Uptake and metabolism of diclofenac in Typha latifolia--how plants cope with human pharmaceutical pollution

Drugs in the environment - Impact on plants: A review

Medicines, like food, are necessities. Many of the commonly used pharmaceuticals, especially antibiotics and NSAIDs end up in the environment and are detected in it (especially in water) at concentrations in the ng·L-1- μg·L-1 range. Although the concentrations of individual drugs in the environment are low, their high biological activity can cause them to be toxic to the environment. This review analyzes and summarizes the effects of drugs, primarily antibiotics and NSAIDs on photosynthesizing organisms, i.e., algae, aquatic and terrestrial plants. Acute drug toxicity to algae and plants occurs most often at high, often non-existent environmental concentrations, while sublethal effects occur at low drug concentrations. The review also points out the problems associated with ecotoxicological studies and the lack of systemic solutions to better assess the risks associated with the presence of drugs in the environment.

Pharmaceutical metabolite identification in lettuce (Lactuca sativa) and earthworms (Eisenia fetida) using liquid chromatography coupled to high-resolution mass spectrometry and in silico spectral library

Pharmaceuticals released into the aquatic and soil environments can be absorbed by plants and soil organisms, potentially leading to the formation of unknown metabolites that may negatively affect these organisms or contaminate the food chain. The aim of this study was to identify pharmaceutical metabolites through a triplet approach for metabolite structure prediction (software-based predictions, literature review, and known common metabolic pathways), followed by generating in silico mass spectral libraries and applying various mass spectrometry modes for untargeted LC-qTOF analysis. Therefore, Eisenia fetida and Lactuca sativa were exposed to a pharmaceutical mixture (atenolol, enrofloxacin, erythromycin, ketoprofen, sulfametoxazole, tetracycline) under hydroponic and soil conditions at environmentally relevant concentrations. Samples collected at different time points were extracted using QuEChERS and analyzed with LC-qTOF in data-dependent (DDA) and data-independent (DIA) acquisition modes, applying both positive and negative electrospray ionization. The triplet approach for metabolite structure prediction yielded a total of 3762 pharmaceutical metabolites, and an in silico mass spectral library was created based on these predicted metabolites. This approach resulted in the identification of 26 statistically significant metabolites (p < 0.05), with DDA + and DDA - outperforming DIA modes by successfully detecting 56/67 sample type:metabolite combinations. Lettuce roots had the highest metabolite count (26), followed by leaves (6) and earthworms (2). Despite the lower metabolite count, earthworms showed the highest peak intensities, closely followed by roots, with leaves displaying the lowest intensities. Common metabolic reactions observed included hydroxylation, decarboxylation, acetylation, and glucosidation, with ketoprofen-related metabolites being the most prevalent, totaling 12 distinct metabolites. In conclusion, we developed a high-throughput workflow combining open-source software with LC-HRMS for identifying unknown metabolites across various sample types.

Exploring the defense strategies of benzalkonium chloride exposures on the antioxidant system, photosynthesis and ROS accumulation in Lemna minor

With the advent of technological advancements post the industrial revolution, thousands of chemicals are introduced into the market annually to enhance different facets of human life. Among these, pharmaceutical and personal care products (PPCPs), including antibiotics and disinfectants, such as benzalkonium chlorides (BACs), are prominent. BACs, often used for surface and hand disinfection in high concentrations or as preservatives in health products such as nasal sprays and eye drops, may present environmental risks if they seep into irrigation water through prolonged exposure or improper application. The primary objective of this study is to elucidate the tolerance mechanisms that may arise in Lemna minor plants, known for their remarkable capability to accumulate substances efficiently, in response to exogenously applied BACs at varying concentrations. The study applied six different concentrations of BACs, ranging from 0.25 to 10 mg L-1. The experimental period spanned seven days, during which the treatments were conducted in triplicate to ensure reliability and reproducibility of the results. It was observed that low concentrations of BACs (0.25, 0.5 and 1 mg L-1) did not elicit any statistically significant changes in growth parameters. However, higher concentrations of BACs (2.5, 5, and 10 mg L-1) resulted in a reduction in RGR by 20%, 28%, and 36%, respectively. Chlorophyll fluorescence declined significantly at BAC doses of 5 and 10 mg L-1, with Fv/Fm ratios decreasing by 9% and 15%, and Fv/Fo ratios by 40% and 39%, respectively. Proline content decreased in all treatment groups, with a 46% reduction at 10 mg L-1 BAC. TBARS and H2O2 contents increased proportionally with BAC dosage, showing the highest increases of 30% and 40% at 10 mg L-1, respectively. The noticeable increase in SOD enzyme activity at BAC concentrations of 0.5, 1, and 2.5 mg L-1, with increases of 2.7-fold, 2.2-fold, and 1.7-fold respectively, along with minimal accumulation of H2O2, suggests that L. minor plants have a strong tolerance to BAC. This is supported by the efficient functioning of the CAT and GST enzymes, especially evident at the same concentrations, where increased activities effectively reduce the buildup of H2O2. In the AsA-GSH cycle, although variations were observed between groups, the contribution of the GR enzyme to the preservation of GSH content by recycling GSSG likely maintained redox homeostasis in the plant, especially at low concentrations of BACs. The study revealed that L. minor effectively accumulates BAC alongside its tolerance mechanisms and high antioxidant activity. These results underscore the potential for environmental cleanup efforts through phytoremediation.

Phytoremediation of diclofenac and sulfamethoxazole in Arabidopsis thaliana cells and seedlings

Diclofenac (DLF), a widely recognized non-steroidal anti-inflammatory drug (NSAID), and sulfamethoxazole (SMX), a broad-spectrum sulfonamide antibiotic, are commonly prescribed medications that have raised concerns as significant contributors to pharmaceutical pollution in natural ecosystems despite their clinical effectiveness. This study investigates the potential phytoremediation pathways for these two drugs in plant systems by tracking and quantifying the fate of the parent compounds and their metabolites in Arabidopsis thaliana using cell and seedling cultures. Results indicated significant differences in the dissipation of DLF according to the treatment and time interaction within the cell cultures. Viable plant cells showed complete dissipation of DLF from an initial concentration of 2758 ng/mL in 96 h, whereas non-viable cells and blank solutions remained stable. The dissipation of SMX was comparable across viable, non-viable, and blanks, showing a minor decrease from 842 to 799 ng/mL over 120 h following the treatment of viable cells. DLF metabolites including 4'-hydroxy-diclofenac, 5-hydroxy-diclofenac, acyl-glutamatyl-diclofenac, 1-(2,6-dichlorophenyl)-5-hydroxy-2-indolinone, 5-sulfooxy-diclofenac, 5-glucopyranosyloxy-diclofenac, 1-(2,6-dichloro-4-hydroxyphenyl)-2-indolinone, and 4'-glucopyranosyloxy-diclofenac were recognized, likely formed through acylation, glutamyl conjugation, hydroxylation, dehydration, cyclization, sulfonation, and glucosidation. While for SMX, metabolites including sulfamethoxazole-glucuronide, nitroso-sulfamethoxazole, N4-acetylsulfamethoxazole, and N4-acetyl-5-OH-sulfamethoxazole were identified, potentially produced through glucuronidation, nitrosation, acetylation, and hydroxylation. Phase I metabolite concentrations of DLF and SMX peaked earlier than those of phase II metabolites. Hydroponic A. thaliana demonstrated comparable efficiencies in the phytoremediation of DLF and SMX, with concentrations varying from 1 mg/L to 10 mg/L. Detectable levels of both parent compounds and their metabolites confirmed successful absorption and metabolism within the plant system. This study provides valuable insights into the potential of phytoremediation as a sustainable approach for reducing the environmental toxicity of DLF and SMX and suggests comparable metabolic efficiency. These findings contribute to the growing body of knowledge on phytoremediation and its application in addressing pollution from pharmaceuticals and personal care products.

Wastewater reuse and pharmaceutical pollution in agriculture: Uptake, transport, accumulation and metabolism of pharmaceutical pollutants within plants

The presence of pharmaceutical pollutants in water sources has become a growing concern due to its potential impacts on human health and other organisms. The physicochemical properties of pharmaceuticals based on their intended therapeutical application, which include antibiotics, hormones, analgesics, and antidepressants, is quite diverse. Their presence in wastewater, sewerage water, surface water, ground water and even in drinking water is reported by many researchers throughout the world. Human exposure to these pollutants through drinking water or consumption of aquatic and terrestrial organisms has raised concerns about potential adverse effects, such as endocrine disruption, antibiotic resistance, and developmental abnormalities. Once in the environment, they can persist, undergo transformation, or degrade, leading to a complex mixture of contaminants. Application of treated wastewater, compost, manures or biosolids in agricultural fields introduce pharmaceutical pollutants in the environment. As pharmaceuticals are diverse in nature, significant differences are observed during their uptake and accumulation in plants. While there have been extensive studies on aquatic ecosystems, the effect on agricultural land is more disparate. As of now, there are few reports available on the potential of plant uptake and transportation of pharmaceuticals within and between plant organs. This review summarizes the occurrence of pharmaceuticals in aquatic water bodies at a range of concentrations and their uptake, accumulation, and transport within plant tissues. Research gaps on pharmaceutical pollutants' specific effect on plant growth and future research scopes are highlighted. The factors affecting uptake of pharmaceuticals including hydrophobicity, ionization, physicochemical properties (pKa, logKow, pH, Henry's law constant) are discussed. Finally, metabolism of pharmaceuticals within plant cells through metabolism phase enzymes and plant responses to pharmaceuticals are reviewed.

