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Nanoscale zero-valent iron (nZVI) has been widely applied in the environmental field to degrade organic pollutants. The potential risk posed from nZVI on crop species is not well understood and is critical for sustainable application in the future. In this study, maize (Zea mays L.) plants were cultivated in field soils mixed with nZVI at 0, 50, and 500 mg/kg soil for four weeks. Upon exposure to 500 mg/kg nZVI, ICP-MS results showed that Fe accumulated by roots and translocated to leaves was increased by 36% relative to untreated controls. At 50 mg/kg, root elongation was enhanced by 150–200%; at 500 mg/kg, pigments, lipid peroxidation, and polyphenolic levels in leaves were increased by 12, 87 and 23%, respectively, whereas the accumulation of Al, Ca, and P were decreased by 62.2%, 19.7%, and 13.3%, respectively. A gas chromatography–mass spectrometry (GC–MS) based metabolomics analysis of maize roots revealed that antioxidants and stress signaling-associated metabolites were downregulated at 50 mg/kg, but were upregulated at 500 mg/kg. At 50 mg/kg, the content of glutamate was increased by 11-fold, whereas glutamine was decreased by 99% with respect to controls. Interestingly, eight metabolic pathways were disturbed at 50 mg/kg, but none at 500 mg/kg. This metabolic reprogramming at the lower dose represented potential risks to the health of exposed plants, which could be particularly important although no phenotypic impacts were noted. Overall, metabolites analysis provides a deeper understanding at the molecular level of plant response to nZVI and is a powerful tool for full characterization of risk posed to crop species as part of food safety assessment.

This work presents the most extensive proteomic description of Arabidopsis thaliana in the knowledge of its responses to BPA and TiO2-NPs. Previous studies have reported that nanoparticles (NPs) and Bisphenol A (BPA) are toxic to the environment. However, the jointed toxicity is not yet well understood. This study was aimed to investigate the combined toxicity of BPA and TiO2-NPs to plants. Model plant Arabidopsis thaliana was selected as the target plant. The seedlings were randomly separated into 5 groups and treated with BPA (1000, 100, 10 and 0 µg/kg) and TiO2-NPs (100, 10, 1 and 0 mg/kg). The plant height, biomass and root length indicated no significant toxicity of low concentration of BPA and TiO2-NPs to the growth. In the results of comparative proteomics, both positive and negative effects were observed in root growth, plant development and energy metabolism, et.al, according to GO and KEGG analysis.

In this study, spinach plants exposed to fresh/unweathered (UW) or weathered (W) copper compounds in soil were analyzed for growth and nutritional composition. Plants were exposed for 45 days to freshly prepared or soil-aged (35 days) nanoparticulate CuO (nCuO), bulk-scale CuO (bCuO), or CuSO

Metallic nanoparticles (NPs) are being extensively used in electronics, cosmetics, sporting goods, and medicine. Only recently, use of metallic nanomaterials extended to agricultural production, which could lead to their buildup in arable lands and affect soil productivity. Several investigations, with different NPs and under different exposure conditions, have been conducted to understand the effects of metallic NPs on terrestrial plants. These studies have propelled the application of NPs as agrochemicals that are able to supply nutrients, combat pests and weeds, and alleviate abiotic stress. The applications of novel, high-throughput technologies and advanced spectroscopic techniques have been of great help to understand the complex metabolic responses of plants to NP exposure. However, there is still limited information about the interactions of metallic NPs with plant molecules and soil components and their repercussions on agricultural productivity. This work discusses the benefits and disadvantages that metallic NPs might represent for crops. Additionally, the effects of the metallic NPs on plant physiology are analyzed by scrutinizing recent spectroscopic and gene expression/transcriptomic studies.

Foliar spray of engineered nanoparticles (NPs) as nanofertilizers, nanopesticides, nanosensors, and nanocarriers is increasingly being employed in the agricultural industry. Foliar spraying of NPs improves the effectiveness of plant protection technologies compared to traditional soil–root application. Foliar-sprayed NPs mainly enter the leaves through stomata and are transported to different plant parts via apoplastic and symplastic pathways. Foliar NPs enhance defenses and resistance against pests and diseases and improve the yield and quality of crops. However, the mechanisms of damage caused by foliar NPs need further elucidation. Moreover, important factors limiting foliage uptake of NPs such as wax deposits on leaf surfaces, environmental factors (e.g., light, temperature, and humidity), and physical and chemical properties of NPs should be investigated to further improve this technology.

This chapter highlights interactions of nanomaterials with plants at the level of plant life cycle stages: germination, seedling development, growth, and includes transgenerational influence of nanomaterial exposures. About a decade ago, scientists moved from the traditional method of petri-dish-based germination study to more expansive long-term exposure studies up to half maturity or full maturity of the plant. Such studies have shown that responses depend on the physiochemical properties of the nanomaterial and its interaction with plant material-environmental conditions including the type of plant (mono or dicotyledonous), growing medium (soil matrix or hydroponics), contact type (foliar or root exposure), edible portion (root, stem, leaf or flower/fruit), constitution of the nanomaterial (powder or suspension), and the exposure concentration and duration. The exposure concentration determines beneficial (nutrient stimulatory) or detrimental (nutrient inhibitive) effects on the plant. This chapter includes both metal-based and carbon-based engineered nanoparticles (ENPs). The models of plant study range from rice, corn, cereal grains, and other food crops (monocot) to tomato, peas and beans, and cucumber (dicot) among others. Another important concern addressed is harmful elemental bioaccumulation in the plant and its biomagnification in the food chain.

Rutile titanium dioxide nanoparticles (nTiO2) were weathered in field soil at 0, 100, 200, and 400 mg Ti/kg soil for four months. Two types of nTiO2 with different surface coatings (hydrophilic and hydrophobic), uncoated nTiO2 (pristine), and the untreated control were included. Thereafter, carrot seeds (Daucus carota L.) were sown in those soils and grown in a growth chamber for 115 days until full maturity. A comparison was made between this and our previous unaged study, where carrots were treated in the same way in soil with freshly amended nTiO2. The responses of plants depended on the nTiO2 surface coating and concentration. The aged hydrophobic and hydrophilic-coated nTiO2 induced more positive effects on plant development at 400 and 100 mg Ti/kg soil, respectively, compared with control and pristine treatments. Taproot and leaf fresh biomass and plant height were improved by up to 64%, 40%, and 40% compared with control, respectively. Meanwhile, nutrient elements such as Fe in leaves, Mg in taproots, and Ca, Zn, and K in roots were enhanced by up to 66%, 64%, 41, 143% and 46%, respectively. However, the contents of sugar, starch, and some other metal elements in taproots were negatively affected, which may compromise their nutritional quality. Taken together, the overall growth of carrots was benefited by the aged nTiO2 depending on coating and concentration. The aging process served as a potential sustainable strategy to alleviate the phytotoxicity of unweathered nanoparticles.

The production and environmental release of surface-modified titanium dioxide nanoparticles (nTiO

The recent application of nano copper (Cu) compounds in the agrosystem has shown potential to improve the physiological performance and agronomical parameters of crops. We grew alfalfa (Medicago sativa) in potting mix amended with bulk, nano, and ionic Cu compounds at 80 and 280 mg Cu/kg; then, we evaluated plant performance at physiological and molecular levels. Plants treated with bulk/nano Cu presented better agronomical responses. The P and S content was reduced in bulk and ionic Cu-exposed plants, compared to controls (p ≤ .05). All Cu forms increased the content of Fe and Zn in roots and Fe in leaves, compared to controls (p ≤ .05). Leaf-superoxide dismutase expression was augmented ~27-fold and rubisco mRNA was unaffected in bulk/nano Cu-treated plants, compared to controls (p ≤ .05). Bulk/nano Cu incremented the relative abundance of microorganisms involved in the elemental uptake. These results indicate that nano Cu improved the physiology of alfalfa and can be considered as potential nanofertilizers.

