Reclaimed water (RW) offers a sustainable solution for agricultural irrigation and freshwater conservation, but its microbial and chemical composition, shaped by treatment and storage processes, requires careful consideration for environmental and public health impacts. This study compared two RW types (conventional activated sludge with sand filtration and chlorination - CAS + SFC-RW - and membrane bioreactor - MBR-RW) with a tube well (TW) water control. The goal was to assess how storage influences the microbial composition, key antibiotic resistance and mobilome genes, and RW the impact on irrigated lysimeter soils during lettuce cultivation. Total bacteria were profiled using 16S rRNA gene sequencing and ddPCR, while antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) were quantified by ddPCR and analysed by metagenomics. Initial RW samples had 1-1.5 orders of magnitude more 16S rRNA copies compared with the control, with significantly different bacterial and ARG/MGE profiles. Actinomycetota dominated CAS + SFC-RW, Bacteroidota the MBR-RW, and Pseudomonadota the TW water. Class 1 integrons and Tn916/Tn1545 were more abundant in CAS + SFC-RW compared with the MBR-RW. Storage reduced these differences toward convergence with the TW water profile, with putative pathogenic taxa, however, being more recalcitrant to change. RW irrigation altered soil bacterial composition, with MBR-RW having a greater impact as declared by the enhanced presence of Bacteroidota in the receiving soils. The RW influence was inversely related with vertical distance of the irrigation point, while the lettuce crop presence showed minimal/no impact. These results highlight the need for careful management of RW treatment and storage to ensure safe, resilient agricultural practices.

Recent studies conducted globally have identified a rising trend in alcohol consumption during the last years, generating a great concern, due to the negative consequences on human health and the broader effects on society. Monitoring of ethyl sulphate (EtS) by applying wastewater epidemiology (WBE) has been proven to be an effective technique for the assessment of alcohol use within a community. This work reports the results of a WBE-based study, conducted for the first time in the Republic of Cyprus, on alcohol consumption, throughout a one-year systematic monitoring. Daily influent wastewater samples from two wastewater treatment plants (WWTPs), one serving part of the capital city and one a coastal touristic area, were collected every three days for one year, and EtS was determined by means of liquid chromatography tandem mass spectrometry. The analysis revealed a relatively stable mean monthly alcohol consumption in the capital area, with daily consumption ranging from 0.31 to 10.60 mL/day/inh. In the coastal area, significant variations in alcohol consumption were observed, with tourist activity during the summer months being associated with nearly a tenfold increase in alcohol use compared to the winter months. Furthermore, four weekly campaigns were conducted for the determination of five stimulant illicit drugs. The results indicated a statistically significant association between alcohol and some stimulants, namely methamphetamine, MDMA, and ketamine. While this association does not imply direct causation or co-consumption, it highlights potential patterns of concurrent presence in wastewater.

In recent decades, climate change and global warming have intensified water scarcity, while the growing global population demands have increased. Reclaimed water (RW) has become essential, offering a viable alternative for crop irrigation in line with circular economy principles. However, although RW reuse is crucial for addressing water shortages, the presence of micropollutants still poses a challenge. The potential for micropollutants to be taken up by crops and enter the food chain still raises significant scientific concern. This work studies RW treated by conventional activated sludge followed by sand filtration and chlorination (CAS+SFC-RW) and membrane-bioreactor-treated RW (MBR-RW) in terms of micropollutant concentrations, providing insights into the differences in micropollutant profiles between the two treatments. The results demonstrate that MBR-RW generally exhibits lower cumulative concentrations of target analytes. However, the study also indicates that the storage of RW for irrigation significantly affects the presence of micropollutants, contributing to their degradation, increase or persistence. Soil analysis revealed fewer detectable micropollutants in the topsoil (0-20 cm) compared to RW, likely attributed to attenuation processes, and more micropollutants (both with respect to concentration and number) compared to deeper soil layers. Carbamazepine, 10,11-epoxide-carbamazepine, and telmisartan were found to migrate to deeper soil levels. The analysis revealed 13 micropollutants in lettuce irrigated with CAS+SFC-RW and 8 with MBR-RW, with carbamazepine and sulfamethoxazole being the most abundant. These differences are likely driven by the physicochemical properties of the compounds and plant-specific factors. Leachates examination showed the potential for contaminants to leach through soil, posing a risk for groundwater contamination. The study showed that the presence of micropollutants in RW is not directly associated with their presence in soil or lettuce, underscoring the need for regulatory policies that address not only their presence in RW but their eventual fate within the agricultural and environmental context.

