Long-term effects on the agroecosystem of using reclaimed water on commercial crops

Impact of the wastewater treatment technology and storage on micropollutant profiles during reclaimed water irrigation: A wide-scope HRMS screening in a water-soil-lettuce-leachate system

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.

Analytical methodology for challenging persistent, mobile, and toxic substances in vegetal matrices after irrigation with contaminated water

Reusing wastewater for irrigation is proposed as a strategy to address water scarcity. However, the long-term environmental consequences of this practice are still unknown, especially when reclaimed water contains contaminants of emerging concern, such as persistent, mobile, and toxic (PMT) compounds, due to the inefficiency of wastewater treatment plants in removing certain pollutants. As a result, irrigation with contaminated water could lead to their uptake by crops and enter the food chain. While data on the presence of PMTs in environmental samples is starting to emerge, the analysis of certain compounds in vegetable matrices remains unexplored. In this study, an analytical methodology was developed and validated for the determination of 8 PMTs (i.e., benzophenone-3, clarithromycin, imazalil, metformin, sulpiride, terbutryn, tiapride, and tramadol) in escarole, tomatoes, and tomato leaves. The proposed analytical methodology used a QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) extraction method prior to mixed-mode liquid chromatography tandem mass spectrometry analysis. Method validation, performed according to SANTE guidelines, presented satisfactory results at studied concentrations (1, 10 and 100 ng·g-1 for each compound/matrix combination, except for metformin in escarole (50 and 500 ng·g-1). Recoveries ranged from 70 to 120 %, with a precision of ≤ 20 % for most compounds. Benzophenone-3 and tiapride, for which no isotopically labelled internal standard was available, could be adjusted by applying a correction factor. The limit of quantification was 1 ng·g-1 for all compounds in the three matrices, except for benzophenone-3 and metformin in both escarole and tomato leaves. The applicability of the method was tested by analysing samples from an experimental greenhouse plot where crops were irrigated with water spiked with the selected PMTs.

Co-contaminant risks in water reuse and biosolids application for agriculture

Agriculture made the shift toward resource reuse years ago, incorporating materials such as treated wastewater and biosolids. Since then, research has documented the widespread presence of contaminants of emerging concern in agricultural systems. Chemicals such as pesticides, pharmaceuticals and poly- and -perfluoroalkyl substances (PFASs); particulate matter such as nanomaterials and microplastics; and biological agents such as antibiotic resistance genes (ARGs) and bacteria (ARB) are inadvertently introduced into arable soils where they can be taken up by crops and introduced to the food-web. Thus, concern about the presence of contaminants in agricultural environments has grown in recent years with evidence emerging linking agricultural exposure and accumulation in crops to ecosystem and human health effects. Our current assessment of risk is siloed by working within disciplines (i.e., chemistry and microbiology) and mostly focused on individual chemical classes. By not acknowledging the fact that contaminants are mostly introduced as a mixture, with the potential for interactions, with each other and with environmental factors, we are limiting our current approach to evaluate the real potential for ecosystem and human health effects. By uniting expertise across disciplines to integrate recent understanding regarding the risks posed by a range of chemically diverse contaminants in resources destined for reuse, this review provides a holistic perspective on the current regulatory challenges to ensure safe and sustainable reuse of wastewater and biosolids to support a sanitation-agriculture circular economy.

Ecological risk assessment of emerging contaminants on soil and terrestrial ecosystems (2005-2024): a bibliometric and scientometric review

Growing awareness exists regarding the dangers posed by emerging contaminants (ECs) to terrestrial ecosystems and human health. This study reviewed ecological risk assessment studies on ECs, emphasizing their environmental presence, toxicological effects, behavior, and potential negative impacts on soil and terrestrial ecosystems. The work aims to identify key trends, research hotspots, and gaps to provide policy recommendations, inform regulatory frameworks, and suggest future research directions for the sustainable management of ECs in terrestrial environments. A systematic literature review was conducted using the Web of Science database, selecting studies from the past decade related to ECs, soil, terrestrial ecosystems, and ecological risk assessment. A total of 450 documents were analyzed using VOSviewer and CiteSpace to visualize key research patterns. Results indicate a 26.26% annual growth in publications, highlighting increasing scholarly interest. Citation analysis identifies China, the USA, and Italy as leading contributors, with Switzerland exhibiting the highest citation impact per article. Co-authorship network analysis reveals key researchers and collaboration clusters, though cross-group interactions remain limited. Institutional analysis underscores the dominance of the Chinese Academy of Sciences, with notable global partnerships from CSIC (Spain) and King Saud University. Journal analysis highlights Environmental Toxicology and Chemistry and Journal of Environmental Monitoring as highly influential sources. Temporal keyword trends indicate a shift toward ecological risk assessment and contaminant interactions. The study underscores the need for advanced monitoring techniques to manage ECs. Understanding broader ecological impacts, including ecosystem responses and bioaccumulation, is crucial for informed environmental management and policy-making. The findings have significant implications for environmental policy, management strategies, and mitigation measures to protect ecosystem and human health.

