Progress 02/24/15 to 12/31/19
Outputs
Target Audience:This research is intended for use by researchers and practitioners involved in predicting the fate and behavior of agricultural antibiotics in the environment. The findings will also be used by practitioners involved in predicting how the application of soil management practices influence the mobilization of antibiotics from soil to affect sensitive aquatic environments. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Two graduate students performed the salient research under the guidance of a mentor. An undergraduate student was also involved in aspects of the research, completing an undergraduate special problems activity and reporting the findings at two University of Tennessee sponsored undergraduate research symposia. The graduate and undergraduate students and mentor attended and presented findings at the Science Society of America International Meetings. How have the results been disseminated to communities of interest?The findings were presented at the Soil Science Society of America International Meetings, and in published abstracts. The results were presented in peer-reviewed scientific publications. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
(N/A)
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Call, J.J., M.E. Essington, and S. Rakshit. 2019. The cation exchange behavior of tylosin in loess-derived soil. Chemosphere 233:615-624.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Call, J.J., S. Rakshit, and M.E. Essington. 2019. The adsorption of tylosin by montmorillonite and vermiculite: exchange selectivity and intercalation. Soil Sci. Soc. Am. J. 83:584-596.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Anuo, C., S. Rakshit, and M. Essington. 2019. Competitive sorption mechanism of boron (B) and selected veterinary antibiotics on iron oxide minerals In International Soils Meetings Abstracts. SSSA, Madison, WI.
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Progress 10/01/18 to 09/30/19
Outputs
Target Audience:The target audiences of the project are soil and environmental science students and professions. The knowledge was delivered through formal classroom instruction and through a presentation and abstract at a scientific conference. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?A graduate student performed the salient research under the guidance of a mentor. The graduate student and mentor attended and presented findings at the Science Society of America International Meetings. How have the results been disseminated to communities of interest?The findings were presented at the Soil Science Society of America International Meetings, and in a published abstract. The results were presented in peer-reviewed scientific publications. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Veterinary antibiotics and macro- and micronutrients that occur as oxyanions (e.g., phosphate, borate, and molybdate) co-exist in the soil environment when livestock manure is applied to agricultural lands, when fertilizer applications are followed by manure applications, or when agricultural lands are irrigated with surface or groundwater contaminated with antibiotics. In these scenarios, strong retention of the oxyanions by soil minerals can potentially influence the biogeochemical cycling of antibiotics. Conversely, the surface interactions of antibiotics may impact the environmental behavior of micronutrients. It was shown in previous research that the coadsorption of phosphate and the veterinary antibiotic oxytetracycline (OTC) by kaolinite proceeded by different pathways. Thus, competitive adsorption was absent. It was also shown that the retention of the antibiotic tylosin in soil predominately occurred via strong interactions with iron oxyhydroxides, in addition to weak interactions with the soil exchange complex. Studies were initiated to examine the influence of antibiotics on the coadsorption of boron (B) by hematite, a common soil iron oxyhydroxide. The competitive adsorption B and OTC was evaluated as a function of various soil solution chemical properties using macroscopic techniques. The microscopic surface interaction mechanisms were investigated using in-situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. Macroscopic sorption experiments show that B was desorbed from the hematite surface in the presence of OTC in the pH range of 4.5-10. The highest B release was noticed at ~ pH 8. Thus, the experimental data supporting the fact that the presence of strongly adsorbing antibiotics, such as OTC, can release B from the mineral surface. The microscopic ATR-FTIR spectroscopic data supported the macroscopic observation. The characteristic IR bands that illustrate B interactions with the hematite surface were diminished in the presence of OTC, while the IR bands of adsorbed OTC were prominence. Thus, the increased mobility of B in soil environments may be induced by strongly adsorbed antibiotics. This research provided new fundamental knowledge that established the competitive interactions of OTC and B at the surface of hematite, a common soil mineral. This information may be used to predict the mobility and availability of agrochemicals in soils where livestock manure is used as a major source of nutrients, or as a complementary source to chemical fertilizers.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Call, J.J., M.E. Essington, and S. Rakshit. 2019. The cation exchange behavior of tylosin in loess-derived soil. Chemosphere 233:615-624.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Call, J.J., S. Rakshit, and M.E. Essington. 2019. The adsorption of tylosin by montmorillonite and vermiculite: exchange selectivity and intercalation. Soil Sci. Soc. Am. J. 83:584-596.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Anuo, C., S. Rakshit, and M. Essington. 2019. Competitive sorption mechanism of boron (B) and selected veterinary antibiotics on iron oxide minerals In International Soils Meetings Abstracts. SSSA, Madison, WI.
