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Hays SM, Kirman CR, Flippin J, Lopez T. Biomonitoring Equivalents for glyphosate. Regul Toxicol Pharmacol 2023; 144:105481. [PMID: 37633328 DOI: 10.1016/j.yrtph.2023.105481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 08/09/2023] [Accepted: 08/22/2023] [Indexed: 08/28/2023]
Abstract
One of the most widely used herbicides worldwide, glyphosate is registered for use in many agricultural and non-agricultural settings. Accordingly, regulatory authorities develop toxicology reference values (TRVs) to conduct risk assessments for potential exposures. Exposures to glyphosate are typically biomonitored via measures of glyphosate in urine. However, measured concentrations of glyphosate in urine, with units mg/L urine, cannot be directly interpreted using the available TRVs as they are presented in terms of daily intake levels (e.g. mg/kg-bw per day). In this evaluation, we review available health-based risk assessments and TRVs for glyphosate and derive Biomonitoring Equivalent (BE) values for interpretation of population biomonitoring data. Biomonitoring Equivalents (BEs) are defined as the concentration or range of concentrations of a chemical or its metabolite in a biological medium (blood, urine, human milk, etc.) that is consistent with an existing health-based TRVs such as a reference dose (RfD) or tolerable daily intake (TDI). The BE values derived in this manuscript are screening values that can help public health officials and regulators interpret glyphosate biomonitoring data.
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2
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The role of surface activity on the amyloid fibrillation pathway of bovine serum albumin upon interaction with glyphosate. Int J Biol Macromol 2023; 226:1166-1177. [PMID: 36427623 DOI: 10.1016/j.ijbiomac.2022.11.230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 11/20/2022] [Accepted: 11/21/2022] [Indexed: 11/25/2022]
Abstract
As an active ingredient in its derivative products, glyphosate has emerged as the most widespread herbicide in recent decades. Bovine serum albumin (BSA) as a carrier protein may be adversely affected by structural changes due to binding affinity with glyphosate, which may lead to dysfunctionality or metabolic disorders. This study aimed to investigate the interaction of glyphosate with BSA and its thermal fibrillation pathway employing techniques such as dynamic surface tension, fluorescence quenching, ThT binding, circular dichroism spectroscopy, and reactive oxygen species (ROS) measurement, as well as molecular dynamics (MD) studies. The adsorption dynamic analysis suggested hydrophobic moiety at higher concentrations of glyphosate upon interaction with BSA. MD results suggested a slight fluctuation due to glyphosate interaction with protein molecules. The carboxy group presented in glyphosate made a hydrogen bond with the hydroxyl group of TYR147. The fluorescence quenching and diffusion studies approved BSA's increased unfolding and hydrophobicity resulting from glyphosate interaction, which would induce fibrillation/aggregation, according to our fibrillation kinetics data. The surface activity of glyphosate at higher concentrations and its approved involvement in structural changes of BSA through hydrogen bonding may raise concerns about its potential side effect on farm animals and the food cycle.
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Grau D, Grau N, Gascuel Q, Paroissin C, Stratonovitch C, Lairon D, Devault DA, Di Cristofaro J. Answer to "Comments on 'Quantifiable urine glyphosate levels detected in 99% of the French population, with higher values in men, in younger people, and in farmers'". ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:46377-46379. [PMID: 35596860 DOI: 10.1007/s11356-022-20862-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 05/12/2022] [Indexed: 06/15/2023]
Affiliation(s)
- Daniel Grau
- Association Campagne Glyphosate, Foix, France
| | - Nicole Grau
- Association Campagne Glyphosate, Foix, France
| | | | | | - Cécile Stratonovitch
- ARSEAA, Pôle Guidance Infantile, Psychiatrie infanto-juvénile secteur III, Labège, France
| | - Denis Lairon
- Faculté de Médecine de La Timone, Aix Marseille Université, INSERM, INRA, C2VN, Marseille, France
| | - Damien A Devault
- Centre Universitaire de Formation Et de Recherche de Mayotte, Dembeni, France
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Reeves W, Vicini JL, Swarthout JT, Young BM, Jensen PK. Comments on "Quantifiable urine glyphosate levels detected in 99% of the French population, with higher values in men, in younger people, and in farmers". ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:46375-46376. [PMID: 35595902 PMCID: PMC9209360 DOI: 10.1007/s11356-022-20860-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 05/12/2022] [Indexed: 06/15/2023]
Affiliation(s)
- William Reeves
- Bayer Crop Science, 700 Chesterfield Parkway West, Chesterfield, MO, 63017, USA.
