NANOMATERIAL TRANSFORMATION IN SOIL: IMPACTS ON CO-CONTAMINANT FATE AND TOXICITY TO AGRICULTURALLY RELEVANT BIOTA

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1014829
• Project Start Date: Jan 2, 2018
• Project End Date: Jan 1, 2022
• Program Code: [(N/A)]- (N/A)

Recipient Organization
CONNECTICUT AGRICULTURAL EXPERIMENT STATION
PO BOX 1106
NEW HAVEN,CT 06504

Performing Department
Analytical Chemistry

Non Technical Summary
The global nanotechnology industryhas expaned rapidly over the last decade and is projected to exceed a value of $3 trillion by 2020. Nearly every industrial sector has been or will be impacted by nanotechnology, including disease treatment (nanomedicine), electronics, communications, water treatment, food packaging, textiles and cosmetics. Importantly, agriculture has also benefitted from this research and development; nano-fertilizers, nano-pesticides, and nanosensorsfor precision agricultureare examples of platformswhere nanotechnology has or will play a key role in improving performance over traditional products and practices. However, due to thisrapid increase in the development andapplication of nanomaterials (NM), concerns over potential adverse environmental and health effects have been expressed. To understand the potentially delicate balance between the tremendous benefits and the adverse effects of nanotechnology in agricultural applications, one must first understand the underlying principles of NM fate and behavior, as well as key interactions co-contaminants that can impactplants and associated biota.Anassessment of theexisting literature clearly shows thatan understanding of nanoparticle toxicity, accumulation and disposition within agricutlural systems is lacking. Although interest in this area has increased, a mechanistic understanding of the key processesoccuring underrealistic exposure regimes (soil, weathering/transformation scenarios, co-contaminants, multiple species) is needed. The large number of studies showing increased availability/toxicity and greater translocation of NM-forms of elements clearly highlight differential activity as a function of particle size and perhaps most importantly, suggests an increased likelihood for NM contamination of the food chain. Importantly, several key areas with regard to NM fate remain almost completely unexplored and this proposal seeks to generate critical data so as to begin closing these knowledge gaps. The primary goal of this proposal is to determine the impact of NM weathering/transformation in soil, as well as interactions with co-contaminants, on particle fate and toxicity to plant and earthworm species.

Animal Health Component

25%

Research Effort Categories

Basic

75%

Applied

25%

Developmental

0%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
203	0110	1150	100%

Knowledge Area
203 - Plant Biological Efficiency and Abiotic Stresses Affecting Plants;

Subject Of Investigation
0110 - Soil;

Field Of Science
1150 - Toxicology;

Keywords

nanomaterial

nanotechnology

nanoparticle

co-contamination

food safety

Goals / Objectives
ObjectivesThe primary goal of this proposal is to determine the impact of weathering and NM transformation on the fate and effects of these materials and co-existing contaminants on plant and earthworm species.Objective 1- Determine the impact of weathering and NM transformation on toxicity and accumulation by plant and earthworm species. It is widely known that the availability and reactivity of both organic and inorganic contaminants will change with aging and/or transformation in soil. Although a large number of studies have been conducted that investigate the impacts of engineered nanomaterials on a range of biota, few studies have sought to assess the impact how NM transformation during weathering in soil influences observed fate and effects. In one recent study from our group, we demonstrated that the weathering of CuO nanoparticles for 70 days resulted in an increase in metal accumulation within lettuce roots and that this increased uptake was a function of particle transformation to reduced species during weathering. Importantly, this phenomena was not observed for bulk CuO, suggesting that the transformation was specific to the nanoscale. In another recent study, Gao et al showed that the extractability of CuO nanoparticles increased with weathering time but that the reverse was true for copper nitrate. Given the likelihood of weathering and transformation in the field, this lack of understanding relative to particle fate is disconcerting and will be addressed under this objective.Objective 2- Determine the impact of weathering and NM transformation on co-contaminant toxicity and accumulation by plant and earthworm species. As mentioned above, it is known that engineered nanomaterials can significantly influence the bioavailability and toxicity of co-existing contaminants. However, few of these studies were conducting under conditions where the nanomaterial or co-contaminant (or both) were permitted to weather in soil and undergo potentially significant and environmentally realistic transformation processes. In previous work, wemeasured that the availability of weathered chlordane residues to lettuce in the presence of CuO NPs and bulk CuO upon weathering for 0 or 70 days prior to exposure. In the unweathered soils, lettuce chlordane content was decreased by NP exposure; however, upon weathering, the availability of chlordane in bulk CuO treated plants declined but no such change was noted for the NPs. Similar to objective 1, given the likelihood of weathering and transformation processes in the field, this lack of understanding relative to co-contaminant fate and effects is disconcerting and will be addressed under objective 2.

