Fate of contaminants of emerging concern in the reclaimed wastewater-soil-plant continuum

Circular water management in agriculture: Screening of contaminants of emerging concern in a real-world water-soil-crop system and human health risk assessment

Water reuse in agriculture supports climate resilience and circular economy principles, yet concerns remain regarding contaminants of emerging concern (CECs) in reclaimed water. This study investigates the occurrence, uptake, and potential risks of CECs in maize cultivated under two irrigation scenarios: precision drip irrigation using groundwater and reclaimed wastewater. A wide-scope target analysis of over 2200 CECs was performed in groundwater, raw and treated wastewater, irrigated soil, and maize plant tissues. A total of 104 CECs across nine chemical classes were detected in water samples, with wastewater treatment reducing 67 % of detected compounds. However, several pharmaceuticals and transformation products persisted post-treatment. Soil irrigated with treated wastewater exhibited a greater variety and higher concentrations of CECs than groundwater-irrigated soil. Maize plants accumulated 14 CECs in roots, stems, leaves, and corn, with higher concentrations in reclaimed water-irrigated crops. A human health risk assessment, based on the threshold of toxicological concern and hazard quotient approaches, indicated negligible risks at detected concentrations and expected dietary exposure levels. However, substances flagged for potential genotoxicity via in silico tools, such as acetaminophen and harmane, warrant further evaluation. These findings highlight the need for improved monitoring and targeted removal strategies to ensure safe and sustainable agricultural applications.

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.

EFSA Panel on Food Additives and Flavourings (FAF), Castle L, Andreassen M, Aquilina G, Bastos ML, Boon P, Fallico B, FitzGerald R, Frutos Fernandez MJ, Grasl‐Kraupp B, Gundert‐Remy U, Gürtler R, Houdeau E, Kurek M, Louro H, Morales P, Passamonti S, Batke M, Bruzell E, Chipman J, Cheyns K, Crebelli R, Fortes C, Fürst P, Halldorsson T, Leblanc J, Mirat M, Lindtner O, Mortensen A, Wright M, Barmaz S, Civitella C, Le Gall P, Mazzoli E, Rasinger JD, Rincon A, Tard A, Lodi F. Re-evaluation of acesulfame K (E 950) as food additive

The present opinion deals with the re-evaluation of acesulfame K (E 950) as a food additive. Acesulfame K (E 950) is the chemically manufactured compound 6-methyl-1,2,3-oxathiazin-4(3H)-one-2,2-dioxide potassium salt. It is authorised for use in the European Union (EU) in accordance with Regulation (EC) No 1333/2008. The assessment involved a comprehensive review of existing authorisations, evaluations and new scientific data. Acesulfame K (E 950) was found to be stable under various conditions; at pH lower than 3 with increasing temperatures, it is degraded to a certain amount. Based on the available data, no safety concerns arise for genotoxicity of acesulfame K (E 950) and its degradation products. For the potential impurities, based on in silico data, a concern for genotoxicity was identified for 5-chloro-acesulfame; a maximum limit of 0.1 mg/kg, or alternatively, a request for appropriate genotoxicity data was recommended. Based on the synthesis of systematically appraised evidence of human and animal studies, the Panel concluded that there are no new studies suitable for identification of a reference point (RP) on adverse effects. Consequently, the Panel established an acceptable daily intake (ADI) of 15 mg/kg body weight (bw) per day based on the highest dose tested without adverse effects in a chronic toxicity and carcinogenicity study in rats; a study considered of moderate risk of bias and one of two key studies from the previous evaluations by the Scientific Committee on Food (SCF) and the Joint FAO/WHO Expert Committee on Food Additives (JECFA). This revised ADI replaces the ADI of 9 mg/kg bw per day established by the SCF. The Panel noted that the highest estimate of exposure to acesulfame K (E 950) was generally below the ADI in all population groups. The Panel recommended the European Commission to consider the revision of the EU specifications of acesulfame K (E 950).

Real-time wastewater quality monitoring by fluorescence sensors: Validation for COD and CEC monitoring and implication for carbon footprint reduction

This study investigated the applicability of a protein-like fluorescence sensor for wastewater quality monitoring. Several wastewater matrices, including raw, primary, secondary and tertiary effluents from three different wastewater treatment plants were used. Furthermore, the sensor was tested for the monitoring of quaternary effluent in a pilot scale plant installed downstream of a water reuse facility. The pilot plant involved advanced oxidation processes (AOPs) and granular activated carbon (GAC) adsorption. Corrections on excitation/emission matrices (EEMs), including Inner Filter Effect (IFE) and scattering, showed no effect on linear correlation (R2=0.99) between sensor measurement and either raw or corrected benchtop protein-like fluorescence data, suggesting that for this application the signal from the sensor might be interpreted without the need for further adjustments. Furthermore, the use of quenched, diluted and filtered samples did not affect such correlations. Overall, the fluorescence sensor showed a very high capability to monitor a wide range of wastewater matrices, including raw, primary, secondary, tertiary, and quaternary effluents, providing fast information on the efficiency of the processes. The protein-like fluorescence monitoring by the real-time sensor was validated online through 9 days of 24-hour continuous monitoring of tertiary wastewater effluents. The employed fluorescence sensor was validated for monitoring the removal of contaminants of emerging concern (CEC), including a wide range of pharmaceuticals, in different AOP systems (ozone and UV based). In view of the results reported in this study, possible environmental implications for the reduction of the carbon footprint have emerged: the use of fluorescence sensors may contribute to the optimization of processes and the reduction of secondary pollution.