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Progress 10/01/17 to 09/30/18
Outputs
Target Audience:Soil and environmental science professionals. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?A graduate student performed the salient research under the guidance of a mentor. How have the results been disseminated to communities of interest?The results were presented in a peer-reviewed scientific publication. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Tylosin (Tyl) is a broad-spectrum veterinary antibiotic that may enter the environment through animal manure applications. The compound bears a methylamine functional group that is protonated in acidic to circumneutral pH, and cation exchange of Tyl through this functional group has been identified as an important soil retention mechanism. A study was conducted to investigate the exchange interactions of Tyl with the expansive phyllosilicates, montmorillonite and vermiculite. Tylosin is retained on the phyllosilicates by exchange and nonexchange mechanisms. Exchange isotherms show that Tyl is preferred relative to Na throughout a broad range of exchanger composition on STx-1 smectite. Tylosin is also preferred relative to Ca on STx-1, but only when Ca is the dominant exchangeable cation. Tylosin does not intercalate Libby vermiculite, total adsorption is minor, and exchangeable Tyl is at or below detectable levels. X-ray diffraction indicates that Tyl is intercalated into STx-1, but not into vermiculite. A comparison of experimental to simulated x-ray diffraction profiles of Tyl intercalated smectite suggests that demixing of exchangeable cations occurs with the random interstratification of Tyl layers. In situ FTIR spectroscopic analysis confirmed the importance of the exchange mechanism for Tyl retention. In addition, other polar and covalent bonding surface interactions were also inferred, particularly in the Ca-smectite, where the nonexchangeable forms of adsorbed Tyl predominate. The findings directly establish the intercalation of Tyl into smectite, the distribution of Tyl between exchangeable and nonexchangeable forms, and the selectivity of Tyl relative to common soil cations for the smectite surface. The presence of co-adsorbing ions can influence antibiotic retention behavior on mineral surfaces. Thus, an evaluation of antibiotic adsorption in single ion and in competitive systems is necessary to predict antibiotic fate and behavior in the environment. A study was performed to investigate the adsorption mechanisms of oxytetracycline (OTC) on kaolinite in a single ion and in binary mixtures with phosphate (P) as a function of solution properties using in situ FTIR spectroscopy. Three different systems were investigated: P adsorption, OTC adsorption, and competitive adsorption of OTC and P. The results of P alone and OTC alone systems indicated that adsorption increased with decreasing pH and with increasing initial adsorbate concentration. The major IR bands for P indicated that the retention occurred via an inner-sphere mechanism. For OTC, involvement of amide, carbonyl, and dimethyl amine groups in retention were noted by the IR bands. For sorption of OTC and P in binary mixtures, the IR bands of OTC and P adsorption on kaolinite did not change relative to the single adsorbate systems, indicating a lack of competitive effects. These findings are important for assessing the potential mobilization of OTC in chemically-complex soil and sediment environments where P can co-occur.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Dolui, M., S. Rakshit, M.E. Essington, and G. Lefevre. 2018. Probing oxytetracycline sorption mechanism on kaolinite in a single ion and binary mixtures with phosphate using in situ ATR-FTIR spectroscopy. Soil Sci. Sci. Am. J. 82:826-838.