With the exponential growth of nanomaterial production in the last years, nano copper (Cu)-based compounds are gaining more consideration in agriculture since they can work as pesticides or fertilizers. Chinese scallions (Allium fistulosum), which are characterized by their high content of the antioxidant allicin, were the chosen plants for this study. Spectroscopic and microscopic techniques were used to evaluate the nutrient element, allicin content, and enzyme antioxidant properties of scallion plants. Plants were harvested after growing for 80 days at greenhouse conditions in soil amended with CuO particles [nano (nCuO) and bulk (bCuO)] and CuSO4 at 75–600 mg/kg]. Two-photon microscopy images demonstrated the particulate Cu uptake in nCuO and bCuO treated roots. In plants exposed to 150 mg/kg of the Cu-based compounds, root Cu content was higher in plants treated with nCuO compared with bCuO, CuSO4, and control (p ≤ 0.05). At 150 mg/kg, nCuO increased root Ca (86%), root Fe (71%), bulb Ca (74%), and bulb Mg (108%) content, compared with control (p ≤ 0.05). At the same concentration, bCuO reduced root Ca (67%) and root Mg (33%), compared with control (p ≤ 0.05). At all concentrations, nCuO and CuSO4 increased leaf allicin (56–187% and 42–90%, respectively), compared with control (p ≤ 0.05). The antioxidant enzymes were differentially affected by the Cu-based treatments. Overall, the data showed that nCuO enhances nutrient and allicin contents in scallion, which suggests they might be used as a nanofertilizer for onion production.

The comparative toxicity of nano/bulk cupric oxide (CuO) and ionic copper (Cu) in Rosie and Green bok choy (Brassica rapa) varieties, with higher and lower anthocyanin contents, respectively, was investigated. Both phenotypes were cultivated for 70 days in natural soil amended with nano CuO (nCuO), bulk CuO (bCuO), and Cu chloride (CuCl2) at 75, 150, 300, and 600 mg Cu/kg soil. Essential elements in tissues, agronomical parameters, chlorophyll content, and Cu distribution in leaf were determined. In both varieties, nCuO treatments significantly increased Cu uptake in roots, compared with bCuO and CuCl2 (p ≤ 0.05). At all treatment concentrations, Rosie variety had more Cu than Green. More physiological impairments such as chlorophyll and leaf biomass reduction were observed in treated-Rosie varieties, compared to Green plants. The adverse effects were higher in nCuO-treated plants than their bCuO- or ionic Cu-exposed counterparts. Different distribution patterns of the translocated Cu in leaf midrib and parenchyma depended on particle size and plant phenotype, as demonstrated by two-photon microscopy. The different effects of CuO-based compounds in Rosie and Green varieties may be related to the anthocyanin content. These findings help to understand the factors involved in nanoparticles uptake and translocation to plant edible parts.

Certain engineered nanoparticles (NPs) have unique properties that have exhibited significant potential for promoting photosynthesis and enhancing crop productivity. Understanding the fundamental interactions between NPs and plants is crucial for the sustainable development of nanoenabled agriculture. Leaf mesophyll protoplasts, which maintain similar physiological response and cellular activity as intact plants, were selected as a model system to study the impact of NPs on photosynthesis. The mesophyll protoplasts isolated from spinach were cultivated with different NMs (Fe, Mn3O4, SiO2, Ag, and MoS2) dosing at 50 mg/L for 2 h under illumination. The potential maximum quantum yield and adenosine triphosphate (ATP) production of mesophyll protoplasts were significantly increased by Mn3O4 and Fe NPs (23% and 43%, respectively), and were decreased by Ag and MoS2 NPs. The mechanism for the photosynthetic enhancement by Mn3O4 and Fe is to increase the photocurrent and electron transfer rate, as revealed by photoelectrochemical measurement. GC-MS based single cell type metabolomics reveal that NPs (Fe and MoS2) altered the metabolic profiles of mesophyll cells during 2 h of illumination period. Separately, the effect of NPs exposure on photosynthesis and biomass were also conducted at the whole plant level. A strong correlation was observed with protoplast data; plant biomass was significantly increased by Mn3O4 exposure (57%) but was decreased (24%) by treatment of Ag NPs. The use of mesophyll protoplasts can be a fast and reliable tool for screening NPs to enhance photosynthesis for potential nanofertilizer use. Importantly, inclusion of a metabolic analysis can provide mechanistic toxicity data to ensure the development "safer-by-design" nanoenabled platforms.

The rapid development of nanotechnology makes the environmental impact assessment a necessity to ensure the sustainable use of engineered nanomaterials. Here, silver nanoparticles (AgNPs) at 100 mg/kg were added to soils in the absence or presence of cucumber (Cucumis sativa) plants for 60 days. The response of the soil microbial community and associated soil metabolites was investigated by 16S rRNA gene sequencing and gas chromatography-mass spectrometry (GC-MS)-based metabolomics, respectively. The results show that AgNP exposure significantly increased the soil pH in both unplanted and cucumber-planted soils. The soil bacterial community structure was altered upon Ag exposure in both soils. Several functionally significant bacterial groups, which are associated with carbon, nitrogen, and phosphorus cycling, were compromised by AgNPs in both unplanted and cucumber-planted soils. Generally, plants played a limited role in mediating the impact of AgNPs on the bacterial community. Soil metabolomic analysis showed that AgNPs altered the metabolite profile in both unplanted and cucumber-planted soils. The significantly changed metabolites are involved in sugar and amino acid-related metabolic pathways, indicating the perturbation of C and N metabolism, which is consistent with the bacterial community structure results. In addition, several fatty acids were significantly decreased upon exposure to AgNPs in both unplanted and cucumber-planted soils, suggesting the possible oxidative stress imposed on microbial cell membranes. These results provide valuable information for understanding the biological and biochemical impact of AgNP exposure on both plant species and on soil microbial communities; such understanding is needed to understand the risk posed by these materials in the environment.

Little information is available on the interaction of CuO nanoparticles (nCuO) with tuberous roots. In this study, Beauregard-14 (B-14, low lignin) and Covington (COV, high lignin) sweetpotato varieties were cultivated until maturity in soil amended with nCuO, bulk copper oxide (bCuO) and CuCl2 at 25–125 mg/kg. The Cu treatments had no significant influence on chlorophyll content. Gas exchange parameters were not affected in B-14. In COV, however, at 125 mg/kg treatments, bCuO reduced the intercellular CO2 (11%), while CuCl2 increased it by 7%, compared with control (p ≤ 0.035). At 25 mg/kg nCuO increased the length of COV roots (20.7 ± 2.0 cm vs. 14.6 ± 0.8 cm, p ≤ 0.05). In periderm of B-14, nCuO, at 125 mg/kg, increased Mg by 232%, while the equivalent concentration of CuCl2 reduced P by 410%, compared with control (p ≤ 0.05). The data suggest the potential application of nCuO as nanofertilizer for sweetpotato storage root production.

