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Globally, the reuse of treated sewage effluent for irrigation purposes is increasingly encouraged as a practical solution against the mismatch between the demand for and availability of freshwater resources. The reuse of sewage effluent for sub-surface irrigation (SSI) in agriculture serves the dual purpose of supplying water to crops and diminishing emissions of contaminants of emerging concern (CoECs) into surface water. To investigate such reuse, in a real scale cropland with SSI using sewage effluent, from September 2017 to March 2019 including the extremely dry year 2018, residues were followed of 133 CoECs as related to their physicochemical properties and quantified by liquid chromatography coupled to high-resolution mass spectrometry. Of the 133 target CoECs, 89 were retrieved in the field, most non-detect CoECs have low persistency. During the growing season with sub-surface irrigation, CoECs spread to the shallow groundwater and rhizosphere. Significantly lower concentrations are found between infiltration pipes as compared to directly next to the pipes in shallow groundwater for all persistency-mobility classes. CoECs belonging to the class pm (low persistency and low mobility) or class PM (high persistency and high mobility) class show no change amongst their removal in the rhizosphere and groundwater in a dry versus normal year. CoECs belonging to the class pM (low persistency and high mobility) show high seasonal dynamics in the rhizosphere and shallow groundwater, indicating that these CoECs break down. CoECs of the class Pm (high persistency and low mobility) only significantly build up in the rhizosphere next to infiltration pipes. Climatic conditions with dry summers and precipitation surplus and drainage in winter strongly affect the fate of CoECs. During the dry summer of 2018 infiltrated effluent is hardly diluted, resulting in significantly higher concentrations for the CoECs belonging to the classes pM and Pm. After the extremely dry year of 2018, cumulative concentrations are still significantly higher, while after a normal year during winter precipitation surplus removes CoECs. For all persistency-mobility classes in the shallow groundwater between the pipes, we find significant removal efficiencies. For the rhizosphere between the pipes, we find the same except for Pm. Next to the pipes however we find no significant removal for all classes in both the rhizosphere and shallow groundwater and even significant accumulation for Pm. For this group of persistent moderately hydrophobic CoECs risk characterization ratio's were calculated for the period of time with the highest normalized concentration. None of the single-chemical RCRs are above one and the ΣRCR is also far below one, implying sufficiently safe ambient exposures. Overall the deeper groundwater (7.0–11.8 m below soil surface) has the lowest response to the sub-surface irrigation for all persistency-mobility. When adopting a SSI STP effluent reuse system care must be taken to monitor the CoECs that are (moderately) hydrophobic as these can build up in the SSI system. For the deeper groundwater and for the discharge to the surface water, we find significant removal for the pM and the PM class but not for other classes. In conclusion, relatively high removal efficiencies are shown benefiting the surface waters that would otherwise receive the STP effluent directly.

Globally, the reuse of treated sewage effluent for irrigation purposes is increasingly encouraged as a practical solution against the mismatch between the demand for and availability of freshwater resources. The reuse of sewage effluent for sub-surface irrigation (SSI) in agriculture serves the dual purpose of supplying water to crops and diminishing emissions of contaminants of emerging concern (CoECs) into surface water. To investigate such reuse, in a real scale cropland with SSI using sewage effluent, from September 2017 to March 2019 including the extremely dry year 2018, residues were followed of 133 CoECs as related to their physicochemical properties and quantified by liquid chromatography coupled to high-resolution mass spectrometry. Of the 133 target CoECs, 89 were retrieved in the field, most non-detect CoECs have low persistency. During the growing season with sub-surface irrigation, CoECs spread to the shallow groundwater and rhizosphere. Significantly lower concentrations are found between infiltration pipes as compared to directly next to the pipes in shallow groundwater for all persistency-mobility classes. CoECs belonging to the class pm (low persistency and low mobility) or class PM (high persistency and high mobility) class show no change amongst their removal in the rhizosphere and groundwater in a dry versus normal year. CoECs belonging to the class pM (low persistency and high mobility) show high seasonal dynamics in the rhizosphere and shallow groundwater, indicating that these CoECs break down. CoECs of the class Pm (high persistency and low mobility) only significantly build up in the rhizosphere next to infiltration pipes. Climatic conditions with dry summers and precipitation surplus and drainage in winter strongly affect the fate of CoECs. During the dry summer of 2018 infiltrated effluent is hardly diluted, resulting in significantly higher concentrations for the CoECs belonging to the classes pM and Pm. After the extremely dry year of 2018, cumulative concentrations are still significantly higher, while after a normal year during winter precipitation surplus removes CoECs. For all persistency-mobility classes in the shallow groundwater between the pipes, we find significant removal efficiencies. For the rhizosphere between the pipes, we find the same except for Pm. Next to the pipes however we find no significant removal for all classes in both the rhizosphere and shallow groundwater and even significant accumulation for Pm. For this group of persistent moderately hydrophobic CoECs risk characterization ratio's were calculated for the period of time with the highest normalized concentration. None of the single-chemical RCRs are above one and the ΣRCR is also far below one, implying sufficiently safe ambient exposures. Overall the deeper groundwater (7.0–11.8 m below soil surface) has the lowest response to the sub-surface irrigation for all persistency-mobility. When adopting a SSI STP effluent reuse system care must be taken to monitor the CoECs that are (moderately) hydrophobic as these can build up in the SSI system. For the deeper groundwater and for the discharge to the surface water, we find significant removal for the pM and the PM class but not for other classes. In conclusion, relatively high removal efficiencies are shown benefiting the surface waters that would otherwise receive the STP effluent directly.

