Progress 06/01/20 to 05/31/24
Outputs
Target Audience:Target audiences: The scietific research community; undergraduate and graduate students; state extension specialists; producers, other stakeholders, and the lay public Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Since 2022, a microplastics Community of Scholars (CoS) was created at Univ. of Tennessee to bring together people from scientists, educators, to indsutry partners that share a common interest in the problems created by plastics in the envrionment. This is financially supported via internal funds to hold workshops and small conferences, and to pay for speaker travel costs. To date, this CoS holds roughly 6 of these types of meetings per year. We wrote a DOE EMSL-FICUS proposal to better characterize micro- and nanoplastics, but this proposal was not funded. We also worked on a perspective article, discussing the more recent literature findings on the use of biodegradable plastics in general, and with respect to agriculture in particular. This article is still under preparation and is intended to be submitted to the Nature portfolio journal npj Materials Sustainability. How have the results been disseminated to communities of interest?For this reporting period results have been disseminated to: Scientists, educators, to indsutry partners that share a common interest in the problems created by plastics in the envrionment through our UTK Community of Scholars Undergraduate and graduate students via a UT course (Microplastics: Introduction and Overview, ESS 494/593) The scietific research community via peer-reviewed publications and presentations at scientific meetings Undergraduate and graduate students via in-class presentations, as well as peer-reviewed publications and presentations at scientific meetings What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
For Obj. 1. We prepared a manuscript on the size reduction process for microplastics into nanoplastics forPolybutylene Adipate-Co-Terephthalate (PBAT) and Polylactic Acid (PLA) films that was published in Science of the Total Environment. We found that the resultant nanoplastics possessed a bimodal size distribution and that environmental weathering strongly impacted the size reduction process.we prepared a manuscript on the size reduction process for microplastics into nanoplastics for PBAT and PLA films that was published in Science of the Total Environment. We found that the resultant nanoplastics possessed a bimodal size distribution and that environmental weathering strongly impacted the size reduction process. This work was completed by a PhD student who graduated in 2022, but continued on the project as a postdoc. A second PhD student at University of Tennessee is set to graduate in Fall 2024. She has develped a protocol for quanitfying total amounts of Polybutylene adipate terephthalate (PBAT) in soil using a quantitative 1H NMR (QNMR) approach. PBAT is the main constituent of many commercial BDMs. This looks to be a promising method for quantifying in total situ soil plastic polymer concentration that includes all particle size fractions from micro to nano plastic particles. The results are in revision for a manuscript sent to the Journal of Visualized Experiments. We have received minor comments from reviewers and a revised version of the manscript has been sent to the editors for approval. For Obj. 2. We completed our set of small-angle neutron scattering measurements that probed the agglomeration behavior and size reduction of nanoplastics prepared from polyethylene pellets and PBAT and PLA mulch films in the presence and absence of soil (vermiculite) and ex situ convective stirring at different times and temperatures. We have reduced all of the data and have prepared a manuscript draft that focuses upon PBAT nanoplastics. We have received minor corrections from our coauthors and expect the manuscript to be submitted within the next 2 weeks. An additional manuscript that focuses upon the impact of temperature and investigates agglomeration behavior for PLA and LDPE will be drafted over the next quarter. We completed our experimental work on the impacts of microplastics on soil physical properties. We wrote up the results in form of a technical journal article, and successfully published. The main message from this article is that microplastics at environmentally relevant concentrations have no significant effects on soil physical properties. This was demonstrated by measuring the physical properties of a silt loam in response to the incorporation of polyester fibers and polypropylene granules over a wide range of concentrations. We further elucidated the underlying mechanisms through determining the role of microplastic shape and the baseline effects from the amendment of soil particles. The incorporation of microplastics into soil tended to increase contact angle and saturated hydraulic conductivity, decrease bulk density and water holding capacity, while did not affect aggregate stability. Polyester fibers affected soil physical properties more profoundly than polypropylene granules, due to the vastly different shape of fibers from that of soil particles. However, changes in soil properties were gradual, and significant changes did not occur until a high concentration of microplastics was reached (i.e., 0.5 percent w/w for polyester fibers and 2 percent w/w for polypropylene granules). We combined QNMR with visual microscopy, mesh bag, and soil respiration measurements to estimate field rates of biodegradation in soils unexposed, and previously exposed to PBAT based mulches. We fouhnd a significant effect of pre-exposure in degradation rates. This observed acclimation effect is often dubbed "homefield advantage". The results of this experiment are in a manuscript in review