| | - John L Vicini
- Bayer Crop Science, 700 Chesterfield Parkway West, Chesterfield, MO, 63017, USA
| | - John T Swarthout
- Bayer Crop Science, 700 Chesterfield Parkway West, Chesterfield, MO, 63017, USA
| | - Bruce M Young
- Bayer Crop Science, 700 Chesterfield Parkway West, Chesterfield, MO, 63017, USA
| | - Pamela K Jensen
- Bayer Crop Science, 700 Chesterfield Parkway West, Chesterfield, MO, 63017, USA
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Oláh M, Farkas E, Székács I, Horvath R, Székács A. Cytotoxic effects of Roundup Classic and its components on NE-4C and MC3T3-E1 cell lines determined by biochemical and flow cytometric assays. Toxicol Rep 2022; 9:914-926. [PMID: 35875257 PMCID: PMC9301602 DOI: 10.1016/j.toxrep.2022.04.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 04/06/2022] [Accepted: 04/15/2022] [Indexed: 11/26/2022] Open
Abstract
Cytotoxic effects of the market leading broad-spectrum, synthetic herbicide product Roundup Classic, its active ingredient glyphosate (in a form of its isopropylamine (IPA) salt) and its formulating surfactant polyethoxylated tallowamine (POE-15) were determined on two murine cell lines, a neuroectodermal stem cell-like (NE-4C) and a high alkaline phosphatase activity osteoblastic cell line (MC3T3-E1). Cytotoxicity, genotoxicity, effects on cell viability and cell cycles were examined in five flow cytometry tests, the two former of which were compared by the enzymatic-assay and the alkaline single cell gel electrophoresis (Comet) assay. All of the tests indicated the NE-4C cells being more sensitive, than the MC3T3-E1 cell line to the treatments with the target compounds. Higher sensitivity differences were detected in the viability test by flow cytometry (7-9-fold), than by the MTT assay (1.5-3-fold); in the genotoxicity test by the Comet assay (3.5-403-fold), than by the DNA-damage test (9.3-158-fold); and in the apoptosis test by the Annexin V dead cell kit (1.1-12.7-fold), than by the Caspase 3/7 kit (1-6.5-fold). Cell cycle assays indicated high count of cells (~70%) in the G0/G1 phase for MC3T3-E1 cells, than in NE-4C cell (~40%) after 24 h. The order of the inhibitory potency of the target substances has unequivocally been POE-15 > Roundup Classic > > glyphosate IPA salt.
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Affiliation(s)
- Marianna Oláh
- Agro-Environmental Research Centre, Institute of Environmental Sciences, Hungarian University of Agriculture and Life Sciences, Herman Ottó u. 15, H-1022 Budapest, Hungary
| | - Enikő Farkas
- Nanobiosensorics Laboratory, Institute of Technical Physics and Materials Science, Centre for Energy Research, Konkoly-Thege M. u. 29-33, H-1121 Budapest, Hungary
| | - Inna Székács
- Nanobiosensorics Laboratory, Institute of Technical Physics and Materials Science, Centre for Energy Research, Konkoly-Thege M. u. 29-33, H-1121 Budapest, Hungary
| | - Robert Horvath
- Nanobiosensorics Laboratory, Institute of Technical Physics and Materials Science, Centre for Energy Research, Konkoly-Thege M. u. 29-33, H-1121 Budapest, Hungary
| | - András Székács
- Agro-Environmental Research Centre, Institute of Environmental Sciences, Hungarian University of Agriculture and Life Sciences, Herman Ottó u. 15, H-1022 Budapest, Hungary
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Alcántara-de la Cruz R, Cruz-Hipolito HE, Domínguez-Valenzuela JA, De Prado R. Glyphosate ban in Mexico: potential impacts on agriculture and weed management. PEST MANAGEMENT SCIENCE 2021; 77:3820-3831. [PMID: 33723895 DOI: 10.1002/ps.6362] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/10/2021] [Accepted: 03/15/2021] [Indexed: 06/12/2023]
Abstract
Since glyphosate was classified as potentially carcinogenic by the International Agency for Research on Cancer, public debate regarding the environmental impact and health risks from its use has intensified. Almost all regulatory agencies throughout the world have concluded that the judicious use of glyphosate does not pose risks to the environment and human health. However, on the last day of 2020 the Mexican government decreed a ban of this herbicide beginning January, 2024. In current Mexican agriculture there are no safer chemical and/or other weed management technologies that allow for the economical substitution of glyphosate for weed control. Many Mexican weed scientists agree that glyphosate use should be reduced, but not banned outright. This decree could have more negative economic and social consequences as well as environmental and human health risks than benefits, which could compromise the country's food and public security. Crop yields are projected by some to decline by up to 40% with this ban, increasing food prices, making food less accessible to low-income consumers. In addition, a black market for the smuggling and illegal sale of glyphosate is possible. The possible environmental, economic and social impacts caused by the glyphosate ban in Mexico are discussed, emphasizing the impact on weed management. © 2021 Society of Chemical Industry.
