Analyzing water hyacinth plants from two South African rivers for the detection of seven pharmaceuticals and their metabolites.

Water hyacinth plants (Eichhornia crassipes Mart.) collected from two South African rivers were analyzed in order to investigate their suitability for judging the presence of pharmaceuticals in the water. Thereby, a number of drugs, including amitriptyline, atenolol, citalopram, orphenadrine, lidocaine, telmisartan, and tramadol, could be detected. Particularly for the latter substance, relatively high concentrations (more than 5000 ng g-1 dry plant material) were detected in the water plants. Subsequently, the plant extracts were also screened for drug-derived transformation products, whereby a series of phase-one metabolites could be tentatively identified.

From Water to Water: Insight into the Translocation of Pesticides from Plant Rhizosphere Solution to Leaf Guttation and the Associated Ecological Risks.

Plant guttation is an important source of water/nutrients for many beneficial insects, while the presence of pesticides in guttation has been considered as a new exposure route for nontarget insects. This study aimed to elucidate how 15 diverse pesticides are translocated from growth media to guttation by maize plants through a hydroponic experiment. All pesticides were effectively translocated from the growth solution to maize guttation and reached a steady state within 5 days. The strong positive correlation (R2 = 0.43-0.84) between the concentrations of pesticides in guttation and in xylem sap demonstrated that xylem sap was a major source of pesticides in guttation. The relationship between the bioaccumulation of pesticides in guttation (BCFguttation) and the chemical Kow was split into two distinct patterns: for pesticides with log Kow > 3, we identified a good negative linear correlation between log BCFguttation and log Kow (R2 = 0.71); however, for pesticides with log Kow < 3, all data fall close to a horizontal line of BCFguttation ≅ 1, indicating that hydrophilic pesticides can easily pass through the plants from rhizosphere solution to leaf guttation and reach saturation status. Besides, after feeding with pesticide-contaminated guttation, the mortality of honeybees was significantly impacted, even at very low levels (e.g., ∑600 µg/L with a mortality of 93%). Our results provide essential information for predicting the contamination of plant guttation with pesticides and associated ecological risks.

A review of Per- and polyfluoroalkyl substances (PFASs) removal in constructed wetlands: mechanisms, enhancing strategies and environmental risks.

PER: and polyfluoroalkyl substances (PFASs), typical persistent organic pollutants detected in various water environments, have attracted widespread attention due to their undesirable effects on ecology and human health. Constructed wetlands (CWs) have emerged as a promising, cost-effective, and nature-based solution for removing persistent organic pollutants. This review summarizes the removal performance of PFASs in CWs, underlying PFASs removal mechanisms, and influencing factors are also discussed comprehensively. Furthermore, the environmental risks of PFASs-enriched plants and substrates in CWs are analyzed. The results show that removal efficiencies of total PFASs in various CWs ranged from 21.3% to 98%. Plant uptake, substrate absorption and biotransformation are critical pathways in CWs for removing PFASs, which can be influenced by the physiochemical properties of PFASs, operation parameters, environmental factors, and other pollutants. Increasing dissolved oxygen supply and replacing traditional substrates in CWs, and combining CWs with other technologies could significantly improve PFASs removal. Further, CWs pose relatively lower ecological and environmental risks in removing PFASs, which indicates CWs could be an alternative solution for controlling PFASs in aquatic environments.

The fate of sulfonamides in microenvironments of rape and hot pepper rhizosphere soil system.

Sulfonamides (SAs) in agricultural soils can be degraded in rhizosphere, but can also be taken up by vegetables, which thereby poses human health and ecological risks. A glasshouse experiment was conducted using multi-interlayer rhizoboxes to investigate the fate of three SAs in rape and hot pepper rhizosphere soil systems to examine the relationship between the accumulation and their physicochemical processes. SAs mainly entered pepper shoots in which the accumulation ranged from 0.40 to 30.64 mg kg-1, while SAs were found at high levels in rape roots ranged from 3.01 to 16.62 mg kg-1. The BCFpepper shoot exhibited a strong positive linear relationship with log Dow, while such relationship was not observed between other bioconcentration factors (BCFs) and log Dow. Other than lipophilicity, the dissociation of SAs may also influence the uptake and translocation process. Larger TF and positive correlation with log Dow indicate preferential translocation of pepper SAs. There was a significant (p < 0.05) dissipation gradient of SAs observed away from the vegetable roots. In addition, pepper could uptake more SAs under solo exposure, while rape accumulated more SAs under combined exposure. When SAs applied in mixture, competition between SAs might occur to influence the translocation and dissipation patterns of SAs.