Phytodegradation of neonicotinoids in Cyperus papyrus from enzymatic and transcriptomic perspectives

Neonicotinoids are widely used but environmentally hazardous insecticides. Constructed wetlands offer potential for neonicotinoid removal, but the corresponding metabolic pathways and mechanisms in wetland plants are incompletely understood. This study investigated the fate of six neonicotinoids and their metabolites in Cyperus papyrus, a common wetland plant, and the underlying metabolic mechanisms through enzymatic and transcriptomic analyses. Neonicotinoids were absorbed by roots and translocated upward, causing high levels in shoots. Concentrations of neonicotinoids and their metabolites declined to their minimum at day 28 of exposure. Nitro reduction, hydroxylation, and demethylation were the major metabolic reactions with which C. papyrus responded to neonicotinoids. These reactions may be mediated by cytochrome P450 enzyme, aldehyde oxidase, glutathione-disulfide reductase, and glucuronate reductase. The toxicity of neonicotinoids in C. papyrus was evaluated according to the peroxidase and catalase enzymatic activities. Transcriptomic analysis revealed that differentially expressed genes (DEGs) mainly encoded proteins related to immune processes and cell growth regulation. Co-expression correlation analysis of DEGs revealed that the genes encoding P450s, peroxidase and glutathione S-transferase were the key functional genes. This study elucidates the stress response and degradation mechanism of neonicotinoids in wetland plants, providing new insights into the phytoremediation of organic contaminants in constructed wetlands.

Tracing COVID-19 drugs in the environment: Are we focusing on the right environmental compartment?

The Coronavirus Disease 2019 (COVID-19) pandemic led to over 770 million confirmed cases, straining public healthcare systems and necessitating extensive and prolonged use of synthetic chemical drugs around the globe for medical treatment and symptom relief. Concerns have arisen regarding the massive release of active pharmaceutical ingredients (APIs) and their metabolites into the environment, particularly through domestic sewage. While discussions surrounding this issue have primarily centered on their discharge into aquatic environments, particularly through treated effluent from municipal wastewater treatment plants (WWTPs), one often overlooked aspect is the terrestrial environment as a significant receptor of pharmaceutical-laden waste. This occurs through the disposal of sewage sludge, for instance, by applying biosolids to land or non-compliant disposal of sewage sludge, in addition to the routine disposal of expired and unused medications in municipal solid wastes. In this article, we surveyed sixteen approved pharmaceuticals for treating COVID-19 and bacterial co-infections, along with their primary metabolites. For this, we delved into their physiochemical properties, ecological toxicities, environmental persistence, and fate within municipal WWTPs. Emphasis was given on lipophilic substances with log Kow >3.0, which are more likely to be found in sewage sludge at significant factions (25.2%-75.0%) of their inputs in raw sewage and subsequently enter the terrestrial environment through land application of biosolids, e.g., 43% in the United States and as high as 96% in Ireland or non-compliant practices of sewage sludge disposal in developing communities, such as open dumping and land application without prior anaerobic digestion. The available evidence underscores the importance of adequately treating and disposing of sewage sludge before its final disposal or land application in an epidemic or pandemic scenario, as mismanaged sewage sludge could be a significant vector for releasing pharmaceutical compounds and their metabolites into the terrestrial environment.

Congener-specific uptake and accumulation of bisphenols in edible plants: Binding to prediction of bioaccumulation by attention mechanism multi-layer perceptron machine learning model

Plant accumulation of phenolic contaminants from agricultural soils can cause human health risks via the food chain. However, experimental and predictive information for plant uptake and accumulation of bisphenol congeners is lacking. In this study, the uptake, translocation, and accumulation of five bisphenols (BPs) in carrot and lettuce plants were investigated through hydroponic culture (duration of 168 h) and soil culture (duration of 42 days) systems. The results suggested a higher bioconcentration factor (BCF) of bisphenol AF (BPAF) in plants than that of the other four BPs. A positive correlation was found between the log BCF and the log Kow of BPs (R2carrot = 0.987, R2lettuce = 0.801, P < 0.05), while the log (translocation factor) exhibited a negative correlation with the log Kow (R2carrot = 0.957, R2lettuce = 0.960, P < 0.05). The results of molecular docking revealed that the lower binding energy of BPAF with glycosyltransferase, glutathione S-transferase, and cytochrome P450 (-4.34, -4.05, and -3.52 kcal/mol) would be responsible for its higher accumulation in plants. Based on the experimental data, an attention mechanism multi-layer perceptron (AM-MLP) model was developed to predict the BCF of eight untested BPs by machine learning, suggesting the relatively high BCF of bisphenol BP, bisphenol PH, and bisphenol TMC (BCFcarrot = 1.37, 1.50, 1.03; BCFlettuce = 1.02, 0.98, 0.67). The prediction of BCF for ever-increasing varieties of BPs by machine learning would reduce repetitive experimental tests and save resources, providing scientific guidance for the production and application of BPs from the perspective of priority pollutants.

Influence of exposure time, physicochemical properties, and plant transpiration on the uptake dynamics and translocation of pharmaceutical and personal care products in the aquatic macrophyte Typha latifolia

Typha latifolia is widely used as a phytoremediation model plant for organic compounds. However, the dynamic uptake and translocation of pharmaceutical and personal care products (PPCPs) and their relationship with physicochemical properties, such as lipophilicity (LogKow), ionization behavior (pKa), pH-dependent lipophilicity (LogDow), exposure time and transpiration, are scarcely studied. In the current study, hydroponically grown T. latifolia was exposed to carbamazepine, fluoxetine, gemfibrozil, and triclosan at environmentally relevant concentrations (20 μg/L each). Eighteen out of thirty-six plants were exposed to the PPCPs and the other eighteen were untreated. Plants were harvested at 7, 14, 21, 28, 35, and 42 days and separated into root, rhizome, sprouts, stem, and lower, middle, and upper leaf sections. Dry tissue biomass was determined. PPCP tissue concentrations were analyzed by LC-MS/MS. PPCP mass per tissue type was calculated for each individual compound and for the sum of all compounds during each exposure time. Carbamazepine, fluoxetine, and triclosan were detected in all tissues, while gemfibrozil was detected only in roots and rhizomes. In roots, triclosan and gemfibrozil mass surpassed 80% of the PPCP mass, while in leaf carbamazepine and fluoxetine mass represented 90%. Fluoxetine accumulated mainly in the stem and the lower and middle leaf, while carbamazepine accumulated in the upper leaf. The PPCP mass in roots and rhizome was strongly positively correlated with LogDow, while in leaf it was correlated with water transpired and pKa. PPCP uptake and translocation in T. latifolia is a dynamic process determined by the properties of contaminants and plants.

LC-HRMS method for study of pharmaceutical uptake in plants: effect of pH under aeroponic condition

Global climate changes cause water scarcity in many regions, and the sustainable use of recycled water appears crucial, especially in agriculture. However, potentially hazardous compounds such as pharmaceuticals can enter the food chain and pose severe risks. This paper aims to study the presence of selected pharmaceutical active compounds (PhACs) and their metabolites in crops grown in aeroponic conditions and evaluate the potential of PhAC plant uptake. A solvent extraction with an acidified mixture of acetonitrile and water followed by LC-HRMS was developed and validated for quantifying nine pharmaceuticals and their nine metabolites in three plants. We aimed for a robust method with a wide linear range because an extensive concentration range in different matrices was expected. The developed method proved rapid and reliable determination of selected pharmaceuticals in plants in the wide concentration range of 10 to 20,000 ng g-1 and limit of detection range 0.4 to 9.0 ng g-1. The developed method was used to study the uptake and translocation of pharmaceuticals and their metabolites in plant tissues from an aeroponic experiment at three different pH levels. Carbamazepine accumulated more in the leaves of spinach than in arugula. On the other hand, sulfamethoxazole and clindamycin evinced higher accumulation in roots than in leaves, comparable in both plants. The expected effect of pH on plants' uptake was not significant.

Effective bioremediation of clarithromycin and diclofenac in wastewater by microbes and Arundo donax L

Bioremediation of pharmaceuticals has gained large research efforts, but there is still a need to improve the performance of bioremediation systems by selecting effective organisms. In this study, we characterized the capability to remove clarithromycin (CLA) and diclofenac (DCF) by the bacterium Streptomyces rochei, and the fungi Phanerochaete chrysosporium and Trametes versicolor. The macrolide antibiotic CLA and the non-steroid anti-inflammatory DCF were selected because these are two of the most frequently detected drugs in water bodies. Growth and content of the PhCs and a DCF metabolite (MET) by the energy crop Arundo donax L. were also evaluated under hydroponic conditions. The removal rate (RR) by S. rochei increased from 24 to 40% at 10 and 100 µg CLA L-1, respectively, averaged over incubation times. At 144 h, the RR by P. chrysosporium was 84%, while by T. versicolor was 70 and 45% at 10 and 100 CLA µg L-1. The RR by S. rochei did not exceed 30% at 1 mg DCF L-1 and reached 60% at 10 mg DCF L-1, whereas approached 95% and 63% by P. chrysosporium and T. versicolor, respectively, at both doses. Root biomass and length of A. donax were strongly affected at 100 µg CLA L-1. CLA concentration in roots and shoots increased with the increase of the dose and translocation factor (TF) was about 1. DCF severely affected both shoot fresh weight and root length at the highest dose and concentration in roots and shoots increased with the increase of the dose. DCF concentrations were 16-19 times higher in roots than in shoots, and TF was about 0.1. MET was detected only in roots and its proportion over the parent compound decreased with the increase of the DCF dose. This study highlights the potential contribution of A. donax and the tested microbial inoculants for improving the effectiveness of bioremediation systems for CLA and DCF removal.

