Progress 01/01/24 to 12/31/24
Outputs
Target Audience:We presented the research related to potential for product to parent reversion of phytometabolites in food crops at the American Chemical Society (ACS) meeting Division of Agrochemicals in Denver Colorado. The target audience was other scientists in academia and industry, which was useful because these are people would both be interested in the science of the discoveries made as well as the practitioners who would be able to implement the new knowledge in the field.ACS Fall 2024 is a major national meeting organized by the American Chemical Society (ACS). These biannual meetings are significant events in the field of chemistry, bringing together researchers, educators, professionals, and students from around the world to discuss recent advancements, share research findings, and explore new trends and innovations in chemistry and related sciences. Presenting research at the conference allows for constructive feedback from a knowledgeable audience, helping to refine the work and increase its visibility within the scientific community. The conference showcases the latest advancements and trends in chemistry, providing insights into innovative research methodologies and findings. This helps to broaden perspectives and enhance our ability to evaluate different methodologies. Networking opportunities are another major advantage. The ACS conference attracts a diverse group of researchers, academicians, and industry professionals, offering a platform to build valuable connections and potential collaborations. We also presented the research related to plant uptake and transformation of emerging contaminants at the Gordon Research Conference (GRC) Environmental Sciences Water conference, as well as at the Iowa Water Conference (IWC) and the Iowa Stormwater Conference. The target audience at the GRC is other academic scientists. The Iowa Stormwater Conference is comprised of practioners in engineering and local municipalities. The target audience at the IWC is a mixture of water stakeholders from throughout Iowa, including those from the agricultural community. One of the ways that we reached a targeted outreach audience for the project was to interact with middle school students from throughout Iowa educating them on water quality through hands-on demonstrations that displayed water treatment, water risks, the water cycle, and water-food connections. The activities were physical "wet" models and games that engaged 6 and 7th grade students from middle schools across the state on two occasions. One underserved population that we engaged was students from the Meskwaki Nation (Sac & Fox Tribe of the Mississippi in Iowa), a federally-recognized tribe that resides within Iowa. Changes/Problems:Due to pandemic-related supply chain issues obtaining radio-labeled chemicals, we recieved a 1 year no cost extension on the work. We are now on track and appear to be where we need to be on the project progress, and look forward to submitting the manuscripts soon that use these new data. What opportunities for training and professional development has the project provided?There were three PhD students that have been involved in the project to date (1 has graduated, who worked on Objective 3). One PhD student started in 2021 and another in 2020. We also have an undergraduate student working in the lab on the project, and we hosted a visiting high school student through the UIowa Secondary Student Training Program from California who conducted research on the project, and is a co-author on a paper that we have in progress. Both PhD students are now post-comps, so these are important training milestones that help further the research, and are thus fully engaged in the research (i.e., will be all finished with classes after this semester). One of these PhD students is working on Object 1, and another on Object 2, as part of their respective dissertation research. These students have also participated in presenting at conferences as professional development activities that were supported by this work (and also disseminate the research). Finally, the PI (LeFevre) is using some of the motivating approaches for non-target mass spec analysis conducted for this work to initiate a research exchange while on professional development leave (sabbatical) for a semester. He will be working with the US Geological Survey California Water Science Center in Sacramento and spending time there to learn new analytical techniques at the USGS National Pesticide Lab. How have the results been disseminated to communities of interest?We presented the research related to potential for product to parent reversion of phytometabolites in food crops at the American Chemical Society meeting Division of Agrochemicals in Denver Colorado. The target audience was other scientists in academia and industry, which was useful because these are people would both be interested in the science of the discoveries made as well as the practitioners who would be able to implement the new knowledge in the field. We also presented the research related to plant uptake and transformation of emerging contaminants at the Gordon Research Conference (GRC) Environmental Sciences Water conference, as well as at the Iowa Water Conference (IWC) and the Iowa Stormwater Conference. The target audience at the GRC is other academic scientists. The Iowa Stormwater Conference is comprised of practioners in engineering and local municipalities. The target audience