The phloem and xylem structure of plants and the neutral and ionic partitioning of sulfonamides (SAs) influence the uptake and translocation of SAs.A significant (p < 0.05) dissipation gradient of SAs was observed away from the vegetable roots.Combined exposure could promote the correlation between log BCF and log D_ow.

Impact of four surfactants on the uptake of per- and polyfluoroalkyl substances (PFAS) by red fescue grass.

Per- and polyfluoroalkyl substances (PFAS) pose great risks to human health and the ecosystem, necessitating effective remediation strategies such as phytoremediation. Surfactants, due to their ability to increase the bioavailability of hydrophobic contaminants, are considered as potential agents to improve phytoremediation for PFAS. In this research, we explored the impact of four surfactants (sodium dodecyl sulfate (SDS), rhamnolipid, Triton X-100, and Glucopone 600 CS UP) on plant growth and the uptake of PFAS by red fescue over 110 days. The results showed that while surfactants at lower concentrations did not negatively affect plant growth, the highest dose (2,500 mg/kg) significantly reduced the dry weight of plant shoots. Although none of the four surfactants led to an increased overall removal efficiency of ∑PFAS by red fescue over 110 days, SDS did enhance the uptake of PFAS compounds with long carbon chain lengths. With SDS addition at 2,500 mg/kg, the average fold increases of long chain PFAS removal were 1.99 for perfluorooctanoic acid (PFOA), 2.44 for perfluorononanoic acid (PFNA), 2.11 for perfluorodecanoic acid (PFDA), 1.52 for perfluoroundecanoic acid (PFUnA), 1.88 for perfluorohexanesulphonic acid (PFHxS), and 2.97 for perfluorooctanesulfonic acid (PFOS). The research indicated that using surfactants, such as SDS at appropriate doses could improve phytoremediation effectiveness in mitigating long-chain PFAS, which is a known challenge in soil remediation.

This study proposed an approach to accelerate plant uptake and removal of long chain PFAS. The improved removal of long chain PFAS coupled with less plant biomass by amending soil with SDS at a proper dose potentially increases the attractiveness of phytoremediation.

Assessment of sulfamethoxazole removal by three wetland plant species under hydroponic conditions: uptake, accumulation, and physiological responses.

Plants play a crucial role as a removal pathway in constructed wetlands, demonstrating the ability to absorb and tolerate antibiotics from wastewater. However, the specific contribution of plants in this regard has not yet to be sufficiently established. To gain a more comprehensive insight into the associated processes, we selected three common wetland plant species, Canna indica L. (C. indica), Cyperus alternifolius L. (C. alternifolius), and Thalia dealbata Fraser (T. dealbata), to evaluate their capacity for uptake, accumulation, and physiological response in the removal of sulfamethoxazole (SMX) at varying initial concentrations (10, 30, 100, and 300 µg/L) under hydroponic conditions. The results showed that SMX removal was more efficient at lower concentrations (10 and 30 µg/L) than at higher concentrations (100 and 300 µg/L). Moreover, plant systems were found to consistently outperform unplanted systems in SMX removal. Among the assessed species, C. indica was identified as being relatively effective in the removal of SMX, whereas the performance of C. alternifolius was notably less pronounced. A positive correlation was observed between the concentration of SMX in the plant tissues and that in the external aqueous medium. However, plant tissue residues contributed only a minor fraction to the overall removal of SMX. Wetland plants absorb SMX through their roots, and we accordingly detected significantly higher concentrations in submerged plant tissues. Furthermore, we also detected reductions in net photosynthetic rates indicative of potential phytotoxicity, which is associated with the accumulation of antibiotic in the shoot tissues. Accumulation of SMX in the roots and rhizomes was also found to be associated with the development of shorter roots, with this effect becoming more pronounced with an increase in the concentration of exogenous SMX. However, despite these adverse effects, plants can detoxify antibiotics via the glutathione pathway. Of the assessed plant species, C. indica was identified as the most SMX tolerant, as indicated by Km and Vmax values, with C. alternifolius being the least tolerant. Our findings in this study reveal the potential value of wetland plants in the sequestration of antibiotics and provide evidence for the underlying mechanisms of action. These findings could make an important contribution to the implementation of phytoremediation in antibiotic-contaminated water.