Plant -microbe assisted emerging contaminants (ECs) removal and carbon cycling

Continuous increase in the level of atmospheric CO₂ and environmental contaminates has aggravated various threats resulting from environmental pollution and climate change. Research into plant -microbe interaction has been a central concern of ecology for over the year. However, despite the clear contribution of plant -microbe to the global carbon cycle, the role of plant -microbe interaction in carbon pools, fluxes and emerging contaminants (ECs) removal are still a poorly understood. The use of plant and microbes in ECs removal and carbon cycling is an attractive strategy because microbes operate as biocatalysts to remove contaminants and plant roots offer a rich niche for their growth and carbon cycling. However, bio-mitigation of CO₂ and removal of ECs is still under research phase because of the CO₂ capture and fixation efficiency is too low for industrial purposes and cutting-edge removal methods have not been created for such emerging contaminants.

Ambiguous changes in photosynthetic parameters of Lemna minor L. after short-term exposure to naproxen and paracetamol: Can the risk be ignored?

Non-steroidal anti-inflammatory drugs (NSAID) are recently monitored in the aquatic environment. Naproxen (NPX), paracetamol (PCT) and their transformation products can influence the biochemical and physiological processes at the sub-cellular and cellular levels taking part in the growth and development of plants. This study aimed to compare the effects of NPX and PCT, drugs with different physico-chemical properties, on the growth and photosynthetic processes in Lemna minor during a short-term (7 days) exposure. Although duckweed took up more than five times higher amount of PCT as compared to NPX (275.88 µg/g dry weight to 43.22 µg/g when treated with 10 mg/L), only NPX limited the number of new plants by 9% and 26% under 1 and 10 mg/L, respectively, and increased their dry weight (by 18% under 10 mg/L) and leaf area per plant. A considerable (by 30%) drop in the content of photosynthetic pigments under 10 mg/L treatment by both drugs did not significantly affect the efficiency of the primary processes of photosynthesis. Values of induced chlorophyll fluorescence parameters (F₀, F_V/F_M, Φ_II, and NPQ) showed just a mild stimulation by PCT and a negative effect by NPX (by up to 10%), especially on the function of photosystem II and electron transport in both intact duckweed plants and isolated chloroplasts. Lowered efficiency of Hill reaction activity (by more than 10% under 0.1 - 10 mg/L treatments) in isolated chloroplasts suspension proved the only inhibition effect of PCT to primary photosynthetic processes. In intact plants, higher treatments (0.5 - 10 mg/L) by both NPX and PCT induced an increase in RuBisCO content. The results prove that the potential effect of various drugs on plants is hard to generalise.

Phytoremediation of diclofenac using the Green Liver System: Macrophyte screening to system optimization

Green Liver Systems employ the ability of macrophytes to take up, detoxify (biotransform), and bioaccumulate pollutants; however, these systems require optimization to target specific pollutants. In the present study, the aim was to test the applicability of the Green Liver System for diclofenac remediation considering the effects of selected variables. As a starting point, 42 macrophyte life forms were evaluated for diclofenac uptake. With the three best performing macrophytes, the system efficiency was evaluated at two diclofenac concentrations, one environmentally relevant and that other significantly higher (10µg/L and 150µg/L) and in two system sizes (60L and 1000L) as well as at three flow rates (3, 7, and 15L/min). The effect of single species and combinations on removal efficiency was also considered. The highest internalization percentage was recorded in Ceratophyllum spp., Myriophyllum spp., and Egeria densa. Phytoremediation efficiency with species combinations was far superior to utilizing only a single macrophyte type. Furthermore, the results indicate that the flow rate significantly affected the removal efficiency of the pharmaceutical tested, with the highest remediation efficiency obtained with the highest flow rate. System size did not significantly affect phytoremediation; however, increase diclofenac concentration reduced the systems performance significantly. When planning the setup of a Green Liver System for wastewater remediation, basic knowledge about the water, i.e., pollutant types and flow, must be utilized during planning to optimize remediation. Various macrophytes show diverse uptake efficiencies for different contaminants and should be selected based on the pollutant composition of the wastewater.

Green alga Chlamydomonas reinhardtii can effectively remove diclofenac from the water environment - A new perspective on biotransformation

The use of unicellular algae to remove xenobiotics (including drugs) from wastewaters is one of the rapidly developing areas of environmental protection. Numerous data indicate that for efficient phycoremediation three processes are important, i.e. biosorption, bioaccumulation, and biotransformation. Although biosorption and bioaccumulation do not raise any serious doubts, biotransformation is more problematic since its products can be potentially more toxic than the parent compounds posing a threat to organisms living in a given environment, including organisms that made this transformation. Thus, two questions need to be answered before the proper algae strain is chosen for phycoremediation, namely what metabolites are produced during biotransformation, and how resistant is the analyzed strain to a mixture of parent compound and metabolites that appear over the course of culture? In this work, we evaluated the remediation potential of the model green alga Chlamydomonas reinhardtii in relation to non-steroidal anti-inflammatory drugs (NSAIDs), as exemplified by diclofenac. To achieve this, we analysed the susceptibility of C. reinhardtii to diclofenac as well as its capability to biosorption, bioaccumulation, and biotransformation of the drug. We have found that even at a relatively high concentration of diclofenac the algae maintained their vitality and were able to remove (37.7%) DCF from the environment. A wide range of phase I and II metabolites of diclofenac (38 transformation products) was discovered, with many of them characteristic rather for animal and bacterial biochemical pathways than for plant metabolism. Due to such a large number of detected products, 18 of which were not previously reported, the proposed scheme of diclofenac transformation by C. reinhardtii not only significantly contributes to broadening the knowledge in this field, but also allows to suggest possible pathways of degradation of xenobiotics with a similar structure. It is worth pointing out that a decrease in the level of diclofenac in the media observed in this study cannot be fully explained by biotransformation (8.4%). The mass balance analysis indicates that other processes (total 22%), such as biosorption, a non-extractable residue formation, or complete decomposition in metabolic cycles can be involved in the diclofenac disappearance, and those findings open the prospects of further research.

Titanium (IV) oxide anatase nanoparticles as vectors for diclofenac: assessing the antioxidative responses to single and combined exposures in the aquatic macrophyte Egeria densa

Titanium dioxide, frequently used in commonplace products, is now regularly detected in aquatic environments. Understanding its toxic effects on native biota is essential. However, combined toxicity with commonly occurring pollutants, such as the pharmaceutical diclofenac, may provide more insight into environmental situations. Therefore, the present study aimed to evaluate the effects of titanium dioxide and diclofenac, individually and combined, on the macrophyte Egeria densa. Diclofenac uptake and removal by the macrophyte were assessed. Diclofenac and titanium dioxide were mixed prior to exposure to allow binding, which was assessed. Toxicity of the individual compounds and the combination was evaluated by assaying enzymes as bioindicators of biotransformation and the antioxidative system. Cytosolic glutathione S-transferase and glutathione reductase activities were increased by diclofenac, titanium dioxide, and the combination. Both enzymes' activities were more significantly elevated by diclofenac and the combination than nanoparticles alone. Microsomal glutathione S-transferase was unaffected by diclofenac exposure but inhibited with titanium dioxide and the mixture. Diclofenac elicited the most significant response. Based on the data, the cytosolic enzymes effectively prevented damage.

Root uptake and metabolization of Alternaria toxins by winter wheat plants using a hydroponic system

Fungi of the genus Alternaria are ubiquitous in the environment. Their mycotoxins can leach out of contaminated plants or crop debris into the soil entering the plant via the roots. We aim to evaluate the importance of this entry pathway and its contribution to the overall content of Alternaria toxins (ATs) in wheat plants to better understand the soil-plant-phytopathogen system. A hydroponic cultivation system was established and wheat plants were cultivated for up to two weeks under optimal climate conditions. One half of the plants was treated with a nutrient solution spiked with alternariol (AOH), alternariol monomethyl ether (AME), and tenuazonic acid (TeA), whereas the other half of the plants was cultivated without mycotoxins. Plants were harvested after 1 and 2 weeks and analyzed using a QuEChERS-based extraction and an in-house validated LC-MS/MS method for quantification of the ATs in roots, crowns, and leaves separately. ATs were taken up by the roots and transported throughout the plant up to the leaves after 1 as well as 2 weeks of cultivation with the roots showing the highest ATs levels followed by the crowns and the leaves. In addition, numerous AOH and AME conjugates like glucosides, malonyl glucosides, sulfates, and di/trihexosides were detected in different plant compartments and identified by high-resolution mass spectrometry. This is the first study demonstrating the uptake of ATs in vivo using a hydroponic system and whole wheat plants examining both the distribution of ATs within the plant compartments and the modification of ATs by the wheat plants.