Effective management of water resources is crucial for global food security and sustainable development. In this Review, we explore the potential benefits and challenges associated with treated wastewater (TW) reuse for irrigation. Currently, 400 km(3) yr(-1) of wastewater is generated globally, but <20% is treated, and of that TW, only 2-15% is reused for irrigation depending on region. The main limitation of TW for irrigation is the inability of current treatment technologies to completely remove all micropollutants and contaminants of emerging concern, some of which have unknown impacts on crops, environment and health. However, advanced water treatment and reuse schemes, supported by water quality monitoring and regulations, can provide a stable water supply for agricultural production, as demonstrated in regions such as the USA and Israel. Such schemes could potentially serve a net energy source, as the embedded energy in wastewater exceeds treatment needs by 9 to 10 times. Agriculturally useful nutrients such as nitrogen, phosphorus and potassium could be also recovered and reused. TW reuse for irrigation could act as a major contributor to a circular economy and sustainable development, but the first steps will be funding and implementation of advanced and sustainable treatment technologies and social acceptance.

The validation of a cross-country, national-scale SARS-CoV-2 wastewater surveillance system for the monitoring of public health in the Republic of Cyprus, took place during October 2021-September 2022. The chronicle of SARS-CoV-2 genetic marker concentrations and prevailing Variants of Concern (VoCs) in all large Wastewater Treatment Plants (WWTPs) of Cyprus for a continuous period of 1 year, was recorded through an integrated, multi-disciplinary sewage-based surveillance system set up to track, visualize and make the collected information and statistical analysis outcomes, publicly available. Composite sampling and physicochemical parameter normalization of Population Equivalents (PE) and SARS-CoV-2 genetic marker concentration loads were utilized.Chemical Oxygen Demand (COD) was selected for normalization of genetic fragment loads. The selection of a normalization method should be tailored according to the characteristics of each individual city/WWTP population structure, flows and wastewater origin. Metagenomic sequencing showed the transition of the SARS-CoV-2 genome from the Delta to the Omicron variant prevalence, in agreement with changes in wastewater gene concentrations. Differences in the early detection of SARS-CoV-2 genetic markers were found among cities. The established system was able to track and monitor the trend of SARS-CoV-2, even in times of absence of other public health measures such as tracing of confirmed COVID-19 cases, showing the capacity of the wastewater system to quickly capture shifts in infections.The work done in the framework of this project, confirmed the ability of the national-scale system to timely observe pandemic trends, evaluate effects of control measures implemented and monitor the burden of infected patients that shed SARS-CoV-2 fragments.

The current work reports on a new low-cost solid phase extraction (SPE) material obtained by crosslinking cellulose with 4,4-methylenebisphenyldiisocyanate (CMDI-1) for the pre-concentration of two contaminants of emerging concern (CEC): Chloramphenicol (CAP) and Bisphenol-A (BPA) from water. The results obtained show good analytical performance with low Limit of Detection of 71.9 ng/L and 10 ng/L for the pre-concentration of CAP and BPA respectively, and a good linear range between 0.5 and 8 mu g/L, with r(2) values > 0.99. The application of the developed method for the analysis of real water samples achieved good percentage recoveries (86.8 - 96.2 %), comparable to that of an expensive commercial HLB adsorbent (89.8 - 107 %). Response Surface Methodology modelling indicates that adsorbent dose, elution volume, and sample volume had a significant influence on CAP recovery, while solution pH, elution volume, and ionic strength had a significant influence on BPA recovery. From our economic assessment, a pack of 30 SPE tubes of 500 mg CMDI-1 SPE adsorbent will cost 82 % less than a similar amount of Oasis HLB adsorbent. This study demonstrates and validates a feasible and inexpensive approach to the use of cellulose to develop low-cost SPE adsorbents for the effective pre-concentration and determination of trace contaminants in water. The CMDI-1 SPE adsorbent can be easily prepared and adopted for use by water professionals in developing countries to enhance understanding on the presence and fate of such contaminants in the environment and also in technical systems, towards developing relevant environmental protection measures for sustainability.