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Progress 10/01/16 to 09/30/17
Outputs
Target Audience:Soil and environmental science professionals. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?A graduate student performed the salient research under the guidance of a mentor. An undergraduate student was also involved in aspects of the research, completing an undergraduate special problems activity and reporting the findings at two University of Tennessee sponsored undergraduate research symposia. The mentor attended and presented findings at the Soil Science Society of America International Meetings. How have the results been disseminated to communities of interest?The findings were presented at the Soil Science Society of America International Meetings, and in a published abstract. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Agricultural antibiotics are used extensively in livestock production. Because antibiotics are slowly absorbed by animals, a large amount (> 80%) is excreted in urine and feces, potentially impacting soil and other aquatic systems. One such antibiotic is tylosin (Tyl). Tylosin is used as a feed additive in swine and poultry production and can be found in manure and litter leachates, with concentrations as high as 4.0 mg L−1. Tylosin is a large molecule (~1,000 g mol−1) that bears a protonated methylamine group when solution pH < 7.5. Adsorption studies indicate that an important soil retention mechanism for Tyl is cation exchange, as retention is influenced by background electrolyte and ionic strength. Research continued to probe the exchange selectivity of Tyl in competition with Na+ and Ca2+ in Libby vermiculite and STx smectite (montmorillonite), to determine the location of the adsorbed Tyl in the mineral structures, and to use ATR-FTIR to examine the surface bonding mechanism. Homoionic (NaX−TylX) and heteroionic (CaX2−TylX) binary exchange studies were performed and exchange isotherms were developed to establish cation preference and to determine the Vanselow selectivity coefficient (KV) as a function of exchange phase composition. X-ray diffraction was used to determine the d-values of the 00l spacing of the reference clays saturated with varied ratios of NaX−TylX and CaX2−TylX. Both freeze-dried and aqueous presentations of TylX samples were examined using ATR-FTIR. In addition, in situ ATR-FTIR experiments were carried out to understand the bonding mechanisms. Tylosin adsorption by hematite (Fe2O3), alone and in competition with phosphate was also examined using in situ ATR-FTIR to provide additional information on Tyl binding by mineral surfaces. In both the NaX−TylX and CaX2−TylX systems, Tyl+ is preferred by the STx exchange phase. The KV values are positive and vary with exchange phase composition in the CaX2−TylX system, but are relatively invariant and positive in the NaX−TylX system. Tylosin adsorption is greater in the Na systems relative to the Ca systems. The bulk of the adsorbed Tyl in the Na system is exchangeable, while only a small portion of the adsorbed Tyl in the Ca system is exchangeable. Total Tyl adsorption by the vermiculite was very minor, approximately 10% of that observed for smectite adsorption. Nearly none of the adsorbed Tyl on vermiculite was exchangeable; exchange sites were not accessible to Tyl due to the limited expandability of the 2:1 structure. The d-value of STx increased from 1.26 nm for Na+-saturated to 3.13 nm when Tyl+ was 100% of the exchange complex. The d-value of STx increased from 1.53 nm for Ca2+-saturated to 2.85 nm when Tyl+ was >90% of the exchange complex. In both cation systems, random and segregated interstratification occurs in STx. FTIR analysis corroborates the exchangeable nature of the adsorbed tylosin. For the in situ ATR-FTIR experiments with 10 and 100 μM Tyl and Na-saturated STx, the IR bands corresponding to ν(Si-O) vibrations (~1075, 1049, 1026, and 996 cm-1) increased with time until equilibrium. The N-H bending band at 1590 cm-1 was minor, indicating that cation exchange was a predominate retention mechanism. The spectral region (1075-996 cm-1) reflected a broad band, which most likely is suggesting weak electrostatic interactions of Tyl in the smectite interlayer. The IR bands for Tyl adsorbed by hematite differed from the smectite systems, and showed strong surface bonding through the dimethyl amine group. Further, phosphate did not affect the surface binding of Tyl by either STx or hematite. The findings indicate that Tyl is intercalated into smectite interlayers, but not into vermiculite, potentially affecting the environmental fate, bioaccessibility, and protection of the antibiotic in smectite-containing soils.
Publications
- Type:
Theses/Dissertations
Status:
Accepted
Year Published:
2017
Citation:
Jaime J. Call: Cation exchange processes involving the agricultural antibiotic tylosin in soil and soil minerals. MS Thesis, 2017.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Essington, M.E., S. Rakshit, and J. Call. 2017. Interactions of tylosin with smectite clay. In Annual International Meetings Abstracts. ASA, CSSA, and SSSA, Madison, WI.