In this study, the impact of cerium oxide nanoparticles on the nutritional value of tomato (

The current study reports synthesis and characterization of an ecofriendly, cheap and efficient biosorbent, sulfonated spent coffee waste (SCW-SO3H) for water remediation. SCW-SO3H was synthesized through introducing sulfonic acid polar functionalities over the polymeric biomass (cellulose and lignin) of the spent coffee waste (SCW) by a simple, facile and versatile method. ICP-OES, SEM-EDX, FT-IR, XPS, TGA, Raman and UV–vis spectroscopy were used to analyze the developed SCW-SO3H biosorbent and its adsorption capacity towards the removal of different environmental pollutants. In order to optimize and maximize adsorption capacity of the developed biosorbent, different variables such as initial concentration, biosorbent dosage, pH, time and temperature were evaluated. The chemically engineered biosorbent showed excellent pollutant removal capacity of 812 mg/g, 462 mg/g and 302 mg/g toward methylene blue, tetracycline and Cr (VI), respectively. Isotherms studies showed that while organic pollutants adsorption follow Langmuir isotherm, Cr(VI) adsorption follows Freundlich isotherm. It was also found that adsorption of all the adsorbates follow pseudo-second order rate kinetic and thermodynamic values, ΔH >0 and ΔG

The advent of industrialization has led to the discovery of a wide range of chemicals designed for multiple uses including plant protection. However, after use, most of the chemicals and their derivatives end up in soil and water, interacting with living organisms. Plants, which are primary producers, are intentionally or unintentionally exposed to several chemicals, serving as a vehicle for the transfer of products into the food chain. Although the exposure of pesticides towards plants has been witnessed over a long time in agricultural production, other chemicals have attracted attention very recently. In this review, we carried out a comprehensive overview of the plant uptake capacity of various contaminants of emerging concern (CEC) in soil, such as pesticides, polycyclic aromatic hydrocarbons, perfluorinated compounds, pharmaceutical and personal care products, and engineered nanomaterials. The uptake pathways and overall impacts of these chemicals are highlighted. According to the literature, bioaccumulation of CEC in the root part is higher than in aerial parts. Furthermore, various factors such as plant species, pollutant type, and microbial interactions influence the overall uptake. Lastly, environmental factors such as soil erosion and temperature can also affect the CEC bioavailability towards plants.

The interaction of CuO nanoparticles (nCuO), a potential nanopesticide, with the growth hormone indole-3-acetic acid (IAA) is not well understood. This study aimed to evaluate the nutritional components in seeds of green pea (Pisum sativum) cultivated in soil amended with nCuO at 50 or 100mgkg-1, with/without IAA at 10 or 100μM. Similar treatments including bulk CuO (bCuO) and CuCl2 were set as controls. Bulk CuO at 50mgkg-1 reduced seed yield (52%), compared with control. Bulk CuO at 50mgkg-1 and nCuO at 100mgkg-1, plus IAA at 100μM, increased iron in seeds (41 and 42%, respectively), while nCuO at 50mgkg-1, plus IAA at 100μM reduced boron (80%, respect to control and 63%, respect to IAA at 100μM). IAA, at 10μM increased seed protein (33%), compared with control (p≤0.05). At both concentrations IAA increased sugar in seeds (20%). Overall, nCuO, plus IAA at 10μM, does not affect the production or nutritional quality of green pea seeds.

There is a lack of information about the transgenerational effects of titanium dioxide nanoparticles (nano-TiO2) in plants. This study aimed to evaluate the impacts of successive exposure of nano-TiO2 with different surface properties to basil (Ocimum basilicum). Seeds from plants exposed or re-exposed to pristine, hydrophobic, or hydrophilic nano-TiO2 were cultivated for 65 days in soil unamended or amended with 750 mg·kg−1 of the respective particles. Plant growth, concentration of titanium and essential elements, as well as content of carbohydrates and chlorophyll were evaluated. There were no differences on Ti concentration in roots of plants sequentially exposed to pristine or hydrophobic nano-TiO2, or in roots of plants exposed to the corresponding particle, only in the second cycle. However, sequential exposure to hydrophilic particles resulted in 65.2% less Ti in roots, compared to roots of plants exposed the same particles, only in the second cycle. The Ti concentrations in shoots were similar in all treatments. On the other hand, pristine and hydrophilic particles reduced Mg in root by 115% and 81%, respectively, while pristine and hydrophobic particles reduced Ni in shoot by 84% and 75%, respectively, compared to unexposed plants in both cycles. Sequential exposure to pristine nano-TiO2 increased stomatal conductance (214%, p ≤ 0.10), compared to plants that were never exposed. Hydrophobic and hydrophilic nano-TiO2 reduced chlorophyll b (52%) and total chlorophyll (30%) but increased total sugar (186%) and reducing sugar (145%), compared to unexposed plants in both cycles. Sequential exposure to hydrophobic or hydrophilic nano-TiO2 resulted in more adverse effects on photosynthesis but in positive effects on plant growth, compared to pristine nano-TiO2.

A series of highly efficient adsorbents were developed using Ni3(BTC)2 and Co3(BTC)2 metal-organic frameworks (MOFs) and Fe3O4 magnetic nanoparticles (MNPs) to functionalize graphene oxide (GO). XRD results show high crystallinity of the prepared nanomaterials and the successful decoration of Ni3(BTC)2 and Co3(BTC)2 MOFs over the GO substrate (BTC = benzene-1,3,5-tricarboxylic acid). SEM and TEM imaging show the successful formation of nanoscale MOFs and Fe3O4 MNPs over GO. IR spectroscopy supports the characterization and successful preparation of the Fe3O4/MOF@GO hybrid composite nanoadsorbents. The prepared composite nanoadsorbents were used to sorb Methylene Blue (MB) as a model for common organic pollutants in water and common ions (Na+, Ca2+, Mg2+, SO42−, SiO32−) from a brackish water model. The adsorbed concentration at equilibrium of MB of the prepared composite nanoadsorbents increases by an average of 30.52 and 13.75 mg/g for the Co and Ni composite, respectively, when compared to the MOFs parent materials. The adsorbed amount of sulfate ions increases by 92.1 mg/g for the Co composite and 112.1 mg/g for the Ni composite, when compared to graphene oxide. This adsorption enhancement is attributed to suppressed aggregation through increased dispersive forces in the MOFs due to the presence of GO, formation of nanoscale MOFs over the GO platform, and the hindering of stacking of the graphene layers by the MOFs. Leaching tests show that the release of Co and Ni ions to water is reduced from 105.2 and 220 mg/L, respectively, in the parent MOF materials to 0.5 and 16.4 mg/L, respectively, in the composite nanoadsorbents. These findings show that the newly developed composite nanoadsorbents can sorb organic pollutants, and target sulfate and silicate anions, which makes them suitable candidates for water and wastewater treatments.

Engineered nanomaterials (ENMs) can enter agroecosystems because of their widespread use and disposal. Within soil, ENMs may affect legumes and their dinitrogen (N2) fixation, which are critical fo...

This study evaluated weathered and fresh ZnO-nanoparticles and Zn-salt effects on nutrient acquisition and redistribution in wheat. Weathered and fresh ZnO-nanoparticles and Zn-salt significantly increased grain yield by 15% and 29%, respectively. Postharvest soil acidification indicated ZnO-nanoparticles dissolved during growth. Zn was significantly bioaccumulated from both Zn types, but with low root-to-shoot bioaccumulation efficiency: 24% and 20% for weathered nanoparticles and salt, and 48% and 30% for fresh nanoparticles and salt. Grain Zn content was increased 186% and 229% by weathered nanoparticles and salt, and 229% and 300% by fresh nanoparticles and salt. Shoot-to-grain translocation efficiency was high: 167% and 177% for weathered nanoparticles and salt, and 209% and 155% for fresh nanoparticles and salt. However, Zincon assay indicated grain Zn does not exist as ions. This study demonstrates that ZnO-nanoparticles and Zn-salt vary in their effects on nutrient acquisition in wheat, with relevance for biofortification of Zn for human nutrition.