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Affiliation(s)
- Ricardo Alcántara-de la Cruz
- Departamento de Química, Universidade Federal de São Carlos, São Carlos, Brazil
- Departamento de Parasitología Agrícola, Universidad Autónoma Chapingo, Texcoco, Mexico
| | | | | | - Rafael De Prado
- Department of Agricultural Chemistry, Edaphology and Microbiology, University of Cordoba, Cordoba, Spain
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7
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Pu Y, Ma L, Shan J, Wan X, Hammock BD, Hashimoto K. Autism-like Behaviors in Male Juvenile Offspring after Maternal Glyphosate Exposure. CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE 2021; 19:554-558. [PMID: 34294625 PMCID: PMC8316667 DOI: 10.9758/cpn.2021.19.3.554] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 09/25/2020] [Indexed: 12/27/2022]
Abstract
Objective Exposure to the herbicide glyphosate during pregnancy and lactation may increase the risk for autism spectrum disorder (ASD) in offspring. Recently, we reported that maternal exposure of formulated glyphosate caused ASD-like behaviors in juvenile offspring. Here, we investigated whether maternal exposure of pure glyphosate could cause ASD-like behaviors in juvenile offspring. Methods Water or 0.098% glyphosate was administered as drinking water from E5 to P21 (weaning). Behavioral tests such as grooming test and three-chamber social interaction test in male offspring were performed from P28 to P35. Results Male offspring showed ASD-like behavioral abnormalities (i.e., increasing grooming behavior and social interaction deficit) after maternal exposure of glyphosate. Conclusion The findings suggest that the exposure of glyphosate during pregnancy and lactation may cause ASD-like behavioral abnormalities in male juvenile offspring. It is likely that glyphosate itself, but not the other ingredients, may contribute to ASD-like behavioral abnormalities in juvenile offspring.
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Affiliation(s)
- Yaoyu Pu
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, Chiba, Japan
| | - Li Ma
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, Chiba, Japan
| | - Jiajing Shan
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, Chiba, Japan
| | - Xiayun Wan
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, Chiba, Japan
| | - Bruce D Hammock
- Department of Entomology and Nematology and UC Davis Comprehensive Cancer Center, University of California, Davis, CA, USA
| | - Kenji Hashimoto
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, Chiba, Japan
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Vera-Herrera L, Sadutto D, Picó Y. Non-Occupational Exposure to Pesticides: Experimental Approaches and Analytical Techniques (from 2019). Molecules 2021; 26:3688. [PMID: 34208757 PMCID: PMC8235395 DOI: 10.3390/molecules26123688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 06/04/2021] [Accepted: 06/07/2021] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Pesticide residues are a threat to the health of the global population, not only to farmers, applicators, and other pesticide professionals. Humans are exposed through various routes such as food, skin, and inhalation. This study summarizes the different methods to assess and/or estimate human exposure to pesticide residues of the global population. METHODS A systematic search was carried out on Scopus and web of science databases of studies on human exposure to pesticide residues since 2019. RESULTS The methods to estimate human health risk can be categorized as direct (determining the exposure through specific biomarkers in human matrices) or indirect (determining the levels in the environment and food and estimating the occurrence). The role that analytical techniques play was analyzed. In both cases, the application of generic solvent extraction and solid-phase extraction (SPE) clean-up, followed by liquid or gas chromatography coupled to mass spectrometry, is decisive. Advances within the analytical techniques have played an unquestionable role. CONCLUSIONS All these studies have contributed to an important advance in the knowledge of analytical techniques for the detection of pesticide levels and the subsequent assessment of nonoccupational human exposure.
