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Parven A, Md Meftaul I, Venkateswarlu K, Gopalan S, Megharaj M. Pre-emergence herbicides widely used in urban and farmland soils: fate, and potential human and environmental health risks. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2024; 46:132. [PMID: 38483701 PMCID: PMC10940459 DOI: 10.1007/s10653-024-01907-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Accepted: 02/08/2024] [Indexed: 03/17/2024]
Abstract
We determined the distribution, fate, and health hazards of dimethenamid-P, metazachlor, and pyroxasulfone, the effective pre-emergence herbicides widely used both in urban and agricultural settings globally. The rate-determining phase of sorption kinetics of these herbicides in five soils followed a pseudo-second-order model. Freundlich isotherm model indicated that the herbicides primarily partition into heterogeneous surface sites on clay minerals and organic matter (OM) and diffuse into soil micropores. Principal component analysis revealed that soil OM (R2, 0.47), sand (R2, 0.56), and Al oxides (R2, 0.33) positively correlated with the herbicide distribution coefficient (Kd), whereas clay (R2, ‒ 0.43), silt (R2, ‒ 0.51), Fe oxides (R2, ‒ 0.02), alkaline pH (R2, ‒ 0.57), and EC (R2, ‒ 0.03) showed a negative correlation with the Kd values. Decomposed OM rich in C=O and C-H functional groups enhanced herbicide sorption, while undecomposed/partially-decomposed OM facilitated desorption process. Also, the absence of hysteresis (H, 0.27‒0.88) indicated the enhanced propensity of herbicide desorption in soils. Leachability index (LIX, < 0.02-0.64) and groundwater ubiquity score (GUS, 0.02‒3.59) for the soils suggested low to moderate leaching potential of the herbicides to waterbodies, indicating their impact on water quality, nontarget organisms, and food safety. Hazard quotient and hazard index data for human adults and adolescents suggested that exposure to soils contaminated with herbicides via dermal contact, ingestion, and inhalation poses minimal to no non-carcinogenic risks. These insights can assist farmers in judicious use of herbicides and help the concerned regulatory authorities in monitoring the safety of human and environmental health.
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Affiliation(s)
- Aney Parven
- Global Centre for Environmental Remediation (GCER), College of Engineering, Science and Environment, The University of Newcastle, ATC Building, University Drive, Callaghan, NSW, 2308, Australia
- Department of Agricultural Chemistry, Sher-e-Bangla Agricultural University, Dhaka, 1207, Bangladesh
| | - Islam Md Meftaul
- Global Centre for Environmental Remediation (GCER), College of Engineering, Science and Environment, The University of Newcastle, ATC Building, University Drive, Callaghan, NSW, 2308, Australia
- Department of Agricultural Chemistry, Sher-e-Bangla Agricultural University, Dhaka, 1207, Bangladesh
| | - Kadiyala Venkateswarlu
- Formerly Department of Microbiology, Sri Krishnadevaraya University, Anantapuramu, 515003, India
| | - Saianand Gopalan
- Global Centre for Environmental Remediation (GCER), College of Engineering, Science and Environment, The University of Newcastle, ATC Building, University Drive, Callaghan, NSW, 2308, Australia
| | - Mallavarapu Megharaj
- Global Centre for Environmental Remediation (GCER), College of Engineering, Science and Environment, The University of Newcastle, ATC Building, University Drive, Callaghan, NSW, 2308, Australia.
- crcCARE, University Drive, Callaghan, NSW, 2308, Australia.
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Sun L, Wang K, Li W, Pang X, Zhao P, Hua R, Yang X, Zhu M. Enantioselective effects of chiral prothioconazole and its metabolites: Oxidative stress in HepG2 cells and lysozyme activity. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2023; 197:105696. [PMID: 38072551 DOI: 10.1016/j.pestbp.2023.105696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 11/03/2023] [Accepted: 11/10/2023] [Indexed: 12/18/2023]
Abstract
Chiral pesticides may exhibit enantioselectivity in terms of bioconcentration, environmental fate, and reproductive toxicity. Here, chiral prothioconazole and its metabolites were selected to thoroughly investigate their enantioselective toxicity and mechanisms at the molecular and cellular levels. Multispectral techniques revealed that the interaction between chiral PTC/PTCD and lysozyme resulted in the formation of a complex, leading to a change in the conformation of lysozyme. Meanwhile, the effect of different conformations of PTC/PTCD on the conformation of lysozyme differed, and its metabolites were able to exert a greater effect on lysozyme compared to prothioconazole. Moreover, the S-configuration of PTCD interacted most strongly with lysozyme. This conclusion was further verified by DFT calculations and molecular docking as well. Furthermore, the oxidative stress indicators within HepG2 cells were also affected by chiral prothioconazole and its metabolites. Specifically, S-PTCD induced more substantial perturbation of the normal oxidative stress processes in HepG2 cells, and the magnitude of the perturbation varied significantly among different configurations (P > 0.05). Overall, chiral prothioconazole and its metabolites exhibit enantioselective effects on lysozyme conformation and oxidative stress processes in HepG2 cells. This work provides a scientific basis for a more comprehensive risk assessment of the environmental behaviors and effects caused by chiral pesticides, as well as for the screening of highly efficient and less biotoxic enantiomeric monomers.