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Progress 10/01/15 to 09/30/16
Outputs
Target Audience:Soil and environmental science professionals. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?A graduate student is performing the salient research under the guidance of a mentor. An undergraduate student was also involved in aspects of the research, completing an undergraduate special problems activity. The students and mentor attended and presented findings at the Soil Science Society of America International Meetings. How have the results been disseminated to communities of interest?The findings were presented at the Soil Science Society of America International Meetings, and in a published abstract. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Tylosin (Tyl) is a broad-spectrum antibiotic used to treat livestock. Only a small amount of Tyl is actually absorbed by animals, while the remainder is excreted in urine and feces. Tylosin is a large molecule (~1,000 g mol−1) that bears a protonated methylamine group when solution pH < 7.5. Adsorption studies indicate that an important soil retention mechanism for Tyl is cation exchange. Further, exchange isotherms show the Tyl+ is preferred by soil and smectite clays, relative to Na+ and Ca2+. These studies also show that adsorbed Tyl is distributed between non-exchangeable and exchangeable forms, and that adsorbed Tyl reduces the CEC of clay minerals. To determine the location of adsorbed Tyl in Na- and Ca-saturated source clays (STx and SWy) and soil smectite, solutions having differing Tyl-Na or Tyl-Ca ratios (with a total normality of 4 mM) were equilibrated with Na- or Ca-saturated solids. X-ray diffraction was then preformed to determine d-values of the 00l spacing. The d-value of STx increased from 1.26 nm for Na+-saturated to 3.13 nm when Tyl+ was 75% of the exchange complex. Similarly, the d-value of SWy increased from 1.24 nm to 2.69 nm. The impact of Tyl+ on the d-value of Ca2+-saturated clays was minor due to the competitive nature of Ca2+ for exchange sites. The d-value of STx increased from 1.54 nm for Ca2+-saturated to 1.72 nm when Tyl+ was approximately 10% of the exchange complex. Similarly, the d-value of SWy increased from 1.51 nm to 1.69 nm. In the Na-saturated soil clays, the d-value shifted from 1.30 nm to approximately 2.7 nm when Tyl+ occupied 40% of the exchange complex. The d-value shifted from 1.45 nm to 1.6 nm when Tyl+ occupied 10% of the exchange complex in Ca-saturated soil clays. Random and segregated interstratification occurs in both the NaX-TylX and CaX2-TylX exchange systems for STx. Segregation occurs when adjacent interlayers have similar compositions, such as [Tyl][Tyl][Tyl][Na] or [Tyl][Tyl][Tyl][Ca] with d = 2.7 to 2.8 nm, and [Tyl][Na][Na][Na] or [Tyl][Ca][Ca][Ca] with d = 1.58 to 1.68 nm.The findings indicate that Tyl is intercalated into smectite interlayers, affecting the environmental fate and bioavailability of the antibiotic.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Koziol, H.A., M.E. Essington, and J. Call. 2016. Intercalation of phyllosilicate minerals by tylosin: influence of solution and exchange phase composition. In Annual International Meetings Abstracts [CD-ROM]. ASA, CSSA, and SSSA, Madison, WI.
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Progress 02/24/15 to 09/30/15
Outputs
Target Audience:Soil and environmental science professionals. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?A graduate student is performing the salient research under the guidance of a mentor. The student and mentor attended and presented findings at the Soil Science Society of America International Meetings. How have the results been disseminated to communities of interest?The findings were presented at the Soil Science Society of America International Meetings, and in a published abstract. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Binary exchange studies were initiated and exchange isotherms were developed to establish preference and to determine the Vanselow selectivity coefficient (KV) as a function of exchange phase composition for Na+-Tylosin+ (Tyl+) exchange on a vermiculitic soil. The cation exchange capacity (CEC) of the soil (the innate reactivity of the soil) was approximately 45 cmolc kg−1; however, in the exchange studies the CEC was reduced and a function of the initial cation saturation; 15.6 cmolc kg−1 for Na+-saturated soils, and 4.2 cmolc kg−1 for Tyl+-saturated. This finding indicates that a portion of the adsorbed tylosin occupies exchange locations, but is non-exchangeable. Mass balance computations indicate that approximately 50% of the adsorbed tylosin is nonexchangeable in the Na+-saturated, NaX-TylX systems, but approximately 90% is nonexchangeable in the Tyl+-saturated systems. For NaX-TylX exchange, the exchange isotherms indicate that Tyl+ is preferred by the soil exchange phase when the soil is initially Na+-saturated. The KV values are generally invariant with exchange phase composition, with an average KV = 1.32 for the Tyl+ + NaX = TylX + Na+ exchange reaction. However, when soil is initially Tyl+-saturated, KV values and preference vary with exchange phase composition (increasing Na+ preference with increasing TylX). Although preliminary, the findings are significant and unconventional. The antibiotic tylosin effectively competes with Na+ for cation exchange sites; tylosin collapses layer silicate structures, blocks exchange sites and becomes nonexchangeable; and the Vanselow selectivity coefficent (KV) is invariant with exchange phase composition, offering a mechanism to predict tylosin adsorption behavior.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2015
Citation:
Call, J., and M.E. Essington. 2015. Retention of tylosin and chlortetracycline by soil colloids. In Annual International Meetings Abstracts [CD-ROM]. ASA, CSSA, and SSSA, Madison, WI.
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