In-situ electrochemical method for detecting freely dissolved polycyclic aromatic hydrocarbons in waters

A new sensing system for polycyclic aromatic hydrocarbons (PAH) in waters is being developed. The system consists of a wafer based device with chip-based mercury (Hg) on platinum microelectrode as working electrode and platinum auxiliary electrode, incorporated in to a flow cell system with an external reference electrode. Hg microelectrode was coated with a phospholipid/triglyceride mixed layer and interactions between anthracene, phenanthrene, pyrene and fluoranthene and the layer were monitored using rapid cyclic voltammetry (RCV). The layer proved sensitive to interactions with PAHs in “organic matter free” seawater, with the detection limits of 0.33 μg/L for phenanthrene, 0.35 μg/L for pyrene, 0.15 μg/L for anthracene and 0.32 μg/L for fluoranthene. Tested interferences, such as sodium humate, dextran T–500 and bovine serum albumin, representative humic substances, polysaccharides and proteins, did not have an influence on the layer response. The system was also tested with a river water sample where concentrations of PAHs were determined using the standard addition method and compared to the results obtained by using gas chromatography–mass spectrometry (GC–MS). The concentration of total PAH obtained by the standard addition method is about 80% lower compared to the results obtained by GC MS analysis. The difference is explained by the fact that the electrochemical method measures water-soluble and free PAHs while chromatographic methods measures both dissolved and particulate/organic PAH

Sveobuhvatna analiza nitrata, sulfata i pesticida u procjednim vodama iz intenzivno poljoprivrednog područja - Studija slučaja u Hrvatskoj

To better understand the impact of conventional agricultural practices on soil and water resources, two main objectives were established in this study: to measure nitrate (NO3-) and sulphate (SO4 2-) concentrations in lysimeters and drainpipes leachates in response to different nitrogen fertilization levels and soil amendments and to identify organic contaminants that could have originated from the long-term use of agrochemicals in historically intensive agricultural area in Croatia. During the two-year study period leachate samples were collected from lysimeters and drainpipes. Research results indicate NO3- content in both lysimeters and drainpipes increased with rising doses of N fertilizer. The highest concentration of SO4 2- was recorded in the treatment with added phosphogypsum, while in all other treatments the concentrations were low. Over 40% of the 287 target substances were detected at least once during the two-year study period but only two substances (IPC/propham and carbosulfan) were found to have concentrations above 0.5 µg/L. Additionally, three priority substances were continuously present in the leachate samples: atrazine, simazine and isoproturon.Da bi se bolje razumio utjecaj konvencionalne poljoprivredne prakse na tlo i vodne resurse, u ovom radu uspostavljena su dva glavna cilja: mjerenje koncentracija nitrata (NO3-) i sulfata (SO4 2-) u lizimetarskim i drenskim procjednim vodama kao odgovor na gnojidbu različitim razinama dušika te poboljšivača tla te identificirati organske onečišćivače čije je moguće izvorište u dugotrajnoj uporabi pesticida na povijesno intenzivno poljoprivrednom području u Hrvatskoj. Tijekom dvogodišnjeg razdoblja uzorci procjednih voda prikupljani su iz lizimetara i drenskih cijevi. Rezultati istraživanja pokazuju da se sadržaj NO3- u lizimetrima i u drenskim cijevima povećavao s porastom doza N gnojiva. Najveća koncentracija SO4 2- zabilježena je u tretmanu s dodanim fosfogipsom, dok su u svim ostalim tretmanima koncentracije bile niske. Preko 40% od 287 ciljnih tvari otkriveno je barem jednom tijekom dvogodišnjeg razdoblja ispitivanja, ali utvrđeno je da su samo dvije tvari (IPC/propham i carbosulfan) imale koncentracije iznad 0,5 µg/L. Uz to, tri prioritetne tvari bile su kontinuirano prisutne u uzorcima procjednih voda: atrazin, simazin i izoproturon

A thorough analysis of the occurrence, removal and environmental risks of organic micropollutants in a full-scale hybrid membrane bioreactor fed by hospital wastewater

The recent draft of the Urban Wastewater Treatment Directive pays attention to contaminants of emerging concern including organic micropollutants (OMPs) and requires the removal of some of them at large urban wastewater treatment plants (WWTPs) calling for their upgrading. Many investigations to date have reported the occurrence of a vast group of OMPs in the raw influent and many technologies have been tested for their removal at a lab- or pilot-scale. Moreover, hospital wastewater (HWW) may contain specific OMPs at a high concentration and therefore its treatment deserves attention. In this study, a 1-year investigation was carried out at a full-scale membrane bioreactor (MBR) treating mainly HWW. To promote the removal of OMPs, powdered activated carbon (PAC) was added to the bioreactor at 0.1 g/L and 0.2 g/L which resulted in the MBR operating as a hybrid MBR. Its performance was tested for 232 target and 90 non-target OMPs, analysed by UHPLC-QTOF-MS using a direct injection method. The wastewater arriving at the WWTP was characterized and the performance of both the MBR and hybrid MBR was assessed for: key OMPs selected on the basis of their frequency, occurrence, persistence to removal, bioaccumulation and toxicity; OMP classes; and the whole list of OMPs. Finally, an environmental risk assessment of the OMP residues was conducted by means of the risk quotient approach. The results indicate that PAC addition increased the removal of most of the key OMPs (e.g., sulfamethoxazole, diclofenac, lidocaine) and OMP classes (e.g., antibiotics, psychiatric drugs and stimulants) with the highest loads in the WWTP influent. The hybrid MBR also reduced the risk in the receiving water as the PAC dosage increased mainly for spiramycin, lorazepam, oleandomycin. Finally, uncertainties and issues related to the investigation being carried out at full-scale under real conditions are discussed in depth