at the IWC is a mixture of water stakeholders from throughout Iowa, including those from the agricultural community. One of the ways that we reached a targeted outreach audience for the project was to interact with middle school students from throughout Iowa educating them on water quality through hands-on demonstrations that displayed water treatment, water risks, the water cycle, and water-food connections. The activities were physical "wet" models and games that engaged 6 and 7th grade students from middle schools across the state on two occasions. One underserved population that we engaged was students from the Meskwaki Nation (Sac & Fox Tribe of the Mississippi in Iowa), a federally-recognized tribe that resides within Iowa. I have also initiated a new collaboration with researchers in engineering and animal science at the land-grant Iowa State University (via an invited seminar) to expand elements of this work with them on other contaminant classes relevant to agriculture. Additionally, we were invited by the College of Public Health (with their environmental, occupational, and rural health programs) to initiate a new collaboration based on a presentation of preliminary results of this work. We believe that the informal dissemination of work through research seminars and collaborations will leverage this work to improve future outcomes. What do you plan to do during the next reporting period to accomplish the goals?Our goal for the next reporting period will be to finalize the experiments and data analysis related to the bioaccessibility of the benzotriazole in the simulated digestion system and the conjugated plant metabolites (under Objective 1). We will finalize specific mechanisms for components of the in-vitro digestion tests (e.g., acid catalyzed hydrolysis). Our analytical methods, organisms, simulated gastric systems, and 14-C systems are now set up, and experiments are working and thus we will finalize the manuscript for this work. High resolution mass spectrometry has been challenging, but we have made major strides and discovered novel transformation product that will be reported in the manuscript. The additional PhD student who has joined to progress has helped the progress forward. We expect to continue to make positive progress forward and have additional major significant results including additional high-impact publications during the next reporting period. We expect to complete all of the research tasks as planned (which were made possible by the additional time allotted), and our promising results to date and positive experimental set ups since the prior reporting period are strong developments.
Impacts
What was accomplished under these goals?
During the immediate prior project period, we have completed Objective 3. There were two peer reviewed publications that resulted from this work in high-impact journals; these were part of the dissertation work of one PhD student. The works were significant because the demonstrated, active, enzyme-facilitated uptake of small polar emerging contaminants by plants. We discovered novel transformation products and pathways using metabolomics. Importantly, and in the context that we as a research community cannot take a compound-by-compound experimental approach to every emerging contaminant, we published a paper that focused on the role of functional group (electrostatic) properties and molecular position on predicting plant uptake kinetics when active uptake occurs. We used experimental and computational chemistry (QSAR) modeling to probe these effects, with the ultimate goal of predicting chemical characteristics of emerging contaminants that are likely to be taken up into plants during water recycling operations, with the ultimate outcome of helping to inform exposure risk. We continue to make solid good progress on the other Objectives 1 and 2. The experimental lab work for Objective 1 has been completed and we are now in the data analysis and manuscript drafting stage. We have a major manuscript in draft form that we expect to submit soon. We completed the laboratory portion of experiments that now are able to fulfill the simulated digestion system, and have run experiments with this system. We have preliminary results, and are able to obtain reasonable mass balances with the parent compound and for multiple metabolites. Based on our preliminary results, it indicates that there is likely deconjugation of the benzotriazole plant metabolites. One major challenge had been supply chain issues with 14C-radio labeled compounds needed for one experiment; we were able to have the chemicals obtained and now completed this portion of the experiment. Additionally, the commercially-available freeze-dried anaerobic gut bacteria we ordered could not be cultured previously, but we were able to overcome this by obtaining a culture from a colleague at another university. These cultures are now growing and we have begun using them for experiments. For Objective 1, we also conducted an untargeted metabolomics study with high-resolution mass spectrometry to identify novel products formed in the in vitro digestion system. We have completed the experimental portion, and are finalizing the data analysis portion, which will be included in the manuscript. For Objective 2, we have conducted preliminary studies for each of the tasks, and are refining the experiments to generate publication quality data (we expect a publication from each task). For task 2.1, we have proven a full molar