demographic, dietary, and behavioral factors than by environmental exposure appeared to drive urinary levels. These findings suggest that urinary levoglucosan is not a suitable biomarker for assessing residential wood smoke exposure, with similar conclusions drawn for mannosan and galactosan.

Source water quality is a key determinant of drinking water quality. The recast European Union 2020/2184 drinking water directive (DWD) introduced the obligation for comprehensive risk assessment in drinking water supplies, including the water source and incorporated new elements of natural origin in the list of parameters to be monitored. The current study is the first comprehensive assessment of 15 natural elements (B, Ba, Be, Ca, Co, K, Li, Mg, Mo, Na, Se, Sr, Ti, U and V) in 1155 (82%) Hungarian drinking water sources, including surface water, bank filtered and groundwater sources. Parameters posing a risk to health (Se, V and U) were typically below the lower limit of quantification (LOQ), but higher concentrations (max. 7.0, 17 and 41 µg/L, respectively) may occur in confined locations, the latter exceeding the DWD parametric value in one water supply. Li in a small geographical area, Mg and Ca in the majority of the water supplies reached the concentration range assumed to be protective to health. Water sources were grouped in 6 clusters based on their element distribution, some of them also showing clear geographical patterns. Water types were not differentiated, with the exception of karstic waters (dominated by Ca and Mg). None of the investigated parameters are expected to be a source of public health concern.