Differences in the accumulation of pentachloronitrobenzene and cadmium in vegetables grown in contaminated soils

The capability of different vegetable species to accumulate Pentachloronitrobenzene (PCNB) and cadmium (Cd) in soils varies significantly. Investigating these characteristics can guide the rational use of farmland contaminated with PCNB and Cd. The growth of five common vegetables (three vegetable species and three varieties of one species) in PCNB and Cd co-contaminated soils in Southwest China was investigated through a 100-day simulated contamination pot experiment. Interspecific and intervariety differences in the uptake and accumulation of PCNB and Cd were also examined. These vegetables included leafy types such as Lactuca sativa (CL), Lactuca sativa var. longifolia (RL), and Brassica rapa subsp. chinensis (BC), and root types such as Red Raphanus sativus (RR) and Lactuca sativa var. angustata (AL). Results showed that light to medium PCNB contamination (0.44-6.74 mg kg-1) promoted the growth of leafy vegetables, while severe contamination (9.88-9.96 mg kg-1) inhibited their growth. Root vegetables were inhibited by PCNB. Soil Cd contamination reduced the biomass of all five vegetables. In co-contamination soil (PCNB: 0.47-9.88 mg kg-1; Cd: 0.46-1.63 mg kg-1), vegetable growth was affected by the interaction between PCNB and Cd. In severely PCNB-contaminated soil, PCNB contents of CL, RL, BC, and AL leaves exceeded food safety limits, while those in RR and AL stems did not. The five vegetables showed varying Cd contamination, with AL leaves being the most contaminated, exceeding the standard by 60 times. PCNB accumulation followed the order: AL leaves > BC > AL stems > RL > CL > RR. Cd accumulation was highest in AL leaves, followed by stems, RR, BC, CL, and lowest in RL, with significant differences (P < 0.05). Co-contaminated soil did not promote PCNB and Cd uptake in vegetables. CL and RL, with low PCNB and Cd accumulation capacities, could be considered low-accumulation varieties for lightly contaminated soils.

Online control of UV and UV/H2O2 processes targeted for the removal of contaminants of emerging concern (CEC) by a fluorescence sensor

This study assessed the online and real-time monitoring of contaminants of emerging concern (CEC) using a microbial/tryptophan-like fluorescence sensor in a quaternary AOP (advanced oxidation process) pilot plant installed downstream of a tertiary municipal wastewater treatment plant (WWTP). Real-time fluorescence measurements were validated with lab-scale tryptophan-like fluorescence. Changes in water quality induced by different UV or UV/H2O2 doses were detected by the fluorescence sensor allowing real-time control of processes. The removal of CEC was discussed considering their photo-susceptibility and reactivity with •OH and then classified into three groups based on their reactivity and removal efficiency (RE). Linear models of CEC removal developed using real-time fluorescence removal as a surrogate parameter resulted very accurate (overall R2≥0.90) for most of CEC. Furthermore, real-time fluorescence data were successfully used to predict i) pseudo-observed first-order degradation rate constants of CEC (R2=0.99), and ii) UV doses during both UV and UV/H2O2 processes (R2>0.90). The findings of this study demonstrated that fluorescence sensors can be employed in operational relevant environment to monitor a broad range of CEC and control UV doses during UV-AOPs. Therefore, the implementation of fluorescence sensors is expected for optimizing costs, energy consumption and efficiency of quaternary wastewater treatments.

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.

Regional Water and Food Security Require Joint Israeli-Palestinian Guidelines for Wastewater Reuse and Food Safety

BACKGROUND

Water and food security in Israel and the Palestinian Authority are deeply interconnected due to the region's arid climate and water scarcity, shared water resources, and interrelated agricultural sectors. Therefore, jointly addressing water reuse is vital to supporting sustainable agricultural production and ensuring food safety.

OBJECTIVES

This paper examines the food safety implications of the cross-border trade of fresh fruits and vegetables between the Palestinian Authority and Israel, with an emphasis on the influence of, water technologies, agricultural practices, and environmental health.

METHODS

This paper provides a comprehensive review of existing data to assess water irrigation quality, food safety, and water reuse regulations in the Palestinian Authority and Israel.

RESULTS

Significant discrepancies in food safety, food quality, and exposure to contaminants from fresh produce result from different water reuse regulations, practices, and socioeconomic conditions. Given the volume of trade, consumer mobility, and environmental sustainability, coupled with geopolitical limitations between the Palestinian Authority and Israel, there is an urgent need for a unified regulatory strategy for wastewater reuse ensuring food safety and security. We propose a single, coordinated approach to overseeing wastewater reuse to enhance public health and address contaminants of emerging concern that are not currently regulated. Navigating the political and legislative complexities in a proactive stance requires both Israeli and Palestinian decision-makers to address the matter conscientiously. Existing data and the precautionary principle are sufficient to propose an interim prohibition on treated wastewater irrigation for leafy vegetables to mitigate pollution risks and act as a catalyst for improving irrigation water quality.

CONCLUSIONS

Our proposed strategy for a unified water reuse regulation emphasizes the necessary steps for its implementation and addresses potential obstacles. This strategy underscores the importance of responsible wastewater management in advancing common goals of environmental sustainability, food safety, and human health.

SHORT SYNOPSIS

We propose a coordinated Israeli-Palestinian approach to wastewater reuse to ensure food safety based on shared environmental and health concerns, economic considerations, and the precautionary principle.

A Call for Joint Israeli-Palestinian Guidelines for Water Recycling to Improve Food Security and Safety.