Presence of antibiotic contaminants in drinking water is increasing in epidemic proportions in recent times. Here, we report a scalable and cost-effective approach to prepare sulfonated saw dust (SD-SO3H) derived from saw dust (SD) that exhibits high-capacity adsorbent properties for the removal of antibiotics such as Tetracycline (TC), Sulfamethoxazole (SMX), and endocrine-disruptive chemicals such as Bisphenol A (BPA). The adsorption capacities of SD-SO3H towards the removal of TC, SMX, and BPA are 270.53 mg/g, 295.06 mg/g, and 263.75 mg/g, respectively. The adsorption capacity of SD-SO3H is about 2 and 4 times higher than commercially available activated carbon towards the removal of SMX and BPA, respectively according to the literature. For TC, the adsorption capacity of SD-SO3H is comparable to the commercially available activated carbon. The adsorbent was characterized using Scanning Electron Microscopy (SEM), Energy-dispersive X-ray Spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy, Thermogravimetric analysis (TGA), and Zeta potential measurements. The effect of initial concentration, dosage, time, pH and temperature on the adsorption process was systematically investigated. Isotherms studies showed that the TC and SMX adsorption follow Langmuir isotherm whereas, BPA adsorption follows Freundlich isotherm. The kinetics data can be well defined by the pseudo-second order kinetic model. A thermodynamic study of adsorption showed that the TC adsorption process was endothermic while the SMX and BPA adsorption processes were exothermic, and the adsorption process was spontaneous in all cases. Altogether, SD-SO3H can be a scalable, cost-effective adsorbent for the efficient removal of TC, SMX and BPA from wastewater.

In this study, we report a facile method for the preparation of sulfonic acid functionalized carbonaceous adsorbent (TW-SO3H) from tea leaves. The adsorbent was characterized using Fourier-transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy-dispersive X-ray Spectroscopy (EDS), Thermogravimetric analysis (TGA), Raman Spectroscopy and Zeta potential measurements. The adsorbent was utilized for the adsorptive removal of antibiotics such as sulfamethoxazole (SMX) and endocrine disrupting chemicals such as bisphenol A (BPA) from water. The calculated adsorption capacities of TW-SO3H were 258.87 mg/g and 236.80 mg/g towards the removal of SMX and BPA, respectively at 25 °C. The new adsorbent has the ability to form electrostatic interaction and π–π stacking that allow the efficient adsorption of SMX and BPA. The Langmuir and Temkin isotherm models best fit the experimental data for the BPA and SMX adsorption processes, respectively. The results of the kinetic studies showed that the removal of SMX and BPA by TW-SO3H followed pseudo-second order kinetic model. A thermodynamic study indicated that the adsorption process was spontaneous as well as exothermic. The adsorbent was facilely regenerated and recycled for three cycles with a nominal loss of adsorption capacity. Our results indicated that TW-SO3H could be utilized as a promising adsorbent for the rapid removal of SMX and BPA from the contaminated water.

Natural nanoparticles (NNPs) in rivers, lakes, oceans and ground water predate humans, but engineered nanoparticles (ENPs) are emerging as potential pollutants due to increasing regulatory and public perception concerns. This Review contrasts the sources, composition and potential occurrence of NNPs (for example, two-dimensional clays, multifunctional viruses and metal oxides) and ENPs in surface water, after centralized drinking water treatment, and in tap water. While analytical detection challenges exist, ENPs are currently orders of magnitude less common than NNPs in waters that flow into drinking water treatment plants. Because such plants are designed to remove small-sized NNPs, they are also very good at removing ENPs. Consequently, ENP concentrations in tap water are extremely low and pose low risk during ingestion. However, after leaving drinking water treatment plants, corrosion by-products released from distribution pipes or in-home premise plumbing can release incidental nanoparticles into tap water. The occurrence and toxicity of incidental nanoparticles, rather than ENPs, should therefore be the focus of future research.

This study explored the use of foliar sprays with nanoparticles (NP) of B, CuO, MnO, SiO, TiO, and ZnO to protect watermelon against Fusarium wilt. Leaves of young watermelon plants were sprayed (1 to 2 ml per plant) with NP suspensions (500 to 1,000 µg/ml) and were planted in potting mix infested with Fusarium oxysporum f. sp. niveum. In five of eight greenhouse experiments, CuO NP suppressed disease and, in six of eight experiments, CuO NP increased biomass or yield more than in untreated controls or other tested NP. More root Cu was detected in CuO NP-treated plants than other treatments (P = 0.015). In Griswold, CT, plants treated with CuO NP yielded 39% more fruit than untreated controls. In Hamden, CT, treatment with CuO NP produced 53% more fruit when compared with controls (P = 0.02) and was superior to other Cu fungicides. Gene expression in watermelon roots revealed strong upregulation of polyphenol oxidase (PPO) and PR1 genes when CuO NP and F. oxysporum f. sp. niveum were both present. Enzymatic assays for PPO supported the gene expression results. CuO NP may serve as a highly effective delivery agent for this micronutrient to suppress disease.

The use of nanoparticles in plant protection may reduce pesticide usage and contamination and increase food security. In this study, three-week-old Solanum lycopersicum seedlings were exposed, by root or foliar pathways, to CeO2 nanoparticles and cerium acetate at 50 and 250 mg/L prior to transplant into sterilized soil. One week later, the soil was inoculated with the fungal pathogen Fusarium oxysporum f. sp. lycopersici (1 g/kg), and the plants were cultivated to maturity in a greenhouse. Disease severity, biomass/yield, and biochemical and physiological parameters were analyzed in harvested plants. Disease severity was significantly reduced by 250 mg/L of nano-CeO2 and CeAc applied to the soil (53% and 35%, respectively) or foliage (57% and 41%, respectively), compared with non-treated infested controls. Overall, the findings show that nano-CeO2 has potential to suppress Fusarium wilt and improve the chlorophyll content in tomato plants.

Titanium dioxide nanoparticles (NPs) have become widely used and studied in industry, cosmetics, and water treatment; however, due to their surface charge and composition, uncoated nanoparticles often aggregate and settle in a solution. This leads to loss of function and suspension, abandoning the NPs' properties that make them ideal for many applications. Loss of NP suspension can also complicate analysis of solutions containing nanoparticles. Therefore, titanium dioxide nanoparticles are good candidates for surface coatings that enable hydrophilic interactions and improved suspension. Many coating processes require complex synthesis methods and begin with titanium dioxide precursors rather than with already synthesized nanoparticles. The method presented herein examines additive processes that may increase suspension capabilities and inhibit loss of function through aggregation of large nanoparticles (50 ± 25 nm). Nineteen chelating organic compounds were tested via a 1, 2, or 3 equivalent additions to pristine, unmodified TiO2 nanoparticles in solution. Furthermore, ligands that showed the best chelating behavior were diluted and the pH was modified to understand pH dependent behavior. Dynamic light scattering and electrophoretic light scattering were used in the study of the chemical behavior of the modified TiO2 nanoparticles. Results show that nanoparticles interacting with dimethylethanolamine, dimercaptosuccinic acid, sodium citrate, dimethylglyoxime, and oxalic acid showed improved ζ-potential at a pH of 5. Physico-chemical processes are discussed in the understanding of these results.