Project Methods
Technical ApproachTechnical Approach for Objective 1- Determine the impact of weathering and NM transformation on toxicity and accumulation by plant and earthworm species.The primary goal of this task is to determine how particle weathering processes and transformation influence the toxicity, uptake and translocation (plants) of nanomaterials in comparison to the equivalent non-nanoscale materials.Nanomaterials/Nanoparticles- A range of materials are available and relevant in agricultural systems. Those to be evaluated will include Ag and multiwall carbon nanotubes (MWCNT). Other potential materials could include fullerenes, single wall carbon nanotubes, CuPO4 nanosheets and mesoporous NP Si. Bulk material and ion controls (where appropriate) will be included. Exposure concentrations in soil will be from 0-500 mg/kg.Plants and earthworms- Several representative dicot species (tomato, potato) and monocot species (wheat) will be used. Other potential species that could be investigated if time or resources permit include carrot, corn, and pumpkin. The earthworm species to be used will be Eisenia fetida; in addition, Lumbriculus terrestris and Metaphire guillelmi may be used.Growth conditions- Seeds will be pre-germinated in pro-mix or vermiculite. Nanopowders, as well as appropriate bulk and ion controls, will be added to aqueous solutions and stably dispersed with either a bath sonicator or a probe sonicator. Solutions will be added to beakers or pots containing 400 g of air dried soil. Two separate soil types will be used; soil from our Lockwood farm (fine sandy loam) and a commercially available garden soil. Once the particle solutions are mixed in homogenously, individual seedlings (number dependent on species but between 1 and 4) will be added to replicate containers. For pots receiving earthworms, 5 individuals will be added per replicate. To assess the impact of weathering and particle transformation on toxicity and accumulation, NP-amended soils will be allowed to incubate for 0, 5, 10, 30 or 90 days prior to the addition of plant or worm species. The growth/exposure period for plants will be from 30 days, although separate experiments may be conducted which include the full reproductive life cycle of the crops. For earthworm trials, the exposure period will be 14 days, although addition endpoints may be added to assess the time-dependent nature of toxicity and/or accumulation.Harvest and analysis- At harvest, plant roots and shoots (including stems, leaves, flowers, fruit where possible) will be removed, rinsed with distilled water and dilute nitric acid and the tissue mass will be determined. Earthworms will be transferred to clean soil for 5 days and subsequently depurated for 48 hours on filter paper. Tissues from metal treatments will be separately dried and digested in concentrated nitric acid on a hot block at approximately 95oC for 1 hour. Hydrogen peroxide will subsequently be added to complete the digestion. The digests will be analyzed by ICP-MS for the appropriate elements, including key nutrients. For tissues from the carbon-based nanomaterials, samples will be dried and extracted with toluene. The toluene extract will be analyzed by LC-MS/MS (fullerenes) or LC-UV (nanotubes) for carbon nanomaterials. Select tissues from all treatments will also be analyzed for pigment content (plants only), lipid peroxidation, and membrane leakage/damage by methods currently in use in our laboratories. Last, through an informal collaboration at the Katherine A. Kelley State Public Health Laboratory, scanning/transmission electron microscopy with energy dispersive X-ray spectroscopy (S/TEM-EDX) on select tissue samples may be possible. In addition, informal collaborators at the European Synchrotron Research Facility (ESRF) may have available beamline time for analysis of select samples. Last, select tissues will be subjected to a transcriptomic analysis to determine to molecular response of exposed species as a function of NP and weathering time.Technical Approach for Objective 2- Determine the impact of weathering and NM transformation on co-contaminant toxicity and accumulation by plant and earthworm species. The primary goal of this task is to measure the potentially differential toxicity, uptake and translocation of select organic and inorganic contaminants as a function of NP and co-contaminant residence time in the soil. Much of the experimental protocol will be identical to that in objective 1, with the exception of the co-contaminant amendment and analysis.Nanomaterials/Nanoparticles- Identical to objective 1.Co-contaminants- Co-contaminants will be added/weathered in a fashion similar to the nanoparticles and will include DDE (DDT metabolite), imidicloprid, arsenic (As) and select polycyclic aromatic hydrocarbons (PAH). Concentrations to be investigated will range from 0-500 mg/kg.Plants and earthworms- Identical to objective one.Growth conditions- Identical to objective one with the exception of co-contaminant presence. The co-contaminants to be added will include arsenic (As), DDE (DDT metabolite), imidicloprid and select polycyclic aromatic hydrocarbons.Harvest and analysis- Identical to objective one, including the addition of As analysis by ICP-MS after sample digestion. For DDE, PAH, or imidicloprid determination, select plant and earthworm tissue samples will be subjected to an in-house acetonitrile based QuEChERS extraction followed by GC-MS or LC-HRMS.

