Background: Groundwater contamination with chlorinated hydrocarbons (CLHCs), particularly with tetrachloroethylene (PCE) and trichloroethylene (TCE), which are used in industry for degreasing and cleaning, can be considered a serious problem concerning the entire world. In addition to conventional groundwater monitoring from a network of wells, several screening methods have been proposed to identify and delineate groundwater contamination with volatile organic compounds (VOCs), such as soil gas measurement, bioindicators, direct-push technologies or geophysical techniques. The main objectives of this study were to confirm the feasibility of active soil gas screening for the characterisation of groundwater contamination with CLHCs under the wider area of the former refrigerator manufacturer (city of Zlaté Moravce, western Slovakia) and to evaluate the human health risks through exposure to CLHCs present in groundwater. Methods: a conventional site investigation based on concentration measurements using gas chromatography-mass spectrometry from monitoring wells and soil gas measurements using a portable photo-ionisation detector device were applied. Results: The chemical analyses showed the persistent contamination of groundwater, with PCE, TCE and other CLHCs, such as cis-1,2-dichloroethylene (cis-DCE) or 1,1,2-trichloroethane (TCA), being most severe in the zone of the former factory (up to 2690, 83,900, 6020 and 156 µg/L for PCE, TCE, cis-DCE and TCA, respectively), but also extended into the residential zone located 600 m along the groundwater flow line. Soil gas measurements of VOCs and other chemical parameters (methane (CH₄), total petroleum (TP), carbon dioxide (CO₂) and oxygen (O₂)) from a densely designed network of sampling points (n = 300) helped trace the current state of groundwater contamination. Spatial distribution maps of VOCs concentrations in soil gas clearly marked the areas of the highest CLHCs concentrations in groundwater. Principal component analysis (PCA) confirmed a significant correlation of VOCs and CLHCs with the first principal component, PC1, explaining up to 84% of the total variability of the concentration data, suggesting that VOCs in soil gas were a suitable marker of the extent of groundwater contamination with CLHCs. Despite severe groundwater contamination with CLHCs reaching residential areas, local residents were not exposed to non-carcinogenic risks, but a potential carcinogenic risk was present. Conclusions: based on the results, it could be confirmed that soil gas screening is an efficient and quick tool for identifying the sources of groundwater contamination with CLHCs as well as the level of this contamination.

Pharmaceutical (PAC) residues in soils and sewage sludges may occur in water-extractable forms, representing potential diffuse sources of contamination for groundwater and surface waters via leaching and runoff. Waste-derived sorbents may decrease this potentially mobile PAC fraction, while valorizing residual materials within circular-economy-based remediation. Five waste-derived sorbents (two biochars and three iron-based materials) were tested for removal and operationally defined immobilization of carbamazepine (CBZ), diclofenac (DCF) and fexofenadine (FEX) at environmentally relevant aqueous concentrations and controlled solid-matrix levels. Sorption was assessed in single- and multi-compound aqueous systems. The best-performing sorbents were then applied to spiked sewage sludge and soil followed by water extraction. In aqueous tests, sewage sludge biochar (BSS) showed consistently high removal (single: 97% CBZ, 92% DCF, 99.5% FEX; multi: 93% CBZ, 95% DCF, 97% FEX). Zero-valent iron grit (CH) showed compound-dependent sorption (83% CBZ, 56% DCF, 99% FEX), with improved DCF removal in the mixture (94%). Hardwood biochar (BHW) was less effective and iron sludges (R, S) showed low or partly non-evaluable performance. In sewage sludge, BSS and CH did not significantly change aqueous PAC concentrations and spike release remained high (31–63%). In soil, BSS and CH showed mean water-extractable fractions that were 53%, 27% and 66% lower for CBZ, DCF and FEX, respectively, compared with unamended spiked control, and nutrient release was altered. Overall, BSS and CH showed practical potential to decrease readily extractable PAC amounts in the tested soil under laboratory conditions, whereas sewage sludge showed stronger matrix control and may require adapted immobilization strategies.

Railway sites are characterized by the frequent occurrence of soil and groundwater pollution by oil. The primary reason for pollution is usually the handling of large volumes of fuels and lubricants and, to a lesser extent, other hazardous substances, which represent an increased likelihood of potential spills due to inattention and accidents. The second factor is spills due to inadequate (aged) process equipment. In the Slovak Republic, a network of locomotive depots, strategically located throughout the country, has been operated in the past. In 2008, a pilot project was implemented to survey groundwater quality at 45 sites, followed by monitoring of the quality status until 2014. The levels of petroleum hydrocarbons in groundwater were determined by spectrophotometric methods (NEC-IR and NEC-UV). The NEC-IR parameter documented very-high pollution at 14 sites, while the NEC-UV parameter documented the same very-high pollution degree at 23 sites. Statistical evaluation using Kruskal–Wallis test followed by Dunn’s post hoc test revealed a significant effect of the size of the site as well as activity status on the presence and intensity of pollution. The presence of light non-aqueous phase liquids (LNAPLs) was observed at almost half of the sites. Based on the evaluated data, railway sites represent a specific type of site with frequent occurrence of severe oil pollution, posing a significant environmental and health risk.