A framework to assess pharmaceutical accumulation in crops: from wastewater irrigation to consumption

The reuse of treated wastewater for irrigation can inadvertently introduce a suite of emerging contaminants such as pharmaceuticals into agri-ecosystems. However, current monitoring efforts to characterise exposure usually focus on a limited range of analytes. A modelling framework was developed that employs a sequence of pre-developed models to predict accumulative potential in a model crop, Zea mays (corn), using chemical structure and excretion rate as the only model inputs. Z. mays was selected as the model crop as it is a major food source, stands as one of the highest cultivated crops globally, and is characterised as having a medium uptake potential. The framework was used to predict uptake in Z. mays in three regions characteristic of high wastewater reuse (Australia, the US and the Middle East). Despite regional and plant specific differences, 72.7 % of the calculated concentrations were within a factor of ten of those reported in the literature. Topiramate, furosemide, and gemfibrozil were observed to accumulate to the greatest extent in Z. mays, predicted concentrations ranged between 50.27 and 418.01 ng/g (dw) for the top 10. Acids predominantly accumulated in leaves and fruit whereas a higher proportion of bases were predicted to accumulate in the roots. To the best of our knowledge 56.7 % of the 30 highest-ranked pharmaceuticals have not been previously documented in existing literature or monitoring campaigns. This presented framework demonstrates a method to assess risk posed by pharmaceutical compounds with limited experimental data.

Beta-adrenergic blockade via atenolol negatively affects body and heart mass and renal morphology in the developing chicken (Gallus Gallus Domesticus)

Atenolol is a widely prescribed β1-cardioselective blocker. We studied atenolol effects on cardiac and renal development in day 18 (D18) chicken embryos. Embryos were dosed with atenolol (3 μg atenolol/g estimated embryo mass) for three days during one of the mesonephric kidney stage (D7-D9), mesonephric-metanephric stage (D11-D13), or metanephric stage (D15-D17), and then sampled on D18. Wet embryo body mass in atenolol-treated groups was reduced at D18 (P < 0.01). Wet heart mass of atenolol-treated embryos was significantly (P < 0.01) reduced in the mesonephric stage on D18. Similarly, kidney mass in atenolol-treated mesonephric and metanephric stages was significantly reduced at D18. Nephron density was 40 % lower following atenolol treatment during the mesonephros stage. Individual glomerular areas of mesonephric- and metanephric-treated stages were significantly larger (P < 0.01) than controls, but overall glomerular area was reduced in the meso- and meso-metanephros populations. Collectively, these data suggest that chronic atenolol treatment results in major renal remodeling and that the mesonephros renal stage (D7-D9), is the critical window for effects of atenolol on renal morphology. Acute atenolol application at D11 through D19 had no effect on mean arterial blood pressure or heart rate, even though these variables were acutely altered as early as Day 15 by isoproterenol. Collectively, these data suggest that the morphological effects of atenolol were not the result of altered perfusion. Further experiments are required to determine if reduced embryo, cardiac and renal masses are specific to chronic atenolol treatment, or whether other β blockers might have similar effects.