Congener-Specific Uptake and Metabolism of Bisphenols in Carrot Cells: Dissipation Kinetics, Biotransformation, and Enzyme Responses

Food consumption has been considered a key pathway of bisphenol compound (BP) exposure for humans. However, there is a lack of evidence concerning their congener-specific behavior and metabolism in plants. Herein, we examined the uptake and metabolism of five BPs in plants using carrot cells. Bisphenol S (BPS) and bisphenol AF (BPAF) exhibited substantially lower dissipation rates in the cells than the other BPs, indicating a strong selectivity in the uptake and metabolism among bisphenol congeners. For a total of 23 metabolites of BPs, the predominant biotransformation pathways were found to be glycosylation, methoxylation, and conjugation, while hydroxylation, methylation, and glutathionylation were only observed for some BPs. The changes in the mRNA expression of cytochrome P450 (P450) and the activities of glycosyltransferase and glutathione S-transferase were remarkably higher in cells exposed to bisphenol F, bisphenol A, and bisphenol B than in cells exposed to BPS and BPAF, indicating congener specificity in their effects on enzymes and the associated biotransformation processes. Consequently, the potential congener-specific differences in plant uptake, metabolism, and accumulation must be considered when assessing the environmental risks posed by these commonly used plasticizers.

Rapid plant uptake of isothiazolinone biocides and formation of metabolites by hydroponic Arabidopsis

Isothiazolinones biocides are water-soluble, low molecular weight, nitrogenous compounds widely used to prevent microbial growth in a variety of applications including personal care products and building façade materials. Because isothiazolinones from buildings wash off and enter stormwater, interactions with terrestrial plants may represent an important part of the environmental fate of these compounds (e.g., in green stormwater infrastructure). Using the model plant Arabidopsis thaliana grown hydroponically, we observed rapid (≥99% within 24 hours), plant-driven removal of four commonly used isothiazolinones: benzisothiazolinone (BIT), chloromethylisothiazolinone, methylisothiazolinone, and octylisothiazolinone. No significant differences in uptake rate occurred between the four compounds; therefore, BIT was used for further detailed investigation. BIT uptake by Arabidopsis was concentration-dependent in a manner that implicates transporter-mediated substrate inhibition. BIT uptake was also minimally impacted by multiple BIT spikes, suggesting constituently active uptake. BIT plant uptake rate was robust, unaffected by multiple inhibitors. We investigated plant metabolism as a relevant removal process. Proposed major metabolites that significantly increased in the BIT-exposure treatment compared to the control included: endogenous plant compounds nicotinic acid (confirmed with a reference standard) and phenylthioacetohydroximic acid, a possible amino acid-BIT conjugate, and two accurate masses of interest. Two of the compounds (phenylthioacetohydroximic acid and TP 470) were also present in increased amounts in the hydroponic medium after BIT exposure, possibly via plant excretion. Upregulation of endogenous plant compounds is environmentally significant because it demonstrates that BIT impacts plant biology. The rapid plant-driven isothiazolinone removal observed here indicates that plant-isothiazolinone processes could be relevant to the environmental fate of these stormwater compounds.

Plant species compositions alleviate toxicological effects of bisphenol A by enhancing growth, antioxidant defense system, and detoxification

Bisphenol A (BPA), a broadly disseminated endocrine disturbing chemicals in environment, is harmful to creatures and plants. Plants can uptake and metabolize BPA, but a single plant species ability is limited. Undeniably, plant species compositions have a more vital ability to remove pollutants than a single plant species. However, the mechanisms of plant species compositions alleviating toxicological effects of bisphenol A are poorly understood. Here, we administered plant species compositions, which based on a full-factorial design of Phragmites australis (A), Typha latifolia (B), and Arundo donax (C), to unveil their role in BPA exposure. The results illustrated that the root activity, biomass, and photosynthetic pigment contents of the mixed hydroponic group (e.g., sp(ABC)) were significantly increased under concentration of BPA(1.5, 5, and 10 mg L^-1), which showed that the root activity, fresh weight, dry weight, chlorophyll a, and total chlorophyll contents of shoots were increased. While mixed-hydroponic culture groups (e.g., sp(AB), sp(ABC)) significantly increased antioxidant enzyme activity and antioxidant substances under concentration of BPA(5 and 10 mg L^-1), it astoundingly diminished responsive oxygen species (ROS) and malondialdehyde (MDA) substance, proposing that mixed-hydroponic culture groups calmed oxidative stress. Further analysis revealed that mixed-hydroponic culture groups (e.g., sp(AB), sp(AC), sp(ABC)) of 1.5, 5, and 10 mg L^-1 BPA exposure significantly increased detoxification enzyme activity of NADPH-cytochrome P450 reductase (CPR), glutathione S-transferase (GST), and glycosyltransferase (GT). Moreover, mixed-hydroponic culture groups (e.g., sp(AB), sp(AC), sp(ABC)) decreased the BPA substance in leaves, proposing that mixed-hydroponic culture groups advanced BPA metabolism by improving CPR, GST, and GT enzyme activities. These results demonstrated that a mixed-hydroponic culture strategy can alleviate BPA phytotoxicity and possibly offer natural and potential phytoremediation methods for BPA.

The in vivo and vitro degradation of sulfonamides in wetland plants reducing phytotoxicity and environmental pollution

Aquatic plants can be used for in situ remediation of water-borne pharmaceutical compounds; however, such information and that of the potential risks of metabolites released into the environment are limited. This study determined the capacity of Canna indica and Acorus calamus used in the remediation of water-borne sulfonamides (SA). The tolerance, removal, accumulation, and biotransformation of various water-borne SAs were investigated in vivo by exposing plants to SA solutions (50 µg/L and 500 µg/L). After 28 days, C. indica removed more SAs (89.3-97.8%) than A. calamus (12.8-84.6%) and non-planted systems (8.0-69.3%). The SA removal results, except from the A. calamus system with 500 µg/L SA, fit the first-order kinetics model. The estimated half-lives of all SAs were 3-40 h and 2-60 h in the C. indica and A. calamus systems, respectively. In vivo biotransformation and rhizosphere degradation were the major phyto-removal mechanisms, constituting 24.9-81.1% and 0.0-37.1% of all SAs in the C. indica and A. calamus systems, respectively. SA acetyl metabolites were detected only in plant tissues supporting evidence for plant metabolic processes without risk into the environment. SA metabolism including oxidation, methylation, and conjugation via acetylation was potentially beneficial to accumulation and tolerate stress of antibiotic. Canna indica was more suitable for cleaning SA. Our findings better clarify the potential and low risks of phytoremediation in antibiotic-contaminated waters.

Fate and impact of wastewater-borne micropollutants in lettuce and the root-associated bacteria

The reuse of water for agricultural practices becomes progressively more important due to increasing demands for a transition to a circular economy. Treated wastewater can be an alternative option of blue water used for the irrigation of crops but its risks need to be evaluated. This study assesses the uptake and metabolization of pharmaceuticals and personal care products (PPCPs) derived from treated wastewater into lettuce as well as the impact on root-associated bacteria under a realistic and worst-case scenario. Lettuce was grown in a controlled greenhouse and irrigated with water or treated wastewater spiked with and without a mixture of fourteen different PPCPs at 10 μg/L or 100 μg/L. After harvesting the plants, the same soil was reused for a consecutive cultivation campaign to test for the accumulation of PPCPs. Twelve out of fourteen spiked PPCPs were detected in lettuce roots, and thirteen in leaves. In roots, highest concentrations were measured for sucralose, sulfamethoxazole and citalopram, while sucralose, acesulfame and carbamazepine were the highest in leaves. Higher PPCP concentrations were found in lettuce roots irrigated with spiked treated wastewater than in those irrigated with spiked water. The absolute bacterial abundance remained stable over both cultivation campaigns and was not affected by any of the treatments (type of irrigation water (water vs. wastewater) nor concentration of PPCPs). However, the irrigation of lettuce with treated wastewater had a significant effect on the microbial α-diversity indices at the end of the second cultivation campaign, and modified the structure and community composition of root-associated bacteria at the end of both campaigns. Five and fourteen bacterial families were shown to be responsible for the observed changes at the end of the first and second cultivation campaign, respectively. Relative abundance of Haliangium and the clade Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium was significantly affected in response to PCPPs exposure. Caulobacter, Cellvibrio, Hydrogenophaga and Rhizobacter were significantly affected in microcosms irrigated with wastewater.

Uptake, Occurrence, and Effects of Nonsteroidal Anti-Inflammatory Drugs and Analgesics in Plants and Edible Crops

The plant uptake of pharmaceuticals that include nonsteroidal anti-inflammatory drugs (NSAIDs) and analgesics from contaminated environment has benefits and drawbacks. These pharmaceuticals enter plants mostly through irrigation with contaminated water and application of sewage sludge as soil fertilizer. Aquatic plants withdraw these pharmaceuticals from water through their roots. Numerous studies have observed the translocation of these pharmaceuticals from the roots into the aerial tissues. Furthermore, the occurrence of the metabolites of NSAIDs in plants has been observed. This article provides an in-depth critical review of the plant uptake of NSAIDs and analgesics, their translocation, and toxic effects on plant species. In addition, the occurrence of metabolites of NSAIDs in plants and the application of constructed wetlands using plants for remediation are reviewed. Factors that affect the plant uptake and translocation of these pharmaceuticals are examined. Gaps and future research are provided to guide forthcoming investigations on important aspects that worth explorations.