for Soil Biology and Biochemistry. We have also completed work on determining in situ degradation rates in two different soil types, and at multiple depths. Degradation rates, though lower in deeper soil, appear to be relatively higher per unit microbial biomass. This suggests that even though microbial population denisty at depth (>20cm) is relatively low, the propensity to use mulch-dervied C as a substrate is unchnaged, or even increased. These results are in a manuscript currently in preparation. For Obj. 3. Field experiments described in the last annual report were completed and the results analyzed. As previously reported, a graduate student at University of Tennessee has collected preliminary data that show microplastic particles from BDMs remain in field soils longer than previously thought. She used these data to calculate that the potential maximum accumulation of microplastic particles may be at least 25% greater than previously thought. She has also observed vertical transport of particles down to at least 60 cm in fields with four consecutive years of BDM use. At Washington State University, in-field degradation of biodegradable plastic mulch films was used to quantify mulch recovery 2 years after the final incorporation, and to compare in-field degradation with the laboratory standard in terms of calendar and thermal times based on a zeroth-order kinetics model. A zeroth-order kinetics model was developed to analyze mulch degradation after. Model extrapolations indicate it would take 21 to 58 months to reach 90% mulch degradation in a Mediterranean climate in Mount Vernon, WA. In addition, a graduate student (PhD) from Washington State University has published a paper (from a separate project) that shows particles >10μm tend to not be transported in soil by physical processes. Combined with our data, this suggests that biological mechanisms may be responsible.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2023
Citation:
Gillmore, A. B., S. Sistla, A. F. Astner, D. G. Hayes, S. M. Schaeffer. Quantitative 1H-NMR spectroscopy to measure PBAT microplastics in soil. 2023 American Geophysical Union Fall meeting Abstracts, San Francisco CA
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2024
Citation:
Gillmore, A. B., S. M. Schaeffer. Degradation of Agricultural Biodegradable Microplastics in Subsurface Soil. 2024 ASA-CSSA-SSSA International Annual Meeting, San Antontio TX
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2024
Citation:
Hatcher, W., A. B. Gillmore, S. M. Schaeffer. Utilizing Organic Matter Digestion to Identify Biodegradable Mulch (PBAT) Microplastic Particles in Agricultural Soils. 2024 ASA-CSSA-SSSA International Annual Meeting, San Antontio TX
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2023
Citation:
Gillmore, A. B., S. A. Sistla, S. M. Schaeffer. Biodegradable Plastic Disintegration in Agricultural Soil at Two Depths in Mesic and Xeric Climates. 2023 ASA, CSSA, SSSA International Annual Meeting
- Type:
Journal Articles
Status:
Published
Year Published:
2023
Citation:
Adhikari, K., A. F. Astner, J. M. DeBruyn, Y. Yu, D. G. Hayes, B. T. O⿿Callahan, and M. Flury, Interactions of earthworms with polyethylene and PBAT microplastics in soil: Microplastic characterization and microbial community analysis, ACS Agricultural Sci. Technol., 3, 340⿿349
- Type:
Journal Articles
Status:
Published
Year Published:
2024
Citation:
Yu, Y., M. Velandia, D.G. Hayes, L.W. DeVetter, C.A. Miles, M. Flury. Biodegradable plastics as alternatives for polyethylene mulch. Advances in Agronomy, 183, 121-192,
- Type:
Journal Articles
Status:
Under Review
Year Published:
2024
Citation:
Gillmore, A.B., S.A. Sistla, S.M. Schaeffer. Homefield advantage in soil degradation of a biodegradable polybutylene adipate terephthalate microplastic. In review for Soil Biology and Biochemistry
- Type:
Journal Articles
Status:
Under Review
Year Published:
2024
Citation:
Gillmore, A.B., C.A. Steren, D.G. Hayes, S.M. Schaeffer. Quantification of polybutylene adipate terephthalate (PBAT)-based micro- and nanoplastics from soil using proton nuclear magnetic resonance spectroscopy. In review for Journal of Visualized Experimentation
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2024
Citation:
Hayes, D.G., A.F. Astner, S.V. Pingali, H.M. ONeill, B.R. Evans, V.S. Urban, W.-R. Chen, K. Littrell. Dynamics between nanoplastic and soil particles suspended in water: a small-angle neutron scattering (SANS) and Ultra-SANS (USANS) Study. American Conference on Neutron Scattering (ACNS), Knoxville, TN
- Type:
Journal Articles
Status:
Published
Year Published:
2023
Citation:
Bandopadhyay, S., M. English, M. B. Anunciado, M. Starrett, J. Hu, J. E. Liquet y González, D. G. Hayes, S. M Schaeffer, J. M. DeBruyn. Organic and inorganic nitrogen amendments reduce biodegradation of biodegradable plastic mulch films. Soil, 9:2, 499-516
- Type:
Journal Articles
Status:
Published
Year Published:
2023
Citation:
Astner, A. F., A. B. Gillmore, Y. Yu, M. Flury, J. M. DeBruyn, S. M. Schaeffer, D. G. Hayes. Formation, behavior, properties and impact of micro-and nanoplastics on agricultural soil ecosystems (A Review). Nanoimpact, 100474
- Type:
Journal Articles
Status:
Published
Year Published:
2023
Citation:
Yu, Y., A. K. Battu, T. Varga, A. C. Denny, T. M. Zahid, I. Chowdhury, and M. Flury, Minimal impacts of microplastics on soil physical properties under environmentally relevant concentrations, Environ. Sci. Technol., 57, 5296⿿5304
|
Progress 06/01/22 to 05/31/23
Outputs