Dynamic interaction of antibiotic resistance between plant microbiome and organic fertilizers: sources, dissemination, and health risks

Antibiotic resistance is a global health problem driven by the irrational use of antibiotics in different areas (such as agriculture, animal farming, and human healthcare). Sub-lethal concentrations of antibiotic residues impose selective pressure on environmental, plant-associated, and human microbiome leading to the emergence of antibiotic-resistant bacteria (ARB). This review summarizes all sources of antibiotic resistance in agricultural soils (including manure, sewage sludge, wastewater, hospitals/pharmaceutical industry, and bioinoculants). The factors (such as the physicochemical properties of soil, root exudates, concentration of antibiotic exposure, and heavy metals) that facilitate the transmission of resistance in plant microbiomes are discussed. Potential solutions for effective measures and control of antibiotic resistance in the environment are also hypothesized. Manure exhibits the highest antibiotics load, followed by hospital and municipal WW. Chlortetracycline, tetracycline, and sulfadiazine have the highest concentrations in the manure. Antibiotic resistance from organic fertilizers is transmitted to the plant microbiome via horizontal gene transfer (HGT). Plant microbiomes serve as transmission routes of ARB and ARGS to humans. The ingestion of ARB leads to human health risks (such as ineffectiveness of medication, increased morbidity, and mortality).

Modelling the impacts generated by reclaimed wastewater reuse in agriculture: From literature gaps to an integrated risk assessment in a One Health perspective

The reuse of reclaimed wastewater is increasingly recognized as a viable alternative water source for irrigation. Its application, whether direct or indirect, impacts several interconnected compartments, including groundwater, surface water, soil, crops, and humans. Reclaimed wastewater provides essential resources for crops, like water and nutrients. However, it also introduces pathogens, and contaminants of emerging concern (CECs), defined as chemicals that may pose risks to human health and ecosystems but are not yet fully regulated, such as pharmaceuticals and personal care products, among others. Additionally, reclaimed wastewater may contain antibiotic-resistant bacteria (ARBs) and disinfection by-products (DBPs), all of which present potential health and environmental risks. Therefore, regulatory bodies stress the need for preventive risk assessments to ensure safe reuse. This paper critically reviews available models for assessing the impacts of reclaimed wastewater reuse in agriculture. It identifies gaps in current modelling approaches and outlines future research directions. Key areas requiring further investigation include the fate and transfer of CECs, ARBs and DBPs, and the co-occurrence of multiple risks in such interconnected systems, especially in the indirect reuse. To address these gaps, we proposed a simplified approach to integrate three types of risk associated with CECs in indirect reuse, focusing on risks posed by antibiotics and other pharmaceuticals: human health risk, environmental risk and risk from antibiotic resistance development. This approach aids in identifying the most critical endpoints within the One Health approach, supporting (i) CECs prioritization in regulations based on their critical endpoints and (ii) the adoption of CEC-specific mitigation measures.

Analytical Methods for the Determination of Pharmaceuticals and Personal Care Products in Solid and Liquid Environmental Matrices: A Review

Among the various compounds regarded as emerging contaminants (ECs), pharmaceuticals and personal care products (PPCPs) are of particular concern. Their continuous release into the environment has a negative global impact on human life. This review summarizes the sources, occurrence, persistence, consequences of exposure, and toxicity of PPCPs, and evaluates the various analytical methods used in the identification and quantification of PPCPs in a variety of solid and liquid environmental matrices. The current techniques of choice for the analysis of PPCPs are state-of-the-art liquid chromatography coupled to mass spectrometry (LC-MS) or tandem mass spectrometry (LC-MS2). However, the complexity of the environmental matrices and the trace levels of micropollutants necessitate the use of advanced sample treatments before these instrumental analyses. Solid-phase extraction (SPE) with different sorbents is now the predominant method used for the extraction of PPCPs from environmental samples. This review also addresses the ongoing analytical method challenges, including sample clean-up and matrix effects, focusing on the occurrence, sample preparation, and analytical methods presently available for the determination of environmental residues of PPCPs. Continuous development of innovative analytical methods is essential for overcoming existing limitations and ensuring the consistency and diversity of analytical methods used in investigations of environmental multi-class compounds.

