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Degrendele C, Klánová J, Prokeš R, Příbylová P, Šenk P, Šudoma M, Röösli M, Dalvie MA, Fuhrimann S. Current use pesticides in soil and air from two agricultural sites in South Africa: Implications for environmental fate and human exposure. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 807:150455. [PMID: 34634720 DOI: 10.1016/j.scitotenv.2021.150455] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 09/15/2021] [Accepted: 09/15/2021] [Indexed: 05/27/2023]
Abstract
Concerns about the possible negative impacts of current use pesticides (CUPs) for both the environment and human health have increased worldwide. However, the knowledge on the occurrence of CUPs in soil and air and the related human exposure in Africa is limited. This study investigated the presence of 30 CUPs in soil and air at two distinct agricultural sites in South Africa and estimated the human exposure and related risks to rural residents via soil ingestion and inhalation (using hazard quotients, hazard index and relative potency factors). We collected 12 soil and 14 air samples over seven days during the main pesticide application season in 2018. All samples were extracted, purified and analyzed by high-performance liquid chromatography coupled with tandem mass spectrometry. In soils, nine CUPs were found, with chlorpyrifos, carbaryl and tebuconazole having the highest concentrations (up to 63.6, 1.10 and 0.212 ng g-1, respectively). In air, 16 CUPs were found, with carbaryl, tebuconazole and terbuthylazine having the highest levels (up to 25.0, 22.2 and 1.94 pg m-3, respectively). Spatial differences were observed between the two sites for seven CUPs in air and two in soils. A large dominance towards the particulate phase was found for almost all CUPs, which could be related to mass transport kinetics limitations (non-equilibrium) following pesticide application. The estimated daily intake via soil ingestion and inhalation of individual pesticides ranged from 0.126 fg kg-1 day-1 (isoproturon) to 14.7 ng kg-1 day-1 (chlorpyrifos). Except for chlorpyrifos, soil ingestion generally represented a minor exposure pathway compared to inhalation (i.e. <5%). The pesticide environmental exposure largely differed between the residents of the two distinct agricultural sites in terms of levels and composition. The estimated human health risks due to soil ingestion and inhalation of pesticides were negligible although future studies should explore other relevant pathways.
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Affiliation(s)
| | - Jana Klánová
- Masaryk University, RECETOX Centre, 625 00 Brno, Czech Republic
| | - Roman Prokeš
- Masaryk University, RECETOX Centre, 625 00 Brno, Czech Republic
| | - Petra Příbylová
- Masaryk University, RECETOX Centre, 625 00 Brno, Czech Republic
| | - Petr Šenk
- Masaryk University, RECETOX Centre, 625 00 Brno, Czech Republic
| | - Marek Šudoma
- Masaryk University, RECETOX Centre, 625 00 Brno, Czech Republic
| | - Martin Röösli
- University of Basel, 4002 Basel, Switzerland; Swiss Tropical and Public Health Institute (Swiss TPH), 4002 Basel, Switzerland
| | - Mohamed Aqiel Dalvie
- Centre for Environmental and Occupational Health Research, School of Public Health and Family Medicine, University of Cape Town, 7925 Cape Town, South Africa
| | - Samuel Fuhrimann
- University of Basel, 4002 Basel, Switzerland; Swiss Tropical and Public Health Institute (Swiss TPH), 4002 Basel, Switzerland; Institute for Risk Assessment Sciences (IRAS), Utrecht University, 3584 Utrecht, the Netherlands
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Bamiduro GJ, Kumar N, Solo-Gabriele HM, Zahran EM. Persistence of aerially-sprayed naled in coastal sediments. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 794:148701. [PMID: 34323772 DOI: 10.1016/j.scitotenv.2021.148701] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 06/21/2021] [Accepted: 06/22/2021] [Indexed: 06/13/2023]
Abstract
Aerial sprays of the organophosphate pesticide, naled, were intensified over beach areas during the summer of 2016 to control the locally-acquired Zika outbreak in the continental U.S. Concerns were raised in beach frequented areas about contaminated sediments. The aim of this study was to evaluate the persistence and levels of naled and its byproduct, dichlorvos, in sediments obtained from the affected areas. Laboratory experiments were designed to simulate the effect of various natural conditions on the decomposition of naled in three sediment types (beach sand, marl, and calcinated beach sand). The three sediment samples were also exposed to field aerial sprays. After 30 min of exposure, more dichlorvos was detected in the sediments than naled, with 33 to 43% of the molar concentration initially applied as either naled or dichlorvos. Under dark conditions, trace levels of naled were observed after 24 h on sediments. Higher temperature accelerated the natural decomposition of both naled and dichlorvos in sediments. The half-life of naled ranged from 3 to 5 h at 22.5 °C and ranged from 1 to 3 h at 30 °C. Expedited decomposition of naled was observed under sunlight conditions with a half-life of naled of 20 min. In the field, only dichlorvos was detected in the sediment samples at concentrations between 0.0011 and 0.0028 μmol/g 1 h after aerial sprays. This data can be used towards a risk assessment that evaluates exposures to naled and dichlorvos through beach sands impacted by aerial spray activities.