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Affiliation(s)
- Long Sun
- School of Chemical and Environmental Engineering, Anhui Polytechnic University, Wuhu, Anhui 241000, China
| | - Kangquan Wang
- School of Chemical and Environmental Engineering, Anhui Polytechnic University, Wuhu, Anhui 241000, China
| | - Wenze Li
- School of Chemical and Environmental Engineering, Anhui Polytechnic University, Wuhu, Anhui 241000, China
| | - Xiaohui Pang
- School of Chemical and Environmental Engineering, Anhui Polytechnic University, Wuhu, Anhui 241000, China
| | - Pengfei Zhao
- Anhui Environmental Science and Technology Research Institute Co., Ltd., No. 699 Dabieshan Road, High tech Zone, Hefei, Anhui 230000, China
| | - Rimao Hua
- Key Laboratory of Agri-Food Safety of Anhui Province, School of Resources and Environment, Anhui Agricultural University, No. 130 Changjiang West Road, Hefei 230036, China
| | - Xiaofan Yang
- School of Chemical and Environmental Engineering, Anhui Polytechnic University, Wuhu, Anhui 241000, China.
| | - Meiqing Zhu
- School of Chemical and Environmental Engineering, Anhui Polytechnic University, Wuhu, Anhui 241000, China.
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Wu F, Wang Z, Li X, Wang X. Amide herbicides: Analysis of their environmental fate, combined plant-microorganism soil remediation scheme, and risk prevention and control strategies for sensitive populations. JOURNAL OF HAZARDOUS MATERIALS 2023; 460:132452. [PMID: 37683346 DOI: 10.1016/j.jhazmat.2023.132452] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 08/21/2023] [Accepted: 08/30/2023] [Indexed: 09/10/2023]
Abstract
In this study, we predicted the environmental fate of amide herbicides (AHs) using the EQC (EQuilibrium Criterion) model. We found that the soil phase is the main reservoir of AHs in the environment. Second, a toxicokinetic prediction indicated that butachlor have a low human health risk, while the alachlor, acetochlor, metolachlor, napropamide, and propanil are all uncertain. To address the environmental and human-health-related threats posed by AHs, 27 new proteins/enzymes that easily absorb, degrade, and mineralize AHs were designed. Compared with the target protein/enzyme, the comprehensive evaluation value of the new proteins/enzymes increased significantly: the absorption protein increased by 20.29-113.49%; the degradation enzyme increased by 151.26-425.22%; and the mineralization enzyme increased by 23.70-52.16%. Further experiments revealed that the remediating effect of 13 new proteins/enzymes could be significantly enhanced to facilitate their applicability under real environmental conditions. The hydrophobic interactions, van der Waals forces, and polar solvation are the key factors influencing plant-microorganism remediation. Finally, the simulations revealed that appropriate consumption of kiwifruit or simultaneous consumption of ginseng, carrot, and spinach, and avoiding the simultaneous consumption of maize and carrot/spinach are the most effective means reduce the risk of exhibiting AH-linked toxicity.
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Affiliation(s)
- Fuxing Wu
- College of Plant Science, Jilin University, Changchun 130062, China
| | - Zini Wang
- College of Plant Science, Jilin University, Changchun 130062, China
| | - Xinao Li
- Moe Key Laboratory of Resources and Environmental System Optimization, North China Electric Power University, Beijing 102206, China.
| | - Xiaoli Wang
- College of Plant Science, Jilin University, Changchun 130062, China.