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Affiliation(s)
| | | | - Yolanda Picó
- Food and Environmental Safety Research Group of the University of Valencia (SAMA-UV), Desertification Research Centre (CIDE), CSIC-GV-UV, Moncada-Naquera Road km 4.5, Moncada, 46113 Valencia, Spain; (L.V.-H.); (D.S.)
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9
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Abdul K, De Silva PMC, Ekanayake E, Thakshila W, Gunarathna S, Gunasekara T, Jayasinghe S, Asanthi H, Chandana E, Chaminda G, Siribaddana S, Jayasundara N. Occupational Paraquat and Glyphosate Exposure May Decline Renal Functions among Rural Farming Communities in Sri Lanka. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:3278. [PMID: 33810013 PMCID: PMC8005187 DOI: 10.3390/ijerph18063278] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/12/2021] [Accepted: 03/18/2021] [Indexed: 01/21/2023]
Abstract
Extensive use of herbicides is common among rural agricultural workers in Sri Lanka. Recent studies have postulated their role in the development of chronic kidney disease of unknown etiology (CKDu). Paraquat and glyphosate are leading herbicides used by sugarcane farmers (SF), hence occupational exposure is inevitable. This study examined the expression of urinary paraquat, glyphosate and biomarkers among residential SF in CKDu emerging regions, Warunagama (WA) and Rahathangama (RH), in the Uva Province with non-endemic Matara (MA) in the Southern Province of Sri Lanka. Urinary glyphosate, Paraquat, kidney injury molecule -1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL) and β2-microglobulin (B2M) were determined using enzyme-linked immunosorbent assays (ELISA). Urinary creatinine, microalbumin, serum creatinine (SCr), serum cystatin C, estimated glomerular filtration rate (eGFR), and albumin creatinine ratio (ACR) were also assessed. Generally, herbicide residues and kidney injury biomarkers were higher in SF compared to the non-endemic MA. Creatinine-adjusted urinary glyphosate and paraquat levels were significantly higher in WA compared to MA. ACR in RH (median 14.9; IQR 5.4-393.1 mg/g) and WA (23.7; 11.5-64.6) was significantly higher than MA (4.3; 2.2-6.7). This study reports 39 individuals with impaired kidney function among SF in Sri Lanka for the first time. Urinary NGAL levels were significantly higher in both WA (median 2.14; IQR 1.28-6.15 ng/mg Cr) and RH (3.09; 1.15-9.09) compared to MA (1.28; 0.56-2.81). However, urinary KIM-1 levels in RH (3.2; 1.29-106.1 ng/g Cr) and WA (3.6; 1.94-115.1) were not significantly higher in MA (1.74; 0.76-116.9). Urinary NGAL (r = 0.493), eGFR (r = -0.147) and ACR (r = 0.171) significantly correlated with urinary glyphosate, but not with urinary paraquat levels. Urinary KIM-1 levels did not correlate with either urinary glyphosate or paraquat, while urinary B2M and serum cystatin C levels showed significant correlation with urinary glyphosate levels. The current study reports higher urinary herbicide levels among sugarcane farmers in WA and RH, and that is potentially linked to the subsequent decline in kidney function, as indicated by ACR, eGFR, and NGAL. We posit that these indicators may serve as markers to detect renal injury among herbicide-exposed SF in Rural Sri Lanka.
