Occurrence of chemical contaminants in peri-urban agricultural irrigation waters and assessment of their phytotoxicity and crop productivity

Response of crop seed germination and primary root elongation to a binary mixture of diclofenac and naproxen

Non-steroidal anti-inflammatory drugs, diclofenac (DCF) and naproxen (NPX), represent a group of environmental contaminants often detected in various water and soil samples. This work aimed to assess possible phytotoxic effects of DCF and NPX in concentrations 0.1, 1 and 10 mg/L, both individually and in binary mixtures, on the seed germination and primary root elongation of crops, monocots Allium porrum and Zea mays, and dicots Lactuca sativa and Pisum sativum. Results proved that the seed germination was affected by neither individual drugs nor their mixture. The response of primary root length in monocot and dicot species to the same treatment was different. The Inhibition index (%) comparing the root length of drug-treated plants to controls proved to be approximately 10% inhibition in the case of dicots lettuce and pea, and nearly 20% inhibition in monocot leek, but almost 20% stimulation in monocot maize. Assessment of the binary mixture effect confirmed neither synergistic nor antagonistic interaction of DCF and NPX on early plant development in the applied concentration range.

Occurrence of pharmaceuticals in rice (Oryza sativa L.) plant through wastewater irrigation

The present investigation focuses on the identification of popular PhACs in roots, leaves and rice grains, which are cultivated in soil irrigated with waters and wastewater. The present study reveals the presence of PhACs in rice grains from different brands which are available in the current market, which has thus motivated these experiments. The rice plants were cultivated in garden containers and irrigated with three different water sources. All PhAC compounds were recovered within an 89-111 % range using the extraction technique, reproducibility, and sensitivity (LOQ <25 µg/g). Further, PhAC compounds were identified using liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QqTOF-MS). Interestingly, several PhAC compounds were detected in rice grains, aligning with hypotheses and findings from published literature. A total of ten (10) PhACs were found in the root, leaf, and rice grain of the 20 popular PhACs that were targeted. The annual exposure and medical dose equivalent for individual PhACs was negligible. According to our knowledge, this study is the first to show the accumulation of several categories (cocktail) of PhACs in rice grains and show the approximate human health risk assessment by its consumption. The study's results provide valuable insights for researchers, policymakers, and agricultural practitioners working on sustainable agriculture and public health.

Assessing the phytotoxicity of wastewater from the structured-bed hybrid baffled reactor (SBHBR) for agricultural reuse during the germination phase

This study investigated the quality of anaerobic (AnE) and oxic/anoxic (O/A) effluents from a continuous-feed structured-bed hybrid baffled reactor (SBHBR) treating dairy wastewater impacts on lettuce and cucumber germination. While sustainable technologies like SBHBR have successfully removed organic matter and total nitrogen from dairy wastewater, residual concentrations may still represent a risk to water resources. Therefore, phytotoxicity bioassays were conducted with lettuce and cucumber seeds in contact with effluent during early stages to evaluate the potential implications of dairy wastewater reuse in agriculture. The study also explored the potential of SBHBR technology in promoting water resource preservation and creating a sustainable energy and nutrient cycling system. The physicochemical parameters of both effluents were characterized, and the phytotoxicity was evaluated by measuring the germination index (GI), root length (RL), the number of germinated seeds (SG), and epicotyl elongation (EE) for both lettuce and cucumber. The study revealed that the O/A effluent demonstrated lower phytotoxicity than the AnE effluent. The mean results indicate that the O/A zone wastewater was more conducive to cucumber germination than the AnE zone. Moreover, a positive influence of organic matter in the effluent on root growth and epicotyl elongation in cucumber, as well as the presence of nitrogen on the germination index, in both plant species. These findings emphasize the importance of considering effluent characteristics for suitable irrigation, highlighting SBHBR's potential as an effective solution for treating and reusing dairy wastewater in agriculture. This approach helps conserve water resources and promote a sustainable energy and nutrient cycling system.

Personal care products in soil-plant and hydroponic systems: Uptake, translocation, and accumulation

Personal care products (PCPs) are organic compounds that are incorporated in several daily life products, such as shampoos, lotions, perfumes, cleaning products, air fresheners, etc. Due to their massive and continuous use and because they are not routinely monitored in the environment, these compounds are considered emerging contaminants. In fact, residues of PCPs are being discharged into the sewage system, reaching wastewater treatment plants (WWTPs), where most of these compounds are not completely degraded, being partially released into the environment via the final effluents and/or accumulating in the sewage sludges. Environmental sustainability is nowadays one of the main pillars of society and the application of circular economy models, promoting the waste valorisation, is increasingly encouraged. Therefore, irrigation with reclaimed wastewater or soil fertilization with sewage sludge/biosolids are interesting solutions. However, these practices raise concerns due to the potential risks associated to the presence of hazardous compounds, including PCPs. When applied to agricultural soils, PCPs present in these matrices can contaminate the soil or be taken up by crops. Crops can therefore become a route of exposure for humans and pose a risk to public health. However, the extent to which PCPs are taken up and bioaccumulated in crops is highly dependent on the physicochemical properties of the compounds, environmental variables, and the plant species. This issue has attracted the attention of scientists in recent years and the number of publications on this topic has rapidly increased, but a systematic review of these studies is lacking. Therefore, the present paper reviews the uptake, accumulation, and translocation of different classes of PCPs (biocides, parabens, synthetic musks, phthalates, UV-filters) following application of sewage sludge or reclaimed water under field and greenhouse conditions, but also in hydroponic systems. The factors influencing the uptake mechanism in plants were also discussed.