Progress 10/01/19 to 09/30/20

Outputs
Target Audience:The target audience includes other investigators seeking to fully characterize the the influence of biotic and abiotic transformations on the fate and effects of nanomateirals in the environment under single and co-exposure conditions, with a particular focus on the impacts to agriculture and food safety. Risk assessors and public health officals at the federal, state, and local levels will also have interest in our work. Last, growers that may be using nanotechnology in agrochemicals and other applications will be interested in our findings. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?Project results were presented at the PAN-NANO 2020 conference in Brazil (March), as well as virtually at a number of other conferences such as the annual Sustainable Nanotechnology Organization Conference, theannual Society for Environmental Toxicology and Chemistry Conference, the Nanoinnovation 2020 Conference and Exhibition, the Sustainable Innovation of Microbiome Applications in the Food System Conference (SIMBA), and the NanoforAgri 2020 conference. What do you plan to do during the next reporting period to accomplish the goals?Additonal experiments under objectives 1 and 2 will continue, including an assessment of how weathering and co-contaminant exposure to PFAS and microplastics influence nanomaterial toxicity and accumulation

Impacts
What was accomplished under these goals? A number of studies were conducted and published this year; several are highlighted here. First, a series of experiments were conducted investigating the phenanthrene (Phe) in lettuce (Lactuca sativa L.) as affected by carbon nanotubes (CNTs)/magnetic carbon nanotubes (MCNTs) and dissolved humic acids (DHAs) under hydroponic conditions for 10 days. MCNTs alone or combined with DHAs reduced Phe accumulation in roots by more than 50%; in shoots, CNTs increased the Phe accumulation from 72.1 to 114.8%, regardless of the presence of DHAs. DHAs decreased the total Phe metabolites content in lettuce by 21.7-98.9%. Nine Phe-related metabolites were identified and a possible Phe metabolism pathway in lettuce was proposed. Additionally, MCNTs/CNTs and DHAs reduced Phe-induced toxicity to lettuce by elevating the activity of shoot glutathione S-transferase (GST). The addition of MCNTs/CNTs alone and combination with DHAs enhanced photosynthesis. The upregulation of genes related to photosynthesis and carotenoid biosynthesis in the treatments with DHAs or the combinations of CNT/MCNTs and DHAs alleviated Phe- induced phytotoxicity and negative impacts on photosynthesis. These results provide important information on Phe accumulation and its metabolism in plant-soil systems and on the roles of DHAs and MCNTs in alleviating the contaminant-induced phytotoxicity. In a second important study, we used soil metabolomics to reflect the integrated response of both plant and microbial communities to ENM exposure. Maize plants were grown in soil amended with SiO?, TiO?, or Fe?O? ENMs (100 mg kg−¹ soil) for four weeks. Plant and soil metabolomics were then used to investigate the global metabolic response of both the plant and soil to ENM exposure. None of the tested ENMs showed negative impacts on plant growth. However, metabolomics