Source zones containing tar, a dense non-aqueous phase liquid (DNAPL), can contaminate groundwater for centuries. A common occurrence of tar is at former Pintsch gas factories. Little is known about the composition and fate of contaminants dissolving from Pintsch gas tar DNAPL. In this study, we determined the composition and water-soluble characteristics of mobile aromatic hydrocarbons and their biodegradation metabolites in the DNAPL contaminated groundwater at a former Pintsch gas tar plant. We assessed the factors that determine the fate of observed groundwater contaminants. Measured values of density (1.03–1.06 kg/m3) and viscosity (18.6–39.4 cP) were found to be relatively low compared to common coal tars. Analysis showed that unlike common coal tars phenanthrene is the primary component rather than naphthalene. Moreover, it was found that Pintsch gas tar contains a relatively high amount of light molecular aromatic hydrocarbon compounds, such as benzene, toluene, ethylbenzene and xylenes (BTEX). Less commonly reported components, such as styrene, ethyltoluenes, di-ethylbenzene, 1,2,4,5-tetramethylbenzene, were also detected in water extracts from Pintsch gas tar. Moreover, 46 relatively hydrophilic metabolites were found within the tar samples. Metabolites present within the tar suggest biodegradation of mobile aromatic Pintsch gas tar compounds occurred near the DNAPL. Based on eleven detected suspect metabolites, a novel anaerobic biodegradation pathway is proposed for indene. Overall, our findings indicate that Pintsch gas tar has higher invasive and higher flux properties than most coal tars due to its relatively low density, low viscosity and, high content of water-soluble compounds. The partitioning of contaminants from multi-component DNAPL into the aqueous phase and re-dissolution of their slightly less hydrophobic metabolites back from the aqueous phase into the DNAPL is feasible and demonstrates the complexity of assessing degradation processes within a source zone.

Adsorptive interactions of organic molecules with soil minerals often impair their bioavailability. However, little is known about the adsorption behaviour of phenolic and nitrogenous compounds on different minerals and their mutual interaction with respect to competition and surface conditioning (i.e. surface modification induced by preceding adsorption of the other class of compounds). Therefore, batch adsorption experiments were done to study the interaction between phenolic acids (PAs; salicylic acid, Sal; syringic acid, Syr; ferulic acid, Fer; vanillic acid, Van) and amino acids (AAs; lysine, Lys; glutamic acid, Glu; leucine, Leu; phenylalanine, Phe) during adsorption on goethite and Ca2+-montmorillonite at pH 6 by applying adsorbate concentrations of 0.01, 0.05 and 0.1 mm. Larger adsorption of PAs was observed on goethite than montmorillonite, whereas the phyllosilicate was a better adsorbent for AAs than the oxide. Among all tested PAs, Sal was preferentially adsorbed on both minerals. For the AAs, Glu was preferentially adsorbed on goethite and Lys on montmorillonite. The AAs were more competitive than PAs and partially suppressed the adsorption of PAs on both minerals. The adsorption of PAs or AAs on both minerals was enhanced by surface conditioning with the other group, with larger effects for goethite than montmorillonite. For goethite, surface conditioning by PAs enhanced the adsorption of AAs more (by 97–161%) than did AAs for PAs (9–48%). The results support the hypothesis that pre-adsorption of one class of organic compound can enhance the retention of another class. This suggests that adsorbed organic matter on soil mineral phases might be subject to a self-strengthening effect.

In het oppervlaktewater van de Rijn en de Maas zijn lage concentraties aangetoond van twaalf in de Opiumwet opgenomen stoffen. Het gaat om amfetaminen, slaap- en kalmeringsmiddelen (barbituraten en benzodiazepinen), opiaten en cocaïne. Deze stoffen zijn waarschijnlijk al in het watersysteem aanwezig sinds mensen ze gebruiken, maar kunnen nu worden opgespoord dankzij geavanceerde meettechnieken die sinds kort beschikbaar zijn. Tijdens de drinkwaterzuivering worden de meeste stoffen verwijderd of sterk in concentratie verlaagd. In het drinkwater worden uiteindelijk nog drie stoffen aangetroffen, allen barbituraten. De concentraties zijn zeer laag; maximaal 12 nanogram per liter. De gezondheidskundige risiconormen voor drinkwater worden dan ook niet overschreden. Het is raadzaam de aanwezigheid van deze stoffen in het watersysteem te blijven volgen. Daarnaast wordt aanbevolen de mogelijke effecten op het ecosysteem te onderzoeken.

The societal interest in the use and abuse of illicit drugs has spurred researchers to monitor their discharges from households and municipal wastewater treatment plants and to investigate their occurrence in surface waters. A method employing high resolution Orbitrap mass spectrometry coupled to liquid chromatography was used to monitor simultaneously the presence of 32 illicit drugs and their degradation products in samples of wastewater, surface waters and drinking water. Specific aspects of the methodology related to instrument optimization and sample matrix-related aspects of the instrument performance are discussed. The method was used for monitoring campaigns in The Netherlands in the years 2006-2009. The most abundant drugs of abuse encountered in wastewater and surface waters included several diazepines, codeine, methadone, benzylecgonine (a transformation product of cocaine, and MDMA. In Dutch drinking water samples collected in the period 2006-2008, no drugs were found to be present.