Specific glutathione-S-transferases ensure an efficient detoxification of diclofenac in Solanum lycopersicum L. plants

Diclofenac (DCF) is a very common pharmaceutical that, due to its high use and low removal rate, is considered a prominent contaminant in surface and groundwater worldwide. In this study, Solanum lycopersicum L. cv. Micro-Tom (tomato) was used to disclose the role of glutathione (GSH)-related enzymes, as GSH conjugation with DCF is a well reported detoxification mechanism in mammals and some plant species. To achieve this, S. lycopersicum plants were exposed to 0.5 and 5 mg L^-1 of DCF for 5 weeks under a semi-hydroponic experiment. The results here obtained point towards an efficient DCF detoxification mechanism that prevents DCF bioaccumulation in fruits, minimizing any concerns for human health. Although a systemic response seems to be present in response to DCF, the current data also shows that its detoxification is mostly a root-specific process. Furthermore, it appears that GSH-mediated DCF detoxification is the main mechanism activated, as glutathione-S-transferase (GST) activity was greatly enhanced in roots of tomato plants treated with 5 mg L^-1 DCF, accompanied by increased glutathione reductase activity, responsible for GSH regeneration. By applying a targeted gene expression analysis, we provide evidence, for the first time, that SlGSTF4 and SlGSTF5 genes, coding for GSTs from phi class, were the main players driving the conjugation of this contaminant. In this sense, and even though tomato plants appear to be somewhat tolerant to DCF exposure, research on GST activity can prove to be instrumental in remediating DCF-contaminated environments and improving plant growth under such conditions.

Stress symptoms and plant hormone-modulated defense response induced by the uptake of carbamazepine and ibuprofen in Malabar spinach (Basella alba L.)

Due to their wide applications and extensive discharges, pharmaceuticals have recently become a potential risk to aquatic and terrestrial organisms. The uptake of pharmaceuticals have been shown to stimulate plant defense systems and induce phytotoxic effects. Signaling molecules such as plant hormones play crucial roles in plant stress and defense responses, but the relationship between these molecules and pharmaceutical uptake has rarely been investigated. In this study, two common pharmaceuticals, carbamazepine and ibuprofen, and three stress-related plant hormones, jasmonic acid, salicylic acid, and abscisic acid, were simultaneously tracked in the roots and stems of Malabar spinach (Basella alba L.) via an in vivo solid phase microextraction (SPME) method. We also monitored stress-related physiological markers and enzymatic activities to demonstrate plant hormone modulation. The results indicate that pharmaceutical uptake, subsequent stress symptoms, and the defense response were all significantly correlated with the upregulation of plant hormones. Moreover, the plant hormones in the exposure group failed to recover to normal levels, indicating that plants containing pharmaceutical residues might be subject to potential risks.

Exposure of Mytilus trossulus to diclofenac and 4'-hydroxydiclofenac: Uptake, bioconcentration and mass balance for the evaluation of their environmental fate

Diclofenac (DIC) is one of the most widely consumed drugs in the world, and its presence in the environment as well as potential effects on organisms are the subject of numerous recent scientific works. However, it is becoming clear that the risk posed by pharmaceuticals in the environment needs to be viewed more broadly and their numerous derivatives should also be considered. In fact, already published results confirm that the transformation products of NSAIDs including DIC may cause a variety of potentially negative effects on marine organisms, sometimes showing increased biological activity. To date, however, little is known about bioconcentration of DIC and DIC metabolites and the role of sex in this process. Therefore, the present study for the first time evaluates sex-related differences in DIC bioconcentration and estimates bioconcentration potential of DIC metabolite, 4-OH DIC, in the Mytilus trossulus tissues. In the experiment lasting 7 days, mussels were exposed to DIC and 4-OH DIC at concentrations 68.22 and 20.85 μg/L, respectively. Our study confirms that DIC can be taken up by organisms not only in its native form, but also as a metabolite, and metabolised further. Furthermore, in the present work, mass balance was performed and the stability of both studied compounds under experimental conditions was analysed. Obtained results suggest that DIC is more stable than its derivative under the tested conditions, but further analyses of the environmental fate of these compounds are necessary.

Metabolism of non-steroidal anti-inflammatory drugs by non-target wild-living organisms

The presence of the non-steroidal anti-inflammatory drugs (NSAIDs) in the environment is a fact, and aquatic and soil organisms are chronically exposed to trace levels of these emerging pollutants. This review presents the current state of knowledge on the metabolic pathways of NSAIDs in organisms at various levels of biological organisation. More than 150 publications dealing with target or non-target analysis of selected NSAIDs (mainly diclofenac, ibuprofen, and naproxen) were collected. The metabolites of phase I and phase II are presented. The similarity of NSAIDs metabolism to that in mammals was observed in bacteria, microalgae, fungi, higher plants, invertebrates, and vertebrates. The differences, such as newly detected metabolites, the extracellular metabolism observed in bacteria and fungi, or phase III metabolism in plants, are highlighted. Metabolites detected in plants (conjugates with sugars and amino acids) but not found in any other organisms are described. Selected, in-depth studies with isolated bacterial strains showed the possibility of transforming NSAIDs into assimilable carbon sources. It has been found that some of the metabolites show higher toxicity than their parent forms. The presence of metabolites of NSAIDs in the environment is the cumulative effect of their introduction with wastewaters, their formation in wastewater treatment plants, and their transformation by non-target wild-living organisms.

Ecotoxicological risk assessment of wastewater irrigation on soil microorganisms: Fate and impact of wastewater-borne micropollutants in lettuce-soil system

The implementation of the new Water Reuse regulation in the European Union brings to the forefront the need to evaluate the risks of using wastewater for crop irrigation. Here, a two-tier ecotoxicological risk assessment was performed to evaluate the fate of wastewater-borne micropollutants in soil and their ecotoxicological impact on plants and soil microorganisms. To this end, two successive cultivation campaigns of lettuces were irrigated with wastewater (at agronomical dose (not spiked) and spiked with a mixture of 14 pharmaceuticals at 10 and 100 µg/L each) in a controlled greenhouse experiment. Over the two cultivation campaigns, an accumulation of PPCPs was observed in soil microcosms irrigated with wastewater spiked with 100 μg/L of PPCPs with the highest concentrations detected for clarithromycin, hydrochlorothiazide, citalopram, climbazole and carbamazepine. The abundance of bacterial and fungal communities remained stable over the two cultivation campaigns and was not affected by any of the irrigation regimes applied. Similarly, no changes were observed in the abundance of ammonium oxidizing archaea (AOA) and bacteria (AOB), nor in clade A of commamox no matter the cultivation campaign or the irrigation regime considered. Only a slight increase was detected in clade B of commamox bacteria after the second cultivation campaign. Sulfamethoxazole-resistant and -degrading bacteria were not impacted either. The irrigation regimes had only a limited effect on the bacterial evenness. However, in response to wastewater irrigation the structure of soil bacterial community significantly changed the relative abundance of Acidobacteria, Chloroflexi, Verrucomicrobia, Beta-, Gamma- and Deltaprotebacteria. Twenty-eight operational taxonomic units (OTUs) were identified as responsible for the changes observed within the bacterial communities of soils irrigated with wastewater or with water. Interestingly, the relative abundance of these OTUs was similar in soils irrigated with either spiked or non-spiked irrigation solutions. This indicates that under both agronomical and worst-case scenario the mixture of fourteen PPCPs had no effect on soil bacterial community.

Hazardous impact of diclofenac on mammalian system: Mitigation strategy through green remediation approach

Diclofenac is an anti-inflammatory drug used as an analgesic. It is often detected in various environmental sources around the world and is considered as one of the emerging contaminants (ECs). This paper reviews the distribution of diclofenac at high concentrations in diverse environments and its adverse ecological impact. Recent studies observed strong evidence of the hazardous effect of diclofenac on mammals, including humans. Diclofenac could cause gastrointestinal complications, neurotoxicity, cardiotoxicity, hepatotoxicity, nephrotoxicity, hematotoxicity, genotoxicity, teratogenicity, bone fractures, and skin allergy in mammals even at a low concentration. Collectively, this comprehensive review relates the mode of toxicity, level of exposure, and route of administration as a unique approach for addressing the destructive consequence of diclofenac in mammalian systems. Finally, the mitigation strategy to eradicate the diclofenac toxicity through green remediation is critically discussed. This review will undoubtedly shed light on the toxic effects of pseudo-persistent diclofenac on mammals as well as frame stringent guidelines against its common usage.

Insights on the role of periphytic biofilm in synergism with Iris pseudacorus for removing mixture of pharmaceutical contaminants from wastewater

The potential of Iris pseudacorus and the associated periphytic biofilm for biodegradation of two common pharmaceutical contaminants (PCs) in urban wastewater was assessed individually and in consortium. An enhanced removal for sulfamethoxazole (SMX) was achieved in consortium (59%) compared to individual sets of I. pseudacorus (50%) and periphytic biofilm (7%) at concentration of 5 mg L^-1. Conversely, individual sets of periphytic biofilm (77%) outperformed removal of doxylamine succinate (DOX) compared to individual sets of I. pseudacorus (59%) and consortium (67%) at concentration of 1 mg L^-1. Enhanced relative abundance of microflora containing microalgae (Sellaphora, Achnanthidium), rhizobacteria (Acidibacter, Azoarcus, Thioalkalivibrio), and fungi (Serendipita) in periphytic biofilm was observed after treatment. SMX treatment for five days elevated cytochrome P450 enzymes' expressions, including aniline hydroxylase (48%) and aminopyrine N-demethylase (54%) in the periphytic biofilm. Nevertheless, I. pseudacorus showed 175% elevation of aniline hydroxylase along with other biotransformation enzymes, such as peroxidase (629%), glutathione S-transferase (514%), and dichloroindophenol reductase (840%). A floating bed phytoreactor planted with I. pseudacorus and the periphytic biofilm consortium removed 67% SMX and 72% DOX in secondary wastewater effluent. Thus, the implementation of this strategy in constructed wetland-based treatment could be beneficial for managing effluents containing PCs.