Target Audience:Target audiences: The scietific research community; undergraduate and graduate students; state extension specialists; producers, other stakeholders, and the lay public Efforts: Presentations at national/international meetings; publication in peer-reviewed journals; field and laboratory technician training; special lectures; extension and outreach; field days; networking via USDA-ARS and National Soil Survey. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?This project has provided training and professional development opportunities for three graduate students from the University of Tennessee and two from Washington State University. Training opportunities include: 1) microscopy and 1H NMR training at the UT Joint Institute for Advanced Materials, 2) luminescence spectroscopy at the Center for Environmental Biology at UT, 3) training and use of the Neutron Scattering Facilities at Oak Ridge National Laboratory. Professional development opportunities for students include: 1) in class presentation of research results, 2) presentation at regional and national meetings, 3) participation in writing development for a larger-scale USDA-SCRI proposal that was funded in 2022, 4) participation in writing two review articles on the topic of agricultural plastics. How have the results been disseminated to communities of interest?For this reporting period results have been disseminated to: Undergraduate and graduate students via a UT course (Microplastics: Introduction and Overview, ESS 494/593) The scietific research community via peer-reviewed publications and presentations at scientific meetings Undergraduate and graduate students via in-class presentations, as well as peer-reviewed publications and presentations at scientific meetings State extension specialists, producers, other stakeholders via presentations at regional meetings and special seminars What do you plan to do during the next reporting period to accomplish the goals?The California and Tennessee long-term field experiments will be concluded in early 2023 and the data will be analyzed and published in peer-reviewed journals. Along with this long-term experiment, the results of the homefield advantage experiment will also be analyzed and published. There is still some questions remaining regarding the acclimatization of microbial communities to biodegradation of these agricultural plastics. The results from biodegradation studies of μPs compared to nPs will completed and submitted as a manuscript to a technical journal. Some additional analyses need to be performed to address concerns that the observed degradation is not due to addtitives (carbon black, Calcium carbonate, etc.) in the mixtures. These results will be compared to field degradation rates in Tennessee, California and Washington. We plan to conduct contact angle measurements on the soil treated with different plastic types and concentrations. We expect that the samples that were exposed to field weathering will be more hydrophilic. We will also start to analyze the data to determine critical plastic concentrations when negative impacts on soil hydraulic properties are being materialized. All the experiments and data will be written up as a scientific manuscript.
Impacts
What was accomplished under these goals?
For Obj. 1, we have refined methods for quantifying microplastic particles in soils using particle and denisty fractionation combined with microscopy. A graduate student has developed a method for using 1-H NMR spectroscopy for quantifying PBAT and other biodegradable plastic polymers in soil. A graduate student/postdoc developed a protocol for generating micro- and nanoplastic particles for use in subsequient proposed experiments. This protocol has been published in the Journal of Visualized Experiments (JoVE). The protocol uses precision milling to obtain finely binned particle size classes. Two graduate students (PhD) at the University of Tennessee have been working on these aspects of the project for the past year. One PhD student at the University of Tennessee completed his degree in 2022 and the results of his research relative to Obj. 1 are been written up for publication in peer-reviewed journals including JoVE and Science of the Total Environment. A major finding of his research is that there may be a fundamental difference in biodegradability and transport in soil of micro - and nano-plastic particles derived from biodegradable mulches (BDMs). A second PhD student at University of Tennessee has set up field plots in Tennessee and California to track field biodegrdation of BDMs. She has develped a protocol for quanitfying total amounts of Polybutylene adipate terephthalate (PBAT) in soil using 1H NMR. PBAT is the main constituent of many commercial BDMs. She is combining this with visual microscopy, mesh bag, and soil respiration measurements to estimate field rates of biodegradation. These results have been shared at national and regional meetings, and this student has contributed to a review article on the subject. In addition, the student has added a field experiment to test the acclimation of soil microbial communities to degrading BDMs, so called "homefield advantage". For Obj. 2, A graduate student at the University of Tennessee has adapted a commercially avaialble bacterial ecotoxicological assay to soil extract samples. The luminescence bacteria Vibrio fischeri is used to test for ecotoxicity in the soil samples containing biodegradable mulches (BDM) microplastic. The inhibition of luminesces compared to controls indicates a slight inhibitory effect of BDM particles added to soil relative to standar low density polyethylene (LDPE). This same student is also measuring the substrate use and substrate use efficiency (as carbon use effeciency, CUE) of BDMs in soil. She found that as BDM concentration increased, the use of BDMs as a carbon substrate by microbes also increased, but that CUE of the microbial community decreased. This suggests that even if there is some ecoxtoxic effect of BDM addition in soil, microbial