Three wetland plants with fibrous root systems, namely Canna indica, Cyperus alterniflius, and Thalia dealbata, were selected to investigate the removal efficiencies of sulfamethoxazole in the hydroponic system by different emergent plants, quantify the contribution of uptake and accumulation for sulfamethoxazole in plant tissues, and assess the physiological responses of plants and their effect on the removal of sulfamethoxazole. The knowledge obtained from this study shows the potential use of wetland plants for removing antibiotics and the inherent mechanisms, which will be useful for the application of phytoremediation in antibiotic contaminated water.

Uptake and metabolization of four sartan drugs by eight different plants: Targeted and untargeted analyses by HPLC-drift-tube-ion-mobility quadrupole time-of-flight mass spectrometry.

In this study, we investigated the uptake and metabolization of four drugs (plus the associated prodrugs) from the sartan family by eight edible plants. Growing the plants hydroponically in a medium containing the respective drug, more than 40 phases I and II metabolites derived from the four sartan drugs could be tentatively identified. To demonstrate the suitability of the proposed analytical approach for actual environmental samples, garden cress (Lepidium sativum) selected as a model plant was grown in water drawn from the effluent of two local wastewater treatment plants. Thereby, three of the sartans, namely, olmesartan, candesartan, and valsartan, could be found in the plant extracts at concentrations of 3.1, 10.4, and 14.4 ng g-1 , respectively. Additionally, for candesartan and valsartan, a glycosylated transformation product could be detected. In order to extend the present (targeted) workflow also toward the analysis of unknown transformation products (i.e., those not listed in the custom-made database used for this research), a nontargeted approach for the analysis of plant extracts with respect to the presence of drug-related metabolites was developed. Comparison of the targeted and the nontargeted workflows led to the finding of two additional, so far unidentified, transformation products originating from azilsartan.

Phytoscreening for Per- and Polyfluoroalkyl Substances at a Contaminated Site in Germany.

The aim of this study was to perform a phytoscreening of per- and polyfluoroalkyl substances (PFAS) at a contaminated site in Germany, to investigate the applicability of this technique for PFAS contaminations. Foliage of three species, namely, white willow (Salix alba L.), black poplar (Populus nigra L.), and black alder (Alnus glutinosa L.), were sampled to evaluate seasonal and annual variations in PFAS concentrations. The results of the phytoscreening clearly indicated species and specific differences, with the highest PFAS sum concentrations ∑23 observed in October for white willow (0-1800 µg kg-1), followed by black poplar (6.7-32 µg kg-1) and black alder (0-13 µg kg-1). The bulk substances in leaves were highly mobile short-chain perfluoroalkyl carboxylic acids (PFCAs). In contrast, the PFAS composition in soil was dominated by long-chain PFCAs, perfluorooctanoic acid (PFOA) and perfluorodecanoic acid (PFDA), as a result of the lower mobility with ∑23PFAS ranging between 0.18 and 26 µg L-1 (eluate) and between 66 and 420 µg kg-1 (solid). However, the PFAS composition in groundwater was comparable to the spectrum observed in leaves. Spatial interpolations of PFAS in groundwater and foliage correspond well and demonstrate the successful application of phytoscreening to detect and delineate the impact of the studied PFAS on groundwater.

Averaging Strategy for Interpretable Machine Learning on Small Datasets to Understand Element Uptake after Seed Nanotreatment.