Bean (Phaseolus vulgaris) plants were cultivated in nanoparticle-unamended soil, and their second-generation seeds (S2) were analyzed to determine the transgenerational effects of uncoated nano-ZnO (Z-COTE), coated nano-ZnO (Z-COTE HP1), bulk ZnO, or ionic Zn (ZnCl2) at 0–500 mg kg–1. Antioxidant enzymatic activity was determined in immature seeds, while the yield and nutritional composition of the seeds were measured at the end of the growth cycle. None of the treatments affected seed production, maturation time, Zn accumulation, or the content of sugar, starch, or protein in S2, compared with controls. The accumulation of K, P, S, Mg, Fe, Mn, B, Mo, and Cu in S2 seeds also remained unaffected. However, Z-COTE at 500 mg kg–1 and Z-COTE HP1 at 125 and 500 mg kg–1 reduced Ni in S2 seeds by 60%, 41%, and 74%, respectively, compared with the control. The Zn nanomaterials (NMs) did not impact the activity of ascorbate peroxidase, catalase, and superoxide dismutase (SOD) in the seeds. However, ZnCl2 at 500 mg ...

In this study, low and high anthocyanin basil (Ocimum basilicum) varieties (LAV and HAV) were sprayed with 4.8 mg Cu/per pot from Cu(OH)2 nanowires, Cu(OH)2 bulk (CuPro), or CuSO4 and cultivated for 45 days. In both varieties, significantly higher Cu was determined in leaves of CuSO4 exposed plants (691 and 672.6 mg/kg for LAV and HAV, respectively); however, only in roots of HAV, Cu was higher, compared to control (p ≤ 0.05). Nanowires increased n-decanoic, dodecanoic, octanoic, and nonanoic acids in LAV, but reduced n-decanoic, dodecanoic, octanoic, and tetradecanoic acids in HAV, compared with control. In HAV, all compounds reduced eugenol (87%), 2-methylundecanal (71%), and anthocyanin (3%) (p ≤ 0.05). In addition, in all plant tissues, of both varieties, nanowires and CuSO4 reduced Mn, while CuPro increased chlorophyll contents, compared with controls (p ≤ 0.05). Results suggest that the effects of Cu(OH)2 pesticides are variety- and compound-dependent.

The effects of metallic copper nanoparticles (nCu) in plants are not well understood. In this study, soil grown oregano (Origanum vulgare) was exposed for 60days to nCu and Cu microparticles (μCu) at 0-200mgCu/kg. At harvest, Cu accumulation, biomass production, nutrient composition, and Cu fractions in soil were measured. Except for μCu at 50mg/kg, both nCu and μCu increased root Cu (28.4-116.0%) and shoot Cu (83.0-163.0% and 225.4-652.5%, respectively), compared with control. Copper accumulation from μCu increased as the external μCu increased. nCu and μCu did not affect shoot length, malondialdehyde, or chlorophyll, but increased water content (6.9-12.5%) and reduced shoot biomass (21.6-58.5%), compared with control. In addition, at 50mg/kg, μCu decreased root biomass and length (48.6% and 20.5%, respectively) and water content (1.8% and 3.9% at 100 and 200mg/kg, respectively). All treatments modified root and shoot Ca, Fe, Mg, and Mn (p≤0.05). Additionally, all Cu treatments decreased starch (33.9-58.5%), total sugar (39.5-55.7%), and reducing sugar (13.6-33.9%) in leaves. Results showed that metallic Cu nanoparticles/microparticles affected agronomical and physiological parameters in oregano, which could impact human nutrition. However, smaller size particles do not necessarily imply greater toxicity.

Several studies have explored the effects of copper nanoparticles (NPs) on different edible plants. However, no studies on bell pepper (Capsicum annum L.) plants have been reported. In this study, plants were grown for a full life-cycle assessment (90 days of exposure) in natural soil amended with nano CuO (nCuO), bulk CuO (bCuO), and ionic copper (CuCl2) at 0, 125, 250, and 500 mg kg−1. Based on our experimental findings, none of the treatments significantly affected stem elongation, plant dry biomass, foliar area, leaf chlorophyll content, and fruit productivity of bell pepper. However, ionic copper significantly decreased the gas exchange parameters, evapotranspiration, stomatal conductance, and photosynthesis by an average of 41%, 59%, and 38%, respectively, compared to the other treatments at select concentrations (p ≤ 0.05). The ICP-OES data showed that, except for bCuO at 500 mg kg−1, at 250 mg kg−1 and above, the three compounds significantly increased root Cu (196%, 184%, and 184%) with respect to the control. Only at 500 mg kg−1, ionic Cu gave significantly higher root Cu compared to the other Cu treatments. Additionally, at 125 mg kg−1, leaf P was 41% lower for nCuO, compared to the bCuO treatment. At 500 mg kg−1, nCuO reduced Zn by 55% in leaves and 47% in fruits, compared to the control (p ≤ 0.05); however, it is premature to assert that the reduction in fruit Zn compromises the nutritional quality of bell pepper. Overall, this investigation showed that, at the concentrations tested, nCuO presented low toxicity to bell pepper, with rare differences between nano and bulk treatment responses.

Titanium dioxide nanoparticles (nano-TiO2), one of the most produced engineered nanoparticles (ENPs), are used in pigments, photocatalysis, food additives, and personal care products. This broad variety of applications has led to the unusual and widespread distribution of nano-TiO2 in several environmental sectors, with different effects on living organisms. In the last decade, several publications have shown fragments of information about the interaction, detection, uptake, and translocation of nano-TiO2 in plants. This review includes a discussion of the current knowledge about factors affecting the interaction of nano-TiO2 with soil and plants. We also discuss the role of particle size, crystal phase, surface coating, and techniques employed to study the interaction of these nanoparticles with plants. Concluding results from synchrotron based, microscopic, physiological, and biochemical analyses of plants exposed to nano-TiO2 are presented. However, the current information leaves no doubt that there are still many aspects in need of additional investigations to fully understand the effects of nano-TiO2 in plants. For instance, little is known about the transgenerational effects of nano-TiO2 exposure and the changes at agronomical and physiological levels. The effects of such ENPs in proteins and other metabolites are also not well understood. In addition, more information is needed about the interaction of nano-TiO2 with other ENPs-and-organic co-contaminates and the effects of plants. Since nano-TiO2 have been found in edible tissues, it is expected that they will be in the food chain; thus, studies on their trophic transfer are required. The authors hope that, besides contributing to a better understanding of current data about the effects of nano-TiO2 in soil and plants, this review will help to drive future investigations and will contribute to the general knowledge on the environmental interactions of engineered nanomaterials.

The interactions of nanoparticles (NPs) with biochar and soil components may substantially influence NP availability and toxicity to biota. In the present study, earthworms (Eisenia fetida) were exposed for 28 days to a residential or agricultural soil amended with 0–2000 mg of CeO2 NP/kg and with biochar (produced by the pyrolysis of pecan shells at 350 and 600 °C) at various application rates [0–5% (w/w)]. After 28 days, earthworms were depurated and analyzed for Ce content, moisture content, and lipid peroxidation. The results showed minimal toxicity to the worms; however, biochar (350 or 600 °C) was the dominant factor, accounting for 94 and 84% of the variance for the moisture content and lipid peroxidation, respectively, in the exposed earthworms. For both soils with 1000 mg of CeO2/kg at 600 °C, biochar significantly decreased the accumulation of Ce in the worm tissues. Amendment with 350 °C biochar had mixed responses on Ce uptake. Analysis by micro X-ray fluorescence (μ-XRF) and micro X-ray absor...