balance demonstrating microbial deconjugation of one of the excreted plant metabolites; however, other excreted plant metabolites yield an incomplete mass balance. We have also therefore conducted separate high resolution mass spectrometry metabolomics work to elucidate novel products formed as a result of soil microbe transformation of the phytometabolites. We have also conducted hydrolysis experiments across relevant pH conditions (representing mammal/insect gut to environmental surface waters) to quantify acid and/base catalyzed hydrolysis reactions. Initial results indicate that this is a relevant process, and we are following up with more specific kinetics and products investigations. Some of these experiment, primarily due to the chemical supply chain issues described, are taking longer than desired, but are making important progress. Significantly, we have positive preliminary results at this point for all the research tasks in progress. For both Objectives 1 and 2, there are high-impact publications in progress and important research discoveries that will result from these.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2024
Citation:
Investigating Fate and Bioaccessibility of Contaminants of Emerging Concern in Recycled Irrigation Water
Sraboni Chowdhury And Gregory H. LeFevre
University of Iowa, Civil and Environmental Engineering, IIHRHydroscience & Engineering
American Chemical Society Meeting August 2024 Denver Colorado
Program: Division of Agrochemicals
Symposium: Environmental Fate, Transport, and Modeling of Agriculturally-Related Chemicals
Global water stress has led to increased use of recycled water, i.e., treated wastewater for irrigation. Many arid and semi-arid regions, such as the Middle East, East Africa, and the U.S. Southwest, depend on recycled water to meet the high-water demand for agricultural irrigation. Nevertheless, agricultural application of recycled water can introduce trace organic Contaminants of Emerging Concern (CECs), such as pharmaceuticals, personal care products, and corrosion inhibitors, in the soil-plant human continuum, raising widespread concerns about human exposure risk. Prior studies have demonstrated that plants can accumulate CECs and transform them into phytometabolites where the fate of these phytometabolites in consumers is largely unknown. In this study, we investigated the fate of benzotriazole, a prevalent micropollutant present in treated wastewater effluent, and its phytometabolites in the model plant Arabidopsis during in-vitro digestion simulation. Employing radiolabeled benzotriazole, we quantified the bioaccessibility, the released fraction of the plant-stored chemical at three different phases of in-vitro human digestion. We investigated the bioaccessible fraction and the transformation potential of most abundant glucose- and amino acid-conjugated phytometabolites of benzotriazole through the digestion phases. The findings from this study demonstrated that CECs are largely stored in plants as weakly bound conjugated phytometabolites that are bioaccessible and likely subsequently transformed during human digestion; this represents a potentially significant yet previously underestimated human exposure route to CECs. This study underscores the importance of incorporating plant-accumulated CEC phytometabolites into the risk assessment framework to better estimate the dietary exposure risk of CECs with the use of recycled water for agricultural irrigation. By elucidating the fate of plant-stored CECs phytometabolites during human digestion, this study sheds light on the critical need for comprehensive evaluation of dietary exposure risk to CECs, thereby informing safer use of recycled water in agriculture.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2024
Citation:
Innovations in Fungal and Plant Bioremediation Strategies for Green Stormwater Infrastructure
Gregory H. LeFevre (UIowa), Erica A. Wiener, Claire Muerdter Northup
University of Iowa, Civil and Environmental Engineering, IIHRHydroscience & Engineering
American Chemical Society Meeting August 2024 Denver Colorado
Program: Division of Environmental Chemistry
Trace Organic Contaminants (TOrCs; e.g., urban-use pesticides, tire wear compounds, vehicle anticorrosives) are an emerging and increasingly recognized threat to water quality in innovative sustainable stormwater treatment systems such as Green Stormwater Infrastructure (GSI). Many of these contaminants are highly water soluble and can pass through conventional infiltration media. Improving sorption capacity of stormwater geomedia is important for contaminant capture, but we contend that innovative bioremediation approaches are needed to sustain contaminant removal and renew media sorption capacity in situ. Two underappreciated bioremediation processes in GSI are fungal and plant uptake/ transformation of TOrCs. We present novel research related to fungal transformation of tire wear compounds, and prediction of plant uptake of TOrCs. We previously demonstrated that white-rot fungi can biodegrade some tire wear compounds found in stormwater. Here, we address the knowledge gap of fungal function and diversity within stormwater bioretention cells. We collected multiple soil samples from 28 different bioretention cells in eastern Iowa USA, characterized soil physicochemical parameters, sequenced the internal transcribed spacer (ITS) amplicon to identify fungal taxa from extracted DNA, and measured functional gene abundances for two fungal