Qualitative and biochemical characteristics of pomegranate fruit grown using reclaimed water and low input fertigation treatments at harvest and during storage

In recent years, severe climate change leading to by water scarcity reduced water quality has increased the need for effective irrigation strategies for agricultural production. Among these, the reuse of reclaimed water represents a non-expensive and reliable solution. The effect of conventional or reclaimed water, applying convention or smart fertigation system, were investigated during two irrigation seasons on yield, qualitative and biochemical traits of pomegranates fruit (cv Wonderful One) at harvest, and after storage at 7 °C. The results of this study showed that using reclaimed waters with different fertigation systems did not affect the pH values, total soluble solids, and titratable acidity on pomegranates fruit showing slight decrease changes only during postharvest storage. On the other hand, the respiration rate was not affected by water quality. Furthermore, the antioxidant activity was also preserved during storage in pomegranates fruit from plants irrigated with reclaimed water by applying conventional or smart fertigation. The analysis also identified 52 compounds by UHPLC-MSn and HPLC-UV-Vis analyses. A slight decrease (about 17 %) at harvest and during storage in polyphenols content was shown in fruit grown using reclaimed water. The study demonstrates that using reclaimed water is a sustainable and effective way to limit the use of conventional water for irrigating pomegranate crops without significant reduction in yield, or in qualitative and nutritional values of the fruit at harvest and during storage.

Evaluation of chemical contamination of crops produced in greenhouse by irrigation with reclaimed water

Using reclaimed water for agricultural irrigation is increasing worldwide to compensate for water scarcity. The aim of this work was to evaluate the uptake of some of the most commonly detected organic contaminants of emerging concern (CECs) and pesticides in regenerated water in a field study. Furthermore, it was studied their distribution and accumulation in the different parts of a crop (soil, plant and fruit). Three crops (cucumber, pepper and melon) were grown under controlled agronomic conditions in a greenhouse. In order to make an accurate evaluation of the process, "regenerated blank water" was spiked with 70 chemicals (including antibiotics, anti-inflammatories, analgesics, anaesthetics, anxiolytics, anticonvulsants, pesticides) at environmental concentrations (∼1 μg/L) and used for continuous crop irrigation. After crop season, the average total concentration of contaminants detected in the soil samples ranged from 132 to 232 μg/kg d.w depending of the crops type. Between 7 and 10 different contaminants were found in the harvested fruits, up to levels of 27.8 μg/kg f.w. cucumber, 12.4 μg/kg f.w. melon and 7.8 μg/kg f.w pepper. In general, cucumber fruit showed higher accumulation levels of contaminants than pepper and melon for most target analytes. The accumulation rates followed the order: root (0.2 %) < stem/leaf (1-4 %) < fruit (1-6 %) < soil (17-30 %). The experimental data obtained in this study were also used to assess the risk associated with the reuse of reclaimed water for crop irrigation as well to identify those contaminants that, due to their physicochemical properties, show higher accumulation rates and environmental impact.

In five wastewater treatment plants in Xinjiang, China: Removal processes for illicit drugs, their occurrence in receiving river waters, and ecological risk assessment

Residues of illicit drugs are frequently detected in wastewater, but data on their removal efficiency by wastewater treatment plants (WWTPs) and the ecological risks to the aquatic environment are lacking in this study. The research evaluates the residues, mass load, drug removal efficiency, and risk assessment of illicit drugs in WWTPs and aquatic environments (lakes) in Xinjiang, China. Initially, the concentration (incidence) and mass load of 10 selected illicit drugs were analyzed through wastewater analysis. The detected substances included methamphetamine (METH), morphine (MOR), 3,4-methylenedioxy methamphetamine (MDMA), methadone (MTD), cocaine (COC), benzoylecgonine (BE), ketamine (KET), and codeine (COD), with concentrations ranging from 0.11 ± 0.01 ng/L (methadone) to 48.26 ± 25.05 ng/L (morphine). Notably, morphine (59.74 ± 5.82 g/day) and methamphetamine (41.81 ± 4.91 g/day) contributed significantly to the WWTPs. Next, the drug removal efficiency by different sewage treatment processes was ranked as follows: Anaerobic-Oxic (A/O) combined Membrane Bio-Reactor (MBR) treatment process > Oxidation ditch treatment process > Anaerobic-Anoxic-Oxic (A2/O) treatment process > Anaerobic-Anoxic-Oxic combined Membrane Bio-Reactor treatment process. Finally, the research reviewed the concentration and toxicity assessments of these substances in the aquatic environment (lakes). The results indicated that Lake1 presented a medium risk level concerning the impact of illicit drugs on the aquatic environment, whereas the other lakes exhibited a low risk level. As a result, it is recommended to conduct long-term monitoring and source analysis of illicit drugs, specifically in Lake1, for further investigation. In conclusion, to enhance the understanding of the effects of illicit drugs on the environment, future research should expand the list of target analytes.