Assessing Lettuce Exposure to a Multi-Pharmaceutical Mixture in Soil: Insights from LC-ESI-TQ Analysis and the Impact of Biochar on Pharmaceutical Bioavailability

Agricultural practices introduce pharmaceutical (PhAC) residues into the terrestrial environment, potentially endangering agricultural crops and human health. This study aimed to evaluate various aspects related to the presence of pharmaceuticals in the lettuce-soil system, including bioconcentration factors (BCFs), translocation factors (TFs), ecotoxicological effects, the influence of biochar on the PhAC bioavailability, persistence in soil, and associated environmental and health risks. Lettuce (Lactuca sativa L.) was exposed to a mixture of 25 PhACs in two scenarios: initially contaminated soil (ranging from 0 to 10,000 ng·g-1) and soil irrigated with contaminated water (ranging from 0 to 1000 μg·L-1) over a 28-day period. The findings revealed a diverse range of BCFs (0.068-3.7) and TFs (0.032-0.58), indicating the uptake and translocation potential of pharmaceuticals by lettuce. Significant ecotoxicological effects on L. sativa, including weight change and increased mortality, were observed (p < 0.05). Interestingly, biochar did not significantly affect PhAC uptake by L. sativa (p > 0.05), while it significantly influenced the soil degradation kinetics of 12 PhACs (p < 0.05). Additionally, the estimated daily intake of PhACs through the consumption of L. sativa suggested negligible health risks, although concerns arose regarding the potential health risks if other vegetable sources were similarly contaminated with trace residues. Furthermore, this study evaluated the environmental risk associated with the emergence of antimicrobial resistance (AMR) in soil, as medium to high. In conclusion, these findings highlight the multifaceted challenges posed by pharmaceutical contamination in agricultural environments and emphasize the importance of proactive measures to mitigate the associated risks to both environmental and human health.

Farmland's silent threat: Comprehensive multimedia assessment of micropollutants through non-targeted screening and targeted analysis in agricultural systems

Intricate agricultural ecosystems markedly influence the dynamics of organic micropollutants, posing substantial threats to aquatic organisms and human health. This study examined the occurrence and distribution of organic micropollutants across soils, ditch sediment, and water within highly intensified farming setups. Using a non-targeted screening method, we identified 405 micropollutants across 10 sampling sites, which mainly included pesticides, pharmaceuticals, industrial chemicals, and personal care products. This inventory comprised emerging contaminants, banned pesticides, and controlled pharmaceuticals that had eluded detection via conventional monitoring. Targeted analysis showed concentrations of 3.99-1021 ng/g in soils, 4.67-2488 ng/g in sediment, and 12.5-9373 ng/L in water, respectively, for Σ40pesticides, Σ8pharmaceuticals, and Σ3industrial chemicals, indicating notable spatial variability. Soil organic carbon content and wastewater discharge were likely responsible for their spatial distribution. Principal component analysis and correlation analysis revealed a potential transfer of micropollutants across the three media. Particularly, a heightened correlation was decerned between soil and sediment micropollutant levels, highlighting the role of sorption processes. Risk quotients surpassed the threshold of 1 for 13-23 micropollutants across the three media, indicating high environmental risks. This study highlights the importance of employing non-targeted and targeted screening in assessing and managing environmental risks associated with micropollutants.

Identifying organic micropollutants' transformation products from the soil dissipation experiment by non-targeted high-resolution mass spectrometry approach: Can we gain more than transformation product identity?

Risk assessment of environmental hazards originating from xenobiotics extensively used worldwide (e.g., pharmaceuticals, bisphenols, or preservatives) requires a combined study of their effects, mobility, dissipation mechanisms, and subsequent transformation product identification and evaluation. We have developed an efficient accelerated solvent extraction method for a broad range of micropollutants of variable physical-chemical properties in soils to enable more accurate hazard characterisation. Micropollutant recoveries from freeze-dried soils were 60-120%, with the exception of atorvastatin, fexofenadine, and telmisartan, which had reduced recoveries (40-66%). The observed matrix effect ranged from -26% to 17% and was corrected by the matrix matching standard for quantitative analysis. The method allows sensitive and reliable determination of a wide range of analytes in soil samples and, consequently, qualitative analysis of transformation products (TP) with variable physicochemical properties. We identified TPs of five compounds (venlafaxine, telmisartan, valsartan, atorvastatin, and sertraline) by applying suspect and non-targeted data analyses. To our knowledge, the transformation product of atorvastatin was reported for the first time. All others were found in soil or other matrices. Valsartan (formed valsartan acid) and atorvastatin (transformed probably by oxidative decarboxylation of beta, delta dihydroxy heptanoic acid chain to propionic acid) were modified to a relatively large extent. All other compounds identified were only hydroxylated (sertraline and telmisartan) or demethylated (venlafaxine). We estimated the stability and presence of the identified TPs based on the constructed time trends and the ratio between TP formation and degradation rates. We demonstrated how valuable a non-targeted approach can be for complex evaluation of the fate and effect of soil pollutants.

Uptake and translocation of pharmaceutically active compounds by olive tree (Olea europaea L.) irrigated with treated municipal wastewater

Introduction

The use of treated municipal wastewater (TWW) represents a relevant opportunity for irrigation of agricultural crops in semi-arid regions to counter the increasing water scarcity. Pharmaceutically active compounds (PhACs) are often detected in treated wastewater, posing a risk to humans and the environment. PhACs can accumulate in soils and translocate into different plant tissues, reaching, in some cases, edible organs and entering the food chain.

Methods

This study evaluated the uptake and translocation processes of 10 PhACs by olive trees irrigated with TWW, investigating their accumulation in different plant organs. The experiment was conducted in southern Italy, in 2-year-old plants irrigated with three different types of water: freshwater (FW), TWW spiked with 10 PhACs at a concentration of 200 µg L-1 (1× TWW), and at a triple dose (3× TWW), from July to October 2021. The concentration of PhACs in soil and plant organs was assessed, collecting samples of root, stem, shoot, leaf, fruit, and kernel at 0 (T0), 50 (T1), and 107 (T2) days of irrigation. PhACs extraction from soil and plant organs was carried out using the QuEChERS method, and their concentrations were determined by high-resolution mass spectrometry coupled with liquid chromatography.

Results

Results of uptake factors (UF) showed a different behavior between compounds according to their physicochemical properties, highlighting PhACs accumulation and translocation in different plant organs (also edible part) in 1× TWW and 3× TWW compared to FW. Two PhACs, carbamazepine and fluconazole, showed interactions with the soil-plant system, translocating also in the aerial part of the plant, with a translocation factor (TF) greater than 1, which indicates high root-to-leaf translocation.