communites, as a whole, are able to compensate and decompose the material. As previously reported, a graduate student (PhD) at Washington State University set up mesocosm experiments to study the interaction of earthworms (Lumbricus terrestris) with micro- and nanoplastics. After the experiment, they removed and sampled soil (surface, bulk, and earthworm cast) and earthworms and extracted soil and earthworms for micro- and nanoplastics.Earthworms were dissected and guts examined with a microscope for the presence of micro- and nanoplastics. Guts and soil samples are also being analyzed for microbial community structure. Raman spectroscopy was conducted at the Department of Energy's Environmental Molecular Science Laboratory in Richland, WA. These analyses have shown that while earthworms have ingested both polyethylene and biodegradable plastic, there was no negative effect noticed on earthworm vitality and overall health. We also did not observe a preference of the earthworms for either polyethylene and biodegradable plastic, but rather the earthworms ingested the plastics because the plastic particles were attached to their food source (poplar leaves). No treatment effects on microbial community structures were observed. We observed degradation of the biodegradable plastics when the plastics were ingested by the earthworms, but the plastic particles did not accumulate inside the earthworms but were rather excreted with the cast. These results suggest that earthworms have a positive effect on the degradation of biodegradable plastics, by initiating degradation inside the earthworm guts and by incorporation into the microbiological highly active earthworm cast. A scientific manuscript has been prepared and is currently in the final stages for completion. We have also continued to work on examining the effects of micro- and nanoplastics on the water holding capacity of soils. Soils were mixed with different concentrations of micro- and nanoplastics and were then buried in an agricultural field for 50 days to expose plastics and soils to environmental conditions. After recovery from the field, soils were analyzed for a series of soil physical properties (bulk density, water retention properties, hydraulic conductivity, aggregate stability). We have found some significant differences between the two plastic types used (polypropylene granules and polyester fibers) and their impact on soil physical properties. We have also analyzed the surface properties of the plastic particles. For Obj. 3, In, March 2022, field experiments of BDM degradation rates were set up in Tennessee and California. This work is done in collaboration with a new partner at CalPoly San Luis Obispo (Dr. Seeta Sistla). California is a major user of agricultural plastics and the addititon of this work means that the results of this project will be more broadly applicable to growers across the nation. The long-term biodegradation project is set to terminate in early 2023. As previously reported, a graduate student at University of Tennessee has collected preliminary data that show microplastic particles from BDMs remain in field soils longer than previously thought. She used these data to calculate that the potential maximum accumulation of microplastic particles may be at least 25% greater than previously thought. She has also observed vertical transport of particles down to at least 60 cm in fields with four consecutive years of BDM use. At Washington State University, in-field degradation of biodegradable plastic mulch films was used to quantify mulch recovery 2 years after the final incorporation, and to compare in-field degradation with the laboratory standard in terms of calendar and thermal times based on a zeroth-order kinetics model. A zeroth-order kinetics model was developed to analyze mulch degradation after. Model extrapolations indicate it would take 21 to 58 months to reach 90% mulch degradation in a Mediterranean climate in Mount Vernon, WA. In addition, a graduate student (PhD) from Washington State University has published a paper (from a separate project) that shows particles >10μm tend to not be transported in soil by physical processes. Combined with our data, this suggests that biological mechanisms may be responsible.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2022
Citation:
Gillmore, A. B., A. F. Astner, D. G. Hayes, and S. M. Schaeffer. Quantitative 1H-NMR spectroscopy to measure microplastic concentration in agricultural soil over time. 2022 ASA-CSSA-SSSA International Annual Meeting, Baltimore MD
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2022
Citation:
Martin, C., and S. M. Schaeffer. Using bioluminescent bacteria to measure the potential ecotoxicity of non-biodegradable and biodegradable plastic mulch in soil. 2022 ASA-CSSA-SSSA International Annual Meeting, Baltimore MD
- Type:
Journal Articles
Status:
Published
Year Published:
2022
Citation:
Bandopadhyay, S.,M. English, M.B. Anunciado, M. Starrett, J. Hu, J.E. Liquet y Gonz�lez, D.G. Hayes, S.M. Schaeffer, J.M. DeBruyn. Organic and inorganic nitrogen amendments suppress decomposition of biodegradable plastic mulch films. doi.org/10.5194/egusphere-2022-1333
- Type:
Journal Articles
Status:
Published
Year Published:
2023
Citation:
Astner, AF, DG Hayes, H O'Neill, BR Evans, SV Pingali, VS Urban, SM Schaeffer, TM Young. Assessment of cryogenic pretreatment for simulating environmental weathering in the formation of surrogate micro-and nanoplastics from agricultural mulch film. Science of the Total Environment, 870, 161867
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2022
Citation:
Anton F. Astner. Analysis of Physiochemical Properties and Terrestrial Dynamics of Mechanically Formed Micro-nano Scaled Particles From Agricultural Plastic Mulches.