laccases (Cu1, Cu1A) and a fungal nitrite reductase gene (nirKf). Fungal biodegradation functional genes were present in field bioretention soils, with abundance correlated to specific soil parameters. Planting specifications significantly impacted fungal diversity and variation. We are currently using these fungal bioremediation findings to develop novel stormwater GSI bioaugmentation strategies. We also present a novel lab and molecular modeling approach to probe the impact of TOrC functional group electrostatic properties and position on plant uptake and metabolism. The greatest plant uptake rates occurred with an electron-withdrawing functional group at the 2 position; however, uptake was still observed with an electron-donating group. An electron-donating group at the 1 position significantly slowed uptake, indicating possible steric effects. (QSAR) parameters for the studied compounds implicates energy-related molecular descriptors as uptake drivers. In summary, this work presents innovative fungal and plant bioremediation strategies to improve sustained emerging contaminant removal in green stormwater infrastructure.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2024
Citation:
Gordon Research Conference
Environmental Sciences: Water
Holderness, NH
Characterizing Emerging Contaminant Fate and Improving Capture with Transformation in Green Stormwater Infrastructure
Gregory H. LeFevre
Debojit S. Tanmoy, Stanley W. Kohls, Erica A. Wiener, Claire P. Muerdter, Sraboni Chowdhury
Stormwater is increasingly recognized as an important source of emerging contaminants to the environment. Green Stormwater Infrastructure (GSI) can help ameliorate deleterious impacts to water quality, but many hydrophilic polar Trace Organic Contaminants (TOrCs) are not captured by conventional GSI systems during rapid infiltration and can potentially pass through to impact underlying groundwater. Simply increasing sorption capacity through black carbon amendments could accumulate contaminant mass within GSI. There is thus a critical need to understand the fate of emerging TOrCs in GSI and improve the subsequent (bio)transformation of captured contaminants to sustain contaminant removal. In this work, we present research to probe and improve TOrC capture and sustained in situ biotransformation through a multi-faceted approach. First, we use high-resolution Orbitrap mass spectrometry to characterize complex TOrC mixtures in stormwater and evaluate the removal performance of library-matched compounds in a real field-based GSI street system. We demonstrate which compounds are retained/ pass through conventional GSI media and if new compounds are generated endogenously. Second, we characterize fungal communities (via 18S sequencing) for their presence in in real field GSI systems and potential to biodegrade TOrCs. Third, we use lab experiments and computational chemistry models to quantify and predict the potential for plants, a key biological feature in GSI systems, to take up and biotransform TOrCs based on critical chemical functional groups. Finally, we present work on development and testing of novel stormwater geomedia capable of rapidly capturing TOrCs through improved sorption and subsequent biodegradation via encapsulated microorganisms. We developed this scalable, novel assemblage of materials with the goal of bioaugmenting GSI systems and ultimately decoupling the short hydraulic residence time (required for rapid infiltration) from the longer chemical contact time needed for subsequent contaminant biodegradation. Media materials development, pollutant removal testing, enhanced organism viability, and bioaugmentation potential will be presented. The research presented will comprehensively address the mechanistic basis for TOrC fate in GSI and engineering developments for improving water quality.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2024
Citation:
Iowa Water Conference
Coralville, IA September 2024
Cutting Edge Stormwater Quality Research in Iowa: Biotransformation in Green Infrastructure, Development of Novel Geomedia, and Characterizing Complex Contaminant Mixtures
Greg LeFevre, Stan Kohl, Debojit Tanmoy, Erica Wiener, Alyssa Mianecki
Abstract: There is growing concern and realization of the impacts of trace organic contaminants (e.g., pesticides, tire wear compounds, PFAS) in stormwater. In particular, highly water-soluble contaminants are of concern because they can be easily transported or pass through infiltration-based green infrastructure practices. Thus, there is a growing need to capture and degrade contaminants in stormwater to improve water quality. In this Iowa place-based work, we present research on the plant and fungal microbial communities present in green stormwater infrastructure and their potential to biodegrade contaminants. Recently, we developed a novel geomedia to rapidly capture organic contaminants and dissolved phosphorus, with encapsulated biodegrading microorganisms to sustain removal. We demonstrate successful sorption and biodegradation with the media on the lab scale, with potential to bioaugment green infrastructure sites. Additionally, we are applying Non-Target Analysis (NTA) an emerging analytical approach to characterize complex mixtures of contaminants in stormwater and an urban stream site in Coralville, IA. NTA allows us to illuminate the totality of complex mixtures and how they change through best management practices. Use of the technique and place-based results will be presented.