analysis revealed that all ENM treatments altered the leaf, root and soil metabolite profiles in an ENM-dependent manner. Fe?O? and TiO? ENM exposure induced stronger metabolic reprogramming in leaves, roots and soil compared to SiO? ENMs. Interestingly, leaf tissues, which is not the organ directly exposed to ENMs, showed significant amino acid pool alteration upon exposure to ENMs. In soil, levoglucosan, linolenic acid, 4-hydroxycinnamic acid and allo-inositol were significantly increased in response to ENMs. Alteration of the soil metabolite profile indicates that ENMs changed the SOC pool. This study is important because it shows that integration of leaf, root and soil metabolomics enables a thorough characterization of plant metabolism and soil chemistry that can be a powerful tool for ENM risk assessment. In a third important study, we investigated whether the beneficial use of nanoparticle silver or nanosilver is confounded by its antimicrobial properties impact non-target members of natural microbiomes such as those present in soil or the plant rhizosphere. We know that agricultural soils are a likely sink for nanosilver due to its presence in agrochemicals and land- applied biosolids, but a complete assessment of nanosilver's effects on this environment is lacking because the impact on the natural soil microbiome is not known. Consequently, we investigated the use of nanosilver for phytopathogen control with maize and analyzed the metatranscriptome of the maize rhizosphere and observed multiple unintended effects of exposure to 100 mg kg−¹ nanosilver in soil during a growth period of 117 days. We found several unintended effects of nanosilver which could interfere with agricultural systems in the long term. Firstly, the archaea community was negatively impacted with a more than 30% decrease in relative abundance, and as such, their involvement in nitrogen cycling and specifically, nitrification, was compromised. Secondly, certain potentially phytopathogenic fungal groups showed significantly increased abundances, possibly due to the negative effects of nanosilver on bacteria exerting natural biocontrol against these fungi as indicated by negative interactions in a network analysis. Up to 5-fold increases in relative abundance have been observed for certain possibly phytopathogenic fungal genera. Lastly, nanosilver exposure also caused a direct physiological impact on maize as illustrated by increased transcript abundance of aquaporin and phytohormone genes, overall resulting in a stress level with the potential to yield hormetically stimulated plant root growth. This study highlights the occurrence of significant unintended effects of nanosilver use on corn, which could turn out to be negative to crop productivity and ecosystem health in the long term. We therefore highlight the need to include the microbiome when assessing the risk associated with nano-enabled agriculture. Last, we published a review article entitled "Nanomaterial transformation in plants: Implications for food safety and application in agriculture" where we highlighted the importance of transformation processes in nanomaterial fate and effects, as well as the many knowledge gaps that still exist in this developing field of research.