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Affiliation(s)
- K.S.M. Abdul
- Institute of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou 510006, China;
- Department of Zoology, Faculty of Science, University of Ruhuna, Matara 81000, Sri Lanka; (E.M.D.V.E.); (W.A.K.G.T.); (S.D.G.); (T.D.K.S.C.G.)
| | - P. Mangala C.S. De Silva
- Department of Zoology, Faculty of Science, University of Ruhuna, Matara 81000, Sri Lanka; (E.M.D.V.E.); (W.A.K.G.T.); (S.D.G.); (T.D.K.S.C.G.)
| | - E.M.D.V. Ekanayake
- Department of Zoology, Faculty of Science, University of Ruhuna, Matara 81000, Sri Lanka; (E.M.D.V.E.); (W.A.K.G.T.); (S.D.G.); (T.D.K.S.C.G.)
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA
| | - W.A.K.G. Thakshila
- Department of Zoology, Faculty of Science, University of Ruhuna, Matara 81000, Sri Lanka; (E.M.D.V.E.); (W.A.K.G.T.); (S.D.G.); (T.D.K.S.C.G.)
| | - S.D. Gunarathna
- Department of Zoology, Faculty of Science, University of Ruhuna, Matara 81000, Sri Lanka; (E.M.D.V.E.); (W.A.K.G.T.); (S.D.G.); (T.D.K.S.C.G.)
| | - T.D.K.S.C. Gunasekara
- Department of Zoology, Faculty of Science, University of Ruhuna, Matara 81000, Sri Lanka; (E.M.D.V.E.); (W.A.K.G.T.); (S.D.G.); (T.D.K.S.C.G.)
| | - S.S. Jayasinghe
- Department of Pharmacology, Faculty of Medicine, University of Ruhuna, Galle 80000, Sri Lanka;
| | - H.B. Asanthi
- Department of Limnology, Faculty of Fisheries and Marine Sciences and Technology, University of Ruhuna, Matara 81000, Sri Lanka;
| | - E.P.S. Chandana
- Department of Biosystems Technology, Faculty of Technology, University of Ruhuna, Matara 81000, Sri Lanka;
| | - G.G.T. Chaminda
- Department of Civil Engineering, Faculty of Engineering, University of Ruhuna, Hapugala 80000, Sri Lanka;
| | - S.H. Siribaddana
- Department of Medicine, Faculty of Medical & Allied Sciences, Rajarata University, Saliyapura 50008, Sri Lanka;
| | - Nishad Jayasundara
- The Nicholas School of the Environment, Duke University, Durham, NC 27708, USA;
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Sang Y, Mejuto JC, Xiao J, Simal-Gandara J. Assessment of Glyphosate Impact on the Agrofood Ecosystem. PLANTS (BASEL, SWITZERLAND) 2021; 10:405. [PMID: 33672572 PMCID: PMC7924050 DOI: 10.3390/plants10020405] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 02/16/2021] [Accepted: 02/17/2021] [Indexed: 02/07/2023]
Abstract
Agro-industries should adopt effective strategies to use agrochemicals such as glyphosate herbicides cautiously in order to protect public health. This entails careful testing and risk assessment of available choices, and also educating farmers and users with mitigation strategies in ecosystem protection and sustainable development. The key to success in this endeavour is using scientific research on biological pest control, organic farming and regulatory control, etc., for new developments in food production and safety, and for environmental protection. Education and research is of paramount importance for food and nutrition security in the shadow of climate change, and their consequences in food production and consumption safety and sustainability. This review, therefore, diagnoses on the use of glyphosate and the associated development of glyphosate-resistant weeds. It also deals with the risk assessment on human health of glyphosate formulations through environment and dietary exposures based on the impact of glyphosate and its metabolite AMPA-(aminomethyl)phosphonic acid-on water and food. All this to setup further conclusions and recommendations on the regulated use of glyphosate and how to mitigate the adverse effects.