|
Progress 01/01/23 to 12/31/23
Outputs
Target Audience:One of the ways that we reached a targeted outreach audience for the project this year (in contrast to past year efforts focusing on research audiences) was to interact with middle school students from throughout Iowa educating them on water quality through hands-on demonstrations that displayed water treatment, water risks, the water cycle, and water-food connections. The activities were physical "wet" models and games that engaged 6 and 7th grade students from middle schools across the state on two occasions. One underserved population that we engaged was students from the Meskwaki Nation (Sac & Fox Tribe of the Mississippi in Iowa), a federally-recognized tribe that resides within Iowa. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?There were three PhD students that have been involved in the project to date (1 has graduated, and she is still finalized the last paper related to Obj 3). One PhD student started in 2021 and another in 2020. We also have an undergraduate student working in the lab on the project, and we hosted a visiting high school student through the UIowa Secondary Student Training Program from California who conducted research on the project, and is a co-author on a paper that we have in progress.There were three PhD students that have been involved in the project to date (1 has graduated, and she is still finalized the last paper related to Obj 3). One PhD student started in 2021 and another in 2020. We also have an undergraduate student working in the lab on the project, and we hosted a visiting high school student through the UIowa Secondary Student Training Program from California who conducted research on the project, and is a co-author on a paper that we have in progress. One of the PhD students passed their quals exam this year, and one past their comprehensive exam, so these are important training milestones that help further the research. How have the results been disseminated to communities of interest?One of the ways that we reached a targeted outreach audience for the project this year (in contrast to past year efforts focusing on research audiences) was to interact with middle school students from throughout Iowa educating them on water quality through hands-on demonstrations that displayed water treatment, water risks, the water cycle, and water-food connections. The activities were physical "wet" models and games that engaged 6 and 7th grade students from middle schools across the state on two occasions. One underserved population that we engaged was students from the Meskwaki Nation (Sac & Fox Tribe of the Mississippi in Iowa), a federally-recognized tribe that resides within Iowa. I have also initiated a new collaboration with researchers in engineering and animal science at the land-grant Iowa State University (via an invited seminar) to expand elements of this work with them on other contaminant classes relevant to agriculture. Additionally, we were invited by the College of Public Health (with their environmental, occupational, and rural health programs) to initiate a new collaboration based on a presentation of preliminary results of this work. We believe that the informal dissemination of work through research seminars and collaborations will leverage this work to improve future outcomes. What do you plan to do during the next reporting period to accomplish the goals?Our goal for the next reporting period will be to continue moving forward with the experiments on the bioaccessibility of the benzotriazole in the simulated digestion system and the conjugated plant metabolites following the success (and sometimes time setbacks waiting for instruments to be fixed or supply chain impacted chemicals to arrive). We will continue conducting the in-vitro digestion tests, and will quantify potential for back transformation. Our analytical methods, organisms, simulated gastric systems, and 14-C systems are now set up, and experiments are working. High resolution mass spectrometry has been challenging, but we have made major strides. The prior mentioned issues (ie supply chain delays for chemicals needed) have set us back some, but have largely been overcome and do not require any major change in the approach or modification of our overall tasks or objectives. The additional PhD student who has joined to progress has helped the progress forward. We expect to continue to make positive progress forward and have major significant results during the next reporting period. If necessary, we may initiate a request for a 1 year no-cost extension to accomidate some of the chemical supply chain challenges. We expect to complete all of the research tasks as planned (even if additional time is required), and our promising prelimiary results and positive experimental set ups since the prior reporting period are strong developments.
Impacts
What was accomplished under these goals?
During this project period, we have completed Objective 3. There were two peer reviewed publications that resulted from this work; these were part of the dissertation work of one PhD student. The works were significant because the demonstrated, active, enzyme-facilitated uptake of small polar emerging contaminants by plants. We discovered novel transformation products and pathways using metabolomics. Importantly, and in the context that we as a research community cannot take a compound-by-compound experimental approach to every emerging contaminant, we published a paper that focused on the role of functional group (electrostatic) properties and molecular position on predicting plant uptake kinetics when active uptake occurs. We used experimental and computational chemistry (QSAR) modeling to probe these effects, with the ultimate goal of predicting chemical characteristics of emerging contaminants that are likely to be taken up into plants during water recycling operations, with the ultimate outcome of helping to inform exposure risk. We have also been making good progress on the other Objectives 1 and 2. We have set up experiments that now are able to fulfill