The response of plants to copper oxide nanoparticles (nano-CuO) in presence of exogenous phytohormones is unknown. In this study, green pea (Pisum sativum) plants were cultivated to full maturity in soil amended with nano-CuO (10-100nm, 74.3% Cu), bulk-CuO (bCuO, 100-10,000nm, 79.7% Cu), and CuCl2 at 50 and 100mg/kg and indole-3-acetic acid (IAA) at 10 and 100μM. Results showed that IAA at 10 and 100μM, averaged over all Cu treatments, reduced the number of plants by ~23% and ~34%, respectively. IAA at 10μM, nano-CuO at 50mg/kg, b-CuO at 50mg/kg, and CuCl2 at 100mg/kg reduced pod biomass by about 50%. Although some combinations of IAA, mainly at 100μM, with the Cu compounds altered nutrient accumulation in tissues, none of them affected pod elements. Conversely, without IAA, nano-CuO at 50mg/kg, increased pod Fe and Ni by 258% and 325%, respectively, while bCuO at 100mg/kg increased pod Ni by 275%, compared with control. With IAA at 10μM, nano-CuO (100mg/kg) and bCuO (50mg/kg) increased stem Cu by ~84% and ~78%. When IAA increased to 100μM, nano-CuO and bCuO reduced stem Ca by 32% and 37%, and Mg by ~35%. Results suggest that both the nano-CuO and bCuO could improve the nutritional quality of pea pods, while exogenous IAA combined with Cu-based compounds could impact green pea production since these treatments reduced the number of plants and pod biomass.

A series of novel zeolitic imidazolate framework (ZIF) decorated superparamagnetic graphene oxide hybrid nanoadsorbents were synthesized, characterized, and tested for their As(III) adsorbed amount in simulated drinking water. The three composite nanomaterials are based each on three isostructural and water stable ZIFs, (C-1 based on ZIF-8, C-2 based on ZIF-67, and C-3 based on ZIF-Zn/Co). The composite nanomaterials and there parent materials were characterized through pXRD, TEM, FTIR, BET and magnetometry methods (SQUID), and were tested as adsorbents in a representative drinking water matrix containing arsenite (As(III)) at an initial trace concentration (realistic in some natural drinking water sources) of 35 µg/L. The nanoadsorbents were magnetically captured and removed after adsorption in batch conditions. Out of the three composites, C-2 shows the highest As(III) adsorbed amount at an initial concentration of 35 µg/L (q0) of 202 µg/g, followed by C-3 with 102 µg/g and C-1 with 82 µg/g.

Previous studies have shown that ZnO nanoparticles (NPs) affect corn germination and root growth. However, there is a lack of information about the effects of these NPs at different temperatures. In this study, corn seedlings were exposed to ZnO NPs (24 ± 3 nm) at 0–1600 mg L − 1 and ionic Zn 0–250 mg L − 1 for 15 days. Germination, root elongation, Zn uptake and oxidation state, enzyme activity and protein expression were analyzed. At 20 and 25 °C, 400 mg ZnO NPs L − 1 significantly reduced the germination (40 and 53% respectively), while no effect of Zn 2 + was observed. Temperature and Zn concentration affected root growth. At 20 °C, ZnO at 50, 400, and 1600 mg L − 1 reduced root growth by 18, 47, and 26% respectively. At 25 °C, 100 and 800 mg L − 1 increased root growth by 22 and 27%, while at 30 °C, 100 mg L − 1 reduced root growth by 42%. At 30 °C, 0.1 mg L − 1 of Zn 2 + increased the growth by 50%. Zn accumulation in seedlings was significant only at 1600 mg L − 1 ZnO and 250 mg L − 1 Zn 2 + . Ascorbate peroxidase activity increased by 24 and 57% under exposure to ZnO at 400 and 1600 mg L − 1 at 25 °C. At any temperature the XAS analyses showed presence on NPs in roots. Exposure to ZnO NPs did not show changes in protein expression; however, a protein band with molecular weight of 85 kDa decreased its expression at 30 °C, while a protein of 75 kDa increased its expression at 30 °C. This study suggests that temperature may alter the way the ZnO NPs interact with plants.

Given increasing use of copper-based nanomaterials, particularly in applications with direct release, it is imperative to understand their human and ecological risks. A comprehensive and systematic approach was used to determine toxicity and fate of several Cu nanoparticles (Cu NPs). When used as pesticides in agriculture, Cu NPs effectively control pests. However, even at low (5–20 mg Cu/plant) doses, there are metabolic effects due to the accumulation of Cu and generation of reactive oxygen species (ROS). Embedded in antifouling paints, Cu NPs are released as dissolved Cu + 2 and in nano- and micron-scale particles. Once released, Cu NPs can rapidly (hours to weeks) oxidize, dissolve, and form CuS and other insoluble Cu compounds, depending on water chemistry (e.g. salinity, alkalinity, organic matter content, presence of sulfide and other complexing ions). More than 95% of Cu released into the environment will enter soil and aquatic sediments, where it may accumulate to potentially toxic levels (> 50–500 μg/L). Toxicity of Cu compounds was generally ranked by high throughput assays as: Cu + 2 > nano Cu(0) > nano Cu(OH) 2 > nano CuO > micron-scale Cu compounds. In addition to ROS generation, Cu NPs can damage DNA plasmids and affect embryo hatching enzymes. Toxic effects are observed at much lower concentrations for aquatic organisms, particularly freshwater daphnids and marine amphipods, than for terrestrial organisms. This knowledge will serve to predict environmental risks, assess impacts, and develop approaches to mitigate harm while promoting beneficial uses of Cu NPs.

Agricultural soils are among the depositories of engineered nanomaterials (ENMs). Soil exposure to ENMs occurs through the intentional use of nano-agrochemicals, as well as through incidental contamination from industrial-waste release, irrigation with wastewater or gray water, amendment with ENMs-loaded sludge (soil conditioning to stimulate plant growth), or atmospheric fallouts. Concerns about ENM interactions with plants raise two questions. (1) Are ENMs taken up from soil by plants? (2) If they are taken up, do they remain in the nanoform within plant tissues? Experiments with crop plants have demonstrated that some ENMs such as TiO2 are taken up by roots and translocated to aboveground tissues, including fruits, without biotransformation. CeO2 ENM is also taken up by the roots; however, although most of it remains as ENM, it releases cerium ions that are incorporated into organic compounds. CeO2 ENM has been shown to be translocated from roots to seeds in soybean grown in soil amended with such ENM. On the other hand, ZnO ENM is transformed at the soil/root interface, leading to tissue Zn enrichment. Overall, most ENMs are taken up by plants with either low or no transformation, and accumulate in tissues.