Linking the use of reclaimed water to indicators of crop stress by metabolomic and transcriptomic analyses. A tool to compare water irrigation quality

The occurrence of contaminants of emerging concern (CECs) or heavy metals in reclaimed water used for agricultural irrigation may affect crop morphology and physiology. Here, we analyzed lettuce (Lactuca sativa) grown in outdoor lysimeters and irrigated with either tap water, used as a control, or reclaimed water: CAS-reclaimed water, an effluent from a conventional activated sludge system (CAS) followed by chlorination and sand filtration, or MBR-reclaimed water, an effluent from a membrane biological reactor (MBR). Chemical analyses identified seven CECs in the reclaimed waters, but only two of them were detected in lettuce (carbamazepine and azithromycin). Metabolomic and transcriptomic analyses revealed that irrigation with reclaimed water increased the concentrations of several crop metabolites (5-oxoproline, leucine, isoleucine, and fumarate) and of transcripts codifying for the plant stress-related genes Heat-Shock Protein 70 (HSP70) and Manganese Superoxide Dismutase (MnSOD). In both cases, MBR-water elicited the strongest response in lettuce, perhaps related to its comparatively high sodium adsorption ratio (4.5), rather than to its content in CECs or heavy metals. Our study indicates that crop metabolomic and transcriptomic profiles depend on the composition of irrigating water and that they could be used for testing the impact of water quality in agriculture.

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.

Microbiome Interconnectedness throughout Environments with Major Consequences for Healthy People and a Healthy Planet

Microbiomes have highly important roles for ecosystem functioning and carry out key functions that support planetary health, including nutrient cycling, climate regulation, and water filtration. Microbiomes are also intimately associated with complex multicellular organisms such as humans, other animals, plants, and insects and perform crucial roles for the health of their hosts. Although we are starting to understand that microbiomes in different systems are interconnected, there is still a poor understanding of microbiome transfer and connectivity. In this review we show how microbiomes are connected within and transferred between different habitats and discuss the functional consequences of these connections. Microbiome transfer occurs between and within abiotic (e.g., air, soil, and water) and biotic environments, and can either be mediated through different vectors (e.g., insects or food) or direct interactions. Such transfer processes may also include the transmission of pathogens or antibiotic resistance genes. However, here, we highlight the fact that microbiome transmission can have positive effects on planetary and human health, where transmitted microorganisms potentially providing novel functions may be important for the adaptation of ecosystems.

Effects of common antiepileptic drugs on teleost fishes

Antiepileptic drugs (AEDs) are globally prescribed to treat epilepsy and many other psychiatric disorders in humans. Their high consumption, low metabolic rate in the human body and low efficiency of wastewater treatment plants (WWTPs) in eliminating these chemicals results in the frequent occurrence of these pharmaceutical drugs in aquatic systems. Therefore, aquatic organisms, including ecologically and economically important teleost fishes, may be inadvertently exposed to these chemicals. Due to their physiological similarity with humans, fishes may be particularly vulnerable to AEDs. Almost all AED drugs are detectable in natural aquatic ecosystems, but diazepam (DZP) and carbamazepine (CBZ) are among the most widely detected AEDs to date. Recent studies suggest that these drugs have a substantial capacity to induce neurotoxicity and behavioral abnormality in fishes. Here we review the current state of knowledge regarding the potential mode of action of DZP and CBZ as well as that of some other AEDs on teleosts and put observable behavioral effects into a mechanistic context. We find that following their intended mode of action in humans, AEDs also disrupt the GABAergic, glutamatergic and serotonergic systems as well as parasympathetic neurotransmitters in fishes. Moreover, AEDs have non-specific modes of action in teleosts ranging from estrogenic activity to oxidative stress. These physiological changes are often accompanied by dose-dependent disruptions of anxiety, locomotor activity, social behaviors, food uptake, and learning and memory, but DZP and CBZ consistently induced anxiolytic effects. Thereby, AED exposure severely compromises individual fitness across teleost fish species, which may lead to population and ecosystem impairment. We also showcase promising avenues for future research by highlighting where we lack data when it comes to effects of certain AEDs, AED concentrations and behavioral endpoints.

Pea root responses under naproxen stress: changes in the formation of structural barriers in the primary root in context with changes of auxin and abscisic acid levels

Pharmaceuticals belong to pseudo-persistent pollutants because of constant entry into the environment and hazardous potential for non-target organisms, including plants, in which they can influence biochemical and physiological processes. Detailed analysis of results obtained by microscopic observations using fluorescent dyes (berberine hemisulphate, Fluorol Yellow 088), detection of phytohormone levels (radioimmunoassay, enzyme-linked immune sorbent assay) and thermogravimetric analysis of lignin content proved that the drug naproxen (NPX) can stimulate the formation of root structural barriers. In the primary root of plants treated with 0.5, 1, and 10 mg/L NPX, earlier Casparian strip formation and development of the whole endodermis circle closer to its apex were found after five days of cultivation (by 9-20% as compared to control) and after ten days from 0.1 mg/L NPX (by 8-63%). Suberin lamellae (SL) were deposited in endodermal cells significantly closer to the apex under 10 mg/L NPX by up to 75%. Structural barrier formation under NPX treatment can be influenced indirectly by auxin-supported cell division and differentiation caused by its eight-times higher level under 10 mg/L NPX and directly by stimulated SL deposition induced by abscisic acid (higher from 0.5 mg/L NPX), as proved by the higher proportion of cells with SL in the primary root base (by 8-44%). The earlier modification of endodermis in plant roots can help to limit the drug transfer and maintain the homeostasis of the plant.