Understanding plant uptake and translocation of nanomaterials is crucial for ensuring the successful and sustainable applications of seed nanotreatment. Here, we collect a dataset with 280 instances from experiments for predicting the relative metal/metalloid concentration (RMC) in maize seedlings after seed priming by various metal and metalloid oxide nanoparticles. To obtain unbiased predictions and explanations on small datasets, we present an averaging strategy and add a dimension for interpretable machine learning. The findings in post-hoc interpretations of sophisticated LightGBM models demonstrate that solubility is highly correlated with model performance. Surface area, concentration, zeta potential, and hydrodynamic diameter of nanoparticles and seedling part and relative weight of plants are dominant factors affecting RMC, and their effects and interactions are explained. Furthermore, self-interpretable models using the RuleFit algorithm are established to successfully predict RMC only based on six important features identified by post-hoc explanations. We then develop a visualization tool called RuleGrid to depict feature effects and interactions in numerous generated rules. Consistent parameter-RMC relationships are obtained by different methods. This study offers a promising interpretable data-driven approach to expand the knowledge of nanoparticle fate in plants and may profoundly contribute to the safety-by-design of nanomaterials in agricultural and environmental applications.

Uptake, Metabolism, and Accumulation of Tire Wear Particle-Derived Compounds in Lettuce.

Tire wear particle (TWP)-derived compounds may be of high concern to consumers when released in the root zone of edible plants. We exposed lettuce plants to the TWP-derived compounds diphenylguanidine (DPG), hexamethoxymethylmelamine (HMMM), benzothiazole (BTZ), N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (6PPD), and its quinone transformation product (6PPD-q) at concentrations of 1 mg L-1 in hydroponic solutions over 14 days to analyze if they are taken up and metabolized by the plants. Assuming that TWP may be a long-term source of TWP-derived compounds to plants, we further investigated the effect of leaching from TWP on the concentration of leachate compounds in lettuce leaves by adding constantly leaching TWP to the hydroponic solutions. Concentrations in leaves, roots, and nutrient solution were quantified by triple quadrupole mass spectrometry, and metabolites in the leaves were identified by Orbitrap high resolution mass spectrometry. This study demonstrates that TWP-derived compounds are readily taken up by lettuce with measured maximum leaf concentrations between ∼0.75 (6PPD) and 20 µg g-1 (HMMM). Although these compounds were metabolized in the plant, we identified several transformation products, most of which proved to be more stable in the lettuce leaves than the parent compounds. Furthermore, continuous leaching from TWP led to a resupply and replenishment of the metabolized compounds in the lettuce leaves. The stability of metabolized TWP-derived compounds with largely unknown toxicities is particularly concerning and is an important new aspect for the impact assessment of TWP in the environment.

Mechanism and Association between Microbial Nitrogen Transformation in Rhizosphere and Accumulation of Ciprofloxacin in Choysum (Brassica parachinensis).

Rhizosphere microbiota are an important factor impacting plant uptake of pollutants. However, little is known about how microbial nitrogen (N) transformation in the rhizosphere affects the uptake and accumulation of antibiotics in plants. Here, we determined recruitment of N transformation functional bacteria upon ciprofloxacin (CIP) exposure, by comparing differences in assembly processes of both rhizospheric bacterial communities and N transformation between two choysum (Brassica parachinensis) varieties differing in CIP accumulation. The low accumulation variety (LAV) of CIP recruited more host bacteria (e.g., Nitrospiria and Nitrolancea) carrying nitrification genes (mainly nxrA) but fewer host bacteria carrying denitrification genes, especially narG, relative to the high accumulation variety (HAV) of CIP. The nxrA and narG abundance in the LAV rhizosphere were, respectively, 1.6-7.8 fold higher and 1.4-3.4 fold lower than those in the HAV rhizosphere. Considering that nitrate can decrease CIP uptake into choysum through competing for the proton motive force and energy, such specific bacteria recruitment in LAV favored the production and utilization of nitrate in its rhizosphere, thus limiting its CIP accumulation with 1.6-2.4 fold lower than the HAV. The findings give insight into the mechanism underlying low pollutant accumulation, filling the knowledge gap regarding the profound effects of rhizosphere microflora and N transformation processes on antibiotic accumulation in crops.

A systematic review on distribution, sources and sorption of perfluoroalkyl acids (PFAAs) in soil and their plant uptake.