Concerns about the environmental safety of metal-based nanoparticles (MNPs) in aquatic ecosystems are increasing. Simultaneously, elevated atmospheric CO 2 levels are a serious problem worldwide, making it possible for the combined exposure of MNPs and elevated CO 2 to the ecosystem. Here we studied the toxicity of n ZnO to goldfish in a water-sediment ecosystem using open-top chambers flushed with ambient (400 ± 10 μL/L) or elevated (600 ± 10 μL/L) CO 2 for 30 days. We measured the content of Zn in suspension and fish, and analyzed physiological and biochemical changes in fish tissues. Results showed that elevated CO 2 increased the Zn content in suspension by reducing the pH value of water and consequently enhanced the bioavailability and toxicity of n ZnO. Elevated CO 2 led to higher accumulation of Zn in fish tissues (increased by 43.3%, 86.4% and 22.5% in liver, brain and muscle, respectively) when compared to ambient. Elevated CO 2 also intensified the oxidative damage to fish induced by n ZnO, resulting in higher ROS intensity, greater contents of MDA and MT and lower GSH content in liver and brain. Our results suggest that more studies in natural ecosystems are needed to better understand the fate and toxicity of nanoparticles in future CO 2 levels.

Little is known about the effects of surface coating on the interaction of engineered nanoparticles (ENPs) with plants. In this study, basil (Ocimum basilicum) was cultivated for 65 days in soil amended with unmodified, hydrophobic (coated with aluminum oxide and dimethicone), and hydrophilic (coated with aluminum oxide and glycerol) titanium dioxide nanoparticles (nano-TiO2) at 125, 250, 500, and 750 mg nano-TiO2 kg−1 soil. ICP-OES/MS, SPAD meter, and UV/Vis spectrometry were used to determine Ti and essential elements in tissues, relative chlorophyll content, carbohydrates, and antioxidant response, respectively. Compared with control, hydrophobic and hydrophilic nano-TiO2 significantly reduced seed germination by 41% and 59%, respectively, while unmodified and hydrophobic nano-TiO2 significantly decreased shoot biomass by 31% and 37%, respectively (p ≤ 0.05). Roots exposed to hydrophobic particles at 750 mg kg−1 had 87% and 40% more Ti than the pristine and hydrophilic nano-TiO2; however, no differences were found in shoots. The three types of particles affected the homeostasis of essential elements: at 500 mg kg−1, unmodified particles increased Cu (104%) and Fe (90%); hydrophilic increased Fe (90%); while hydrophobic increased Mn (339%) but reduced Ca (71%), Cu (58%), and P (40%). However, only hydrophobic particles significantly reduced root elongation by 53%. Unmodified, hydrophobic, and hydrophilic particles significantly reduced total sugar by 39%, 38%, and 66%, respectively, compared with control. Moreover, unmodified particles significantly decreased reducing sugar (34%), while hydrophobic particles significantly reduced starch (35%). Although the three particles affected basil plants, coated particles impacted the most its nutritional quality, since they altered more essential elements, starch, and reducing sugars.

With increasing use, manufactured nanomaterials (MNMs) may enter soils and impact agriculture. Herein, soybean (Glycine max) was grown in soil amended with either nano-CeO2 (0.1, 0.5, or 1.0gkg-1 soil) or nano-ZnO (0.05, 0.1, or 0.5gkg-1 soil). Leaf chlorosis, necrosis, and photosystem II (PSII) quantum efficiency were monitored during plant growth. Seed protein and protein carbonyl, plus leaf chlorophyll, reactive oxygen species (ROS), lipid peroxidation, and genotoxicity were measured for plants at harvest. Neither PSII quantum efficiency, seed protein, nor protein carbonyl indicated negative MNM effects. However, increased ROS, lipid peroxidation, and visible damage, along with decreased total chlorophyll concentrations, were observed for soybean leaves in the nano-CeO2 treatments. These effects correlated to aboveground leaf, pod, and stem production, and to root nodule N2 fixation potential. Soybeans grown in soil amended with nano-ZnO maintained growth, yield, and N2 fixation potential similarly to the controls, without increased leaf ROS or lipid peroxidation. Leaf damage was observed for the nano-ZnO treatments, and genotoxicity appeared for the highest nano-ZnO treatment, but only for one plant. Total chlorophyll concentrations decreased with increasing leaf Zn concentration, which was attributable to zinc complexes-not nano-ZnO-in the leaves. Overall, nano-ZnO and nano-CeO2 amended to soils differentially triggered aboveground soybean leaf stress and damage. However, the consequences of leaf stress and damage to N2 fixation, plant growth, and yield were only observed for nano-CeO2.

Evidence suggests that CO2 modifies the behavior of nanomaterials. Thus, in a few decades, plants might be exposed to additional stress if atmospheric levels of CO2 and the environmental burden of nanomaterials increase at the current pace. Here, we used a full-size free-air CO2 enrichment (FACE) system in farm fields to investigate the effect of elevated CO2 levels on phytotoxicity and microbial toxicity of nTiO2 (0, 50, and 200 mg kg− 1) in a paddy soil system. Results show that nTiO2 did not induce visible signs of toxicity in rice plants cultivated at the ambient CO2 level (370 μmol mol− 1), but under the high CO2 concentration (570 μmol mol− 1) nTiO2 significantly reduced rice biomass by 17.9% and 22.1% at 50 mg kg− 1 and 200 mg kg− 1, respectively, and grain yield by 20.8% and 44.1% at 50 mg kg− 1 and 200 mg kg− 1, respectively. In addition, at the high CO2 concentration, nTiO2 at 200 mg kg− 1 increased accumulation of Ca, Mg, Mn, P, Zn, and Ti by 22.5%, 16.8%, 29.1%, 7.4%, 15.7% and 8.6%, respectively, but reduced fat and total sugar by 11.2% and 25.5%, respectively, in grains. Such conditions also changed the functional composition of soil microbial communities, alerting specific phyla of bacteria and the diversity and richness of protista. Overall, this study suggests that increases in CO2 levels would modify the effects of nTiO2 on the nutritional quality of crops and function of soil microbial communities, with unknown implications for future economics and human health.

Little is known about the effects of surface modification on the interaction of nanoparticles (NPs) with plants. Tomato (Solanum lycopersicum L.) plants were cultivated in potting soil amended with bare and citric acid coated nanoceria (nCeO2, nCeO2+CA), cerium acetate (CeAc), bulk cerium oxide (bCeO2) and citric acid (CA) at 0–500 mg kg−1. Fruits were collected year-round until the harvesting time (210 days). Results showed that nCeO2+CA at 62.5, 250 and 500 mg kg−1 reduced dry weight by 54, 57, and 64% and total sugar by 84, 78, and 81%. At 62.5, 125, and 500 mg kg−1 nCeO2+CA decreased reducing sugar by 63, 75, and 52%, respectively and at 125 mg kg−1 reduced starch by 78%, compared to control. The bCeO2 at 250 and 500 mg kg−1, increased reducing sugar by 67 and 58%. In addition, when compared to controls, nCeO2 at 500 mg kg−1 reduced B (28%), Fe (78%), Mn (33%), and Ca (59%). At 125 mg kg−1 decreased Al by 24%; while nCeO2+CA at 125 and 500 mg kg−1 increased B by 33%. On the other hand, bCeO2 at 62.5 mg kg−1 increased Ca (267%), but at 250 mg kg−1 reduced Cu (52%), Mn (33%), and Mg (58%). Fruit macromolecules were mainly affected by nCeO2+CA, while nutritional elements by nCeO2; however, all Ce treatments altered, in some way, the nutritional quality of tomato fruit. To our knowledge, this is the first study comparing effects of uncoated and coated nanoceria on tomato fruit quality.