Reclaimed water driven lettuce cultivation in a hydroponic system: the need of micropollutant removal by advanced wastewater treatment

For a novel approach of resource-efficient water reuse, a municipal wastewater treatment plant was extended at pilot scale for advanced wastewater treatment, i.e., ozonation and biological activated carbon filtration, and a hydroponic system for reclaimed water driven lettuce cultivation. The treatment specific wastewater lines with the corresponding lettuce plants, differentiated into roots and shoots, were monitored for priority wastewater micropollutants, i.e., acesulfame (sweetener), caffeine (stimulant), carbamazepine, diclofenac, ibuprofen, sulfamethoxazole with acetyl-sulfamethoxazole (human pharmaceuticals), 1H-benzotriazole, and 4/5-methylbenzotriazole (industrial chemicals). As clearly demonstrated, conventional tertiary treatment could not efficiently clean up wastewater. Removal efficiencies ranged from 3% for carbamazepine to 100% for ibuprofen. The resulting pollution of the hydroponic water lines led to the accumulation of acesulfame, carbamazepine, and diclofenac in lettuce root systems at 32.0, 69.5, and 135 μg kg-1 and in the uptake of acesulfame and carbamazepine into lettuce shoots at 23.4 and 120 μg kg-1 dry weight, respectively. In contrast, both advanced treatment technologies when operating under optimized conditions achieved removal efficiencies of > 90% also for persistent micropollutants. Minimizing the pollution of reclaimed water thus met one relevant need for hydroponic lettuce cultivation.

Antioxidative response of lettuce (Lactuca sativa) to carbamazepine-induced stress

Carbamazepine (CBZ) is a widely used anti-epileptic drug that has been detected in wastewaters from sewage treating plants and thus appears in rivers, streams and other water bodies. As plants can absorb this compound, it can also appear in edible plants like lettuce, entering the food chain. In this study, the effect of carbamazepine in lettuce plants grown in hydroponic solution is analyzed. CBZ was detected both in roots and in leaves and is shown to induce oxidative stress. Hydrogen peroxide levels increased both in leaves and in roots while malondialdehyde increased only in leaves. Regarding the activity of antioxidative enzymes in the leaves, it is shown that superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (GPOD) and ascorbate peroxidase (APX) have a relevant role in quenching reactive oxygen species induced by oxidative stress. In roots, the only enzymes that showed increased activity were CAT, GPOD and glutathione reductase (GR). Ascorbate and glutathione also appear to have an important role as antioxidants in response to increased concentrations of carbamazepine. Although the roots are in direct contact with the contaminant, the leaves showed the strongest oxidative effects.

Response of Two Crop Plants, Zea mays L. and Solanum lycopersicum L., to Diclofenac and Naproxen

Among numerous contaminants, the ubiquitous occurrence of nonsteroidal anti-inflammatory drugs (NSAIDs) in the environment and their plausible harmful impact on nontarget organisms have made them one of the most important areas of concern in recent years. Crop plants can also potentially be exposed to NSAIDs, since the concentration of these pharmaceuticals is constantly rising in the surface water and soil. Our goal was to evaluate the stress response of two crop plants, maize and tomato, to treatment with selected NSAIDs, naproxen and diclofenac. The focus of the research was on the growth response, photosynthetic efficiency, selected oxidative stress factors (such as the H₂O₂ level and the rate of lipid peroxidation) as well as the total phenolic content, which represents the non-enzymatic protectants against oxidative stress. The results indicate that susceptibility to the NSAIDs that were tested is dependent on the plant species. A higher sensitivity of tomato manifested in growth inhibition, a decrease in the content of the photosynthetic pigments and a reduction in the maximum quantum efficiency of PSII and the activity of PSII, which was estimated using the F_v/F_m and F_v/F₀ ratios. Based on the growth results, it was also possible to reveal that diclofenac had a more toxic effect on tomato. In contrast to tomato, in maize, neither the content of the photosynthetic pigments nor growth appeared to be affected by DFC and NPX. However, both drugs significantly decreased in maize F_v and F_m, which are particularly sensitive to stress. A higher H₂O₂ concentration accompanied, in most cases, increasing lipid peroxidation, indicating that oxidative stress occurred in response to the selected NSAIDs in the plant species that were studied. The higher phenolic content of the plants after NSAIDs treatment may, in turn, indicate the activation of defense mechanisms in response to the oxidative stress that is triggered by these drugs.

Diclofenac modified the root system architecture of Arabidopsis via interfering with the hormonal activities of auxin

Diclofenac, a pharmaceutical and personal care product, is accumulating in various environmental matrices worldwide. Increased irrigation has facilitated an influx of environmental diclofenac into agricultural products, which potentially threatens non-target living organisms. In this study, we demonstrated that diclofenac modified the growth and root developmental processes of plants by disturbing the activity of auxin, a group of major phytohormones. Exogenous diclofenac treatment retarded growth and induced oxidative stress in young seedlings of Arabidopsis thaliana. In the developmental perspective, diclofenac altered the root system architecture, which was also similarly observed under exogenous IAA (a natural form of phytoalexins) treatment. The effects of diclofenac on the root development of A. thaliana were mediated through canonical auxin signaling pathways. However, when diclofenac and IAA were treated in combination, diclofenac suppressed the activity of IAA in root system architecture. At the molecular level, diclofenac significantly inhibited the activity of IAA upregulating the expression of early auxin-responsive marker genes. In conclusion, diclofenac modified the root development of A. thaliana via interfering with the activities of natural auxin. These results indicate that diclofenac could potentially act as an environmental contaminant disturbing the natural developmental processes of plants.

Employ of arbuscular mycorrhizal fungi for pharmaceuticals ibuprofen and diclofenac removal in mesocosm-scale constructed wetlands

This study investigated the effects of arbuscular mycorrhizal fungi (AMF) colonization on the growth of wetland plants (Glyceria maxima), and treatment performance in constructed wetlands (CWs) under the stress of pharmaceuticals ibuprofen (IBU) and diclofenac (DCF). Results showed that the growth of G. maxima was significantly increased by AMF colonization. AMF significantly increased the activities of antioxidant enzymes (peroxidase and superoxide dismutase) and soluble protein content in wetland plants, but the contents of malondialdehyde and O₂^•- were reduced. The removal efficiencies of TOC, PO₄^3--P, NH₄⁺-N, and TN were increased in AMF+ treatments by 6%, 11%, 15% and 11%, respectively. AMF increased the removal efficiencies of IBU and DCF by 6-14% and 2-21%, respectively, and reduced the content of their metabolites (2-OH IBU, CA IBU and 4'-OH DCF) in the effluent. Besides, the presence of AMF increased the contents of IBU and DCF in plant roots, while decreased their transportation to shoots. AMF symbiosis decreased the contents of IBU metabolites (2-OH IBU and CA IBU) but increased the contents of DCF metabolite (4'-OH DCF) in the roots of the host plant. In conclusion, these results indicated that AMF plays a promising role in CWs for emerging pollutants removal.

Sewage sludge in agriculture - the effects of selected chemical pollutants and emerging genetic resistance determinants on the quality of soil and crops - a review

In line with sustainable development principles and in order to combat climate change, which contributes to progressive soil depletion, various solutions are being sought to use treated sewage sludge as a soil amendment to improve soil quality and enrich arable soils with adequate amounts of biogenic compounds. This review article focuses on the effects of the agricultural use of biosolids on the environment. The article reviews the existing knowledge on selected emerging contaminants in treated sewage sludge and describes the impact of these pollutants on the environment and living organisms based on 183 publications selected from over 16,000 papers on related topics published over the last ten years. This study deals not only with chemical contaminants but also genetic determinants of resistance to these compounds. Current research has questioned the agricultural use of biosolids due to the presence of mutual interactions between antibiotics, heavy metals, the genetic determinants of resistance (antibiotic resistance genes - ARGs and heavy metal resistance genes - HMRGs) and non-steroidal anti-inflammatory drugs as well as the risks associated with their transfer to the environment. This study emphasizes the need for more extensive legal regulations that account for other pollutants of environmental concern (PEC), particularly in countries where sewage sludge is applied in agriculture most extensively. Future research should focus on more effective methods of eliminating PEC from sewage sludge, especially from the sludge that is used to fertilize agricultural land, because even small amounts of these micropollutants can have serious implications for the health and life of humans and animals.

Effects of diclofenac on sentinel species and aquatic communities in semi-natural conditions

Due to the potential hazard of diclofenac on aquatic organisms and the lack of higher-tier ecotoxicological studies, a long-term freshwater mesocosm experiment was set up to study the effects of this substance on primary producers and consumers at environmentally realistic nominal concentrations 0.1, 1 and 10 µg/L (average effective concentrations 0.041, 0.44 and 3.82 µg/L). During the six-month exposure period, the biovolume of two macrophyte species (Nasturtium officinale and Callitriche platycarpa) significantly decreased at the highest treatment level. Subsequently, a decrease in dissolved oxygen levels was observed. High mortality rates, effects on immunity, and high genotoxicity were found for encaged zebra mussels (Dreissena polymorpha) in all treatments. In the highest treatment level, one month after the beginning of the exposure, mortality of adult fish (Gasterosteus aculeatus) caused effects on the final population structure. Total abundance of fish and the percentage of juveniles decreased whereas the percentage of adults increased. This led to an overall shift in the length frequency distribution of the F₁ generation compared to the control. Consequently, indirect effects on the community structure of zooplankton and macroinvertebrates were observed in the highest treatment level. The No Observed Effect Concentration (NOEC) value at the individual level was < 0.1 µg/L and 1 µg/L at the population and community levels. Our study showed that in more natural conditions, diclofenac could cause more severe effects compared to those observed in laboratory conditions. The use of our results for regulatory matters is also discussed.