Perfluoroalkyl acids (PFAAs) are ubiquitous in environment, which have attracted increasing concerns in recent years. This study collected the data on PFAAs concentrations in 1042 soil samples from 15 countries and comprehensively reviewed the spatial distribution, sources, sorption mechanisms of PFAAs in soil and their plant uptake. PFAAs are widely detected in soils from many countries worldwide and their distribution is related to the emission of the fluorine-containing organic industry. Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are found to be the predominant PFAAs in soil. Industrial emission is the main source of PFAAs contributing 49.9% of the total concentrations of PFAAs (Æ© PFAAs) in soil, followed by activated sludge treated by wastewater treatment plants (WWTPs) (19.9%) and irrigation of effluents from WWTPs, usage of aqueous film-forming foam (AFFFs) and leaching of leachate from landfill (30.2%). The adsorption of PFAAs by soil is mainly influenced by soil pH, ionic strength, soil organic matter and minerals. The concentrations of perfluoroalkyl carboxylic acids (PFCAs) in soil are negatively correlated with the length of carbon chain, log Kow, and log Koc. The carbon chain lengths of PFAAs are negatively correlated with the root-soil concentration factors (RCFs) and shoot-soil concentration factors (SCFs). The uptake of PFAAs by plant is influenced by physicochemical properties of PFAAs, plant physiology and soil environment. Further studies should be conducted to make up the inadequacy of existing knowledge on the behavior and fate of PFAAs in soil-plant system.

Dissemination of nonsteroidal anti-inflammatory drugs (NSAIDs) and metabolites from wastewater treatment plant to soils and agricultural crops via real-scale different agronomic practices.

One of the most consumed pharmaceutical subgroups across the world is nonsteroidal anti-inflammatory drugs (NSAIDs). However, the dissemination of these compounds to the natural environments through agronomic practices is a serious global problem. The hypothesis of this study is to reveal the transition of selected NSAIDs, paracetamol (PAR), diclofenac (DCF), ibuprofen (IBU), and naproxen (NAP) together with six main metabolites, detected in raw/treated wastewater (RWW/TWW) and sewage sludge generated in an urban wastewater treatment plant (WWTP) to soils and agricultural crops (corn, barley, sunflower, and sugar beet) through two widely applied agronomic practices, irrigation with TWW and application of sewage sludge as soil amendment. In other words, the cycles of 10 NSAIDs have been evaluated by simultaneously monitoring their concentrations in RWW/TWW, sewage sludge, soils, and crops. It was determined that the parent compounds and detected metabolites were treated at quite higher removal efficiencies (93.4 - >99.9%) in the studied WWTP, while DCF was eliminated poorly (7.9-52.2%). However, although it changes seasonally for some compounds, it was determined that the concentrations of almost all investigated NSAIDs increased at the determined irrigation points in the discharge channel (DC) where agricultural irrigations were performed. Apart from that, DCF, NAP, and 2-hydroxyibuprofen (2-OH-IBU) were always detected in sewage sludge seasonally up to about 20.5, 11.3, and 3.7 ng/g, respectively. While 2-OH-IBU was determined as the dominant metabolite in RWW, TWW, and sewage sludge, the metabolite of 1-hydroxyibuprofen (1-OH-IBU) was determined as the dominant compound in soils. Although 1-OH-IBU was not detected in TWW and sewage sludge in any season, detecting this metabolite as a common compound in all investigated soils (up to 60.1 ng/kg) reveals that this compound is the primary transformation product of IBU in soils. It was observed that at least one of the metabolites of IBU (1-OH-IBU and/or 2-OH-IBU) was detected in all plants grown (up to 0.75 ng/g), especially during the periods when both agricultural practices were applied. In addition, the detection of 1-OH-IBU with increasing concentrations from root to shoots in corn grown as a result of both agronomic practices shows that this compound has a high translocation potential in the corn plant. Apart from this, it was determined that PAR was detected in corn (up to 43.3 ng/kg) and barley (up to 16.8 ng/kg) within the scope of irrigation with TWW, and NAP was detected in sugar beet (up to 11.2 ng/kg) through sewage sludge application.

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.

Enhanced nitrogen removal from rural domestic sewage via partial nitrification-anammox in integrated vertical subsurface flow constructed wetland.