Multiple applications of metal oxide nanoparticles (MONPs) could result in their accumulation in soil, threatening higher terrestrial plants. Several reports have shown the effects of MONPs on plants. In this review, we analyze the most recent reports about the physiological and biochemical responses of plants to stress imposed by MONPs. Findings demonstrate that MONPs may be taken up and accumulated in plant tissues causing adverse or beneficial effects on seed germination, seedling elongation, photosynthesis, antioxidative stress response, agronomic, and yield characteristics. Given the importance of determining the potential risks of MONPs on crops and other terrestrial higher plants, research questions about field long-term conditions, transgenernational phytotoxicity, genotype specific sensitivity, and combined pollution problems should be considered.

Little is known about the interaction of nanoparticles (NPs) with soil constituents and their effects in plants. Boron (B), an essential micronutrient that reduces crop production at both deficiency and excess, has not been investigated with respect to its interaction with cerium oxide NPs (nano-CeO 2 ). Considering conflicting results on the nano-CeO 2 toxicity and protective role as antioxidant, their possible modulation on B toxicity in sunflower ( Helianthus annuus L.) was investigated. Sunflower was cultivated for 30 days in garden pots containing original or B-spiked soil amended with nano-CeO 2 at 0–800 mg kg −1 . At harvest, Ce and B concentrations in tissues, biomass, and activities of stress enzymes in leaves were determined. Results showed that in the original soil, Ce accumulated mainly in roots, with little translocation to stems and leaves, while reduced root Ce was observed in plants from B-spiked soil. In the original soil, higher levels of nano-CeO 2 reduced plant B concentration. Although morphological effects were not visible, changes in biomass and oxidative stress response were observed. Sunflower leaves from B-spiked soil showed visible symptoms of B toxicity, such as necrosis and chlorosis in old leaves, as well as an increase of superoxide dismutase (SOD) activity. However, at high nano-CeO 2 level, SOD activity decreased reaching values similar to that of the control. This study has shown that nano-CeO 2 reduced both the B nutritional status of sunflower in original soil and the B phytotoxicity in B-spiked soil.

Recent investigations show that carbon-based and metal-based engineered nanomaterials (ENMs), components of consumer goods and agricultural products, have the potential to build up in sediments and biosolid-amended agricultural soils. In addition, reports indicate that both carbon-based and metal-based ENMs affect plants differently at the physiological, biochemical, nutritional, and genetic levels. The toxicity threshold is species-dependent and responses to ENMs are driven by a series of factors including the nanomaterial characteristics and environmental conditions. Effects on the growth, physiological and biochemical traits, production and food quality, among others, have been reported. However, a complete understanding of the dynamics of interactions between plants and ENMs is not clear enough yet. This review presents recent publications on the physiological and biochemical effects that commercial carbon-based and metal-based ENMs have in terrestrial plants. This document focuses on crop plants because of their relevance in human nutrition and health. We have summarized the mechanisms of interaction between plants and ENMs as well as identified gaps in knowledge for future investigations.

The effects of soil properties on nanomaterial (NM) interactions with plants are not well understood. Bean (Phaseolus vulgaris) plants were grown to maturity in natural soil (NS) or organic matter (OM)-enriched soil (ES) amended with either uncoated (Z-COTE), hydrophobically-coated (Z-COTE HP1) ZnO NMs, bulk ZnO, or ZnCl2 at 0–500 mg kg−1. At harvest, yield and seed nutrient composition were assessed. The soil × compound interaction reduced the maturation time by about 25 days and increased the seed yield (∼155%) in ES, compared to NS. In NS, ZnCl2 at 125 mg kg−1 produced 10% less seed protein than the control, and disregarding the concentration, seeds from ZnCl2 showed the highest relative sugar content (102%, compared with the other compounds), while in NS, seeds from Z-COTE HP1 accumulated the highest relative sugar content (44% more than Z-COTE and ZnCl2). In addition, seeds from ES + Z-COTE HP1 had 19% less Zn than the rest of the compounds. In ES, the OM enrichment and reduction in pH enhanced the accumulation of Zn (38%), K (64%), S (44%), P (83%), Mg (86%), Ca (70%), Fe (89%), and Mn (85%), but reduced Mo under Z-COTE HP1 and ZnCl2, in comparison to NS seeds. Compared to the controls, ZnCl2 at 500 mg kg−1 reduced the K content in NS and ES (25% and 13%) but increased the P content in NS (66%). In general, Z-COTE and Z-COTE HP1 affected seed nutritional elements in a similar manner. However, the results indicate that the effects of ZnO NMs in bean plants vary with soil composition.

Soil organic matter plays a major role in determining the fate of the engineered nanomaterials (ENMs) in the soil matrix and effects on the residing plants. In this study, kidney bean plants were grown in soils varying in organic matter content and amended with 0-500mg/kg cerium oxide nanoparticles (nano-CeO2) under greenhouse condition. After 52days of exposure, cerium accumulation in tissues, plant growth and physiological parameters including photosynthetic pigments (chlorophylls and carotenoids), net photosynthesis rate, transpiration rate, and stomatal conductance were recorded. Additionally, catalase and ascorbate peroxidase activities were measured to evaluate oxidative stress in the tissues. The translocation factor of cerium in the nano-CeO2 exposed plants grown in organic matter enriched soil (OMES) was twice as the plants grown in low organic matter soil (LOMS). Although the leaf cover area increased by 65-111% with increasing nano-CeO2 concentration in LOMS, the effect on the physiological processes were inconsequential. In OMES leaves, exposure to 62.5-250mg/kg nano-CeO2 led to an enhancement in the transpiration rate and stomatal conductance, but to a simultaneous decrease in carotenoid contents by 25-28%. Chlorophyll a in the OMES leaves also decreased by 27 and 18% on exposure to 125 and 250mg/kg nano-CeO2. In addition, catalase activity increased in LOMS stems, and ascorbate peroxidase increased in OMES leaves of nano-CeO2 exposed plants, with respect to control. Thus, this study provides clear evidence that the properties of the complex soil matrix play decisive roles in determining the fate, bioavailability, and biological transport of ENMs in the environment.

Hybrid nanocomposites based on Cu-BTC MOF, graphene oxide (GO), carbon nanotubes (CNTs), and Fe3O4 magnetic nanoparticles (MNPs) were developed via a simple green solvothermal method, at which GO and CNT were used as platforms to load nanostructured Cu-BTC MOF and Fe3O4 MNPs. The as-synthesized hybrid nanocomposites were characterized by XRD, SEM, TEM, XPS, IR, Raman, TGA, and BET techniques. XRD measurements show highly crystalline structures for the prepared hybrid nanocomposites. Morphological analyses carried out by SEM and TEM also confirm successful growth of Fe3O4 MNPs and nanoparticulate Cu-BTC MOF over the carbon-based platforms. Chemical, elemental, and TGA analyses verify chemical bonding and successful compositing of the parent materials. Nitrogen isotherms show a cumulative pore volume of 0.360 cm3 g−1 for the hybrid nanocomposite of Fe3O4/Cu-BTC@GO compared to 0.030 cm3 g−1 of the sole Cu-BTC MOF, which suggests potential uses towards small molecule adsorption. We have found that use of GO and CNT substrates (i) diminish the aggregation and increases dispersive forces within the MOFs, (ii) lead to MOFs with different morphology and size, and (iii) result in formation of small pores between the MOF and the platforms. Adsorption capacity of the prepared nanomaterials was examined over methylene blue (MB) as a model organic pollutant. The developed hybrid nanomaterials show enhanced pollutant adsorption capacity compared to that of the parent materials. The improved adsorption capacity is attributed to the synergetic effect of covalent bonding between the parent materials as well as to the unique features of the nanoscale MOF. Overall, these novel materials may be considered as excellent candidates towards a variety of environmental applications such as water remediation.