Uptake study in Juncus sp. and Salicornia europaea of six pharmaceuticals by liquid chromatography quadrupole time-of-flight mass spectrometry

In this work, eight plants of Juncus sp. and ten of Salicornia europaea were used for an uptake assay of pharmaceuticals (flumequine, cirpofloxacin, enrofloxacin, carbamazepine, diclofenac and ibuprofen) by irrigation at three concentration levels: 10 ng mL^-1 (low level); 700 ng mL^-1 (medium level) and 10 μg mL^-1 (high level). Two plants irrigated with pharmaceutical-free water were set up as controls. For each level, two plants were watered every day with 50 mL (Juncus sp.) and every two days with 20 mL (Salicornia europaea) of aqueous solutions containing all the analytes at the described concentrations. Plants irrigated at 10 μg mL^-1 were significantly the most affected, whereas the rest of the plants remained, in general, largely displayed no apparent physiological effects throughout the 30 days (Juncus sp.) and 21 days (Salicornia europaea) assays. Leaves and stems were cut every seven days and roots were collected at the end of the assay. The samples were lyophilized, submitted to a microwave assisted extraction using 5 mL of acetonitrile:water mixture (1:1, v/v) and they were analyzed (in triplicate) in a liquid chromatography-quadrupole time of flight mass spectrometry instrument. Most of the analytes were quantified in many of the samples corresponding to the three exposure levels with the highest concentrations obtained at high exposure levels. Ibuprofen was not detected in any sample and enrofloxacin, ciprofloxacin and diclofenac were not detected in the samples from Salicornia europaea.

Remoción de cinco productos farmacéuticos catalogados como contaminantes emergentes en medio acuoso utilizando la especie vetiver (Chrysopogon zizanioides)

Los productos farmacéuticos constituyen un grupo único de contaminantes emergentes de gran interés, debido a que se ha determinado su presencia frecuente en aguas superficiales, subterráneas y agua potable. Debido al metabolismo y la absorción incompletos en el organismo humano, una cantidad significativa de estos fármacos se excretan y liberan al ambiente a través de las aguas residuales. Por lo que el objetivo de este trabajo fue evaluar el potencial de la especie vetiver (Chrysopogon zizanioides) para eliminar del medio acuoso cinco productos farmacéuticos comúnmente recetados y de venta libre como ciprofloxacina, ibuprofeno, sulfametaxazol, diclofenaco y acetaminofén. La especie fue aclimatada en invernado, donde se llevó a cabo los experimentos en condiciones controladas de temperatura y a un pH de 6,5. Las muestras fueron analizadas utilizando espectrofotometría UV-Vis para leer en forma directa las absorbancias de cada producto farmacéutico. Para el análisis estadístico de los datos se empleó la metodología de superficies de respuesta con el fin de encontrar los modelos que ayuden a determinar tiempos y concentraciones óptimas donde se maximiza la absorción de cada fármaco, así como la obtención de las pendientes de crecimiento para determinar hacia donde se deberá buscar el óptimo. Se utilizó el software estadístico R versión 3.6.0 y RStudio versión 1.1.453. Los resultados obtenidos indican que C. zizanioides removió de manera más eficiente ciprofloxacina (98,3%) a una concentración de 3mg/L en un tiempo de 149h, seguido por ibuprofeno y diclofenaco con un máximo de remoción de 73,33% y sulfametaxazol con 66,53%, obteniéndose el menor porcentaje de remoción para acetaminofén de 38,49% a las 192h, donde se realizó toma de muestras cada 48 horas de las soluciones de cada fármaco a diferentes concentraciones (3 mg/L, 6 mg/L, 9 mg/L, 12 mg/L). En este trabajo de investigación se demostró la capacidad removedora de Chrysopogon zizanioides de los cinco fármacos estudiados en medio acuoso en condiciones controladas, vislumbrando un gran potencial en el ámbito de la biotecnología ambiental para el tratamiento terciario de aguas residuales.

Effect of the pharmaceuticals diclofenac and lamotrigine on stress responses and stress gene expression in lettuce (Lactuca sativa) at environmentally relevant concentrations

Vegetable crops irrigated with treated wastewater can take up the environmentally persistent pharmaceuticals diclofenac and lamotrigine. This study aimed at quantifying the uptake and translocation of the two pharmaceuticals in lettuce (Lactuca sativa) as well as on the elucidation of the molecular and physiological changes triggered by them. Therefore, plants were cultivated in a phytochamber in hydroponic systems under controlled conditions and treated independently with diclofenac (20 μg L-1) and lamotrigine (60 μg L-1) for 48 h. A low translocation of lamotrigine but not of diclofenac or its metabolite 4'-hydroxydiclofenac to leaves was observed, which corresponded with the expression of stress related genes only in roots of diclofenac treated plants. We observed an oxidative burst in roots and leaves occurring around the same time point when lamotrigine was detected in leaves. This could be responsible for the significantly changed gene expression pattern in both tissues. Our results showed for the first time that pharmaceuticals like lamotrigine or diclofenac might act as signals or zeitgebers, affecting the circadian expression of stress related genes in lettuce possibly causing a repressed physiological status of the plant.

Does diclofenac act like a photosynthetic herbicide on green algae? Chlamydomonas reinhardtii synchronous culture-based study with atrazine as reference

The non-steroidal anti-inflammatory drug diclofenac (DCF) is one of the commonly used and frequently detected drugs in water bodies, and several studies indicate its toxic effect on plants and algae. Studies performed with asynchronous Chlamydomonas reinhardtii cultures indicated that DCF inhibit the growth of population of the algae. Here, a synchronous population of C. reinhardtii, in which all cells are in the same developmental phase, is used. Following changes in cells size, photosynthetic activity and gene expression, we could compare, at the level of single cell, DCF-mediated effects with the effects caused by atrazine, a triazine herbicide that inhibits photosynthesis and triggers oxidative stress. Application of DCF and atrazine at the beginning of the cell cycle allowed us to follow the changes occurring in the cells in the subsequent stages of their development. Synchronized Chlamydomonas reinhardtii cultures (strain CC-1690, wild type) were exposed to diclofenac sodium salt (135 mg/L) or atrazine (77.6 µg/L). The cell suspension was sampled hourly (0-10 h) in the light period of the cell cycle to determine cell number and volume, photosynthetic pigment content, chlorophyll a fluorescence (OJIP test) in vivo, and selected gene expression (real-time qPCR), namely psbA, psaA, FSD1, MSD3 and APX1. The two toxicants differently influenced C. reinhardtii cells. Both substances decreased photosynthetic "vitality" (PI - performance index) of the cells, albeit for different reasons. While atrazine significantly disrupted the photosynthetic electron transport, resulting in excessive production of reactive oxygen species (ROS) and limited cell growth, DCF caused silencing of photosystem II (PSII) reaction centers, transforming them into "heat sinks", thus preventing significant ROS overproduction. Oxidative stress caused by atrazine was the probable reason for the rapid appearance of phytotoxic action soon after entering the cells, while the effects of DCF could only be seen several hours after treatment. A comparison of DCF-caused effects with the effects caused by atrazine led us to conclude that, although DCF cannot be regarded as typical photosynthetic herbicide, it exhibits an algicidal activity and can be potentially dangerous for aquatic plants and algae.

Ecotoxicological Effects of Ibuprofen on Plant Growth of Vigna unguiculata L

Despite the prevalence of the common pharmaceutical ibuprofen (IBU) in water and sediments worldwide, the effects of IBU on plants are largely unknown. This study was designed to assess the ecotoxicological effects of emerging pharmaceutical pollutant IBU on plant growth and development in a series of toxicity experiments using cowpea (Vigna unguiculata). Plant growth parameters (morphological and physicochemical) were investigated under a series of IBU concentrations (0, 400, 800, 1200, 1600, 2000 ppm IBU). IBU exposure reduced the shoot and root lengths, fresh and dry weights, leaf area, and chlorophyll a and b, carotenoid, total chlorophyll, mineral (K and Mg), glutathione reductase, and soluble protein contents. Simultaneously, increases in Ca and Mn contents, sodium translocation from roots to shoots, H₂O₂, malondialdehyde, superoxide dismutase, catalase, ascorbate peroxidase, and IBU uptake were observed. The amount of bioaccumulated IBU varied between 7% and 8%. IBU was translocated from roots to shoots with a translocation factor of 3-16%. The IC₅₀ values for biomass and plant length were 1253 and 1955 ppm IBU, respectively, which is much higher than the reported levels of IBU in the environment. This study demonstrates that cowpea plants develop several morphological and physicochemical adaptations to cope under ibuprofen stress; environmentally relevant concentrations of IBU are unlikely to produce negative impacts.