To address water shortage challenges, treated wastewater is used to meet the demand for irrigation water in several countries worldwide. Considering the presence of pollutants in treated wastewater, its use for land irrigation might have an impact in the environment. This review article focuses on the combined effects (or potential joint toxicity) of microplastics (MPs)/nanoplastics (NPs) and other environmental contaminants present in treated wastewater on edible plants after irrigation. Initially, the concentrations of MPs/NPs in wastewater treatment plant effluents and surface waters are summarized, indicating the presence of MPs/NPs in both water matrices (i.e., wastewater after receiving treatment and lakes/rivers). Then, the results of 19 studies related to joint toxicity of MPs/NPs and co-contaminants (e.g., heavy metals and pharmaceuticals) on edible plants, are reviewed and discussed. This concurrent presence may result in several combined effects on edible plants, e.g., rapid root growth, increase in antioxidant enzymes, decrease in photosynthetic rate and increased production of ROS. These effects, as discussed in the various studies on which this review is based, can generate antagonistic or even neutral impact on plants, depending on the size of MPs/NPs and their mixing ratio with the co-contaminants. However, a combined exposure of edible plants to MPs/NPs and co-contaminants can also lead to hormetic adaptive responses. The data reviewed and discussed herein may relieve overlooked environmental impacts of treated wastewater reuse and may be useful to address challenges related to the combined effects of MPs/NPs and co-contaminants on edible plants after irrigation. The conclusions drawn in this review article are relevant to both direct (i.e., treated wastewater irrigation) and indirect (i.e., discharging treated wastewater in surface waters used for irrigation purposes) reuse, and may contribute to the implementation of the European Regulation 2020/741 on the minimum requirements for water reuse.

The outbreak and spread of COVID-19 impacted through various ways the lives of millions of humans globally. In this work, wastewater-based epidemiology (WBE) was applied to investigate the effect of the actions taken by the Republic of Cyprus to confine COVID-19 on the use of illicit stimulant drugs. Daily influent samples were collected from the six main wastewater treatment plants (WWTPs) of the country i) before lockdown (3-9 April 2019), ii) during lockdown (21-27 April 2020), iii) during the post-lockdown period (14-20 July 2020), and, iv) during each season of the following year (20-26 April 2021, 19-25 July 2021, 11-17 October 2021, 25 December 2021-2 January 2022), and analyzed for amphetamine, methamphetamine, MDMA and cocaine. In most areas, amphetamine and methamphetamine use was not affected during the confinement period, but as availability of the substances decreased with time, a drop in their use was observed when most restriction measures were eased (up to 9- and 22-fold decrease, respectively). The limitations on social interactions and events during the quarantine period seem to have led to the reduction of MDMA and cocaine and driven a sharp decrease of their use in most areas studied (up to 11 and 6 times lower, respectively). However, the re-opening of activities led to a pronounced consumption increase, reaching maximum daily values of 800 and 2691 mg/1000 inhabitants/day, respectively. In 2021, drug use was re-established to lower levels. The examination of weekly patterns during this year revealed higher weekend use of methamphetamine, MDMA and cocaine. Our results suggest that both the implementation and the easing of COVID-19 related measures affected the availability and the use of drugs. This study also provides the first insight on the consumption of illicit drugs in the Republic of Cyprus during pre-, post- and pandemic times and demonstrates the importance of WBE.