Discussion

Findings highlight that only few PhACs among the selected compounds can be uptaken by woody plants and accumulated in edible parts at low concentration. No effects of PhACs exposure on plant growth have been detected. Despite the attention to be paid to the few compounds that translocate into edible organs, these results are promising for adapting wastewater irrigation in crops. Increasing knowledge about PhACs behavior in woody plants can be important for developing optimized wastewater irrigation and soil management strategies to reduce PhACs accumulation and translocation in plants.

Metformin and lamotrigine sorption on a digestate amended soil in presence of trace metal contamination

The antidiabetic drug metformin and antiepileptic drug lamotrigine are contaminants of emerging concern that have been detected in biowaste-derived amendments and in the environment, and their fate must be carefully studied. This work aimed to evaluate their sorption behaviour on soil upon digestate application. Experiments were conducted on soil and digestate-amended soil as a function of time to study kinetic processes, and at equilibrium also regarding the influence of trace metals (Pb, Ni, Cr, Co, Cu, Zn) at ratio pharmaceutical/metal 1/1, 1/10, and 1/100. Pharmaceutical desorption experiments were also conducted to assess their potential mobility to groundwater. Results revealed that digestate amendment increased metformin and lamotrigine adsorbed amounts by 210% and 240%, respectively, increasing organic matter content. Metformin adsorption kinetics were best described by Langmuir model and those of lamotrigine by Elovich and intraparticle diffusion models. Trace metals did not significantly affect the adsorption of metformin in amended soil while significantly decreased that of lamotrigine by 12-39%, with exception for Cu2+ that increased both pharmaceuticals adsorbed amounts by 5 - 8%. This study highlighted the influence of digestate amendment on pharmaceutical adsorption and fate in soil, which must be considered in the circular economy scenario of waste-to-resource.

Selection of pharmaceuticals of concern in reclaimed water for crop irrigation in the Mediterranean area

The reuse of reclaimed water in agriculture is being fostered in areas suffering from water scarcity. However, water pollutants can compromise food safety and pose a risk for the environment. This study aims to select the pharmaceutical compounds worth monitoring and investigating when reclaimed water is used for tomato and lettuce irrigation. A comprehensive study was first conducted to identify the pharmaceuticals frequently detected in secondary wastewater effluents in Catalonia (Northeast Spain). Priority pharmaceuticals were further selected based on their occurrence in secondary effluents, persistence (removal in conventional treatment), bioaccumulation potential, toxicity for aquatic organisms, and the risks they pose to the terrestrial environment and human health (through the consumption of crops). Out of the 47 preselected priority compounds, six could pose a risk to organisms living in soil irrigated with reclaimed water and seven could be potentially taken up by the crops. Nonetheless, no risk for human consumption was foreseen.

Evaluation of different QuEChERS-based methods for the extraction of 48 wastewater-derived organic contaminants from soil and lettuce root using high-resolution LC-QTOF with MRMHR and SWATH acquisition modes

The reuse of treated wastewater in agriculture is an important route of introducing a large number of organic contaminants into the agroecosystem. In this study, a modified QuEChERS-based approach was developed for rapid, simple, and simultaneous extraction of 48 organic wastewater-derived contaminants from soil and lettuce root. Twenty-two different (modification) scenarios of the known (or original) QuEChERS method have been tested, in order to obtain best and well-compromised recoveries for all target compounds for soil and roots. Finally, a common method was chosen for both matrices consisting of a single extraction step using EDTA-Mcllvaine buffer and the unbuffered Original QuEChERS salts. Method performance was accomplished by liquid chromatography coupled with high-resolution mass spectrometry on a QToF-MS system using two different acquisition modes, the ultra-fast high-resolution multiple reaction monitoring (MRMHR) mode and the innovative Sequential Window Acquisition of All Theoretical Fragment-Ion (SWATH) mode. Performance characterization was evaluated in terms of recovery, linearity, intra-day precision, method detection limits (MDLs), method quantification limits (MQLs), and matrix effect (ME). Recoveries in MRMHR mode ranged from 63 to 111% and 54 to 104% for lettuce root and soil, respectively, for most of compounds in MRMHR mode and from 56 to 121% and 54 to 104% for lettuce root and soil, respectively, for most of compounds in SWATH. Whereas, MQLs ranged from 0.03 to 0.92 ng g-1 in MRMHR and from 0.03 to 82 ng g-1 in SWATH for lettuce root, and from 0.02 to 0.44 ng g-1 in MRMHR and 0.02 to 0.14 ng g-1 in SWATH for soil. The method was then applied to follow the target compounds in soil and lettuce root, where the system lettuce-soil was irrigated with treated wastewater under real greenhouse conditions. Five and 17 compounds were detected in lettuce root and soil, respectively.

Factors influencing the fate of chemical food safety hazards in the terrestrial circular primary food production system-A comprehensive review

Food safety is recognized as a major hurdle in the transition toward circular food production systems due to the potential reintroduction and accumulation of chemical contaminants in these food systems. Effectively managing these hazardous contaminants in a risk-based manner requires quantitative insights into the factors influencing the presence and fate of contaminants in the entire circular food chain. A systematic literature review was performed to gain an up-to-date overview of the known factors and their influence on the transfer and accumulation of contaminants. This review focused on the terrestrial circular primary food production system, including the pathways between waste- or byproduct-based fertilizers, soil, crops, animal feed, and farmed animals. This review revealed an imbalance in research regarding the different pathways: studies on the soil-to-crop pathway were most abundant. The factors identified can be categorized as compound-related (intrinsic) factors, such as hydrophobicity, molecular weight, and chain length, and extrinsic factors, such as soil organic matter and carbon, pH, milk yield of cows, crop age, and biomass. Quantitative data on the influence of the identified factors were limited. Most studies quantified the influence of individual factors, whereas only a few studies quantified the combined effect of multiple factors. By providing a holistic insight into the influential factors and the quantification of their influence on the fate of contaminants, this review contributes to the improvement of food safety management for chemical hazards when transitioning to a circular food system.