Root response in Pisum sativum under naproxen stress: Morpho-anatomical, cytological, and biochemical traits

Non-steroidal anti-inflammatory drugs as an important group of emerging environmental contaminants in irrigation water and soils can influence biochemical and physiological processes essential for growth and development in plants as non-target organisms. Plants are able to take up, transport, transform, and accumulate drugs in the roots. Root biomass in ten-days old pea plants was lowered by 6% already under 0.1 mg/L naproxen (NPX) due to a lowered number of lateral roots, although 0.5 mg/L NPX stimulated the total root length by 30% as against control. Higher section area (by 40%) in root tip, area of xylem (by 150%) or stele-to-section ratio (by 10%) in zone of maturation, and lower section area in zone of lateral roots (by 18%) prove the changes in primary root anatomy and its earlier differentiation at 10 mg/L NPX. Accumulated NPX (up to 10 μg/g DW at 10 mg/L) and products of its metabolization in roots increased the amounts of hydrogen peroxide (by 33%), and superoxide (by 62%), which was reflected in elevated lipid peroxidation (by 32%), disruption of membrane integrity (by 89%) and lowering both oxidoreductase and dehydrogenase activities (by up to 40%). Elevated antioxidant capacity (SOD, APX, and other molecules) under low treatments decreased at 10 mg/L NPX (both by approx. 30%). Naproxen was proved to cause changes at both cellular and tissue levels in roots, which was also reflected in their anatomy and morphology. Higher environmental loading through drugs thus can influence even the root function.

Can salicylic acid modulate biochemical, physiological and population alterations in a macrophyte species under chemical stress by diclofenac?

Salicylic acid (SA) is a pharmaceutical drug that may exert toxic effects by its own; however, simultaneous exposure of plants to SA and to other substances, often results in the significant changes in the patterns of toxic response/resistance to these other sources of chemical stress. Thus, the aim of this work was to investigate the capacity of SA of modulating Lemna minor responses co-exposed to the pharmaceutical drug, diclofenac - DCF. To attain this objective, L. minor was exposed for 7 days, to DCF alone, and to combinations of DCF with SA. After exposure, biochemical, physiological and population endpoints were analyzed as follows: catalase (CAT) and glutathione S-transferases (GSTs) activities, pigments content (chlorophyll a (Chl a), b (Chl b) and total (TChl), carotenoids (Car) and [Chl a]/[Chl b] and [TChl]/[Car] ratios), and growth specific rate, fresh weight and root length. Single exposures to DCF were capable of causing effects in all analyzed endpoints. However, co-exposure of DCF with SA partially reverted these effects. Finally, we may suggest that SA is capable to prevent the toxicity of DCF in macrophytes, by modulating the toxic response of exposed plants.

Toxicity of NSAID drug (paracetamol) to nontarget organism-Nostoc muscorum

Due to many folds increase in application of human and veterinary medicines, pharmaceuticals, a new category of pollutants, have emerged in our environment. They exist as residues in rivers, sewage effluents, streams, surface, ground, and potable water. Paracetamol (acetaminophen) is one such drug that is used as an antipyretic and analgesic medicine. It is a non-steroidal antiinflammatory drug (NSAID) and is easily available in the market because no medical prescription is necessary for its purchase and use. Paracetamol remains physiologically active even after their expiry period. Their detection in the environment in bioactive form has resulted in adverse effects on nontarget species. To determine the effect of paracetamol on aquatic photosynthetic organic (Cyanobacteria-Nostoc muscorum), present study was performed. Paracetamol (25 mg/L, 50 mg/L, 75 mg/L, 100, 125, and 150 mg/L) exposure showed toxic responses on the test organism by generating oxidative stress (MDA, H₂O_2, O₂^.-). Paracetamol caused a significant decrease in growth of cyanobacteria and showed EC₅₀ 113.68 mg/L after the 6th day of treatment. Photosynthetic pigments (chlorophyll, carotenoid, and phycobiliprotein) decreased with paracetamol increase. Antioxidant enzymatic (SOD, CAT, APX, GST, and GR) and osmolyte (Proline) also increased with increase in paracetamol to counteract the oxidative stress.

Diclofenac shifts the role of root glutamine synthetase and glutamate dehydrogenase for maintaining nitrogen assimilation and proline production at the expense of shoot carbon reserves in Solanum lycopersicum L

The continuous increase of the human population worldwide has led to an increase of pharmaceuticals' consumption, such as diclofenac (DCF), a widely used non-steroidal anti-inflammatory drug (NSAID), that is not removed by wastewater treatment processes. Although there is some research regarding the effects of DCF on animals and aquatic invertebrates, information concerning its influence on plants' metabolism is still scarce. Through an integrated approach, using combined biochemical and molecular biology techniques, this work aimed to evaluate the phytotoxicity of DCF in Solanum lycopersicum L., focusing on the primary plant processes: nitrogen (N) assimilation and photosynthesis. The exposure of tomato plants to increasing concentrations of DCF (0, 0.5, and 5 mg L^-1) revealed that glutamine synthetase (GS) was differentially affected, in an organ-dependent manner, by this contaminant at the gene expression, protein, and activity levels, with an increased activity of 0.2-fold in shoots of plants treated with the lowest concentration of DCF although a general decrease was registered for the SlGS gene family expression, revealing that post-translational regulation was in order, since GS2 polypeptide content did not change. Glutamate dehydrogenase (GDH) activity was generally enhanced, accompanied by increases of 0.4- to 1.9-fold in proline levels, revealing GDH as an important compensatory route for both N assimilation and proline production under stressful conditions. No alterations in most photosynthetic endpoints were noticed after DCF treatments, but small decreases of 0.1- to 0.8-fold in the accumulation of RuBisCO-encoding transcripts were observed, along with a reduction in starch content. Some alterations in the soluble polypeptide profile were also detected in response to DCF, evidencing the participation of some stress-related proteins in the plant's response to DCF.

An analysis of the versatility and effectiveness of composts for sequestering heavy metal ions, dyes and xenobiotics from soils and aqueous milieus

The persistence and bioaccumulation of environmental pollutants in water bodies, soils and living tissues remain alarmingly related to environmental protection and ecosystem restoration. Adsorption-based techniques appear highly competent in sequestering several environmental pollutants. In this review, the recent research findings reported on the assessments of composts and compost-amended soils as adsorbents of heavy metal ions, dye molecules and xenobiotics have been appraised. This review demonstrates clearly the high adsorption capacities of composts for umpteen environmental pollutants at the lab-scale. The main inferences from this review are that utilization of composts for the removal of heavy metal ions, dye molecules and xenobiotics from aqueous environments and soils is particularly worthwhile and efficient at the laboratory scale, and the adsorption behaviors and effectiveness of compost-type adsorbents for agrochemicals (e.g. herbicides and insecticides) vary considerably because of variabilities in structure, topology, bond connectivity, distribution of functional groups and interactions of xenobiotics with the active humic substances in composts. Compost-based field-scale remediation of environmental pollutants is still sparse and arguably much challenging to implement if, furthermore, real-world soil and water contamination issues are to be addressed effectively. Hence, significant research and process development efforts should be promptly geared and intensified in this direction by extrapolating the lab-scale findings in a cost-effective manner.

Investigating the effects of non-steroidal anti-inflammatory drugs (NSAIDs) on the composition and ultrastructure of green leafy vegetables with important nutritional values

The global presence of pharmaceuticals in the environment has been particularly considered a concerning problem with unknown consequences. Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most frequently prescribed drugs in the world, and as a result, they are commonly found in different environmental compartments. In the present work, we studied the effects of NSAIDs (diclofenac, ibuprofen, and naproxen) on the composition and ultrastructure of Atriplex patula L., S. oleracea, and Lactuca sativa L., three green leafy vegetables with significant nutritional value. Contaminant solutions of NSAIDs were applied every two days using concentrations of 0.1 mg L^-1, 0.5 mg L^-1, and 1 mg L^-1. After eight weeks of exposure of the green leafy vegetables to the selected NSAIDs, the chlorophylls (a + b), carotenoids (zeaxanthin, lutein, and ß-carotene), total polyphenol and total flavonoid contents, antioxidant capacity, and the ultrastructural modifications were determined. The obtained results indicated a moderate reduction in the assimilating pigments, total polyphenol and flavonoid contents. In addition, ultrastructural damages of the chloroplasts and cell walls were observed in the leaves of the selected vegetables, which were exposed to abiotic stress-induced by NSAIDs. All data collectively suggest that this group of drugs induced harmful effects on plants, and implicitly they may also negatively affected human health on the long term.

Response of Solanum lycopersicum L. to diclofenac - Impacts on the plant's antioxidant mechanisms

One emerging problem that recently has become a vastly acknowledged topic of concern is the environmental contamination by pharmaceuticals. Diclofenac (DCF) is one of the most common pharmaceuticals found, due to its high utilization and low removal rate in wastewater treatment processes. In this work, Solanum lycopersicum L. was used as a model to unravel how DCF contamination can affect crops, focusing on the internal mechanisms triggered by this exposure. For this purpose, plants were exposed to two different DCF concentrations (0.5 mg L^-1 and 5 mg L^-1). Results obtained here point towards a loss of shoot performance when plants were exposed to very high concentrations of DCF, but no delay or loss of yield in the flowering and fruit stages were ascribed to DCF contamination. Our data shows that a state of oxidative stress due to high reactive oxygen species accumulation was associated with this contamination, with very high DCF levels leading to a rise of lipid peroxidation, possibly accentuated by the inhibition of ROS-scavenging enzymes and unable to be counteracted by the visible upregulation of proline and the thiol-based redox network. Overall, these results allow to infer that in the current environmental context, no noticeable negative effects should be associated with the presence of DCF in soils where this crop is cultivated. However, the oxidative stress and lower biomass associated with the highest concentration are alarming, since DCF levels in the environment are continuously increasing and further measures are necessary to assess this problematic.