Sewage sludge monitoring data on many harmful organic pollutants is scarce. In this study, 23 contaminants of environmental concern were identified, including: Per- and polyfluoroalkyl substances (PFAS), pharmaceuticals and personal care products, hormones, and flame retardants. First, concentration data in sludge from the Nordic countries, was compiled. Several data gaps on concentration data were found, particularly in personal care products and flame retardants groups. There were also large differences in data availability between the countries. Second, removal efficiency of the selected pollutants was reviewed. Three different treatment methods were considered: anaerobic digestion, composting, and pyrolysis. Pyrolysis emerged generally as the most efficient removal method, whereas there were large differences in the reported removal efficiencies in anaerobic digestion and composting. Overall, the most recalcitrant pollutants in sludge in this study were PFAS, certain antibiotics, and estrogens. Several factors behind the variation were identified, such as diversity in plant design, operational and seasonal parameters, and challenges in sampling and analysing the sludge matrix. Coherent study designs are needed to compare removal efficiencies more transparently. Legislative requirements are usually the main drivers for carrying out monitoring, andurrent EU legislation regulating hazardous substances in sewage sludge is outdated. There is great variation in national regulations between the Nordic countries. The lack of regulatory requirements hinders informed/science-based long-term decision-making to protect the environment. Sludge utilization is a complex question requiring consideration from regulative, technological, and societal perspectives. Monitoring contaminants is vital in both assessing risks of sludge-based fertilizers and contaminant removal efficiencies in sludge treatment.

This study investigates the occurrence, attenuation, and ecological risks of phthalates and pharmaceuticals in a long-operating wastewater soil infiltration system in northern Sweden. Concentrations of 15 phthalates, 67 pharmaceuticals, caffeine, and acesulfame K were measured in influent wastewater, groundwater, soil, and a downgradient pond across multiple seasons. Results showed that most micropollutant removal occurred in the unsaturated soil zone prior to groundwater recharge, possibly due to processes such as biodegradation and sorption. Substantial reductions were observed for caffeine (>99 %), carbamazepine (>96 %), losartan (>99 %), and phthalates (51 ± 72 % and 92 ± 5 %), with the higher attenuation for phthalates comparable to conventional activated sludge treatment. In contrast, compounds such as metoprolol exhibited moderate reductions (>71 %), while others showed low or even negative attenuation, including diclofenac (46 % and -180 %) and ibuprofen (33 % and -11 %). After groundwater recharge, only ibuprofen showed attenuation beyond dilution, although the mechanisms for this remains unknown. Several pharmaceuticals, including metoprolol, irbesartan, and metformin, were detected in soil samples, though it is unclear whether they were sorbed to the soil matrix or present in porewater. In downgradient surface water, diclofenac and ibuprofen exceeded risk quotient thresholds, while oxazepam surpassed the lowest predicted no-effect concentration (PNEC) in one sample, indicating ecological risks. Overall, the findings highlight both the strengths and limitations of soil infiltration systems in mitigating micropollutant contamination, emphasizing the importance of vadose zone processes while underscoring uncertainties in sorption and degradation mechanisms.

Per- and polyfluoroalkyl substances (PFAS) are a large group of compounds with a wide range of sources, uses and physicochemical properties, resulting in highly variable environmental behaviour and analytical detectability. This study investigates the occurrence of a large spectrum of PFAS, including precursors of perfluoroalkyl acids, in the River Porvoonjoki system in Southern Finland during two contrasting hydrological periods: high flow (April 2024) and low flow (June 2024). Surface water from up to ten sampling sites, including a stormwater ditch, and three wastewater treatment plants (WWTPs) discharging into the river were analysed using target analysis, Total Oxidizable Precursors (TOP) assay and suspect screening supported by non-target analysis (NTA). Short-chain perfluorocarboxylic acids dominated the PFAS profile in the river. Higher concentrations were observed during the low flow period, suggesting an increased impact from wastewater discharges when dilution is limited. However, mass load calculations propose that a substantial fraction of total PFAS load originates from diffuse sources, such as stormwater, snowmelt-driven surface runoff and background catchment inputs. Oxidizable precursors contributed substantially to total PFAS loads in both wastewater effluents and the four surface water samples that were analysed for TOP in both hydrological periods. Their contribution in these samples was higher in April than in June, potentially reflecting enhanced mobilization during spring snowmelt and wet-weather conditions. Suspect screening showed the presence of four previously unreported PFAS, however, the suspects or their semi-quantitative concentrations could not explain the TOP assay results. The findings emphasize the importance of integrating precursor analysis in PFAS monitoring and to consider varying hydrological conditions, to improve load estimation and to establish management strategies for reducing PFAS inputs to surface waters.

Agricultural soils receive a wide range of organic and inorganic contaminants through long-term fertilization, yet field-based evidence linking complex contaminant mixtures to biological exposure of soil organisms under realistic agricultural conditions remains limited. Here, soils and endogeic earthworms (Aporrectodea cf. caliginosa) were sampled from two adjacent agricultural fields in Finland after more than two decades of contrasting fertilization with sewage sludge-based products and broiler litter. A broad suite of organic contaminants together with multiple metals was analyzed in both matrices, and bioaccumulation factors were used to assess soil-biota transfer. Distinct fertilization-specific contaminant profiles were observed in soils, with higher concentrations of several organic contaminants under sewage sludge fertilization. In earthworms, per- and polyfluoroalkyl substances (PFAS) dominated contaminant profiles and showed pronounced bioaccumulation, particularly for long-chain PFAS including perfluorooctane sulfonate (PFOS). Other contaminants showed variable, compound-specific transfer, and biological exposure was not consistently reflected by bulk soil concentrations. These results provide field-based evidence of distinct soil contaminant profiles under contrasting long-term fertilization histories, but biological exposure cannot be reliably inferred from bulk soil concentrations alone. Instead, contaminant transfer to soil organisms was more consistent with bioavailability-related and substance-specific properties reported in previous studies, highlighting the importance of integrating biota-based measurements into assessments of agricultural soil contamination.