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Affiliation(s)
- Yaxin Sang
- College of Food Science and Technology, Hebei Agricultural University, Baoding 071001, China;
| | - Juan-Carlos Mejuto
- Department of Physical Chemistry, Faculty of Science, University of Vigo—Ourense Campus, E32004 Ourense, Spain;
| | - Jianbo Xiao
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Taipa, Macau, China
- Nutrition and Bromatology Group, Department of Analytical and Food Chemistry, Faculty of Food Science and Technology, University of Vigo—Ourense Campus, E32004 Ourense, Spain
| | - Jesus Simal-Gandara
- Nutrition and Bromatology Group, Department of Analytical and Food Chemistry, Faculty of Food Science and Technology, University of Vigo—Ourense Campus, E32004 Ourense, Spain
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Rodríguez-Gil JL, Prosser RS, Duke SO, Solomon KR. Ecotoxicology of Glyphosate, Its Formulants, and Environmental Degradation Products. REVIEWS OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2021; 255:129-205. [PMID: 34104986 DOI: 10.1007/398_2020_56] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The chemical and biological properties of glyphosate are key to understanding its fate in the environment and potential risks to non-target organisms. Glyphosate is polar and water soluble and therefore does not bioaccumulate, biomagnify, or accumulate to high levels in the environment. It sorbs strongly to particles in soil and sediments and this reduces bioavailability so that exposures to non-target organisms in the environment are acute and decrease with half-lives in the order of hours to a few days. The target site for glyphosate is not known to be expressed in animals, which reduces the probability of toxicity and small risks. Technical glyphosate (acid or salts) is of low to moderate toxicity; however, when mixed with some formulants such as polyoxyethylene amines (POEAs), toxicity to aquatic animals increases about 15-fold on average. However, glyphosate and the formulants have different fates in the environment and they do not necessarily co-occur. Therefore, toxicity tests on formulated products in scenarios where they would not be used are unrealistic and of limited use for assessment of risk. Concentrations of glyphosate in surface water are generally low with minimal risk to aquatic organisms, including plants. Toxicity and risks to non-target terrestrial organisms other than plants treated directly are low and risks to terrestrial invertebrates and microbial processes in soil are very small. Formulations containing POEAs are not labeled for use over water but, because POEA rapidly partitions into sediment, risks to aquatic organisms from accidental over-sprays are reduced in shallow water bodies. We conclude that use of formulations of glyphosate under good agricultural practices presents a de minimis risk of direct and indirect adverse effects in non-target organisms.
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Affiliation(s)
- Jose Luis Rodríguez-Gil
- IISD - Experimental Lakes Area, Winnipeg, MB, Canada.
- Department of Environment and Geography, University of Manitoba, Winnipeg, MB, Canada.
| | - Ryan S Prosser
- School of Environmental Sciences, University of Guelph, Guelph, ON, Canada
| | - Stephen O Duke
- National Center for Natural Products Research, School of Pharmacy, University of Mississippi, Oxford, MS, USA
| | - Keith R Solomon
- Centre for Toxicology, School of Environmental Sciences, University of Guelph, Guelph, ON, Canada
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12
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Duke SO. Glyphosate: Uses Other Than in Glyphosate-Resistant Crops, Mode of Action, Degradation in Plants, and Effects on Non-target Plants and Agricultural Microbes. REVIEWS OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2021; 255:1-65. [PMID: 33895876 DOI: 10.1007/398_2020_53] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Glyphosate is the most used herbicide globally. It is a unique non-selective herbicide with a mode of action that is ideal for vegetation management in both agricultural and non-agricultural settings. Its use was more than doubled by the introduction of transgenic, glyphosate-resistant (GR) crops. All of its phytotoxic effects are the result of inhibition of only 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), but inhibition of this single enzyme of the shikimate pathway results in multiple phytotoxicity effects, both upstream and downstream from EPSPS, including loss of plant defenses against pathogens. Degradation of glyphosate in plants and microbes is predominantly by a glyphosate oxidoreductase to produce aminomethylphosphonic acid and glyoxylate and to a lesser extent by a C-P lyase to produce sarcosine and phosphate. Its effects on non-target plant species are generally less than that of many other herbicides, as it is not volatile and is generally sprayed in larger droplet sizes with a relatively low propensity to drift and is inactivated by tight binding to most soils. Some microbes, including fungal plant pathogens, have glyphosate-sensitive EPSPS. Thus, glyphosate can benefit GR crops by its activity on some plant pathogens. On the other hand, glyphosate can adversely affect some microbes that are beneficial to agriculture, such as Bradyrhizobium species, although GR crop yield data indicate that such an effect has been minor. Effects of glyphosate on microbes of agricultural soils are generally minor and transient, with other agricultural practices having much stronger effects.