Ultrafiltration (UF) was assessed at chemical, microbiological, genetical and toxicological level and in terms of removing specific antibiotic-related microcontaminants from urban wastewater. The UF capacity to remove various antibiotics (clarithromycin, erythromycin, ampicillin, ofloxacin, sulfamethoxazole, trimethoprim, and tetracycline; [A0] = 100 μg L-1) was optimised with respect to the feed recirculation rate (25-50%) and feed/transmembrane pressure (1.5-3/1.5-2.4 bar, respectively). Here, we tested the UF capacity to reduce the cultivable bacteria (faecal coliforms, total heterotrophs, Enterococci, Pseudomonas aeruginosa), enteric opportunistic pathogens, including antibiotic-resistant bacteria (ARB) and antibiotic-resistance genes (ARGs) load. Moreover, the toxicity towards Daphnia magna and three plant species was investigated. Upon optimisation of UF, the removal of antibiotics ranged from 19% for trimethoprim to 95% for clarithromycin. The concentration of cultivable faecal coliforms in the permeate was significantly reduced compared to the feed (P < 0.001), whereas all the bacterial species decreased by more than 3 logs. A similar pattern of reduction was observed for the ARGs (P < 0.001) and enteric opportunistic pathogens (~3-4 logs reduction). A nearly complete removal of the antibiotics was obtained by UF followed by granular activated carbon adsorption (contact time: 90 min), demonstrating the positive contribution of such combination to the abatement of chemical microcontaminants.

The removal of antibiotic resistance genes (ARGs) and taxon-specific markers, the bacterial community structure changes and the permanent inactivation of total bacteria including their antibiotic-resistant counterparts (ARB) in actual wastewater during a Membrane BioReactor (MBR) application followed by solar photo-Fenton oxidation at bench- and then pilot-scale under solar irradiation, were investigated. The presence of enterococci- and pseudomonad-specific taxon markers and of sul1 and ampC ARGs in the MBR effluent was confirmed, indicating the challenge of such processes, for the removal of biological molecules. On the other hand, >99 % reduction of all types of cultivable bacteria examined was observed after MBR treatment, with a 5-log reduction of E. coli and 6-log reduction of P. aeruginosa and Klebsiella spp. There was a shift in the bacterial community structure in the MBR effluent after the bench- and pilot-scale solar photo-Fenton oxidation. Notably, thermotolerant bacterial genera like Ignavibacterium and Thermomonas were prevalent during the pilot-scale process operated at a high ambient temperature, while the most prevalent genera were Mycobacterium, Nocardioides and Mesorhizobium, which are primarily not pathogenic and plant-related. In agreement, a different bacterial community structure according to the G-C content after DGGE analysis was noted between the MBR and solar photo-Fenton oxidation-treated effluents, but interestingly also between the bench- and pilot-scale oxidation-treated effluents. There was complete absence of ARGs after the bench-scale solar photo-Fenton oxidation application but not after the pilot-scale treatment (1.56 and 1.53 log10 CE 100 ng-1 DNA, of sul and ermB, respectively). Taxon-specific markers were found in both oxidation setups. Inactivation of cultivable Escherichia coli, Pseudomonas aeruginosa and Klebsiella spp. (including ARB) was achieved during both oxidation setups, with no further re-activation observed.

The positive effects of biochar applied as soil conditioner for boosting soil fertility and thus plant growth are sufficiently documented, mostly through in-situ experimentation. This field study evaluated the effects of soil amendment (5% v/v) with distinct types of biochar (biosolids-derived biochar, BDB; cattle manure-derived biochar, MDB; spent coffee grounds-derived biochar, SCGDB) on the growth, physiology and quality attributes of lettuce (Lactuca sativa L.) plants grown in sandy clay loam-textured soil, under temperate climatic conditions. Peat moss (PM) was also used, to serve as internal control due to its wide use. Plants grown on MDB-amended soil showed a significant increase of biomass production rate, evident through elevated mean fresh and dry weight values compared with all other treatments. Increased growth was also found in BDB treatment, though failed to reach significance. None of the treatments impacted the photosynthetic pigment content, however they did reduce the nitrates content in leaves. Leaves sampled from BDB and MDB treatments showed reduced soluble solids content (SSC) and titratable acidity (TA), and increased sucrose content. MDB-treated plants showed increased fructose content while BDB-treated plants showed increased total soluble sugar and total phenolics content. Moreover, plants grown in MDB- and BDB-amended soil showed increased total antioxidant capacity, despite maintaining ascorbic acid content in values similar to control. SCGDB and PM treatment did not affect any of the parameters tested. Overall, results showed that BDB and MDB applied as soil amendments may serve as means for enhancing the growth, and partially the nutritional value of lettuce plants.