Impact of organic soil amendments in antibiotic levels, antibiotic resistance gene loads, and microbiome composition in corn fields and crops

The potential spreading of antibiotic resistance genes (ARG) into agricultural fields and crops represent a fundamental limitation on the use of organic fertilization in food production systems. We present here a study of the effect of spreading four types of organic soil amendments (raw pig slurry, liquid and solid fractions, and a digested derivative) on demonstrative plots in two consecutive productive cycles of corn harvest (Zea mays), using a mineral fertilizer as a control, following the application of organic amendments at 32-62 T per ha (150 kg total N/ha) and allowing 5-8 months between fertilization and harvest. A combination of qPCR and high-throughput 16S rDNA sequencing methods showed a small, but significant impact of the fertilizers in both ARG loads and microbiomes in soil samples, particularly after the second harvesting cycle. The slurry solid fraction showed the largest impact on both ARG loads and microbiome variation, whereas its digestion derivatives showed a much smaller impact. Soil samples with the highest ARG loads also presented increased levels of tetracyclines, indicating a potential dual hazard by ARG and antibiotic residues linked to some organic amendments. Unlike soils, no accumulation of ARG or antibiotics was observed in corn leaves (used as fodder) or grains, and no grain sample reached detection limits for neither parameter. These results support the use of organic soil amendments in corn crops, while proposing the reduction of the loads of ARGs and antibiotics from the fertilizers to greatly reduce their potential risk.

Moisture movement, soil salt migration, and nitrogen transformation under different irrigation conditions: Field experimental research

Irrigation and fertilizer application can lead to significant changes in groundwater quality. In this study, a field irrigation experiment was carried out from April 9 to 23, 2021 under irrigation and fertigation conditions to understand the mechanisms of moisture movement, soil salt migration, and nitrogen transformation in the soil profile. Continuous in-situ monitoring and sampling of soil and irrigation water, as well as stable isotopes, chemical parameters, and soluble salt analyses, were performed in this research. The results showed that the time cost by the irrigation water in the vadose zone was about 5 h. The infiltrated irrigation water was accompanied by high concentrations of soluble salts, leached from the soil layers of 20-80 cm and 100-150 cm, which is associated with the leaching of Na⁺, Cl^-, SO₄^2-, and Ca²⁺ and the dissolution of minerals such as gypsum and halite. Furthermore, the variations in nitrogen concentrations (NH₄⁺ and NO₃^-) in the soil profile suggested that fertilizer application was the main source of NO₃^- in the soil and groundwater, while irrigation was the biggest driving force for nitrogen transport and transformation in soil. The application of urea fertilizer can increase the content of ammonium nitrogen at the soil layer of 0-80 cm. This nitrogen form can be subsequently transformed to nitrate nitrogen during the water transport to the groundwater. The current study provides a strong scientific basis for the protection and management of groundwater and soil quality in agricultural areas.

Implications of the use of organic fertilizers for antibiotic resistance gene distribution in agricultural soils and fresh food products. A plot-scale study

The spread of antibiotic resistance genes (ARG) into agricultural soils, products, and foods severely limits the use of organic fertilizers in agriculture. In order to help designing agricultural practices that minimize the spread of ARG, we fertilized, sown, and harvested lettuces and radish plants in experimental land plots for two consecutive agricultural cycles using four types of fertilizers: mineral fertilization, sewage sludge, pig slurry, or composted organic fraction of municipal solid waste. The analysis of the relative abundances of more than 200,000 ASV (Amplicon Sequence Variants) identified a small, but significant overlap (<10%) between soil's and fertilizer microbiomes. Clinically relevant ARG were found in higher loads (up to 100 fold) in fertilized soils than in the initial soil, particularly in those treated with organic fertilizers, and their loads grossly correlated to the amount of antibiotic residues found in the corresponding fertilizer. Similarly, low, but measurable ARG loads were found in lettuce (tetM, sul1) and radish (sul1), corresponding the lowest values to samples collected from minerally fertilized fields. Comparison of soil samples collected along the total period of the experiment indicated a relatively year-round stability of soil microbiomes in amended soils, whereas ARG loads appeared as unstable and transient. The results indicate that ARG loads in soils and foodstuffs were likely linked to the contribution of bacteria from organic fertilizer to the soil microbiomes, suggesting that an adequate waste management and good pharmacological and veterinarian practices may significantly reduce the presence of these ARGs in agricultural soils and plant products.