Contamination of water, soil, and plants by micropollutants from reclaimed wastewater and sludge from a wastewater treatment plant

Several studies have shown that plants can absorb various micropollutants. The behavior of micropollutants from wastewater treatment plant resources was comprehensively investigated in raised beds in which either a mixture of vegetables or maize was grown. The beds were either irrigated with treated wastewater or enriched with sewage sludge or composted sewage sludge. Over the year, samples of wastewater, water drained from the beds, soils and plants were analyzed. Of the seventy-five analyzed substances, fifty-four, thirty-three and twenty-seven were quantified in wastewater, sewage sludge, and composted sludge, respectively. Alarmingly, approximately 20 % of the compounds from wastewater were also detected in the solutions leached from the beds irrigated with wastewater (e.g., gabapentin, tramadol, sertraline, carbamazepine, its metabolites, and benzotriazoles). In addition, a gradual increase in the content of four substances (telmisartan, venlafaxine, carbamazepine, citalopram) was recorded in these beds. The compounds from both biosolids used for soil enrichment tended to remain in the soils (e.g., telmisartan, venlafaxine, sertraline, its metabolite, citalopram, and its metabolite). Only four compounds (sertraline and three benzotriazoles) leached from these beds. Uptake of some chemicals (e.g., gabapentin, tramadol, carbamazepine and its metabolite, and venlafaxine and its metabolite) and their accumulation in plant tissues was observed mainly in vegetables grown on beds irrigated with wastewater. However, daily consumption values for edible plant parts and individual compounds did not indicate a direct threat to human health. Results of this innovative study show possible risks associated with the use of these resources in agriculture. Of particular concern is the possible micropollutants percolation towards groundwater, including those for which high sorption and thus low mobility in the soil environment is expected, such as sertraline. Soil and crop contamination cannot be neglected either.

Pharmacokinetics of the Recalcitrant Drug Lamotrigine: Identification and Distribution of Metabolites in Cucumber Plants

Treated wastewater is an important source of water for irrigation. As a result, irrigated crops are chronically exposed to wastewater-derived pharmaceuticals, such as the anticonvulsant drug lamotrigine. Lamotrigine is known to be taken up by plants, but its plant-derived metabolites and their distribution in different plant organs are unknown. This study aimed to detect and identify metabolites of lamotrigine in cucumber plants grown for 35 days in a hydroponic solution by using LC-MS/MS (Orbitrap) analysis. Our data showed that 96% of the lamotrigine taken up was metabolized. Sixteen metabolites possessing a lamotrigine core structure were detected. Reference standards confirmed two; five were tentatively identified, and nine molecular formulas were assigned. The data suggest that lamotrigine is metabolized via N-carbamylation, N-glucosidation, N-alkylation, N-formylation, N-oxidation, and amidine hydrolysis. The metabolites LTG-N2-oxide, M284, M312, and M370 were most likely produced in the roots and were translocated to the leaves. Metabolites M272, M312, M314, M354, M368, M370, and M418 were dominant in leaves. Only a few metabolites were detected in the fruits. With an increasing exposure time, lamotrigine leaf concentrations decreased because of continuous metabolism. Our data showed that the metabolism of lamotrigine in a plant is fast and that a majority of metabolites are concentrated in the roots and leaves.

Mitigating risks and maximizing sustainability of treated wastewater reuse for irrigation

Scarcity of freshwater for agriculture has led to increased utilization of treated wastewater (TWW), establishing it as a significant and reliable source of irrigation water. However, years of research indicate that if not managed adequately, TWW may deleteriously affect soil functioning and plant productivity, and pose a hazard to human and environmental health. This review leverages the experience of researchers, stakeholders, and policymakers from Israel, the United-States, and Europe to present a holistic, multidisciplinary perspective on maximizing the benefits from municipal TWW use for irrigation. We specifically draw on the extensive knowledge gained in Israel, a world leader in agricultural TWW implementation. The first two sections of the work set the foundation for understanding current challenges involved with the use of TWW, detailing known and emerging agronomic and environmental issues (such as salinity and phytotoxicity) and public health risks (such as contaminants of emerging concern and pathogens). The work then presents solutions to address these challenges, including technological and agronomic management-based solutions as well as source control policies. The concluding section presents suggestions for the path forward, emphasizing the importance of improving links between research and policy, and better outreach to the public and agricultural practitioners. We use this platform as a call for action, to form a global harmonized data system that will centralize scientific findings on agronomic, environmental and public health effects of TWW irrigation. Insights from such global collaboration will help to mitigate risks, and facilitate more sustainable use of TWW for food production in the future.

Quantitative and qualitative approaches for CEC prioritization when reusing reclaimed water for irrigation needs - A critical review

The use of reclaimed water for irrigation is an option that is becoming increasingly widespread to alleviate water scarcity and to cope with drought. However, reclaimed water, if used for irrigation, may introduce Contaminants of Emerging Concern (CECs) into the agroecosystems, which may be taken up by the crops and subsequently enter the food chain. The number of CECs is steadily increasing due to their continuous introduction on the market for different uses. There is an urgent need to draw up a short list of potential high priority CECs, which are substances that could be taken up by plants and accumulated in food produce, and/or that could have negative effects on human health and the environment. This review presents and discusses the approaches developed to prioritize CECs when reclaimed water is (re-)used for irrigation. They are divided into quantitative methodologies, which estimate the risk for environmental compartments (soil and water), predators and humans through equations, and qualitative methodologies, which are instead conceptual frameworks or procedures based on the simultaneous combination of data/information/practices with the judgment of experts. Three antibiotics (erythromycin, sulfamethoxazole and ciprofloxacin), one estrogen (17-α ethinylestradiol) and one analgesic (ibuprofen) were found on at least two priority lists, although comparison among studies is still difficult. The review remarks that it is advisable to harmonize the different methodologies in order to identify the priority CECs to include in monitoring programs in reclaimed water reuse projects and to ensure a high level of protection for humans and the environment.