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Chen SF, Chen WJ, Huang Y, Wei M, Chang C. Insights into the metabolic pathways and biodegradation mechanisms of chloroacetamide herbicides. ENVIRONMENTAL RESEARCH 2023; 229:115918. [PMID: 37062473 DOI: 10.1016/j.envres.2023.115918] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 04/04/2023] [Accepted: 04/13/2023] [Indexed: 05/21/2023]
Abstract
Chloroacetamide herbicides are widely used around the world due to their high efficiency, resulting in increasing levels of their residues in the environment. Residual chloroacetamides and their metabolites have been frequently detected in soil, water and organisms and shown to have toxic effects on non-target organisms, posing a serious threat to the ecosystem. As such, rapid and efficient techniques that eliminate chloroacetamide residues from the ecosystem are urgently needed. Degradation of these herbicides in the environment mainly occurs through microbial metabolism. Microbial strains such as Acinetobacter baumannii DT, Bacillus altitudinis A16, Pseudomonas aeruginosa JD115, Sphingobium baderi DE-13, Catellibacterium caeni DCA-1, Stenotrophomonas acidaminiphila JS-1, Klebsiella variicola B2, and Paecilomyces marquandii can effectively degrade chloroacetamide herbicides. The degradation pathway of chloroacetamide herbicides in aerobic bacteria is mainly initiated by an N/C-dealkylation reaction, followed by aromatic ring hydroxylation and cleavage processes, whereas dechlorination is the initial reaction in anaerobic bacteria. The molecular mechanisms associated with bacterial degradation of chloroacetamide herbicides have been explored, with amidase, hydrolase, reductase, ferredoxin and cytochrome P450 oxygenase currently known to play a pivotal role in the catabolic pathways of chloroacetamides. The fungal pathway for the degradation of these herbicides is more complex with more diversified products, and the degradation enzymes and genes involved remain to be discovered. However, there are few reviews specifically summarizing the microbial degrading species and biochemical mechanisms of chloroacetamide herbicides. Here, we briefly summarize the latest progress resulting from research on microbial strain resources and enzymes involved in degradation of these herbicides and their corresponding genes. Furthermore, we explore the biochemical pathways and molecular mechanisms for biodegradation of chloroacetamide herbicides in depth, thereby providing a reference for further research on the bioremediation of such herbicides.
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Affiliation(s)
- Shao-Fang Chen
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China; Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | - Wen-Juan Chen
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China; Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | - Yaohua Huang
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China; Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | - Ming Wei
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China; Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | - Changqing Chang
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China; Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China.
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Wang WG, Li MY, Diao L, Zhang C, Tao LM, Zhou WX, Xu WP, Zhang Y. The health risk of acetochlor metabolite CMEPA is associated with lipid accumulation induced liver injury. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023:121857. [PMID: 37245791 DOI: 10.1016/j.envpol.2023.121857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 05/01/2023] [Accepted: 05/18/2023] [Indexed: 05/30/2023]
Abstract
Liver injury may cause many diseases, such as non-alcoholic fatty liver disease (NAFLD). Acetochlor is one of the representative chloroacetamide herbicides, and its metabolite 2-chloro-N-(2-ethyl-6-methyl phenyl) acetamide (CMEPA) is the main form of exposure in the environment. It has been shown that acetochlor can cause mitochondrial damage of HepG2 cells and induce apoptosis by activating Bcl/Bax pathway (Wang et al., 2021). But there has been less research on CMEPA. we explored the possibility of CMEPA and liver injury through biological experiments. In vivo, CMEPA (0-16 mg/L) induced liver damage in zebrafish larvae, including increased lipid droplets, changes in liver morphology (>1.3-fold) and increased TC/TG content (>2.5-fold). In vitro, we selected L02 (human normal liver cells) as the model, and explored its molecular mechanism. We found that CMEPA (0-160 mg/L) induced apoptosis (similar to 40%), mitochondrial damage and oxidative stress in L02 cells. CMEPA induced intracellular lipid accumulation by inhibiting AMPK/ACC/CPT-1A signaling pathway and activating SREBP-1c/FAS signaling pathway. Our study provides evidence of a link between CMEPA and liver injury. This raises concerns regarding the health risks of pesticide metabolites to liver health.
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Affiliation(s)
- Wei-Guo Wang
- Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China University of Science and Technology, Shanghai, 200237, China
| | - Mu-Yao Li
- Research Center for Econophysics, School of Business, East China University of Science and Technology, Shanghai, 200237, China
| | - Lin Diao
- Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China University of Science and Technology, Shanghai, 200237, China
| | - Cheng Zhang
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, 75390, United States
| | - Li-Ming Tao
- Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China University of Science and Technology, Shanghai, 200237, China
| | - Wei-Xing Zhou
- Research Center for Econophysics, School of Business, East China University of Science and Technology, Shanghai, 200237, China
| | - Wen-Ping Xu
- Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China University of Science and Technology, Shanghai, 200237, China
| | - Yang Zhang
- Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China University of Science and Technology, Shanghai, 200237, China.