Integrating multiple lines of evidence to assess freshwater ecosystem health in a tropical river basin

Degradation of freshwater ecosystems by uncontrolled human activities is a growing concern in the tropics. In this regard, we aimed at testing an integrative framework based on the IFEQ index to assess freshwater ecosystem health of river basins impacted by intense livestock and agricultural activities, using the Muchacho River Basin (MRB) as a case study. The IFEQ combine multiple lines of evidence such as riverine hydromorphological analysis (LOE 1), physicochemical characterization using ions and pesticides (LOE 2), aquatic macroinvertebrate monitoring (LOE 3), and phytotoxicological essays with L. sativa (LOE 4). Overall, results showed an important reduction in streamflow and an elevated increase in ion concentrations along the MRB caused by deforestation and erosion linked to agricultural and livestock activities. Impacts of the high ion concentrations were evidenced in macroinvertebrate communities as pollution-tolerant families, associated with high conductivity levels, represented 92 % of the total abundance. Pollution produced by organophosphate pesticides (OPPs) was critical in the whole MRB, showing levels that exceeded 270-fold maximum threshold for malathion and 30-fold for parathion, the latter banned in Ecuador. OPPs concentrations were related to low germination percentages of Lactuca sativa in sediment phytotoxicity tests. The IEFQ index ranged from 44.4 to 25.6, indicating that freshwater ecosystem conditions were "bad" at the headwaters of the MRB and "critical" along the lowest reaches. Our results show strong evidence that intense agricultural and livestock activities generated significant impacts on the aquatic ecosystem of the MRB. This integrative approach better explains the cumulative effects of human impacts, and should be replicated in other basins with similar conditions to help decision-makers and concerned inhabitants generate adequate policies and strategies to mitigate the degradation of freshwater ecosystems.

Suspect and non-target screening of contaminants of emerging concern in streams in agricultural watersheds

Surface water runoff is an important source of water contamination affecting nearby rivers and streams. Many rural creeks are documented habitats for important aquatic species and the focus of restoration activities. In this study, we collected creek water samples in watersheds with a range of commercial-to-agricultural land use during rain events, and applied suspect and non-target screening with high-resolution mass spectrometry (HRMS) to characterize the occurrence of contaminants of emerging concern (CECs). In total, 58 CECs were identified, and 36 of them were confirmed and semi-quantified with reference standards. Pesticides were detected in all land use, including urban/commercial areas. Some pesticides were observed at concentrations of >10,000 ng/L demonstrating the strong contamination input during rain events. Five pesticides (azoxystrobin, fludioxonil, 4-hydroxy-chlorothalonil, imidacloprid, 2-methyl-4-chlorophenoxyacetic acid) were prioritized based on their risk quotients. HRMS chemical profiles demonstrated the wide range of chemical exposures in a given stream system and that compounds associated with specific land uses occur across land uses. Temporal trends suggested that some CECs remain present in creek water for months, resulting in chronic exposures across the life stages of aquatic species. These findings highlight the potential for contamination from agricultural runoff and the associated ecological risk to aquatic species. SYNOPSIS: Suspect and non-target screening revealed the chronic occurrence of emerging contaminants in streams in agricultural catchments during rain events.

Phytotoxicity test in check: Proposition of methodology for comparison of different method adaptations usually used worldwide

Seed germination tests have been widely used in recent years to indicate the toxicity levels of samples of organic compounds, biosolids, residues and effluents. Lactuca sativa L, commonly known as lettuce, has been one of the main indicative species for these tests due to its high sensitivity to low levels of toxicity, when compared to other seeds and also because it is cultivated worldwide. Although this type of analysis or essay is being widely used, it is necessary to reflect on the various adaptations of methods used by different researchers worldwide. This work presents an innovative methodology that makes it possible to compare the different phytotoxicity methods currently used in the world, through four stages that include the coefficient of variation (CV) as the main classification criterion, also counting on an eliminatory criterion. The existence of a significant difference (P value < 0.05) between the evaluated tests was proven. The phytotoxicity test that presented the lowest CV was T8 (test with lettuce seeds at 25 °C, 60 min agitation, resting overnight, 5 mL of sample on the plate, 90 mm size plate). It has concluded that not all adaptations of this type of test are reliable. It has also concluded that there is a lack of standardization for the phytotoxicity test on a global scale, which makes the various researchers in the field end up promoting variations, adaptations for the phytotoxicity test; therefore, there is an urgent need for ways to compare these variations, as the innovation proposed by this work. With a single standard methodology, we conclude that it will make it possible to compare phytotoxicity in samples directly between countries and continents, being able to generate a worldwide panorama of phytotoxicity, publicizing and comparing the standardized phytotoxicity levels in each region.

A review of antiepileptic drugs: Part 1 occurrence, fate in aquatic environments and removal during different treatment technologies

Antiepileptic drugs (AEDs) are the main treatment for people with epilepsy. However, in recent years, more and more people are using them for other indications such as: migraine, chronic neuropathic pain, and mood disorders. Consequently, the prescriptions and consumption of these drugs are increasing worldwide. In WWTPs, AEDs can resist degradation processes, such as photodegradation, chemical degradation and/or biodegradation. Until now, only constructed wetlands and photocatalysis have shown good removal rates of AEDs from wastewater. However, their effectiveness depends on the specific conditions used during the treatment. Since the consumption of AEDs has increased in the last decade and their degradation in WWTPs is poor, these drugs have been largely introduced into the environment through the discharge of municipal and/or hospital effluents. Once in the environment, AEDs are distributed in the water phase, as suspended particles or in the sediments, suggesting that these drugs have a high potential for groundwater contamination. In this first part of the AEDs review is designed to fill out the current knowledge gap about the occurrence, fate and removal of these drugs in the aquatic environment. This is a review that emphasizes the characteristics of AEDs as emerging contaminants.