The occurrence of 200 multiclass contaminants of emerging concern (CECs) encompassing 168 medicinal products and transformation products (TPs), 5 artificial sweeteners, 12 industrial chemicals, and 15 other compounds was investigated in influent and effluent wastewater samples collected during 7 consecutive days from 5 wastewater treatment plants (WWTPs) located in Cyprus. The methodology included a generic solid-phase extraction protocol using mixed-bed cartridges followed by Ultra-High Performance Liquid Chromatography coupled with Quadrupole-Time of Flight Mass Spectrometry (UHPLC-QTOF-MS) analysis. A total of 63 CECs were detected at least in one sample, with 52 and 55 out of the 200 compounds detected in influents and effluents, respectively. Ten (10) out of the 24 families of parent compounds and associated TPs were found in the wastewater samples (influent or effluent). 1-H-benzotriazole, carbamazepine, citalopram, lamotrigine, sucralose, tramadol, and venlafaxine (>80 % frequency of appearance in effluents) were assessed with respect to their bioavailability in soil as part of different scenarios of irrigation with reclaimed water following a qualitative approach. A high score of 12 (high probability) was predicted for 2 scenarios, a low score of 3 (rare occasions) for 2 scenarios, while the rest 28 scenarios had scores 5-8 (unlikely or limited possibility) and 9-11 (possibly). Retrospective screening was performed with the use of a target database of 2466 compounds and led to the detection of 158 additional compounds (medicinal products (65), medicinal products TPs (15), illicit drugs (7), illicit drugs TPs (3), industrial chemicals (11), plant protection products (25), plant protection products TPs (10), and various other compounds (22). This work aspires to showcase how the presence of CECs in wastewater could be investigated and assessed at WWTP level, including an expert-based methodology for assessing the soil bioavailability of CECs, with the aim to develop sustainable practices and enhance reclaimed water reuse.

This study investigated the effect of polyethylene and polyvinyl chloride microplastics on the UV fluence response curve for the inactivation of multidrug-resistant E. coli and enterococci in ultrapure water at pH 6.0 ± 0.1. In the absence of microplastics, the UV inactivation of the studied bacteria exhibited an initial resistance followed by a faster inactivation of free (dispersed) bacteria, while in the presence of microplastics, these 2 regimes were followed by an additional regime of slower or no inactivation related to microplastic-associated bacteria (i.e., bacteria aggregated with microplastics resulting in shielding bacteria from UV indicated by tailing at higher UV fluences). The magnitude of the negative effect of microplastics varied with different microplastics (type/particle size) and bacteria (Gram-negative and Gram-positive). Results showed that when the UV transmittance of the microplastic-containing water was not taken into account in calculating UV fluences, the effect of microplastics as protectors of bacteria was overestimated. A UV fluence-based double-exponential microbial inactivation model accounting for both free and microplastic-associated bacteria could describe well the disinfection data. The present study elucidated the effect of microplastics on the performance of UV disinfection, and the approach used herein to prove this concept may guide future research on the investigation of the possible effect of other particles including nanoplastics with different characteristics on the exposure response curve for the inactivation of various microorganisms by physical and chemical disinfection processes in different water and wastewater matrices.

Biochars produced from various organic waste feedstocks have lately been utilized as adsorbents for the decontamination of antibiotics-contaminated environmental matrices. The aims of the present study were a) the assessment of the adsorption capacity of three distinct derived biochars [biosolids (BDΒ), cattle manure (MDB) and spent coffee grounds (SCGDB)], applied either at a low (1 g L−1) or high (10 g L−1) dose on seven antibiotics (tetracycline, TET; erythromycin, ERY; clarithromycin, CLA; ampicillin, AMP; ofloxacin, OFL; sulfamethoxazole, SMX; trimethoprim, TMP) spiked as mixture in environmentally relevant concentration (100 μg L−1) of an aqueous solution (8.27 < pH < 10.48), and b) the understanding of the relative adsorption mechanisms. Batch sorption experiments showed that all biochars applied at the low dose efficiently removed more than 70%, reaching even 100%, of TET, ERY, CLA, whereas MDB also removed AMP. Biochars applied at the high dose (10 g L−1) exhibited enhanced adsorption capacity, resulting in the quick (within 5 min of incubation) and complete removal of TET, ERY, CLA, as well as increased removal (>85%) of AMP and TMP. However, the studied biochars failed to remove OFL and SMX. The adsorption results were best fitted to the Freundlich model with the sole exception of SMX. The main responsible mechanisms for the adsorption of antibiotics included surface complexation, H-bonding, π-π electron-donor-acceptor (EDA) interactions, pore-filling effects or the simultaneous occurrence of several of these mechanisms. Overall, the results highlighted the potential utilization of BDB, MDB and SCGDB for the decontamination of antibiotics-contaminated water bodies, while promoting the circular economy strategy.