|
Progress 06/01/21 to 05/31/22
Outputs
Target Audience:The scietific research community; undergraduate and graduate students; state extension specialists; producers, other stakeholders, and the lay public. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?This project has provided training and professional development opportunities for three graduate students from the University of Tennessee and two from Washington State University. Training opportunities include: 1) microscopy and 1H NMR training at the UT Joint Institute for Advanced Materials, 2) luminescence spectroscopy at the Center for Environmental Biology at UT, 3) training and use of the Neutron Scattering Facilities at Oak Ridge National Laboratory. Professional development opportunities for students include: 1) in class presentation of research results, 2) presentation at regional and national meetings, 3) participation in writing development for a larger-scale USDA-SCRI proposal, 4) participation in writing a review article on the topic of agricultural plastics. How have the results been disseminated to communities of interest?For this reporting period results have been disseminated to: The scietific research community via peer-reviewed publications and presentations at scientific meetings Undergraduate and graduate students via in-class presentations, as well as peer-reviewed publications and presentations at scientific meetings State extension specialists, producers, other stakeholders via presentations at regional meetings and special seminars What do you plan to do during the next reporting period to accomplish the goals?The results from biodegradation studies of μPs compared to nPs will completed and submitted as a manuscript to a technical journal. Some additional analyses need to be performed to address concerns that the observed degradation is not due to addtitives (carbon black, Calcium carbonate, etc.) in the mixtures. These results will be compared to field degradation rates in Tennessee, California and Washington. Laboratory experiments will continue to examine the ecotoxicological effects of a range of biodegradable and non-biodegradable plastic particles. Different concentrations of particles will be added to soil, then microbial activity and potential ecotoxicity be measured. The observed contrast between potential ecotoxicity and cabon use effeciency will be examined with additional measurements of CUE using a different technique (enzyme stoichiometry) to verify our current results. We will finalize the scientific manuscript on the earthworm mesocosms experiments. Some additional measurements need to be made to verify that the plastic extraction procedure does not have an impact on the plastic particles themselves, particularly the biodegradable plastic particles. After these additional measurements, we will complete the manuscript and submit to a technical journal. We will continue with the hydraulic property experiments. We plan to conduct contact angle measurements on the soil treated with different plastic types and concentrations. We expect that the samples that were exposed to field weathering will be more hydrophilic. We will also start to analyze the data to determine critical plastic concentrations when negative impacts on soil hydraulic properties are being materialized. All the experiments and data will be written up as a scientific manuscript.
Impacts
What was accomplished under these goals?