Removal and environmental risk assessment of contaminants of emerging concern from irrigation waters in a semi-closed microalgae photobioreactor

The present study evaluated the efficiency of a semi-closed, tubular, horizontal photobioreactor (PBR) to treat a mixture of irrigation and rural drainage water, focusing in the removal of different contaminants of emerging concern (CECs), and evaluating the environmental impact of the resulting effluent. Target CECs included pharmaceuticals, personal care products and flame retardants. Of the 13 compounds evaluated, 11 were detected in the feed water entering the PBR, and diclofenac (DCF) (1107 ng L^-1) and N,N-diethyl-toluamide (DEET) (699 ng L^-1) were those present at the greatest concentrations. The best removal efficiencies were achieved for the pharmaceuticals diazepam (94%), lorazepam (LZP) (83%) and oxazepam (OXA) (71%), and also for ibuprofen (IBU) (70%). For the rest of the CECs evaluated, attenuation was similar to that obtained after conventional wastewater treatment, ranging from basically no elimination (carbamazepine (CBZ) and tris-(2-chloroethyl) phosphate (TCEP)) to medium efficiencies (DCF and tributyl phosphate (TBP) (50%)). Environmental risk assessment based on hazard quotients (HQs) resulted in HQ values < 0.1 (no risk associated) for most of the compounds and most of the trophic levels considered. Values between 1 and 10 (moderate risk) were obtained for tonalide (AHTN) (fish) and CBZ (invertebrates). The most sensitive trophic level was green algae, whereas fish and aquatic plants were the most resilient. Our results suggest that microalgae-based treatments could become a green, cost-effective alternative to conventional wastewater treatment regarding the efficient elimination of these contaminants.

Impact of China's water pollution on agricultural economic growth: an empirical analysis based on a dynamic spatial panel lag model

The average annual growth rate of China's waste emissions from 2007 to 2017 was 2.3%. The main pollutants in the wastewater are chemical oxygen demand, ammonia nitrogen, total ammonia, total phosphorus, and so on which pollute groundwater and destroy ecosystems. Poor water quality reduces the edible value of agricultural products and has an impact on human health. Based on the panel data of 31 provinces in China from 2007 to 2017, this paper uses a dynamic spatial panel lag model to study the impact of China's water pollution on agricultural economic growth. The results show that the impact of China's water pollution on agricultural economic growth is significant. If the intensity of wastewater discharge is taken as an input factor in the process of agricultural production, the growth of agricultural economy tends to decline with the increase of water pollution. In the effect analysis, the short-term and long-term effects are significant. The absolute value of the long-term total effect is far greater than the short-term total effect, indicating that the inhibitory effect of water pollution on agricultural economic growth is more obvious. The cumulative effect of water pollution on agricultural economic growth continues to expand, resulting in more and more economic losses. The central and local governments should take various measures to reduce water pollution, guide the green development of agriculture, and increase farmers' income to realize the rural revitalization plan.

Occurrence and human health risk assessment of antibiotics and their metabolites in vegetables grown in field-scale agricultural systems

The occurrence of antibiotics (ABs) in four types of commercially grown vegetables (lettuce leaves, tomato fruits, cauliflower inflorescences, and broad bean seeds) was analyzed to assess the human exposure and health risks associated with different agronomical practices. Out of 16 targeted AB residues, seven ABs belonging to three groups (i.e., benzyl pyrimidines, fluoroquinolones, and sulfonamides) were above the method detection limit in vegetable samples ranging from 0.09 ng g^-1 to 3.61 ng g^-1 fresh weight. Data analysis (quantile regression models, principal component and hierarchical cluster analysis) showed manure application, irrigation with river water (indirect wastewater reuse), and vegetable type to be the most significant factors for AB occurrence in the targeted crops. Metabolites were detected in 70 of the 80 vegetable samples analyzed, and their occurrence was both plant- and compound-specific. In 73 % of the total samples, the concentration of AB metabolites was higher than the concentration of their parent compound. Finally, the potential human health risk estimated using the hazard quotient approach, based on the acceptable daily intake and the estimated daily intake, showed a negligible risk for human health from vegetable consumption. However, canonical-correspondence analysis showed that detected ABs explained 54 % of the total variation in AB resistance genes abundance in the vegetable samples. Thus, further studies are needed to assess the risks of antibiotic resistance promotion in vegetables and the significance of the occurrence of their metabolites.

Removal of Diclofenac in Wastewater Using Biosorption and Advanced Oxidation Techniques: Comparative Results

Wastewater treatment is a topic of primary interest with regard to the environment. Diclofenac is a common analgesic drug often detected in wastewater and surface water. In this paper, three commonly available agrifood waste types (artichoke agrowaste, olive-mill residues, and citrus waste) were reused as sorbents of diclofenac present in aqueous effluents. Citrus-waste biomass for a dose of 2 g·L−1 allowed for removing 99.7% of diclofenac present in the initial sample, with a sorption capacity of 9 mg of adsorbed diclofenac for each gram of used biomass. The respective values obtained for olive-mill residues and artichoke agrowaste were around 4.15 mg·g−1. Advanced oxidation processes with UV/H2O2 and UV/HOCl were shown to be effective treatments for the elimination of diclofenac. A significant reduction in chemical oxygen demand (COD; 40–48%) was also achieved with these oxidation treatments. Despite the lesser effectiveness of the sorption process, it should be considered that the reuse and valorization of these lignocellulosic agrifood residues would facilitate the fostering of a circular economy.