the simulated digestion system, and have run experiments with this system. We have preliminary results, and are able to obtain reasonable mass balances with the parent compound and for multiple metabolites. Based on our preliminary results, it indicates that there is likely deconjugation of the benzotriazole plant metabolites. One major challenge has been supply chain issues with 14C-radio labeled compounds needed for one experiment; this is something we have been waiting for several months and only recently were we able to have the chemicals obtained. These are now set up and will allow us to complete the mass balance going forward. Additionally, the commercially-available freeze-dried anaerobic gut bacteria we ordered could not be cultured, but we were able to overcome this by obtaining a culture from a colleague at another university. These cultures are now growing and we have begun using them for experiments. For Objective 2, we have conducted preliminary studies for each of the tasks, and are refining the experiments to generate publication quality data (we expect a publication from each task). For task 2.1, we have proven a full molar balance demonstrating microbial deconjugation of one of the excreted plant metabolites; however, other excreted plant metabolites yield an incomplete mass balance. We have therefore conducted high resolution mass spectrometry metabolomics work to elucidate novel products. We have also conducted hydrolysis experiments across relevant pH conditions (representing mammal/insect gut to environmental surface waters) to quantify acid and/base catalyzed hydrolysis reactions. Initial results indicate that this is a relevant process, and we are following up with more specific kinetics and products investigations. Some of these experiment, primarily due to the chemical supply chain issues described, are taking longer than desired, but are making important progress. Significantly, we have positive preliminary results at this point for all the research tasks in progress.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2023
Citation:
Muerdter, C.P., Powers, M.M., Webb, D.T., Chowdhury, S., Roach, K.E., LeFevre, G.H., 2023. Functional Group Properties and Position Drive Differences in Xenobiotic Plant Uptake Rates, but Metabolism Shares a Similar Pathway. Environ. Sci. Technol. Lett. 10, 596603. doi:10.1021/acs.estlett.3c00282
- Type:
Journal Articles
Status:
Published
Year Published:
2022
Citation:
Muerdter, C.P., Powers, M.M., Chowdhury, S., Mianecki, A.L., LeFevre, G.H., 2022. Rapid plant uptake of isothiazolinone biocides and formation of metabolites by hydroponic Arabidopsis. Environ. Sci. Process. Impacts 24, 17351747. doi:10.1039/D2EM00178K
|
Progress 01/01/22 to 12/31/22
Outputs
Target Audience:The target audience for the work in theis year of the project includes the research community, particularly in the area of emerging contaminants and water recycling in agriculture. We presented work related to Objective 3 of the project at the American Chemical Society meeting, where it was well-received. LeFevre, G.H., Muerdter, C.P., Webb, D.T., Powers, M.M. Discovering novel plant transformation products and alteration of endogenous plant chemicals following exposure to CECs using HRMS. American Chemical Society Spring Meeting, San Diego, CA. 2022. Changes/Problems:We have only had some minor technical difficulties due to instruments being down and delayed as well as the major supply chain issue with purchasing the 14-C radiolabel compound as a tracer in Obj 1. These issues have set us back some, but have largely been overcome and DONOT require any major change in the approach or modification of our overall tasks or objectives. What opportunities for training and professional development has the project provided?There were three PhD students that have been involved in the project to date (1 has graduated, and she is still finalized the last paper related to Obj 3). One PhD student started in 2021 and another in 2020. We also have an undergraduate student working in the lab on the project, and we hosted a visiting high school student through the UIowa Secondary Student Training Program from California who conducted research on the project, and is a co-author on a paper that we have in progress. How have the results been disseminated to communities of interest?We have presented initial results from this work at a conference to the research community in a session on emerging contaminants in recycled irrigation water and uptake into plants. The work was well-received and was helpful to communicate to the community of interest. LeFevre, G.H., Muerdter, C.P., Webb, D.T., Powers, M.M. Discovering novel plant transformation products and alteration of endogenous plant chemicals following exposure to CECs using HRMS. American Chemical Society Spring Meeting, San Diego, CA. 2022. What do you plan to do during the next reporting period to accomplish the goals?Our goal for the next reporting period will be to: (1) We will move forward with publishing the work that we have conducted under Objective 3 which will then be considered accomplished, and (2) we will focus on experimental work for Objectives 1 and 2 of the work plan. We will continue moving forward with the experiments on the bioaccessibility of the benzotriazole and the conjugated plant metabolites following the success (and sometimes time setbacks waiting for instruments to be fixed or supply chain impacted chemicals to arrive). We will continue conducting the in-vitro digestion tests, and will quantify potential for back transformation. This effort will be significant, and our initial efforts at Task 1.1 have been laborious and somewhat slow, but successful, and we expect to make continued progress on Objective 1 during the next reporting period. We also will be moving forward in parallel with Objective 2, because these experiments can be conducted successfully concurrently with Objective 1. One additional PhD student will be working on Obj 2 and aid in moving the work forward more rapidly.
Impacts
What was accomplished under these goals?