An assessment comprising chemical, microbiological and (eco)toxicological parameters of antibiotic-related microcontaminants, during the application of UV-C/H2O2 oxidation in secondary-treated urban wastewater, is presented. The process was investigated at bench scale under different oxidant doses (0-50 mg L-1) with regard to its capacity to degrade a mixture of antibiotics (i.e. ampicillin, clarithromycin, erythromycin, ofloxacin, sulfamethoxazole, tetracycline and trimethoprim) with an initial individual concentration of 100 μg L-1. The process was optimized with respect to the oxidant dose. Under the optimum conditions, the inactivation of selected bacteria and antibiotic resistant bacteria (ARB) (i.e. faecal coliforms, Enterococcus spp., Pseudomonasaeruginosa and total heterotrophs), and the reduction of the abundance of selected antibiotic resistance genes (ARGs) (e.g. blaOXA, qnrS, sul1, tetM) were investigated. Also, phytotoxicity against three plant species, ecotoxicity against Daphnia magna, genotoxicity, oxidative stress and cytotoxicity were assessed. Apart from chemical actinometry, computational fluid dynamics (CFD) modelling was applied to estimate the fluence rate. For the given wastewater quality and photoreactor type used, 40 mg L-1 H2O2 were required for the complete degradation of the studied antibiotics after 18.9 J cm-2. Total bacteria and ARB inactivation was observed at UV doses <1.5 J cm-2 with no bacterial regrowth being observed after 24 h. The abundance of most ARGs was reduced at 16 J cm-2. The process produced a final effluent with lower phytotoxicity compared to the untreated wastewater. The toxicity against Daphnia magna was shown to increase during the chemical oxidation. Although genotoxicity and oxidative stress fluctuated during the treatment, the latter led to the removal of these effects. Overall, it was made apparent from the high UV fluence required, that the particular reactor although extensively used in similar studies, it does not utilize efficiently the incident radiation and thus, seems not to be suitable for this kind of studies.

In the framework of circular economy, the need of new feedstock materials for the production of alternative new products is of high priority. Biowastes such as manure, sewage sludge (biosolids, BS) and food-waste are used as raw materials for the production of biochar. The present study aims at characterizing biochars produced from three distinct biowastes (i) manure from cattle waste (manure-derived biochar; MDB), (ii) biosolids (BS) from a conventional Urban Wastewater Treatment Plant (UWTP) (biosolids-derived biochar; BDB), and (iii) spent coffee grounds (SCG)-derived biochar (SCGDB). Samples were slowly pyrolyzed in a small-scale kiln with a capacity of 20-24 kg. The samples were heated under nitrogen atmosphere at approximately 6-7 degrees Cmin(-1) up to the desired temperature (550 degrees C) and held for 1.5h. The physicochemical characterization of biochars showed the production of alkaline materials with similarities and variations in their characteristics, which depend to the type of feedstock used. The surface area of the raw materials was considerably low (<0.1 m(2)/g) and increased after pyrolysis to 14.03 m(2)/g, 3.98 m(2)/g and 1.53 m(2)/g for MDB, BDB and SCGDB, respectively. The high %C content, the low H/C ratio and the FTIR adsorption peaks revealed high aromaticity, polymerization and carbonization of the biochars and the presence of several functional groups. These, are some of the biochar properties which could lead to different sorption mechanisms of organic and inorganic contaminants. Also, they presented good stability in soil, which enables to be used as soil amendment and C sequestration mechanism. Finally, the produced biochars showed promising properties for environmental applications. (C) 2020 Energy Institute. Published by Elsevier Ltd. All rights reserved.