This study aimed to improve the removal of nitrogen treating rural domestic sewage by developing a novel strategy for achieving partial nitrification-anammox (PNA) in an integrated vertical subsurface flow constructed wetland (VSFCW). The influent ammonia was oxidized to nitrite in the partial nitrification VSFCW (VSFCWPN), and 5 mg/L of hydroxylamine was added under the appropriate dissolved oxygen concentration level (1.2 ± 0.2 mg/L) to stabilize the average nitrite accumulation rate at 88.24% and maintain the effluent NO2--N/NH4+-N ratio at 1.26 ± 0.15. The effluent from VSFCWPN was introduced to the following chamber (VSFCWAN), where ammonia and nitrite were removed by the autotrophic anammox process. This implementation achieved high removal efficiencies for chemical oxygen demand, total nitrogen, and PO43--P, reaching 86.26%, 90.22%, and 78.94%, respectively, with influent concentrations of 120.75 mg/L, 60.02 mg/L, and 5.05 mg/L. Substrate samples were collected from 10 cm height (PN1, AN1) and 25 cm height (PN2, AN2). Microbial community analysis showed that Nitrosomonas dominated the community composition in VSFCWPN, with an increase from 1.61% in the inoculated sludgePN to 16.31% (PN1) and 12.09% (PN2). Meanwhile, Ca. Brocadia accounted for 44.81% (AN1) and 36.50% (AN2) in VSFCWAN. These results confirm the feasibility of the proposed strategy for establishing PNA and efficiently treating rural domestic sewage in an integrated VSFCW.

Assessing plant uptake of organic contaminants by food crops tomato, wheat, and corn through sap concentration factor.

This study investigated uptake of two organic compounds including hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and exogenous caffeine by tomato (Solanum lycopersicum L.), corn (Zea mays L.), and wheat (Triticum aestivum L.). The plants were grown in a growth chamber under recommended conditions and then were exposed to these compounds for 19 days. The uptake of the compounds was measured by sap concentration factor. The plant samples (stem transpiration stream) and solution in the exposure media were taken and analyzed by high performance liquid chromatography-tandem mass spectrometry. The plant stem samples were analyzed after a freeze-thaw centrifugation process. The average sap concentration factor for the RDX by tomato, wheat, and corn was 0.71, 0.67, and 0.65. The average sap concentration factor for the exogenous caffeine by tomato, wheat, and corn was 0.72, 0.50, and 0.34. These relatively high sap concentration factor values were expected as available predictive models offer high sap concentration factor values for moderately hydrophobic and hydrophilic compounds. The generated sap concentration factor values for the RDX and exogenous caffeine are important for improving the accuracy of previously developed machine learning models predicting the uptake and translocation of emerging contaminants.

The uptake of two organic compounds (RDX and exogenous caffeine) was examined in three crop plants (corn, wheat, and tomato). There have not been any uptake studies on exogenous caffeine and also we do not have good data for the uptake of RDX by these three crop plants. The estimated sap concentration factor from these experiments fills the gap in the data for developing predictive models for uptake of emerging contaminants. A novel rapid freeze­thaw/centrifugation extraction method followed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was used to analyze the samples.

Development of microbial fuel cell integrated constructed wetland (CMFC) for removal of paracetamol and diclofenac in hospital wastewater.

Hospital wastewater management has become a significant concern across the globe due to the presence of pharmaceutically active compounds (PhACs) and other toxic substances, which can potentially disrupt ecosystems. The presence of recalcitrant PhACs in hospital wastewater increases the difficulty level for conventional wastewater treatment systems. Furthermore, incorporating advanced oxidation-based treatment systems increase capital and operation costs. To reduce treatment costs, low-cost innovative technology, i.e., composite constructed wetland and microbial fuel cell system (CMFC), has been developed for higher treatment efficiency of PhACs in hospital wastewater along with simultaneous bioelectricity generation as an additional outcome. In this study, influencing operating parameters, such as initial chemical oxygen demand (COD), electrode spacing, and substrate-to-water-depth ratio, were optimized for two plant species: water hyacinth (WH) and duckweed (DW). The optimized systems were run in batch and continuous mode for WH-CMFC and DW-CMFC to treat synthetic hospital wastewater with paracetamol and diclofenac, and the bioelectricity generation was monitored. DW-CMFC system depicted better treatment efficiency and voltage generation as compared to WH-CMFC. In continuous mode, the DW-CMFC system exhibited a removal of 95.3% COD, 97.1% paracetamol, and 87.5% diclofenac. WH-CMFC and DW-CMFC achieved power densities of around 21.26 mW/m2 and 42.93 mW/m2, respectively. The fate of PhACs during and after treatment and toxicity analysis of the transformation products formed were also carried out. Higher bio-electricity generation and efficient wastewater treatment of the DW-CMFC make it a sustainable option for hospital wastewater management.