Factors driving PPCPs uptake by crops after wastewater irrigation and human health implications

Currently, water scarcity affects more than three billion people. Nevertheless, the volume of treated wastewater discharged into the environment is estimated to exceed 100 m3 per inhabitant/year. These water resources are regularly used in agriculture worldwide to overcome water shortages. Such a practice, however, entails the uptake of waterborne pollutants, such as pharmaceuticals and personal care products (PPCPs), by crops and their further access to the food web, constituting an additional route of human exposure to PPCPs, with potential health outcomes. In this study, the occurrence of 56 PPCPs in tomatoes, lettuce, and carrot, together with soil and irrigation water, was evaluated using a QuEChERS-based methodology for extraction and LC-MS/MS for analysis. The influence of the selected cultivation conditions on the plant uptake levels of PPCPs was assessed. Two irrigation water qualities (secondary and tertiary treatment effluents), two soil compositions (sandy and clayey), two irrigation systems (dripping and sprinkling), and three crop types (lettuce, tomato, and carrot) were tested. Carrots showed the highest load of PPCPs (7787 ng/g dw), followed by tomatoes (1692 ng/g dw) and lettuces (1248 ng/g dw). The most translocated PPCPs were norfluoxetine (fluoxetine antidepressant main metabolite) (521 ng/g dw), and the anti-inflammatory diclofenac (360 ng/g dw). Nine PPCPs, are reported to be accumulated in crops for the first time. Water quality was the most important factor for reducing PPCPs' plant uptake. Overall, the best conditions for reducing PPCP uptake by crops were irrigation with reclaimed water by sprinkling in soils with higher clay content. The risk assessment performed revealed that the crops' consumption posed no risk to human health. This study serves as the first comprehensive assessment of the relevance of diverse cultivation factors on PPCPs' plant uptake under field agricultural practices.

Prioritization of organic contaminants in a reclaimed water irrigation system using wide-scope LC-HRMS screening

A prioritization procedure was developed and implemented at the local level to identify the most relevant organic contaminants of emerging concern (CECs) in an agricultural area irrigated with reclaimed water. A wide-scope screening methodology based on UPLC-HRMS analysis was applied to holistically characterize the CEC footprint in water and its spatial and temporal variations. One hundred and fifty-eight CECs, including pharmaceuticals, industrial chemicals, and pesticides, among others, were identified with a confidence level of 2 in the water samples investigated. After water treatment in the reclamation plant and transport within the irrigation channel network, more than a hundred compounds were still detected at the location where water is abstracted for crop irrigation. Compound ecotoxicity and occurrence (semi-quantified concentrations or peak intensity) were the parameters used to prioritize CECs in the water used for irrigation. Results pointed at venlafaxine, O-desmethyl-venlafaxine, galaxolidone, theophylline/paraxanthine, oxybenzone, and N-phenyl-1-naphtylamine, among others, as CECs of concern in the investigated area. This study provides a simple and cost-effective approach to detecting site-specific priority pollutants that could otherwise be overlooked by national or European regulations. The prioritization tool provided contributes to rationally designing monitoring and attenuation programs and efficiently managing water resources, by ensuring the safety of reclaimed water applications.

Dissipation of twelve organic micropollutants in three different soils: Effect of soil characteristics and microbial composition

The dissipation kinetics and half-lives of selected organic micropollutants, including pharmaceuticals and others, were systematically investigated and compared among different soil types. While some pollutants (e.g., atorvastatin, valsartan, and bisphenol S) disappeared rapidly in all the tested soils, many of them (e.g., telmisartan, memantine, venlafaxine, and azithromycin) remained persistent. Irrespective of the soil characteristics, venlafaxine showed the lowest dissipation kinetics and the longest half-lives (250 to approximately 500 days) among the stable compounds. The highest first and second-order kinetics were, however, recorded for valsartan (k1; 0.262 day-1) and atorvastatin (k2; 33.8 g μg-1 day-1) respectively. Nevertheless, more than 90% (i.e., DT90) of all the rapidly dissipated compounds (i.e., atorvastatin, bisphenol S, and valsartan) disappeared from the tested soils within a short timescale (i.e., 5-36 days). Dissipation of pollutants that are more susceptible to microbial degradation (e.g., atorvastatin, bisphenol S, and valsartan) seems to be slower for soils possessing the lowest microbial biomass C (Cmic) and total phospholipid fatty acids (PLFAtotal), which also found statistically significant. Our results revealing the persistence of several organic pollutants in agricultural soils, which might impact the quality of these soils, the groundwater, and eventually on the related biota, is of high environmental significance.

ECHIDNA (Emerging CHemIcals Database for National Awareness): a framework to prioritise contaminants of emerging concern in water

The widespread presence of contaminants of emerging concern (CEC) in surface waters, treated wastewater and drinking water is an ongoing issue for the water industry. The absence of regulatory guidance and limited occurrence, toxicity and removal data are defining criteria of CEC and make it difficult to prioritise which CEC pose the greatest risk. The online Emerging CHemIcals Database for National Awareness (ECHIDNA) aims to classify and prioritise CEC based on their potential risk, with the information presented in an easily accessible and intuitive manner. A candidate list of almost 1,800 potential CEC, including pesticides, pharmaceuticals and industrial compounds, was compiled using both Australian and international resources. These were ranked based on in silico assessment of their persistent, bioaccumulative and toxic (PBT) properties, as well as potential chronic toxicity hazard, yielding 247 CEC for further prioritisation. Risk Quotients (RQ) identified between 5 and 87 CEC posing a risk to human and ecosystem health, respectively, across drinking water, surface water, treated wastewater and raw wastewater. While the ability of the water industry to effectively prioritise CEC is limited by candidate identification and data availability, ECHIDNA can provide valuable information for better decision-making surrounding CEC management.