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Affiliation(s)
- Stephen O Duke
- National Center for Natural Products Research, School of Pharmacy, University of Mississippi, University, MS, USA.
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13
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Duke SO. A Journal of the Plague Year. PEST MANAGEMENT SCIENCE 2021; 77:9-11. [PMID: 33289934 DOI: 10.1002/ps.6175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
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14
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Duke SO. Glyphosate exposure and toxicology. PEST MANAGEMENT SCIENCE 2020; 76:2873. [PMID: 33241655 DOI: 10.1002/ps.5985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Affiliation(s)
- Stephen O Duke
- National Center for Natural Products Research, School of Pharmacy, University of Mississippi, Oxford, Mississippi, USA
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Connolly A, Coggins MA, Koch HM. Human Biomonitoring of Glyphosate Exposures: State-of-the-Art and Future Research Challenges. TOXICS 2020; 8:E60. [PMID: 32824707 PMCID: PMC7560361 DOI: 10.3390/toxics8030060] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 08/11/2020] [Accepted: 08/13/2020] [Indexed: 01/27/2023]
Abstract
Glyphosate continues to attract controversial debate following the International Agency for Research on Cancer carcinogenicity classification in 2015. Despite its ubiquitous presence in our environment, there remains a dearth of data on human exposure to both glyphosate and its main biodegradation product aminomethylphosphonic (AMPA). Herein, we reviewed and compared results from 21 studies that use human biomonitoring (HBM) to measure urinary glyphosate and AMPA. Elucidation of the level and range of exposure was complicated by differences in sampling strategy, analytical methods, and data presentation. Exposure data is required to enable a more robust regulatory risk assessment, and these studies included higher occupational exposures, environmental exposures, and vulnerable groups such as children. There was also considerable uncertainty regarding the absorption and excretion pattern of glyphosate and AMPA in humans. This information is required to back-calculate exposure doses from urinary levels and thus, compared with health-based guidance values. Back-calculations based on animal-derived excretion rates suggested that there were no health concerns in relation to glyphosate exposure (when compared with EFSA acceptable daily intake (ADI)). However, recent human metabolism data has reported as low as a 1% urinary excretion rate of glyphosate. Human exposures extrapolated from urinary glyphosate concentrations found that upper-bound levels may be much closer to the ADI than previously reported.
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Affiliation(s)
- Alison Connolly
- Institute for Prevention and Occupational Medicine of the German Social Accident Insurance—Institute of the Ruhr-University Bochum (IPA), Bürkle-de-la-Camp-Platz 1, 44789 Bochum, Germany
- Centre for Climate and Air Pollution Studies, School of Physics and the Ryan Institute, National University of Ireland, University Road, H91 CF50 Galway, Ireland;
| | - Marie A. Coggins
- Centre for Climate and Air Pollution Studies, School of Physics and the Ryan Institute, National University of Ireland, University Road, H91 CF50 Galway, Ireland;
| | - Holger M. Koch
- Institute for Prevention and Occupational Medicine of the German Social Accident Insurance—Institute of the Ruhr-University Bochum (IPA), Bürkle-de-la-Camp-Platz 1, 44789 Bochum, Germany
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16
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Pu Y, Yang J, Chang L, Qu Y, Wang S, Zhang K, Xiong Z, Zhang J, Tan Y, Wang X, Fujita Y, Ishima T, Wang D, Hwang SH, Hammock BD, Hashimoto K. Maternal glyphosate exposure causes autism-like behaviors in offspring through increased expression of soluble epoxide hydrolase. Proc Natl Acad Sci U S A 2020; 117:11753-11759. [PMID: 32398374 PMCID: PMC7260984 DOI: 10.1073/pnas.1922287117] [Citation(s) in RCA: 83] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Epidemiological studies suggest that exposure to herbicides during pregnancy might increase risk for autism spectrum disorder (ASD) in offspring. However, the precise mechanisms underlying the risk of ASD by herbicides such as glyphosate remain unclear. Soluble epoxide hydrolase (sEH) in the metabolism of polyunsaturated fatty acids is shown to play a key role in the development of ASD in offspring after maternal immune activation. Here, we found ASD-like behavioral abnormalities in juvenile offspring after maternal exposure to high levels of formulated glyphosate. Furthermore, we found higher levels of sEH in the prefrontal cortex (PFC), hippocampus, and striatum of juvenile offspring, and oxylipin analysis showed decreased levels of epoxy-fatty acids such as 8 (9)-EpETrE in the blood, PFC, hippocampus, and striatum of juvenile offspring after maternal glyphosate exposure, supporting increased activity of sEH in the offspring. Moreover, we found abnormal composition of gut microbiota and short-chain fatty acids in fecal samples of juvenile offspring after maternal glyphosate exposure. Interestingly, oral administration of TPPU (an sEH inhibitor) to pregnant mothers from E5 to P21 prevented ASD-like behaviors such as social interaction deficits and increased grooming time in the juvenile offspring after maternal glyphosate exposure. These findings suggest that maternal exposure to high levels of glyphosate causes ASD-like behavioral abnormalities and abnormal composition of gut microbiota in juvenile offspring, and that increased activity of sEH might play a role in ASD-like behaviors in offspring after maternal glyphosate exposure. Therefore, sEH may represent a target for ASD in offspring after maternal stress from occupational exposure to contaminants.