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Liman R, Ali MM, Istifli ES, Ciğerci İH, Bonciu E. Genotoxic and cytotoxic effects of pethoxamid herbicide on Allium cepa cells and its molecular docking studies to unravel genotoxicity mechanism. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:63127-63140. [PMID: 35449332 DOI: 10.1007/s11356-022-20166-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 04/05/2022] [Indexed: 06/14/2023]
Abstract
Pethoxamid is chloroacetamide herbicide. Pethoxamid is commonly used to kill different weeds in various crops. Pethoxamid can leach in the water and soil and can cause toxic effects to other non-target species. Current study is therefore aimed to perform the investigation of the cytotoxic and genotoxic effects of pethoxamid on Allium cepa cells.The root growth, mitotic index (MI), chromosomal aberrations (CAs), and DNA damage were assessed through root growth inhibition, A. cepa ana-telophase, and alkaline comet assays, respectively. Furthermore, molecular docking was performed to evaluate binding affinity of pethoxamid on DNA and very-long-chain fatty acid (VLCFA) synthases. In root growth inhibition test, onion root length was statistically significantly decreased in a concentration dependent manner. Concentration- and time-dependent decreases in MI were observed, whereas increase in CAs such as disturbed ana-telophase, chromosome laggards, stickiness, anaphase bridges, and DNA damage was caused by the pethoxamid on A. cepa root cells. Molecular docking revealed that pethoxamid binds selectively to GC-rich regions in the minor groove of the DNA structure and showed remarkable binding affinity against all synthases taking part in the sequential biosynthesis of VLCFAs. It was concluded that the pethoxamid-induced genotoxicity and cytotoxicity may be through multiple binding ability of this herbicide with DNA and VLCFA synthases.
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Affiliation(s)
- Recep Liman
- Molecular Biology and Genetics Department, Faculty of Arts and Sciences, Uşak University, 1 Eylül Campus, 64300, Usak, Turkey
| | - Muhammad Muddassir Ali
- Institute of Biochemistry and Biotechnology, University of Veterinary and Animal Sciences, Lahore, 54000, Pakistan.
| | - Erman Salih Istifli
- Department of Biology, Faculty of Science and Literature, Cukurova University, 01330, Adana, Turkey
| | - İbrahim Hakkı Ciğerci
- Molecular Biology and Genetics Department, Faculty of Science and Literatures, Afyon Kocatepe University, 03200, Afyon, Turkey
| | - Elena Bonciu
- Department of Agricultural and Forestry Technology, Faculty of Agronomy, University of Craiova, 13 A.I. Cuza Street, 200585, Craiova, Romania
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Tresnakova N, Kubec J, Stara A, Zuskova E, Faggio C, Kouba A, Velisek J. Chronic Toxicity of Primary Metabolites of Chloroacetamide and Glyphosate to Early Life Stages of Marbled Crayfish Procambarus virginalis. BIOLOGY 2022; 11:biology11060927. [PMID: 35741448 PMCID: PMC9219952 DOI: 10.3390/biology11060927] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 06/14/2022] [Accepted: 06/15/2022] [Indexed: 12/16/2022]
Abstract
Degradation products of herbicides, alone and in combination, may affect non-target aquatic organisms via leaching or runoff from the soil. The effects of 50-day exposure of primary metabolites of chloroacetamide herbicide, acetochlor ESA (AE; 4 µg/L), and glyphosate, aminomethylphosphonic acid (AMPA; 4 µg/L), and their combination (AMPA + AE; 4 + 4 µg/L) on mortality, growth, oxidative stress, antioxidant response, behaviour, and gill histology of early life stages of marbled crayfish (Procambarus virginalis) were investigated. While no treatment effects were observed on cumulative mortality or early ontogeny, growth was significantly lower in all exposed groups compared with the control group. Significant superoxide dismutase activity was observed in exposure groups, and significantly higher glutathione S-transferase activity only in the AMPA + AE group. The gill epithelium in AMPA + AE-exposed crayfish showed swelling as well as numerous unidentified fragments in interlamellar space. Velocity and distance moved in crayfish exposed to metabolites did not differ from controls, but increased activity was observed in the AMPA and AE groups. The study reveals the potential risks of glyphosate and acetochlor herbicide usage through their primary metabolites in the early life stages of marbled crayfish.