Publications

• Type: Journal Articles Status: Published Year Published: 2020 Citation: Song, C.; Cheng, X.; White, J.C.; Zhang, H.; Zhao, L.; He, J.; Zhu, Y.; Wang, Y. 2020. Metabolic profile and physiological response of cucumber exposed to engineered MoS2 and TiO2 nanoparticles. NanoImpact 20:100271.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Zhu, J.; Li, J.; Shen, Y.; Liu, S.; Zeng, N.; Zhan, X.; White, J.C.; Gardea-Torresdey, J.; Xing, B. 2020. Mechanism of ZnO nanoparticle entry into wheat seedling leaves. Environ. Sci.: Nano. 7:3901.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Jia, W.; Ma, C.; Yin, M.; Sun, H.; Zhao, Q.; White, J.C.; Wang, C.; Xing, B. 2020. Accumulation of phenanthrene and its metabolites in Lactuca sativa as affected by magnetic carbon nanotubes and dissolved humic acids. Environ. Sci: Nano DOI: 10.1039/d0en00932f.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: De La Torre-Roche, R.; Cantu, J.; Tamez, C.; Zuverza-Mena, N.; Hamdi, H.; Elmer, W.; Gardea-Torresdey, J.; White, J.C. 2020. Seed biofortification by engineered nanomaterials: A pathway to alleviate malnutrition? J. Agric. Food Chem. 68:12189-12202
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Shang, H.; Ma, C.; Li, C.; White, J.C.; Chefetz, B.; Polubesova, T.; Xing, B. 2020. Copper sulfide nanoparticles suppress Gibberella fujikuroi infection in Oryza sativa seeds by multiple mechanisms: contact-mortality, nutritional modulation and phytohormone regulation. Environ. Sci.: Nano 7:2632-2643
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Sillen, W.M.A.; Thijs, S.; Abbamondi, G.R.; De La Torre Roche, R.; Weyens, N.; White, J.C.; Vangronsveld, J. 2020. Nanoparticle treatment of maize analyzed through the metatranscriptome: Compromised nitrogen cycling, possible phytopathogen selection, and plant hormesis. Microbiome 8:127.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Noori, A.; Ngo, A.; Gutierrez, P.; Theberge, S.; White, J.C. 2020. Silver nanoparticle detection and accumulation in tomato (Lycopersicon esculentum). J. Nano. Res. 22:131.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Ma, C.; Liu, H.; Chen, G.; Zhao, Q.; Guo, H.; Minocha, R.; Long, S.; Tang, Y.; Saad, E.M.; De La Torre Roche, R.; White, J.C.; Parkash Dhankher, O.; Xing, B. 2020. Dual roles of glutathione in silver nanoparticle detoxification and enhancement of nitrogen assimilation in soybean (Glycine max L.). Environ. Sci.: Nano.7:1954-1966.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Zhang, P.; Guo, Z.; Zhang, Z.; Fu, H.; White, J.C.; Lynch, I. 2020. Nanomaterial transformation in plants: Implications for food safety and application in agriculture. Small 16:2000705.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Marmiroli, M.; Orazio Lepore, G.; Pagano, L.; d'Acapito, F.; Gianoncelli, A.; Villani, M.; White, J.C.; Marmiroli, N. 2020. The fate of CdS quantum dots in plants as revealed by Extended X-ray Absorption Fine Structure (EXAFS) analysis. Environ. Sci.: Nano 7:1150-1162.