Uptake and accumulation of emerging contaminants in processing tomato irrigated with tertiary treated wastewater effluent: a pilot-scale study

The reuse of treated wastewater for crop irrigation is vital in water-scarce semi-arid regions. However, concerns arise regarding emerging contaminants (ECs) that persist in treated wastewater and may accumulate in irrigated crops, potentially entering the food chain and the environment. This pilot-scale study conducted in southern Italy focused on tomato plants (Solanum lycopersicum L. cv Taylor F1) irrigated with treated wastewater to investigate EC uptake, accumulation, and translocation processes. The experiment spanned from June to September 2021 and involved three irrigation strategies: conventional water (FW), treated wastewater spiked with 10 target contaminants at the European average dose (TWWx1), and tertiary WWTP effluent spiked with the target contaminants at a triple dose (TWWx3). The results showed distinct behavior and distribution of ECs between the TWWx1 and TWWx3 strategies. In the TWWx3 strategy, clarithromycin, carbamazepine, metoprolol, fluconazole, and climbazole exhibited interactions with the soil-plant system, with varying degradation rates, soil accumulation rates, and plant accumulation rates. In contrast, naproxen, ketoprofen, diclofenac, sulfamethoxazole, and trimethoprim showed degradation. These findings imply that some ECs may be actively taken up by plants, potentially introducing them into the food chain and raising concerns for humans and the environment.

Selection of indicator contaminants of emerging concern when reusing reclaimed water for irrigation - A proposed methodology

Organic and microbial contaminants of emerging concern (CECs), even though not yet regulated, are of great concern in reclaimed water reuse projects. Due to the large number of CECs and their different characteristics, it is useful to include only a limited number of them in monitoring programs. The selection of the most representative CECs is still a current and open question. This study presents a new methodology for this scope, in particular for the evaluation of the performance of a polishing treatment and the assessment of the risk for the environment and the irrigated crops. As to organic CECs, the methodology is based on four criteria (occurrence, persistence, bioaccumulation and toxicity) expressed in terms of surrogates (respectively, concentrations in the secondary effluent, removal achieved in conventional activated sludge systems, Log K_ow and predicted-no-effect concentration). It consists of: (i) development of a dataset including the CECs found in the secondary effluent, together with the corresponding values of surrogates found in the literature or by in-field investigations; (ii) normalization step with the assignment of a score between 1 (low environmental impact) and 5 (high environmental impact) to the different criteria based on threshold values set according to the literature and experts' judgement; (iii) CEC ranking according to their final score obtained as the sum of the specific scores; and (iv) selection of the representative CECs for the different needs. Regarding microbial CECs, the selection is based on their occurrence and their highest detection frequency in the secondary effluent and in the receiving water, the antibiotic consumption patterns, and recommendations by national and international organisations. The methodology was applied within the ongoing reuse project SERPIC resulting in a list of 30 indicator CECs, including amoxicillin, bisphenol A, ciprofloxacin, diclofenac, erythromycin, ibuprofen, iopromide, perfluorooctane sulfonate (PFOS), sulfamethoxazole, tetracycline, Escherichia coli, faecal coliform, 16S rRNA, sul1, and sul2.

Contaminant uptake in wastewater irrigated tomatoes

As population growth and climate change add to the problem of water scarcity in many regions, the argument for using treated wastewater for irrigation is becoming increasingly compelling, which makes understanding the risks associated with the uptake of harmful chemicals by crops crucial. In this study, the uptake of 14 chemicals of emerging concern (CECs) and 27 potentially toxic elements (PTEs) was studied in tomatoes grown in soil-less (hydroponically) and soil (lysimeters) media irrigated with potable and treated wastewater using LC-MS/MS and ICP-MS. Bisphenol S, 2,4 bisphenol F, and naproxen were detected in fruits irrigated with spiked potable water and wastewater under both conditions, with BPS having the highest concentration (0.034-0.134 µg kg^-1 f. w.). The levels of all three compounds were statistically more significant in tomatoes grown hydroponically (<LOQ - 0.137 µg kg^-1 f. w.) than in soil (<LOQ - 0.083 µg kg^-1 f. w.). Their elemental composition shows differences between tomatoes grown hydroponically or in soil and tomatoes irrigated with wastewater and potable water. Contaminants at determined levels showed low dietary chronic exposure. When the health-based guidance values for the studied CECs are determined, results from this study will be helpful for risk assessors.

Selective accumulation of pharmaceutical residues from 6 different soils by plants: a comparative study on onion, radish, and spinach

The accumulation of six pharmaceuticals of different therapeutic uses has been thoroughly investigated and compared between onion, spinach, and radish plants grown in six soil types. While neutral molecules (e.g., carbamazepine (CAR) and some of its metabolites) were efficiently accumulated and easily translocated to the plant leaves (onion > radish > spinach), the same for ionic (both anionic and cationic) molecules seems to be minor to moderate. The maximum accumulation of CAR crosses 38,000 (onion), 42,000 (radish), and 7000 (spinach) ng g-1 (dry weight) respectively, in which the most majority of them happened within the plant leaves. Among the metabolites, the accumulation of carbamazepine 10,11-epoxide (EPC - a primary CAR metabolite) was approximately 19,000 (onion), 7000 (radish), and 6000 (spinach) ng g-1 (dry weight) respectively. This trend was considerably similar even when all these pharmaceuticals applied together. The accumulation of most other molecules (e.g., citalopram, clindamycin, clindamycin sulfoxide, fexofenadine, irbesartan, and sulfamethoxazole) was restricted to plant roots, except for certain cases (e.g., clindamycin and clindamycin sulfoxide in onion leaves). Our results clearly demonstrated the potential role of this accumulation process on the entrance of pharmaceuticals/metabolites into the food chain, which eventually becomes a threat to associated living biota.