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Affiliation(s)
- Yaoyu Pu
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, 260-8670 Chiba, Japan
| | - Jun Yang
- Department of Entomology and Nematology and UC Davis Comprehensive Cancer Center, University of California, Davis, CA 95616
| | - Lijia Chang
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, 260-8670 Chiba, Japan
| | - Youge Qu
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, 260-8670 Chiba, Japan
| | - Siming Wang
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, 260-8670 Chiba, Japan
| | - Kai Zhang
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, 260-8670 Chiba, Japan
| | - Zhongwei Xiong
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, 260-8670 Chiba, Japan
| | - Jiancheng Zhang
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, 260-8670 Chiba, Japan
| | - Yunfei Tan
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, 260-8670 Chiba, Japan
| | - Xingming Wang
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, 260-8670 Chiba, Japan
| | - Yuko Fujita
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, 260-8670 Chiba, Japan
| | - Tamaki Ishima
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, 260-8670 Chiba, Japan
| | - Debin Wang
- Department of Entomology and Nematology and UC Davis Comprehensive Cancer Center, University of California, Davis, CA 95616
| | - Sung Hee Hwang
- Department of Entomology and Nematology and UC Davis Comprehensive Cancer Center, University of California, Davis, CA 95616
| | - Bruce D Hammock
- Department of Entomology and Nematology and UC Davis Comprehensive Cancer Center, University of California, Davis, CA 95616
| | - Kenji Hashimoto
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, 260-8670 Chiba, Japan;
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17
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Sensitivity Analysis of Italian Lolium spp. to Glyphosate in Agricultural Environments. PLANTS 2020; 9:plants9020165. [PMID: 32019089 PMCID: PMC7076642 DOI: 10.3390/plants9020165] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 01/27/2020] [Accepted: 01/28/2020] [Indexed: 11/30/2022]
Abstract
Empirical observations generally indicate a shifting and decreased Lolium spp. susceptibility to glyphosate in Italy. This is likely due to the long history of glyphosate use and to the sub-lethal doses commonly used. There is, therefore, a need to determine the variability of response of Lolium spp. to glyphosate and identify the optimum field dose. To perform a sensitivity analysis on Lolium spp. populations in an agriculture area, collection sites were mainly chosen where glyphosate had not been applied intensely. Known glyphosate-resistant or in-shifting populations were included. Two outdoor dose-response pot experiments, including eleven doses of glyphosate, were conducted. The dose to control at least 93%–95% of susceptible Lolium spp. was around 450 g a.e. ha−1. However, to preserve its efficacy in the long term, it would be desirable not to have survivors, and this was reached at a glyphosate dose of 560 ± 88 g a.e. ha−1. Taking into account the variability of response among populations, it was established that the optimal dose of glyphosate to control Lolium spp. in Italy up to the stage BBCH 21 has to be at least 700 g a.e. ha−1. As a consequence, it is recommended to increase the label recommended field rate for Lolium spp. control in Italy to a minimum of 720 g a.e. ha−1.
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