Periurban Transformations in the Global South and Their Impact on Water-Based Livelihoods

Urban sprawl and population increase are fundamentally transforming periurban areas in the Global South. These areas often suffer from inadequate environmental planning, resulting in water sources being overexploited, degraded, and redistributed. These processes affect water-based livelihoods due to disadvantages in water access and inadequate water governance. On the positive side, these transformation processes are leading to alternative water-based livelihoods. We systematically review and critically comment on the literature on water-based livelihoods in periurban areas of the Global South to provide the current scientific knowledge on this topic. Transformations of water-based livelihoods in periurban areas were also evaluated in terms of their sustainability. We conclude that rapid developments of periurban areas contain threats and potentials for water-based livelihoods and some emerging water-based livelihoods, whereas some emerging water-based livelihoods provide interim solutions for institutional supply gaps. Major lacunae in research are the (1) lack of holistic approaches, which address social dimensions of transformations, (2) the lack of studies applying a differentiated perspective on neighbouring areas within the urban fringe and (3) a lack of knowledge on emerging (water-based) livelihoods.

Pharmaceuticals, pesticides, personal care products and microplastics contamination assessment of Al-Hassa irrigation network (Saudi Arabia) and its shallow lakes

This study assess the presence of pharmaceutical and personal care products (PPCPs) and pesticides in different environmental compartments and microplastics in water of a characteristic lagoon wetland in Saudi Arabia to establish the transport, accumulation and fate of these pollutants in a water-stressed area under high anthropogenic pressure. In water, diazinon (up to 1016 ng L^-1), caffeine (up to 20,663 ng L^-1), diclofenac (up to 1390 ng L^-1) and paracetamol (up to 3069 ng L^-1) were at the highest concentrations. The substances with the highest frequency of detection were carbendazim, atorvastatin, caffeine, etoricoxib, lorazepam, metformin, ofloxacin, paracetamol, salicylic acid and tramadol. Considerably less pesticides and PPCPs at concentrations ranging from 0.01 to 126 ng g^-1 dry weight (d.w.) were detected in the other matrices (sediment ≫ soil > plants). The concentration of microplastics in water ranged from 0.7 to 7.8 items/L in the Al-Asfar lake and from 1.1 to 9.0 items/L in the Al-Hubail lake. Risk assessment [using hazards quotients (HQ)] was used to highlight pesticides and PPCPs of major ecological concern that should be closely monitored to avoid adverse effects.

Chemical characterization and phytotoxicity assessment of peri-urban soils using seed germination and root elongation tests

The peri-urban soil is exposed to pollutants because of its proximity to the city, which may influence the quality of agricultural products. In this study, the occurrence of 16 trace elements (TEs), 16 polycyclic aromatic hydrocarbons (PAHs), and 33 contaminants of emerging concern (CECs) was analyzed in two soil sites of the peri-urban area of Barcelona (Spain) (S2 and S3) and a pristine site (S1). Levels of Pb (S2 164 and S3 150 mg kg-1) are around 2.5 times higher than the guideline values. Values for Cu (178 mg kg-1) in S2 are 1.8-fold higher, whereas for Zn, levels are slightly above the threshold in S2 (208 mg kg-1) and S3 (217 mg kg-1). The total concentrations of PAHs are significantly below the limits: 24 ng g-1 dw (S1), 38 ng g-1 dw (S2), 49 ng g-1 dw (S3), whereas only some CECs are detected with low concentrations. We also developed a simple and rapid method to assess soil pollution. Here, we use two plant growth indexes (seed germination rate and root elongation at the initial stage) of three seeds (lettuce, tomato, and cauliflower) to assess soil chemical contamination on agriculture. In the peri-urban soil, the concentration of Pb was 2.5 times higher than the guideline values, whereas for Cu and Zn, values were slightly above their limits, while only few PAHs and CECs were detected. Results for principal component analysis suggest that root elongation is a more sensitive measurement endpoint than germination rate, especially for lettuce. The germination rate of tomato relied on the nitrate in the soil and decreased sharply in the site with pollution of Cu and As. Under the specific conditions of this study, cauliflower should not be recommended to assess environmental pollution due to its low sensitivity to pollutants. In conclusion, this is a low-cost, simple, and rapid method for evaluating the effects of chemical pollution of agriculture soils on seed growth.

Antibiotic resistance gene distribution in agricultural fields and crops. A soil-to-food analysis

Despite the social concern about the generalization of antibiotic resistance hotspots worldwide, very little is known about the contribution of different potential sources to the global risk. Here we present a quantitative analysis of the distribution of Antibiotic Resistance Genes (ARGs) in soil, rhizospheric soil, roots, leaves and beans in tomato, lettuce and broad beans crops (165 samples in total), grown in nine commercial plots distributed in four geographical zones in the vicinity of Barcelona (North East Spain). We also analyzed five soil samples from a nearby forest, with no record of agricultural activities. DNA samples were analyzed for their content in the ARGs sul1, tetM, qnrS1, bla_CTX-M-32, bla_OXA-58, mecA, and bla_TEM, plus the integron intI1, using qPCR methods. In addition, soil microbiomes from the different plots were analyzed by amplicon-targeted 16S rRNA gene sequencing. Our data show a decreasing gradient of ARG loads from soil to fruits and beans, the latter showing only from 0.1 to 0.01% of the abundance values in soil. The type of crop was the main determinant for both ARG distribution and microbiome composition among the different plots, with minor contributions of geographic location and irrigation water source. We propose that soil amendment and/or fertilization, more than irrigation water, are the main drivers of ARG loads on the edible parts of the crop, and that they should therefore be specifically controlled.