During this project period, we have made major progress on Objective 3. We accomplished a major component of Objective 3, which was shown in the paper that was published in ESPI during 2022. We also gathered the final experimental data in the last few months, and are finalizing a predictive computational model. This work is being finalized and the manuscript has been drafted (pending integration of the final model results). We believe that the results of this pending final work for Obj 3 are especially high-impact because they relate and predict active uptake with CEC structural moieties--which is highly transferable knowledge. Once that manuscript has been submitted, revised, and accepted, Objective 3 will be accomplished. These were part of the dissertation work of one PhD student. We have also been making good progress on the other Objectives 1 and 2. We have conducted preliminary investigations and initiated the setup for the bioaccessibility experiments for Objective 1. We have obtained all of the needed chemicals and conducted experiments on the plant growth and digestion, but need to put the system together as an integrated experiment. One major challenge has been supply chain issues with 14C-radio labeled compounds needed for one experiment; this is something we have been waiting for for several months and only recently the order appears to be going forward. We have also been working with the anaerobic gut bacteria; we just recently were able to obtain these, and have had some challenges with the initial culturing. We have reached out to a colleague at another university who is expert at working with these microbes, and she is helping to answer important questions. We anticipate we will be able to overcome these initial challenges through this new input. We have a distinct plan going forward, and believe that we will be slightly behind where we originally anticipated, but are making strong forward progress. For Objective 2, we have just started the experimental design and are conducting scoping / rangefinding experiments on the acid/base catalyzed hydrolysis and soil bacterial transformation rates and extents. These experiments are places where we have substantial experience and do not expect any major challenges.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2022
Citation:
Muerdter, C.P; Powers, M.M; Chowdhury, S.; Mianecki, A.L.; LeFevre, G.H. Rapid Plant Uptake of Isothiazolinone Biocides and Formation of Metabolites by Hydroponic Arabidopsis. Environmental Science: Processes & Impacts. 24(10), 17351747. 2022. DOI: 10.1039/D2EM00178K.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2022
Citation:
LeFevre, G.H., Muerdter, C.P., Webb, D.T., Powers, M.M. Discovering novel plant transformation products and alteration of endogenous plant chemicals following exposure to CECs using HRMS. American Chemical Society Spring Meeting, San Diego, CA. 2022.
|
Progress 01/01/21 to 12/31/21
Outputs
Target Audience:The target audience for the work in the first year of the project includes the research community, particularly in the area of emerging contaminants and water recycling in agriculture. We presented work related to Objective 3 of the project at the international Emerging Contaminants Conference, where it was well-received.? Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?There are multiple graduate students and undergraduate students who have received training from the grant. The student names are listed below. PhD students Muerdter and Webb, and undergraduate student Powers graduated, and PhD student Chowdhury and undergraduate student Deshpande started on the project during this project period (Year 1). Claire P. Muerdter (PhD student) Danielle T. Webb (PhD student) Sraboni Chowdhury (PhD student) Megan M. Powers (undergraduate) Aaditya Deshpande (undergraduate) How have the results been disseminated to communities of interest?We have presented initial results from this work at a conference to the research community in a session on emerging contaminants in recycled irrigation water and uptake into plants. The work was well-received and was helpful to communicate to the community of interest. LeFevre, G.H., Muerdter, C.P., Powers, M.M. Probing Putative Transporter-Mediated Plant Uptake of CECs: The Impact of Functional Group Properties on Plant Uptake Kinetics and Metabolism. EMCON: International Conference on Emerging Contaminants. 2021. What do you plan to do during the next reporting period to accomplish the goals?Our goal for the next reporting period will be dual faceted: (1) We will move forward with publishing the work that we have conducted under Objective 3, and (2) we will focus on experimental work for Objective 1 of the work plan. We will continue moving forward with the experiments on the bioaccessibility of the benzotriazole and the conjugated plant metabolites. We will continue conducting the in-vitro digestion tests, and will quantify potential for back transformation. This effort will be significant, and our initial efforts at Task 1.1 have been laborious and somewhat slow, but successful, and we expect to make continued progress on Objective 1 during the next reporting period. We aim also to have one of the papers from Object 3 published, and another submitted during the next reporting period, which will require some editing and revision to meet journal requirements.
Impacts
What was accomplished under these goals?