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

The use of reclaimed water for crop irrigation has been proposed as a suitable alternative for farmers in the coastal areas of Mediterranean countries, which suffer from greater water scarcity. In this work we study the impact on the water-soil-plant continuum of using reclaimed water for commercial crops irrigated over a long period, as well as the human risks associated with consuming the vegetables produced. Forty-four CECs were identified in the reclaimed water used for crop irrigation. Of these, twenty-four CECs were identified in the irrigated soil samples analysed. Tramadol, ofloxacin, tonalide, gemfibrozil, atenolol, caffeine, and cetirizine were the pharmaceuticals detected at the highest levels in the water samples (between 11 and 44 μg/L). The CECs with the highest average soil concentrations were tramadol (14.6 μg/kg), followed by cetirizine (13.2 μg/kg) and clarithromycin (12.7 μg/kg). In the irrigated vegetable samples analysed over the study period, carbamazepine, lidocaine, and caffeine were only detected at levels from 0.1 to 1.7 μg/kg. The CEC accumulation rate detected in the edible parts of the vegetables permanently irrigated with reclaimed water was very low (~1 %), whereas it was 33 % in the soils. The results revealed that consuming fruits harvested from plants irrigated for a long period with reclaimed water does not represent a risk to human health, opening the door to a circular economy of water. Nevertheless, for crop irrigation, future studies need to be conducted over longer periods and in other matrices to provide more scientific data on the safety of using reclaimed water.

Sorption of Organic Contaminants by Stable Organic Matter Fraction in Soil

Soil organic matter (SOM) and its heterogeneous nature constitutes the main factor determining the fate and transformation of organic chemicals (OCs). Thus, the aim of thus research was to analyze the influence of the molecular chemodiversity of a stable SOM (S-SOM) on the sorption potential of different groups of OCs (organochloride pesticides—OCPs, and non-chlorinated pesticides—NCPs, polycyclic aromatic hydrocarbons—PAHs). The research was conducted as a batch experiment. For this purpose, a S-SOM was separated from six soils (TOC = 15.0−58.7 gkg−1; TN = 1.4−6.6 gkg−1, pH in KCl = 6.4−7.4 and WRB taxonomy: fluvisols, luviosols, leptosols) by alkaline urea and dimethylsulphoxide with sulfuric acid. Isolated S-SOM fraction was evaluated by UV−VIS, FT-IR and EEM spectroscopy to describe molecular diversity, which allowed the assessment of its potential sorption properties regarding OCs. In order to directly evaluate the sorption affinity of individual OCs to S-SOM, the mixture of the 3 deuterated contaminants: chrysene (PAHs), 4,4′DDT (OCPs) atrazine (NCPs) were applied. The sorption experiment was carried out according to the 106 OECD Guidelines. The OCs concentration was analyzed by gas chromatography triple mass spectrometry (GC-MS/MS). OCs were characterized by different sorption rates to S-SOM fractions according to the overall trend: atrazine (87.5−99.9%) > 4,4′DDT (64−81.6%) > chrysene (35.2−79.8%). Moreover, atrazine exhibited the highest saturation dynamic with fast bounding time amounting to 6 h of contact with S-SOM. Proportionally, the chrysene showed the slowest binding time achieving an average of 55% sorption after 78 h. Therefore, S-SOM isolated from different soils demonstrated varying binding capacity to OCs (CoV = 21%, 27% and 33% for atrazine, DDT and chrysene, respectively). Results indicate that each sample contains S-SOM with different degrees of transformation and sorption properties that affect the OCs availability in soil. Spectroscopic analyses have shown that the main component of S-SOM are biopolymers at various stages of transformation that contain numerous aromatic−aliphatic groups with mostly hydrophilic substituents.

Soil self-cleaning capacity: Removal of organic compounds during sub-surface irrigation with sewage effluent

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.

Migration and toxicity of toltrazuril and its main metabolites in the environment

Veterinary drugs heavily used in livestock are passed into the environment through different ways, resulting in risks to terrestrial environments and humans. The migration of toltrazuril (TOL), an important anticoccidial drug used intensively in livestock, and its main metabolites between the chicken manure compost, soil and vegetables was investigated, and then the impacts of TOL on the soil bacterial community and ARGs, soil enzyme activities and phytotoxicity were detected. In the process of aerobic composting for 80 days, except for toltrazuril sulfoxide (the degradation half-life was 59.74 d), TOL and ponazuril (PON) were not significantly degraded. However, TOL and its metabolites were significantly degraded in fertilized soil, and the degradation half-life was 28.17-346.50 d. Among the three drugs, only PON could migrate from soil to vegetables, and the residual concentrations of PON in lettuce and radish were 2.64-70.02 μg kg-1 and 0-2.80 μg kg-1, respectively. Moreover, TOL and its main metabolisms had no significant effect on the bacterial community structure and the abundance of antibiotic resistance genes during composting, but affected the microbial activity in the soil. The presence of TOL and its main metabolites reduced soil urease activity, increased catalase activity, and decreased alkaline phosphatase activity at the beginning and then increased slightly. They had negative effects on plant growth. Compared with the control group, the inhibition rates of TOL and its metabolites on lettuce and radish seed germination were 8.33% and 26.74% respectively, and the inhibition rates of root elongation length were 25.88% and 34.45% respectively. These results showed that TOL and its main metabolites were ineffectively removed by aerobic composting, and could be migrated from composting to soil and vegetables, which had adverse effects on soil enzyme activity and plant growth. Therefore, its environmental ecological risk and human health risk needs to be further evaluated.