For Obj. 1, we have developed, and refined methods for quantifying microplastic particles in soils using particle and denisty fractionation combined with microscopy. We have also developed a protocol for generating micro- and nanoplastic particles for use in subsequient proposed experiments. This protocol has been published in the Journal of Visualized Experiments (JoVE). The protocol uses precision milling to obtain finely binned particle size classes. Two graduate students (PhD) at the University of Tennessee have been working on these aspects of the project for the past year. One PhD student at the University of Tennessee has completed his degree and the results of his research relative to Obj. 1 are been written up for publication in peer-reviewed journals (the above mentioned JoVE article is one). Another major finding of his research is that there may be a fundamental difference in biodegradability and transport in soil of micro - and nano-plastic particles derived from biodegradable mulches (BDMs). A second PhD student at University of Tennessee has set up field plots in Tennessee and California to track field biodegrdation of BDMs. She has develped a protocol for quanitfying total amounts of Polybutylene adipate terephthalate (PBAT) in soil using 1H NMR. PBAT is the main constituent of many commercial BDMs. She is combining this with visual microscopy, mesh bag, and soil respiration measurements to estimate field rates of biodegradation. These results have been shared at national and regional meetings, and this student has contributed to a review article on the subject. For Obj. 2, A graduate student at the University of Tennessee has adapted a commercially avaialble bacterial ecotoxicological assay to soil extract samples. The luminescence bacteria Vibrio fischeri is used to test for ecotoxicity in the soil samples containing biodegradable mulches (BDM) microplastic. The inhibition of luminesces compared to controls will indicate an ecotoxic effect from the microplastics. She has found a slight inhibitory effect of BDM particles added to soil relative to standar low density polyethylene (LDPE). This same student is also measuring the substrate use and substrate use efficiency (as carbon use effeciency, CUE) of BDMs in soil. She found that as BDM concentration increased, the use of BDMs as a carbon substrate by microbes also increased. However, the CUE of this sibstrate decreased as the concentration increased. This suggests that even if there is some ecoxtoxic effect of BDM addition in soil, microbial communites, as a whole, are able to compensate and decompose the material. A graduate student (PhD) at Washington State University set up mesocosm experiments to study the interaction of earthworms (Lumbricus terrestris) with micro- and nanoplastics. After the experiment, they removed and sampled soil (surface, bulk, and earthworm cast) and earthworms and extracted soil and earthworms for micro- and nanoplastics. Earthworms were dissected and guts examined with a microscope for the presence of micro- and nanoplastics. Guts and soil samples are also being analyzed for microbial community structure. Raman spectroscopy was conducted at the Department of Energy's Environmental Molecular Science Laboratory in Richland, WA. These analyses have shown that while earthworms have ingested both polyethylene and biodegradable plastic, there was no negative effect noticed on earthworm vitality and overall health. We also did not observe a preference of the earthworms for either polyethylene and biodegradable plastic, but rather the earthworms ingested the plastics because the plastic particles were attached to their food source (poplar leaves). No treatment effects on microbial community structures were observed. We observed degradation of the biodegradable plastics when the plastics were ingested by the earthworms, but the plastic particles did not accumulate inside the earthworms but were rather excreted with the cast. These results suggest that earthworms have a positive effect on the degradation of biodegradable plastics, by initiating degradation inside the earthworm guts and by incorporation into the microbiological highly active earthworm cast. A scientific manuscript has been prepared and is currently in the final stages for completion. We have also continued to work on examining the effects of micro- and nanoplastics on the water holding capacity of soils. Soils were mixed with different concentrations of micro- and nanoplastics and were then buried in an agricultural field for 50 days to expose plastics and soils to environmental conditions. After recovery from the field, soils were analyzed for a series of soil physical properties (bulk density, water retention properties, hydraulic conductivity, aggregate stability). We have found some significant differences between the two plastic types used (polypropylene granules and polyester fibers) and their impact on soil physical properties. We have also analyzed the surface properties of the plastic particles. For Obj. 3, A graduate student (PhD) at University of Tennessee has collected preliminary data that show microplastic particles from BDMs remain in field soils longer than previously thought. She used these data to calculate that the potential maximum accumulation of microplastic partilces may be at least 25% greater than previously thought. She has also observed vertical transport of particles down to at least 60 cm in fields with four consectutive years of BDM use. At Washington State University, in-field degradation of biodegradable plastic mulch films was used to quantify mulch recovery 2 years after the final incorporation, and to compare in-field degradation with the laboratory standard in terms of calendar and thermal times based on a zeroth-order kinetics model. A zeroth-order kinetics model was developed to analyze mulch degradation after. Model extrapolations indicate it would take 21 to 58 months to reach 90% mulch degradation in a Mediterranean climate in Mount Vernon, WA. A graduate student (PhD) from Washington State University has published a paper (from a separte project) that shows partilces >10μm tend to not be transported in soil by physical processes. Combined with our data, this suggests that biological mechanisms may be responsible. In, March 2022, field experiments of BDM degradation rates were set up in Tennessee and California. This work is done in collaboration with a new partner at CalPoly San Luis Obispo. California is a major user of agricultural plastics and the addititon of this work means that the results of this project will be more broadly applicable to growers across the nation.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2022
Citation:
Madrid, B., S. Wortman, D. G. Hayes, J. M. DeBruyn, C. Miles, M. Flury, T. L. Marsh, S. P. Galinato, K. Englund, S. Agehara, and L. W. DeVetter, End-of-life management options for agricultural mulch films in the United States. A review, Frontiers in Sustainable Food Systems, 6, 921496, doi:10.3389/fsufs.2022.921496, 2022.
- Type:
Journal Articles
Status:
Published
Year Published:
2022
Citation:
Griffin-LaHue, D., S. Ghimire, Y. Yu, E. J. Scheenstra, C. A. Miles, and M. Flury, In-field degradation of soil-biodegradable plastic mulch films in a Mediterranean climate, Sci. Total Environ., 806, 150238, doi.org/10.1016/j.scitotenv.2021.150238, 2022.