Antibiotic resistance (AR) is becoming a worldwide threat due to the increasing occurrence of antibiotic-resistant pathogenic bacterial strains. There is a general consensus about the potential implications of the use of antibiotics in livestock on the onset of antibiotic resistant bacteria (ARB), mainly through meat consumption. However, the ever-increasing use of reclaimed wastewater (RWW) in agriculture may also contribute significantly to the non-accounted exposure to antibiotics, ARB, and antibiotic resistance genes (ARGs). This position paper aims at evaluating the current knowledge concerning the occurrence of antibiotics, ARBs, and ARGs in edible parts of different common crops irrigated with RWW. We will discuss which regulations on the use of RWW may contribute to the minimization of the prevalence of these contaminants in crops, and provide recommendations on how to minimize the impact of these practices.

This work evaluated the removal of a mixture of antibiotics from urban wastewater, by a combined process consisting of solar photo-Fenton (SPF) followed by granular activated carbon (GAC). The effects of the SPF process were investigated at a toxicological, microbiological and genomic level, using species of plants and aquatic organisms, bacteria, antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs). The results demonstrated that SPF could completely degrade antibiotics present in two types of effluent deriving from a conventional activated sludge system (CAS) and a membrane bioreactor (MBR), operated at the optimum oxidant dose ([H2O2](CAS) = 100 mg/L; [H2O2](MBR) = 50 mg/L) and illumination time (t(CAS) = 115 min; t(MBR) = 111 min) at acidic pH (2.82.9). Moreover, total disinfection was achieved by the SPF process, as cultivable bacteria, including ARB, were inactivated after 60 min of treatment, disabling also the bacterial regrowth after 24 h of storage of the treated effluent. Furthermore, SPF was shown to be effective in degrading the cellular DNA of the effluent, which was reduced to the detection limit after 60 min of treatment in both effluents. The abundance of 16S rRNA was found to be preferentially decreased by the SPF in the MBR-treated effluent (8 folds) compared to the CAS-treated effluent (7.4 folds). The abundance of blaOXA, blaCTX-M, qnrS, sul1, and tetM genes was decreased to the limit of quantification after 60 min of SPF treatment in both effluents. However, the SPF treated flow resulted in increased toxicity, probably due to the oxidation of the dissolved effluent organic matter of the wastewater leading to the formation of toxic products. Therefore, SPF-treated samples collected at different time intervals (30, 60, 90, 120, and 180 min) were subjected to adsorption onto GAC (500 mg/L), and the removal of both the toxicity and the residual antibiotics remaining after SPF, was explored. The combined processes (30 min SPF; 15 min GAC) provided almost complete removal of toxicity and elimination of antibiotics, ensuring wastewater decontamination.

The reuse of treated wastewater (TWW) for irrigation and the use of biosolids and manures as soil amendment constitute significant pathways for the introduction of the contaminants of emerging concern (CECs) to the agricultural environment. Consequently, CECs are routinely detected in TWW-irrigated agricultural soils and runoff from such sites, in biosolids- and manure-amended soils, and in surface and groundwater systems and sediments receiving TWW. Crop plants grown in such contaminated agricultural environments have been found to uptake and accumulate CECs in their tissues, constituting possible vectors of introducing CECs into the food chain; an issue that is presently considered of high priority, thus needing intensive investigation. This review paper aims at highlighting the responsible mechanisms for the uptake of CECs by plants and the ability of each crop plant species to uptake and accumulate CECs in its edible tissues, thus providing tools for mitigating the introduction of these contaminants into the food chain. Both biotic (e.g. plants’ genotype and physiological state, soil fauna) and abiotic factors (e.g. soil pore water chemistry, physico-chemical properties of CECs, environmental perturbations) have been proven to influence the ability of crop plants to uptake and accumulate CECs. According to authors’ estimates, based on the thorough elaboration of knowledge produced by existing relevant studies, the ability of crop plants to uptake and accumulate CECs decrease in the order of leafy vegetables > root vegetables > cereals and fodder crops > fruit vegetables; though, the uptake of CECs by important crop plants, such as fruit trees, is not yet evaluated. Overall, further studies must be performed to estimate the potential of crop plants to uptake and accumulate CECs in their edible tissues, and to characterize the risk for human health represented by their presence in human and livestock food products.