Our Team (PD and PhD students) has been working on multiple project objectives concurrently. We had a strong momentum on Objective 3, which has resulted in two PhD thesis chapters (which will later be published;one is submitted, both abstracts for current drafts are below). We are also in progress on Objective 1. Objective 1, Task 1.1: We have begun experiments using the proposed methodology related to testing the bioaccessibility of contaminants in plants. A few photos of our testing method progress to date are below, comparing the simulated digestion with the control. Objective 3, Task 3.1 and 3.2 have been largely addressed, and there are a few areas that are still in progress. We studied plant uptake mechanisms of emerging contaminants to understand the rates and role of chemical structure on uptake.We have two in-progress publications that are related to these: Muerdter, C.P., Powers, M.M., Chowdhury, S. *LeFevre, G.H. Rapid Transporter-Mediated Plant Uptake of Isothiazolinone Biocides and Formation of Novel Metabolites by Hydroponic Arabidopsis. Submitted to: Environmental Science: Processes and Impacts. [Current draft submitted] Abstract: Isothiazolinones biocides are water-soluble, low molecular weight, nitrogenous compounds widely used to prevent microbial growth in a variety of applications including personal care products and building façade materials. Because isothiazolinones from buildings wash off and enter stormwater, interactions with terrestrial plants may represent an important part of the environmental fate of these compounds. Using the model plant Arabidopsis thaliana under hydroponic conditions, we observed rapid (nearly complete within 24 hours), plant-driven removal of four commonly used isothiazolinones: benzisothiazolinone (BIT), chloromethylisothiazolinone (CMI), methylisothiazolinone (MIT), and octylisothiazolinone (OIT). No significant differences in uptake rate occurred between the four compounds; therefore, BIT was used for further investigation. BIT uptake by Arabidopsis was concentration-dependent and decreased over the measured range (8-2,127 µg/L), indicating transporter-mediated substrate inhibition instead of rising to a steady reaction rate as in classical Michaelis-Menten kinetics. BIT uptake was also minimally impacted by multiple BIT spikes (25% increase with the second spike), suggesting that uptake is constituently active. BIT plant uptake was robust, with uptake rate unaffected by multiple inhibitors (competitive, plant uptake, or plant metabolism). After Arabidopsis uptake, the major metabolites in the plant tissue followed known detoxification pathways, generating multiple novel (previously undocumented for BIT) metabolites: hydroxylated BIT, an amino acid conjugate, and a glutathione conjugate. Endogenous nicotinic acid production also increased in BIT-exposed plant tissue vs. unexposed plant tissue, indicating that BIT impacted normal plant metabolic functions beyond direct formation of xenobiotic conjugates. The hydroxylated BIT and glutathione-BIT conjugates also were present in the hydroponic medium, likely through plant excretion. The rapid plant-driven isothiazolinone removal in this work indicates that plant-isothiazolinone processes may be relevant to the environmental fate of these compounds in stormwater and may represent overall detoxification via known detoxification pathways. Muerdter, C.P., Webb, D.T., Powers, M.M., *LeFevre, G.H.Functional Group Properties and Position Drive Differences in Xenobiotic Plant Uptake Rates but Metabolism Follows Similar Pathways. In Preparation for submission to: Environmental Science & Technology Letters. [DRAFT] Abstract: Plant uptake of xenobiotic compounds is crucial for phytoremediation and exposure potential during crop irrigation with recycled water; however, experimentally determining plant uptake for every relevant chemical is impractical. There is a critical need to illuminate the role of specific functional groups on contaminants of emerging concern to enhance predictive power for compounds that may be taken up by plant transporters, an emerging area of research. In this work, we used benzimidazole as a representative molecule with a suite of derivatives that differ by a single functional group in order to probe the impact of functional group electrostatic nature and position on plant uptake and metabolism, using the hydroponic model plant Arabidopsis thaliana. The greatest plant uptake rates occurred with an electron-withdrawing functional group at the 2-position. Electron-donating groups at the 2-position still yielded some plant uptake, indicating possible steric effects between the chemical and transporter protein. An electron-donating group at the 1-position significantly slowed uptake for both benzimidazole and benzotriazole base molecules. For the unsubstituted base molecules, the additional heterocyclic nitrogen in benzotriazole increased plant uptake compared to benzimidazole. Compounds with significantly different uptake rates followed similar metabolic pathways, including hydroxylation, glutathione conjugation, and amino-acid conjugation to generate auxin-like metabolites. Endogenous plant molecules involved in glutathione production were also increased. This study provides novel insights into the impact of specific functional groups on plant uptake, with implications for environmental fate and consumer exposure.
Publications
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2021
Citation:
Vegetation-Facilitated Removal Kinetics and Transformation of Organic Biocides. Claire Penrose Muerdter. PhD Thesis, University of Iowa. 2021.
- Type:
Journal Articles
Status:
Submitted
Year Published:
2021
Citation:
Muerdter, C.P., Powers, M.M., Chowdhury, S. *LeFevre, G.H. Rapid Transporter-Mediated Plant Uptake of Isothiazolinone Biocides and Formation of Novel Metabolites by Hydroponic Arabidopsis. Submitted to: Environmental Science: Processes and Impacts.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2021
Citation:
" LeFevre, G.H., Muerdter, C.P., Powers, M.M. Probing Putative Transporter-Mediated Plant Uptake of CECs: The Impact of Functional Group Properties on Plant Uptake Kinetics and Metabolism. EMCON: International Conference on Emerging Contaminants. Accepted Oral Presentation. 2021.
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