Occurrence and human health implications of chemical contaminants in vegetables grown in peri-urban agriculture

Recent studies have proven that vegetables cultivated in peri-urban areas are exposed to a greater concentration of organic microcontaminants (OMCs) and trace elements (TEs) than those grown in rural areas. In this study, the occurrence and human health risk of chemical contaminants (16 TEs and 33 OMCs) in edible parts of lettuce, tomato, cauliflower, and broad beans from two farm fields in the peri-urban area of the city of Barcelona and one rural site outside the peri-urban area were assessed. The concentration of TEs and OMCs (on fresh weight basis) ranged from non-detectable to 17.4 mg/kg and from non-detectable to 256 μg/kg, respectively. Tomato fruits showed the highest concentration of TEs and OMCs. Principal component analysis indicated that the occurrence of chemical contaminants in vegetables depended on the commodity rather than the location (peri-urban vs rural). Risk assessment using hazardous quotient (HQ) and threshold of toxicological concern (TTC) approaches showed that the risk for the consumption of target vegetables in the peri-urban area was low and similar to that observed for the rural site. Total HQ values for TEs were always below 1, and a minimum consumption of 150 g/day for children and 380 g/day for adults is required to reach the TTC due to the presence of pesticides. Further studies are needed to estimate the combined effect of TEs and OMCs on human health.

Ecotoxicity response of chlorpyrifos in Aedes aegypti larvae and Lactuca sativa seeds after UV/H2O2 and UVC oxidation

Chlorpyrifos (CP) is an organophosphate pesticide widely used in agriculture known to cause neurological and immunological effects in addition to interfering in the reproduction and development of organisms. In this study, CP degradation by UV/H2O2 process and UVC radiation was investigated, and the ecotoxicity and phytotoxicity was evaluated using bioassays of Aedes aegypti larvae and Lactuca sativa seeds. CP degradation was monitored by HPLC-DAD, and kinetic parameters were calculated for all processes evaluated. Results demonstrated that both processes are efficient, showing a reduction of over 97% of initial CP after 20 and 60 min of UV/H2O2 and UVC radiation, respectively. However, samples treated by UV/H2O2 process demonstrated increase of toxicity, leading to larvae mortality (>90% of organisms) and inhibition effects in seed root growth. The relationship between increased toxicity and the CP byproducts formed was not confirmed due to its low concentration. However, the direct influence of acetonitrile solvent, specifically their toxic byproducts, was observed. This study provides insights into parent compound abatement using oxidative treatment and the changes in toxicity due to the transformation of CP byproducts and complex mixtures (acetonitrile as solvent and hydrogen peroxide).

Antibiotic resistance genes distribution in microbiomes from the soil-plant-fruit continuum in commercial Lycopersicon esculentum fields under different agricultural practices

While the presence of antibiotic resistance genes (ARGs) in agricultural soils and products has been firmly established, their distribution among the different plant parts and the contribution of agricultural practices, including irrigation with reclaimed water, have not been adequately addressed yet. To this end, we analyzed the levels of seven ARGs (sul1, bla_TEM, bla_CTX-M-32, mecA, qnrS1, tetM, bla_OXA-58), plus the integrase gene intl1, in soils, roots, leaves, and fruits from two commercial tomato fields irrigated with either unpolluted groundwater or from a channel impacted by treated wastewater, using culture-independent, quantitative real-time PCR methods. ARGs and intl1 sequences were found in leaves and fruits at levels representing from 1 to 10% of those found in roots or soil. The relative abundance of intl1 sequences correlated with tetM, bla_TEM, and sul1 levels, suggesting a high horizontal mobility potential for these ARGs. High-throughput 16S rDNA sequencing revealed microbiome differences both between sample types (soil plus roots versus leaves plus fruits) and sampling zones, and a correlation between the prevalence of Pseudomonadaceae and the levels of different ARGs, particularly in fruits and leaves. We concluded that both microbiome composition and ARGs levels in plants parts, including fruits, were likely influenced by agricultural practices.

Sensitivity of physiological and biochemical endpoints in early ontogenetic stages of crops under diclofenac and paracetamol treatments

Early stages of ontogenesis determining subsequent growth, development, and productivity of crops can be affected by wastewater and sludge contaminated with pharmaceuticals. Diclofenac (DCF) and paracetamol (PCT; both 0.0001 to 10 mg/L) did not affect seed germination and primary root length of onion, lettuce, pea, and tomato. Conversely, 20-day-old pea and maize plants exhibited decrease in biomass production, leaf area (by approx. 40% in pea and 70% in maize under 10 mg/L DCF), or content of photosynthetic pigments (by 10% and 60% under 10 mg/L PCT). Quantum yields of photosystem II were reduced only in maize (F_V/F_M and Φ_II by more than 40% under 10 mg/L of both pharmaceuticals). Contents of H₂O₂ and superoxide increased in roots of both species (more than four times under 10 mg/L PCT in pea). Activities of antioxidant enzymes were elevated in pea under DCF treatments, but decreased in maize under both pharmaceuticals. Oxidative injury of root cells expressed as lowered oxidoreductase activity (MTT assay, by 40% in pea and 80% in maize) and increase in malondialdehyde content (by 60% and 100%) together with the membrane integrity disruption (higher Evans Blue accumulation, by 100% in pea and 300% in maize) confirmed higher sensitivity of maize as a C4 monocot plant to both pharmaceuticals.