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Zhang, H.; Huang, M.; Zhang, W.; Gardea-Torresdey, J.L.; White, J.C.; Ji, R.; Zhao, L. 2020. Silver nanoparticles alter soil microbial community compositions and metabolite profiles in unplanted and cucumber-planted soil. Environ. Sci. Technol. 54(6):3334-3342.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Tian, L.; Zhang, H.; Zhao, X.; Gu, X.; White, J.C.; Li, X.; Zhao, L.; Ji, R. 2020. CdS nanoparticles induce metabolic reprogramming in Broad Bean (Vicia faba L.) roots and leaves. Environ. Sci.: Nano 7:93-104.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Marmiroli, M.; Mussi, F.; Pagano, L.; Imperiale, D.; Lencioni, G.; Villani, M.; Zappettini, A.; White, J.C.; Marmiroli, N. 2020. Cadmium sulfide quantum dots and Cd2+ impact differently on Arabidopsis thaliana physiology and morphology. Chemosphere 240:124856.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Hao, Y.; Wang, Y.; Ma, C.; White, J.C.; Duan, C.; Zhao, Z.; Zhang, Y.; Adeel, M.; Li, G.; Rui, Y.; Xing, B. 2019. Carbon nanomaterials increase methane production from livestock manure in an anaerobic digestion system. J. Clean. Prod. 240:118257.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Majumdar, S.; Pagano, L.; Wohlschlegel, J.A.; Villani, M.; Li, W.; Parkash Dhankher, O.; Zappettini, A.; Marmiroli, N.; White, J.C.; Keller, A. 2019. Proteomic, gene and metabolite characterization reveal uptake and toxicity mechanism of cadmium sulfide quantum dots in soybean plants. Environ. Sci.: Nano. 6:3010.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Adisa, I.; Pullagurala, V.L.R.; Peralta-Videa, J.R.; Dimkpa, C.O.; Ma, C.; Elmer, W.H.; Gardea-Torresdey J.L.; White, J.C. 2019. Recent advances in nano-enabled fertilizers and pesticides: A critical review of mechanisms of action. Environ. Sci.: Nano. 6:2002.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Zhao, L.; Zhang, H.; Chen, X.; Li, H.; Qu, X.; White, J.C.; Ji, R. 2019 Metabolomics reveal that engineered nanomaterial exposure in soil alters both soil rhizosphere metabolite profiles and maize metabolic pathways. Environ. Sci.: Nano. 6:1716-1727.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Petersen, E. J.; Mortimer, M.; Burgess, R.; Handy, R.; Hanna, S.; Ho, K.; Johnson, M.; Loureiro, S.; Selck, H.; Scott-Fordsmand, J.; Spurgeon, D.; Unrine, J.; van den Brink, N.; Wang, Y.; White, J.C.; Holden, P. 2019. Strategies for robust and accurate experimental approaches to quantify nanomaterial bioaccumulation across a broad range of organisms. Environ. Sci.: Nano. 6:1619-1656.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Majumdar, S.; Ma, C.; Villani, M.; Pagano, L.; Zuverza-Mena, N.; Huang, Y.; Zappettini, A.; Keller, A.; Marmiroli, N.; Parkash, O.; White, J.C. 2019. Surface coating determines the response of soybean plants to cadmium sulfide quantum dots. NanoImpact doi.org/10.1016/j.impact.2019.100151.