Mercury distribution in plants and soils from the former mining area of Abbadia San Salvatore (Tuscany, Central Italy).

The distribution of heavy metals in plants (Castanea sativa, Sambucus nigra, Verbascum thapsus, Popolus spp., Salix spp., Acer pseudoplatanus, Robinia pseudoacacia) growing in soils from active and abandoned mining areas is of scientific significance as it allows to recognize their ability to survive in a hostile environment and provide useful indications for phytoremediation operations. In this work, soils from the former Hg-mining area of Abbadia San Salvatore (Tuscany, Central Italy) were analyzed for total, leached Hg, % of organic and inorganic-related Hg. The dehydrogenase enzyme activity (DHA) was also measured with the aim to evaluate the status of the soil, being characterized by high Hg contents (up to 1068 mg kg-1). Eventually, the concentration of Hg in the different parts of the plants growing on these soils was also determined. Most studied soils were dominated by inorganic Hg (up to 92%) while the DHA concentrations were < 151 µg TPF g-1 day-1, suggesting that the presence of Hg is not significantly affecting the enzymatic soil activity. This is also supported by the bioaccumulation factor (BF), being predominantly characterized by values < 1. Sambucus nigra and Verbascum thapsus had the highest Hg contents (39.42 and 54.54 mg kg-1, respectively). The plant leaves appear to be the main pathways of Hg uptake, as also observed in other mining areas, e.g., Almadèn (Spain), indicating that particulate-Hg and Hg0 are the main forms entering the plant system, the latter derived by the GEM emitted by both the edifices hosting the roasting furnaces and the soils themselves.

Timing is everything - obtaining accurate measures of plant uptake of amino acids.

Plants are known to have the capacity to take up and utilise amino acids for growth. The significance of this uptake, however, remains elusive, partly due to methodological challenges and biological implications associated with acquiring and interpreting data. This study compared bulk stable isotope analysis and compound-specific liquid chromatography-mass spectrometry, two established methods for determining amino acid uptake. Root amino acid uptake was assayed using U-13 C5 -15 N2 -l-glutamine and axenically grown Arabidopsis thaliana. After 15-120 min of exposure, the content of intact glutamine measured in the roots was constant, whilst the 15 N and 13 C content increased over time, resulting in very different estimated uptake rates. The 13 C : 15 N ratio in roots declined with time, suggesting a loss of glutamine carbon of up to 15% within 120 min. The results presented indicate that, regardless of method used, time is a crucial factor when determining plant amino acid uptake. Due to post-uptake metabolism, compound-specific methods should primarily be used in experiments with a time frame of minutes rather than hours or days. Post-uptake metabolism in plants may account for significant loss of carbon, suggesting that it is not just pre-uptake metabolism by microbes that accounts for the 15 N-13 C mismatch reported in ecological studies, but also post-uptake metabolism in the plant.

Occurrence and distribution of micro/nanoplastics in soils and their phytotoxic effects: A review.

Some recent studies have reviewed the occurrence and phytotoxicity of micro/nanoplastics, but their distribution in the soil environment, mechanisms of uptake by roots and the mode of action are unclear. Thus, this review comprehensively represents the relative abundance of micro/nanoplastics in different soil types and their toxicities in plants with insights into their partitioning to different soil matrices, uptake mechanisms, and the mode of action. Partitioning of micro/nanoplastics to different soil matrices (like-soil particles, naturally occurring soil organic matters, pore waters and soil fauna) could modify their bioavailability to plants. The small micro/nanoplastic particles can be taken up by roots through the apoplastic and symplastic pathways. In this regard, cellular endocytosis and aquaporin might play a significant role. The shape of the polymers can also regulate their uptake, and the polymers with spherical shapes are more easily absorbed by roots than the polymers with other shapes. Bioaccumulation of micro/nanoplastic induces oxidative stress, which, in turn, causes alterations of gene expressions and different metabolic pathways responsible for plant growth, biomass production and synthesis of secondary metabolites.