Quantification of nitrate sources and fates in rivers in an irrigated agricultural area using environmental isotopes and a Bayesian isotope mixing model

Nitrate (NO₃^-) pollution in rivers caused by intensive human activities is becoming a serious problem in irrigated agricultural areas. To identify NO₃^- sources and reveal the impact of irrigation projects on NO₃^- pollution in rivers, the hydrochemistry and isotopes of irrigation water from the Yellow River (IW) and river water (RW), and potential source samples were analyzed. The mean NO₃^- concentrations in the IW and RW were 24.4 mg/L and 49.9 mg/L, respectively. Approximately 45.2% of RW samples (n = 31) exceeded the Chinese drinking water standard for NO₃^- (45 mg/L). The δ¹⁵N and δ¹⁸O values, combined with the Cl^-/Na⁺, SO₄^2-/Ca²⁺ ratio distributions, indicate that the NO₃^- in the RW mainly originated from chemical fertilizers, manure and sewage. A Bayesian model showed that manure and sewage contributed the most to the overall NO₃^- levels of the IW. In the RW, chemical fertilizers and IW contributed the most to the overall NO₃^- levels. The mean nitrate contribution to the RW from the combination of chemical fertilizers and IW is estimated to be 51.6%. Nitrogen from manure and sewage, soil N and precipitation also contributed. The NO₃^- pollution in rivers was largely influenced by the irrigation regime, with a large amount of nitrogen in chemical fertilizer lost because of low utilization efficiency and subsequent transfer, via irrigation runoff, into the rivers. This study suggests that with a detailed assessment of the sources and fate of NO₃^-, effective reduction strategies and better management practices can be implemented to control NO₃^- pollution in rivers.

Occurrence and bioaccumulation of chemical contaminants in lettuce grown in peri-urban horticulture

Peri-urban horticulture performs environmental and socio-economic functions and provides ecological services to nearby urban areas. Nevertheless, industrialization and water pollution have led to an increase in the exposure of peri-urban vegetables to contaminants such as trace elements (TEs) and organic microcontaminants (OMCs). In this study, the occurrence of chemical contaminants (i.e., 16 TEs, 33 OMCs) in soil and lettuce leaves from 4 farm fields in the peri-urban area of the city of Barcelona was assessed. A rural site, outside the peri-urban area of influence, was selected for comparison. The concentration of TEs and OMCs ranged from non-detectable to 803 mg/kg dw and from non-detectable to 397 μg/kg dw respectively in the peri-urban soil, and from 6 · 10-5 to 4.91 mg/kg fw and from non-detectable to 193 μg/kg fw respectively in lettuce leaves. Although the concentration of Mo, Ni, Pb, and As in the soil of the peri-urban area exceeded the environmental quality guidelines, their occurrence in lettuce complied with human food standards (except for Pb). The many fungicides (carbendazim, dimetomorph, and methylparaben) and chemicals released by plastic pipelines (tris(1-chloro-2-propyl)phosphate, bisphenol F, and 2-mercaptobenzothiazole) used in agriculture were prevalent in the soil and the edible parts of the lettuce. The occurrence of these chemical pollutants in the peri-urban area did not affect the chlorophyll, lipid, or carbohydrate content of the lettuce leaves. PCA (Principal Component Analysis) showed that soil pollution, fungicide application, and irrigation water quality are the most relevant factors determining the presence of contaminants in crops.

Distribution of Chemical Species in the Water-Soil-Plant (Carya illinoiensis) System near a Mineralization Area in Chihuahua, Mexico-Health Risk Implications

The aim of this study was to quantify major and trace elements in the water, soil, and plants (Carya illionensis) in an agricultural area; and to determine the health risks associated with the walnuts ingestion by calculating the risk quotient. Samples of water, soil, tree leaves, and walnuts were collected; in total, 135 samples were analyzed. Physicochemical parameters were obtained in irrigation water and soil samples. Elemental measurements were performed in an ICP, -OES and -MS. In addition, the distribution coefficient (soil–water), transfer factor (soil–plant), and hazard quotient were evaluated. In the irrigation water, As, Cr, and Pb, showed concentrations above the maximum allowable limits. Likewise, high concentrations of As, Cr, Pb, and Sb were found in tree leave samples, indicating a possible tendency of hyperaccumulation of those elements. Furthermore, Cr concentrations in walnuts were high by far than the reference value (FAO/WHO). A possible competition between chemical congeners were detected from transfer factors. Although, Sb concentrations in walnuts were also high, and no legislation for it in fruits exists. The hazard risk quotient for Sb did indicate a potential health risk. Finally, it is important to consider that the health risk increases when exposure through consumption takes place over a prolonged period of time, even in low concentrations.