- Type:
Journal Articles
Status:
Other
Year Published:
2022
Citation:
Adhikari, K., Astner, A.F., DeBruyn, J.M., Yu, Y., Hayes, D.G., O'Callahan, B.T., and Flury, M., Interactions of Earthworms with Polyethylene and PBAT Microplastics in Soil: Microplastic Characterization and Microbial Community Analysis, in preparation.
- Type:
Journal Articles
Status:
Published
Year Published:
2022
Citation:
Astner, A.F., Hayes, D.G., O'Neill, H.M., Evans, B.R., Pingali, S.V., Urban, V.S., Young, T.M., Forming Micro-and Nano-Plastics from Agricultural Plastic Films for Employment in Fundamental Research Studies, Journal of Visualized Experiments: Jove, 185, DOI: 10.3791/64112.
- Type:
Journal Articles
Status:
Published
Year Published:
2022
Citation:
Jin, T., Tang, J., Lyu, H., Wang, L. Gillmore, A.B., Schaeffer, S.M., Activities of Microplastics (MPs) in Agricultural Soil: A Review of MPs Pollution from the Perspective of Agricultural Ecosystems, Journal of Agricultural and Food Chemistry, 70, 3182-4201
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2021
Citation:
Gillmore, A.B., Astner, A.F. Hayes, D.G., Schaeffer, S.M., Degradation rate of biodegradable plastic mulches in an East Tennessee agricultural soil based on field sampling after incorporation. ASA-CSSA-SSSA International Annual Meeting, Salt Lake City, 2021.
|
Progress 06/01/20 to 05/31/21
Outputs
Target Audience:Target audiences: The scietific research community; undergraduate and graduate students; state extension specialists; producers, other stakeholders, and the lay public Efforts: Presentations at national/international meetings; publication in peer-reviewed journals; field and laboratory technician training; special lectures; extension and outreach; field days; networking via USDA-ARS and National Soil Survey. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?This project has provided training and professional development opportunities for three graduate students from the University of Tennessee and one from Washington State University. Training opportunities include: 1) microscopy and 1H NMR training at the UT Joint Institute for Advanced Materials, 2) luminescence spectroscopy at the Center for Environmental Biology at UT, 3) training and use of the Neutron Scattering Facilities at Oak Ridge National Laboratory. Professional development opportunities for students include: 1) in class presentation of research results, 2) presentation at regional and national meetings, 3) participation in writing development for a larger-scale USDA-SCRI proposal, 4) participation in writing a review article on the topic of agricultural plastics. How have the results been disseminated to communities of interest?For this reporting period results have been disseminated to: The scietific research community via peer-reviewed publications and presentations at scientific meetings Undergraduate and graduate students via in-class presentations, as well as peer-reviewed publications and presentations at scientific meetings State extension specialists, producers, other stakeholders via presentations at regional meetings and special seminars What do you plan to do during the next reporting period to accomplish the goals?We will continue the analysis and characterization of the micro- and nanoplastic extractions from soil and earthworm samples from all experiments. Column experiments are being set up to determine how different concetrations of micro-plastics, as well as surface charges of soil and plastic particles, will affect soil hydraulic conductivity. Laboratory experiments are also starting that examine the ecotoxicological effects of a range of biodegradable and non-biodegradable plastic particles. Different concentrations of particles will be added to soil, then microbial activity and potential ecotoxicity be measured. Microbial community analysis as well as plastic counting and FTIR analyses are ongoing. We will also extract the PBAT treatment earthworm mesocosms for Ti, because the PBAT plastic contains Ti that can be measured with ICP-MS. This should give us unique signal for the presence of plastics in soil, earthworm casts, and earthworms. We will also continue the experiments on the water holding capacity of soils. We will further determine hydrophobicity of soils by measuring soil-water-air contact angles. The goal is to determine at what critical concentrations of micro- and nanoplastics we would start to see changes in soil hydraulic properties. First results of our experiments will be presented by graduate studnets, from both Washington State University and the University of Tennessee, at the Annual Meeting of the Soil Science Society in Salt Lake City in November 2021.
Impacts
What was accomplished under these goals?