Progress 10/01/18 to 09/30/19

Outputs
Target Audience:The target audience includes other investigators seeking to fully characterize the the influence of biotic and abiotic transformations on the fate and effects of nanomateirals in the environment under single and co-exposure conditions, with a particular focus on the impacts to agriculture and food safety. Risk assessors and public health officals at the federal, state, and local levels will also have interest in our work. Last, growers that may be using nanotechnology in agrochemicals and other applications will be interested in our findings. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?A number of peer reviewed papers were published. In addition, findings were presented at a number of domestic and international conferences, including the American Chemical Society meeting in Orlando Florida, ICMAT 2019 in Singapore, Nanotech 2019 in Boston, NanoDay in Milan Italy, the National Conference on Environmental Chemistry in Tianjin China, US-EU Bilaterial Conference at Harvard University, the New Millenia Agriculture Conference at CCS Haryana Agricultural University in Hisar India, as well as invited seminars atthe University of Pittsburgh, Nanjing University, Nanjing Agricultural University, and McGill University. What do you plan to do during the next reporting period to accomplish the goals?Data analysis and manuscript writing for a number of studies will continue. Collaborations with Nanjing Agricultural University, Nanjing University and the Universty of Parma will continue. A greater focus on particle transformation will be pursued.

Impacts
What was accomplished under these goals? A number of studies were conducted and published this year. First, work was done to investigate the interactions between Imidacloprid (IMDA), a neonicotinoid insecticide and one of the most widely used pesticides in the United States, and two engineered nanomaterials (CeO2, Ag). The bioaccumulation, translocation, and toxicity of IMDA (10 mg/kg) to Cucurbita pepo L (zucchini) was evaluated upon simultaneous exposure to CeO2 or Ag in bulk (CeBulk or AgBulk) or nanoparticle (CeNP or AgNP) form at 100 mg/kg under soil-grown conditions. Total IMDA and metabolites accumulation in plant root and aerial tissues was equivalent to controls in both CeO2 exposures but co-exposure to AgBulk and AgNP significantly suppressed IMDA accumulation in zucchini aerial tissues. The Ag and Ce concentration in aerial tissues exposed to NPs alone were 85.4% and 79.2%, respectively, higher than plants co-exposed to NPs with IMDA. The expression level of the seven genes studied shows that the response mechanisms of zucchini to IMDA and NPs are different. Moreover, no synergistic effects were observed in gene expression upon IMDA-NPs co-exposure. These findings show that ENMs may not only affect the bioavailability and translocation of currently used pesticides but that the reverse is true as well; these interactions should be considered when assessing the exposure and risk of these materials in the environment. Second, the influence of surface coating that differ in surface charge, size, and polarity on bioavailability and the biological response of soybean to 50-200 mg/L cadmium sulfide quantum dots (CdS-QDs) was investigated. The coatings included trioctylphosphine oxide (TOPO), polyvinylpyrrolidone (PVP), mercaptoacetic acid (MAA), and glycine (GLY). After 14 d of CdS-QD exposure, all plants accumulated statistically similar Cd content in roots across the different particles. In the roots, Cd from QD-MAA and QD-GLY accumulated primarily in the cell wall and organelles, suggesting apoplastic pathway; whereas in QD-TOPO, due to high dissolution, dissolved Cd ions accumulated in the cell membrane. The exception was QD-PVP, which mainly sequestered in the organelles (49%), potentially via symplastic pathway and was more significantly translocated to and accumulated in the shoots, also resulting in reduction in leaf biomass. Results suggested that peroxidases play the dominant role in quenching the oxidative stress due to QDs. At the highest QD treatment level, root lignification allowed the plants to restrict aerial translocation of Cd, except in QD-PVP, where the lignification was reduced by 21% leading to higher content in shoots. Increased amino acid content in the leaves were noted as a stress tolerance mechanism. This study highlights the significant influence that surface coating exerts on QDs fate and effects in a planted system. Third, maize plants were grown in soil amended with NP SiO2, TiO2, or Fe3O4 (100 mg/kg soil) for four weeks. Plant and soil metabolomics were then used to investigate the global metabolic response of both the plant and soil to ENMs exposure. None of the tested ENMs showed negative impacts on plant growth. However, metabolomic analysis revealed that all ENMs treatments altered the leaf, root and soil metabolite profiles in a NP-dependent manner. Fe3O4 and TiO2 ENMs exposure induced stronger metabolic reprogramming in leaves, roots and soil compared to SiO2 ENMs. Leaves showed significant amino acid pool alteration upon exposure. In soil, levoglucosan, linolenic acid, 4-hydroxycinnamic acid and allo-inositol were significantly increased in response to NPs. Alteration of the soil metabolite profile indicates that NPs changed the soil organic carbon pool. Integration of leaf, root and soil metabolomics enable a thorough characterization of plant metabolism and soil chemistry that can be a powerful tool for ENMs risk assessment.