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Affiliation(s)
- Nikola Tresnakova
- South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, Faculty of Fisheries and Protection of Waters, University of South Bohemia in Ceske Budejovice, Zatisi 728/II, 389 25 Vodnany, Czech Republic; (N.T.); (J.K.); (A.S.); (E.Z.); (A.K.); (J.V.)
| | - Jan Kubec
- South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, Faculty of Fisheries and Protection of Waters, University of South Bohemia in Ceske Budejovice, Zatisi 728/II, 389 25 Vodnany, Czech Republic; (N.T.); (J.K.); (A.S.); (E.Z.); (A.K.); (J.V.)
| | - Alzbeta Stara
- South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, Faculty of Fisheries and Protection of Waters, University of South Bohemia in Ceske Budejovice, Zatisi 728/II, 389 25 Vodnany, Czech Republic; (N.T.); (J.K.); (A.S.); (E.Z.); (A.K.); (J.V.)
| | - Eliska Zuskova
- South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, Faculty of Fisheries and Protection of Waters, University of South Bohemia in Ceske Budejovice, Zatisi 728/II, 389 25 Vodnany, Czech Republic; (N.T.); (J.K.); (A.S.); (E.Z.); (A.K.); (J.V.)
| | - Caterina Faggio
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale Ferdinando Stagno d’Alcontres 31, 98166 Messina, Italy
- Correspondence: ; Tel.: +39-348-404-2634
| | - Antonin Kouba
- South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, Faculty of Fisheries and Protection of Waters, University of South Bohemia in Ceske Budejovice, Zatisi 728/II, 389 25 Vodnany, Czech Republic; (N.T.); (J.K.); (A.S.); (E.Z.); (A.K.); (J.V.)
| | - Josef Velisek
- South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, Faculty of Fisheries and Protection of Waters, University of South Bohemia in Ceske Budejovice, Zatisi 728/II, 389 25 Vodnany, Czech Republic; (N.T.); (J.K.); (A.S.); (E.Z.); (A.K.); (J.V.)
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Gideon J, Mulligan J, Hui C, Cheng SY. UV and temperature effects on chloroacetanilide and triazine herbicides degradation and cytotoxicity. Heliyon 2021; 7:e08010. [PMID: 34589629 PMCID: PMC8461356 DOI: 10.1016/j.heliyon.2021.e08010] [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: 04/27/2021] [Revised: 07/25/2021] [Accepted: 09/14/2021] [Indexed: 11/18/2022] Open
Abstract
The purpose of this study was to explore the stability and toxicity of the herbicides and their degradation byproduct after exposure to different environmental factors. Triazines (atrazine, propazine, simazine) and chloroacetanilides (acetochlor, alachlor, metolachlor) which are commonly used herbicides were evaluated for cytotoxicity in different UV (254 nm and 365 nm) and temperature (4 °C, 23 °C, and 40 °C) conditions as well as degradation rates. Atrazine with the highest LD50 (4.23 μg mL-1) was less toxic than the other tested triazine herbicides Chloroacetanilides tested were more toxic than tested triazines, with LD50 0.08-1.42 μg mL-1 vs 1.44-4.23 μg mL-1, respectively. Alachlor with LD50 0.08 μg mL-1 showed the strongest toxic response as compared with other tested herbicides. Temperatures only did not alter cytotoxicity of the tested herbicides, except for acetochlor and alachlor showing about 45 % more cell death after exposure to 40 °C for 2 h. At all 3 tested temperatures, 2 h of UV treatments did not affect cytotoxic effects of the tested herbicides, except for acetochlor and alachlor. At 4 °C, acetochlor toxicity was attenuated about 63 % after UV 365 nm exposure; but alachlor toxicity was enhanced after either UV 254 or 365 nm exposure for about 40 % and 24 %, respectively. At 23 °C, acetochlor toxicity was enhanced about 35 % after UV 254 nm exposure, but attenuated about 48 % after UV 365 nm exposure. Alachlor toxicity was enhanced about 34 % after UV 254 nm and 23 °C exposure. In combination of UV 254 nm and 40 °C, acetochlor toxicity was lowered by 63 % and alachlor toxicity was no change as compared with 4 °C, no UV group. After co-treatment with UV 365 nm and 40 °C both acetochlor and alachlor toxicity was enhanced 55 % and 80 %, respectively. Through degradation analysis by LC-MS/MS, alachlor showed the most dramatic degradation (only 0.58 %-10.58 % remaining) after heat and UV treatments.
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Affiliation(s)
| | | | - Christina Hui
- Department of Sciences, John Jay College of Criminal Justice, The City University of New York, New York, NY, 10019, USA
| | - Shu-Yuan Cheng
- Department of Sciences, John Jay College of Criminal Justice, The City University of New York, New York, NY, 10019, USA
- The Graduate Center of the City University of New York, New York, NY, 10016, USA
- Corresponding author.
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