For Obj. 1, we have developed, and refined methods for quantifying microplastic particles in soils using particle and denisty fractionation combined with microscopy. We have also developed a protocol for generating micro- and nanoplastic particles for use in subsequient proposed experiments. The protocol uses precision milling to obtain finely binned particle size classes. Two graduate students (PhD) at the University of Tennessee have been working on these aspects of the project for the past year. For Obj. 2, A graduate student (MS) at the University of Tennessee has been working to adapt a commercially avaialble bacterial ecotoxicological assay to soil extract samples. The luminescence bacteria Vibrio fischeri is used to test for ecotoxicity in the soil samples containing biodegradable mulches (BDM) microplastic. The inhibition of luminesces compared to controls will indicate an ecotoxic effect from the microplastics. A graduate student (PhD) at Washington State University set up mesocosm experiments to study the interaction of earthworms (Lumbricus terrestris) with micro- and nanoplastics. After the experiment, they removed and sampled soil (surface, bulk, and earthworm cast) and earthworms and extracted soil and earthworms for micro- and nanoplastics. Characterization of the micro- and nanoplastics is ongoing. Earthworms were dissected and guts examined with a microscope for the presence of micro- and nanoplastics. Guts and soil samples are also being analyzed for microbial community structure. We also worked on examining the effects of micro- and nanoplastics on the water holding capacity of soils. Soils were mixed with different concentrations of micro- and nanoplastics and we are determining the water holding capacities with pressure plates and dew point meter technology. We are also using the evaporation method to determine water retention curves. For Obj. 3, A graduate student (PhD) at University of Tennessee has collected preliminary data that show microplastic particles from BDMs remain in field soils longer than previously thought. She used these data to calculate that the potential maximum accumulation of microplastic partilces may be at least 25% greater than previously thought. She has also observed vertical transport of particles down to at least 60 cm in fields with four consectutive years of BDM use. A graduate student (PhD) from Washington State University has published a paper (from a separte project) that shows partilces >10µm tend to not be transported in soil by physical processes. Combined with our data, this suggests that biological mechanisms may be responsible.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2021
Citation:
Wang, Z., M Li, M Flury, SM Schaeffer, Y Chang, Z Tao, Z Jia, S Li, F Ding, and J Wang (2021). Comparison of polyethylene and biodegradable plastic film mulches in terms of soil temperature, nutrients and maize yield and quality in a humid continental climate. Science of the Total Environment 786:147460, doi:10.1016/j.scitotenv.2021.147460
- Type:
Journal Articles
Status:
Published
Year Published:
2021
Citation:
Ding, F, M Flury, SM Schaeffer, Y Xu, J Wang (2021). Does long-term use of biodegradable plastic mulch affect soil carbon stock? Resources, Conservation and Recycling 175:105895, doi:0.1016/j.resconrec.2021.105895
- Type:
Journal Articles
Status:
Published
Year Published:
2021
Citation:
Anunciado, MB, DG Hayes, LC Wadsworth, ME English, SM Schaeffer, HY Sintim, M Flury (2021). Impact of Agricultural Weathering on Physicochemical Properties of Biodegradable Plastic Mulch Films: Comparison of Two Diverse Climates Over Four Successive Years. Journal of Polymers and the Environment 29(1):1-16
- Type:
Journal Articles
Status:
Published
Year Published:
2021
Citation:
Sintim, HY, MB Anunciado, S Bandopadhyay, ME English, AI Bary, DG Hayes, LC Wadsworth, SM Schaeffer, JM DeBruyn, CA Miles, JP Reganold, and M Flury (2020). In situ degradation of biodegradable plastic mulch films in compost and agricultural soils. Science of the Total Environment, 727: 138668
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2021
Citation:
Alexis B Gillmore, AF Astner, DG Hayes, SM Schaeffer. Biodegradable Plastic Detected in Soil Two Years after Incorporation of Agricultural Plastic Mulch. Presented at the Bio-Environmental Polymer Society Meeting
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2021
Citation:
Alexis B Gillmore, AF Astner, DG Hayes, SM Schaeffer. Finding biodegradable plastic in a soil profile toward a plastic cycle. Southeastern Biogeochemistry Seminar
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2020
Citation:
Alexis B Gillmore, AF Astner, DG Hayes, SM Schaeffer. Characterizing Biodegradable Plastic Mulch Fragment Distribution through the SoilProfile in an East Tennessee Agroecosystem. Soil Science Society of America Meeting
- Type:
Journal Articles
Status:
Published
Year Published:
2021
Citation:
Flury, M., and R. Narayan, Biodegradable plastic as integral part of the solution to plastic waste pollution of the environment, Current Opinion Green Sustainable Chem., 30, 100490, doi.org/10.1016/j.cogsc.2021.100490, 2021.
- Type:
Journal Articles
Status:
Published
Year Published:
2021
Citation:
Filipovic, V., K. L. Bristow, L. Filipovic, Y. Wang, H. Y. Sintim, M. Flury, and J. Simunek, Sprayable biodegradable polymer membrane technology for cropping systems: Challenges and opportunities, Environ. Sci. Technol., 54, 47094711, 2020.
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