Publications

• Type: Journal Articles Status: Published Year Published: 2019 Citation: Deng, R., Y. Zhu, J. Hou, J.C. White, J.L. Gardea-Torresdey, D. Lin. 2019. Antagonistic toxicity of carbon nanotubes and pentachlorophenol to Escherichia coli: Physiological and transcriptional response. Carbon. 145:658-667.
• Type: Journal Articles Status: Published Year Published: 2018 Citation: De La Torre Roche, R., L. Pagano, S. Majumdar, B.D. Eitzer, N. Zuverza-Mena, C. Ma, A.D. Servin, N. Marmiroli, O. Parkash Dhankker, J.C. White. 2018. Co-exposure of imidacloprid and nanoparticle Ag or CeO2 to Cucurbita pepo (Zucchini): Contaminant bioaccumulation and translocation. NanoImpact 11:136-145.
• Type: Journal Articles Status: Published Year Published: 2018 Citation: Pagano, L., E. Maestri, M. Caldara, J.C. White, N. Marmiroli, M. Marmiroli, M. 2018. Engineered nanomaterial activity at the organelle level: Impacts on the chloroplast and mitochondria. ACS Sustain. Chem. Eng. 6(10):12562-12579.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Majumdar, S., C. Ma, M. Villani, L. Pagano, N. Zuverza-Mena, Y. Huang, A. Zappettini, A. Keller, N. Marmiroli, O. Parkash Dhankher, J.C. White. 2019. Surface coating determines the response of soybean plants to cadmium sulfide quantum dots. NanoImpact doi.org/10.1016/j.impact.2019.100151.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Zhao, L., H. Zhang, X. Chen, H. Li, X. Qu, J.C. White, R. Ji. 2019. Metabolomics reveal that engineered nanomaterial exposure in soil alters both soil rhizosphere metabolite profiles and maize metabolic pathways. Environ. Sci.: Nano. 6:1716-1727.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Adisa, I., V.L.R. Pullagurala, J.R. Peralta-Videa, C.O. Dimkpa, C. Ma, W.H. Elmer, J.L. Gardea-Torresdey, J.C. White. 2019. Recent advances in nano-enabled fertilizers and pesticides: A critical review of mechanisms of action. Environ. Sci.: Nano. DOI: 10.1039/C9EN00265K.

Progress 01/02/18 to 09/30/18

Outputs
Target Audience:The target audience includes other investigators seeking to fully characterize the the influence of biotic and abiotic transformations on the fate and effects of nanomateirals in the environment under single and co-exposure conditions, with a particular focus on the impacts to agriculture and food safety. Risk assessors and public health officals at the federal, state, and local levels will also have interest in our work. Last, growers that may be using nanotechnology in agrochemicals and other applications will be interested in our findings. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?Preliminary findings from the studies mentioned above were presented at the annual Sustainable Nanotechnology Organization conference (Arlington VA), as well as at an invited lecture at Zhejiang University in Hangzhou China. What do you plan to do during the next reporting period to accomplish the goals?Data analysis and manuscript writing for the three studies described above will continue. Additional collaborative experiments with investigators at Nanjing University are being planned; I will be visiting there in May to discuss present and future work. Additional studies linking nanomaterial weathering with co-contaminant toxicity and accumulation will be planned and initiated.

Impacts
What was accomplished under these goals? As noted above, two separate review articles were published during the current period. In addition, experiments investigating the impact of nanoparticle aging time (4 separate time points; 0, 5, 15, 40 days) on NP Ag and DDE accumulation in earth worms (Eisenia fetida). Two separate nanoparticle concentrations andone DDE levels were used. DDE content will be assessed by GC-MS; Ag content will be assessed by ICP-MS. The experiment has been completed an analysis is ongoing. In addition, experiments were conducted with collaborators from Nanjing University in China on the impact of engineered nanomaterial (SiO2, TiO2, Fe2O3) exposure on themetabolomic profile in the shoot tissues and rhizosphere of corn, as well as the bulk soil. Although phenotypic effects were minimal, there was significant impact on the leaf metabolite profile. In addition, impacts in the rhizosphere were significant. A draft manuscript is currently under preparation and follow up studies are being planned. Last, experiments were conducted with collaborators at China Agricutlural University looking at the impact of nanoscale cerium oxide, as well as cerium ions, on soil enzymmatic and metabolic activity in the rhizosphere of cucumber. Data analysis is currently ongoing.

Publications

• Type: Journal Articles Status: Published Year Published: 2018 Citation: Pagano, L.; Maestri, E.; White, J.C.; Marmiroli, N.; Marmiroli, M. 2018. Quantum dots exposure in plants: Minimizing the adverse response Curr. Op. Environ. Sci. Health doi.org/10.1016/j.coesh.2018.09.001.
• Type: Journal Articles Status: Published Year Published: 2018 Citation: Zuverza-Mena, N.; White, J.C. 2018. Engineered nanomaterials in terrestrial systems: Trophic transfer and interactions with co-existing contaminants. Curr. Op. Environ. Sci. Health 6:60⿿65.