Non-target screening with high-resolution mass spectrometry: critical review using a collaborative trial on water analysis

In this article, a dataset from a collaborative nontarget screening trial organised by the NORMAN Association is used to review the state-of-the-art and discuss future perspectives of non-target screening using high-resolution mass spectrometry in water analysis. A total of 18 institutes from 12 European countries analysed an extract of the same water sample collected from the River Danube with either one or both of liquid and gas chromatography coupled with mass spectrometry detection. This article focuses mainly on the use of high resolution screening techniques with target, suspect, and non-target workflows to identify substances in environmental samples. Specific examples are given to emphasise major challenges including isobaric and co-eluting substances, dependence on target and suspect lists, formula assignment, the use of retention information, and the confidence of identification. Approaches and methods applicable to unit resolution data are also discussed. Although most substances were identified using high resolution data with target and suspect-screening approaches, some participants proposed tentative non-target identifications. This comprehensive dataset revealed that nontarget analytical techniques are already substantially harmonised between the participants, but the data processing remains time-consuming. Although the objective of a Bfullyautomated identification workflow^ remains elusive in the short term, important steps in this direction have been taken, exemplified by the growing popularity of suspect screening approaches. Major recommendations to improve non-target screening include better integration and connection of desired features into software packages, the exchange of target and suspect lists, and the contribution of more spectra from standard substances into (openly accessible) databases.This work was supported in part by the SOLUTIONS project, which received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under Grant Agreement No. 603437

COVID-19 Lockdowns—Effect on Concentration of Pharmaceuticals and Illicit Drugs in Two Major Croatian Rivers

In order to prevent the spread of COVID-19, contingency measures in the form of lockdowns were implemented all over the world, including in Croatia. The aim of this study was to detect if those severe, imposed restrictions of social interactions reflected on the water quality of rivers receiving wastewaters from urban areas. A total of 18 different pharmaceuticals (PhACs) and illicit drugs (IDrgs), as well as their metabolites, were measured for 16 months (January 2020–April 2021) in 12 different locations at in the Sava and Drava Rivers, Croatia, using UHPLC coupled to LCMS. This period encompassed two major Covid lockdowns (March–May 2020 and October 2020–March 2021). Several PhACs more than halved in river water mass flow during the lockdowns. The results of this study confirm that Covid lockdowns caused lower cumulative concentrations and mass flow of measured PhACs/IDrgs in the Sava and Drava Rivers. This was not influenced by the increased use of drugs for the treatment of the COVID-19, like antibiotics and steroidal anti-inflammatory drugs. The decreases in measured PhACs/IDrgs concentrations and mass flows were more pronounced during the first lockdown, which was stricter than the second

Albendazole Degradation Possibilities by UV-Based Advanced Oxidation Processes

Pharmaceuticals are present in an aquatic environment usually in low (ng/L) concentrations. Their continuous release can lead to unwanted effects on the nontarget organisms. The main points of their collection and release into the environment are wastewater treatment plants. The wastewater treatment plants should be upgraded by new technologies, like advanced oxidation processes (AOPs), to be able to degrade these new pollutants. In this study, the degradation of albendazole (ALB), a drug against parasitic helminths, was investigated using four UV-based AOPs: UV photolysis, UV photocatalysis (over TiO2 film), UV + O3, and UV + H2O2. The ranking of the degradation process degree of the ALB and its degradation products for studied processes is as follows: UV photolysis < UV photocatalysis with TiO2 < UV + O3 < UV + H2O2. The fastest degradation of ALB and its degradation products was obtained by UV-C + H2O2 process with a degradation efficiency of 99.95%, achieved in 15 minutes

Assessment of river sediment toxicity: combining empirical zebrafish embryotoxicity testing with in silico toxicity characterization

Quantitative chemical analyses of 428 organic contaminants (OCs) indicated the presence of 313 OCs in the sediment extracts from Sava River, Croatia. Pharmaceuticals were present in higher concentrations than pesticides thus confirming their increasing threat to freshwater ecosystems. Toxicity evaluation of the sediment extracts from four locations (Jesenice, Rugvica, Galdovo and Lukavec) using zebrafish embryotoxicity test (ZET) accompanied with semi-quantitative histopathological analyses exhibited correlation with cumulative number and concentrations of OCs at the investigated sites (10.05, 15.22, 1.25, and 9.13 µg/g respectively). Toxicity of sediment extracts and sediment was predicted using Toxic unit (TU) approach and persistence, bioaccumulation and toxicity (PBT) ranking. Additionally, influential OCs and genes were identified by graph mining of the prior knowledge informed, site-specific chemical-gene interaction models. Predicted toxicity of sediment extracts (TUext) was similar to the results obtained by ZET and associated histopathology with Rugvica sediment being the most toxic, followed by Jesenice, Lukavec and Galdovo. Sediment TU (TUsed) favoured OCs with low octanol-water partition coefficients like herbicide glyphosate and antibiotics ciprofloxacin and sulfamethazine thus indicating locations containing higher concentrations of these OCs (Galdovo and Rugvica) as the most toxic. Results suggest that comprehensive in silico sediment toxicity predictions advocate providing equal attention to organic contaminants with either very low or very high log Kow