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Affiliation(s)
- Gbemisola J Bamiduro
- Department of Chemistry, Ball State University, Muncie, IN, 47306, United States of America
| | - Naresh Kumar
- Department of Public Health Sciences, University of Miami, Miami, FL, United States of America
| | - Helena M Solo-Gabriele
- Department of Civil, Architectural and Environmental Engineering, University of Miami, Coral Gables, FL, United States of America
| | - Elsayed M Zahran
- Department of Chemistry, Ball State University, Muncie, IN, 47306, United States of America.
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Xie E, Zhao X, Li K, Zhang P, Zhou X, Zhao X. Microbial community structure in the river sediments from upstream of Guanting Reservoir: Potential impacts of reclaimed water recharge. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 766:142609. [PMID: 33069478 DOI: 10.1016/j.scitotenv.2020.142609] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 09/18/2020] [Accepted: 09/20/2020] [Indexed: 06/11/2023]
Abstract
This work systematically investigated the microbial community structure in the river sediments from upstream of Guanting Reservoir, Beijing, China. A total of 6 wastewater treatment plants (WWTPs) locate along the main rivers connected to the reservoir. Water and sediment samples were collected at sites near the effluents of WWTPs (regarded as W groups) or at the upstream/downstream rivers (R groups) to reveal the roles of the reclaimed water recharge. Multivariate techniques including typical statistical analysis, redundancy analysis (RDA), nonmetric multidimensional scaling analysis, and molecular ecological network analysis were used to evaluate the results and their relationships. The representative C/N/P water parameters and concentrations of target organic contaminants kept stable for W and R sites, while the microbial community parameters varied greatly for two groups. The microbial population at W sites were higher but with a lower biological diversity (with a lower Shannon index) than that at R sites, indicating WWTPs greatly altered the microbial community structure at the local reach. RDA results revealed that total organic carbon (TOC) and organophosphorus pesticides (OPPs) were two dominant factors affecting the function and composition of microbial communities at the phylum level. The network analysis revealed that the microbes with the most interactions mainly from R sites and they had closer relationships with each other.
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Affiliation(s)
- En Xie
- College of Water Resources and Civil Engineering, China Agricultural University, Beijing, China
| | - Xiaohui Zhao
- Department of Water Ecology and Environment, China Institute of Water Resources and Hydropower Research, Beijing 100038, China.
| | - Kun Li
- Department of Water Ecology and Environment, China Institute of Water Resources and Hydropower Research, Beijing 100038, China
| | - Panwei Zhang
- Department of Water Ecology and Environment, China Institute of Water Resources and Hydropower Research, Beijing 100038, China
| | - Xiuhua Zhou
- Department of Water Ecology and Environment, China Institute of Water Resources and Hydropower Research, Beijing 100038, China
| | - Xiao Zhao
- College of Water Resources and Civil Engineering, China Agricultural University, Beijing, China.
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Wei W, Sivanantham S, Malingre L, Ramalho O, Mandin C. Predicting the rate constants of semivolatile organic compounds with hydroxyl radicals and ozone in indoor air. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 266:115050. [PMID: 32652384 DOI: 10.1016/j.envpol.2020.115050] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 06/15/2020] [Accepted: 06/15/2020] [Indexed: 06/11/2023]
Abstract
Semivolatile organic compounds (SVOCs) in air can react with hydroxyl radicals (OH), nitrate radicals (NO3) and ozone (O3). Two questions regarding SVOC reactivity with OH, NO3 and O3 in the gas and particle phases remain to be addressed: according to the existing measurements in the literature, which are the most reactive SVOCs in air, and how can the SVOC reactivity in the gas and particle phases be predicted? In the present study, a literature review of the second-order rate constant (k) was carried out to determine the SVOC reactivity with OH, NO3 and O3 in the gas and particle phases in ambient and indoor air at room temperature. Measured k values were available in the literature for 90 polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organophosphates, dioxins, di(2-ethylhexyl)phthalate (DEHP) and pesticides including pyrifenox, carbamates and terbuthylazine. PAHs and organophosphates were found to be more reactive than dioxins and PCBs. Based on the obtained data, quantitative structure-activity relationship (QSAR) models were developed to predict the k value using quantum chemical, molecular, physical property and environmental descriptors. Eight linear and nonlinear statistical models were employed, including regression models, bagging, random forest and gradient boosting. QSAR models were developed for SVOC/OH reactions in the gas and particle phases and SVOC/O3 reactions in the particle phase. Models for SVOC/NO3 and SVOC/O3 reactions in the gas phase could not be developed due to the lack of measured k values for model training. The least absolute shrinkage and selection operator (LASSO) regression and random forest models were identified as the most effective models for SVOC reactivity prediction according to a comparison of model performance metrics.
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Affiliation(s)
- Wenjuan Wei
- University of Paris-Est, Scientific and Technical Center for Building (CSTB), Health and Comfort Department, French Indoor Air Quality Observatory (OQAI), 84 Avenue Jean Jaurès, Champs sur Marne, 77447, Marne La Vallée Cedex 2, France.
| | - Sutharsini Sivanantham
- University of Paris-Est, Scientific and Technical Center for Building (CSTB), Health and Comfort Department, French Indoor Air Quality Observatory (OQAI), 84 Avenue Jean Jaurès, Champs sur Marne, 77447, Marne La Vallée Cedex 2, France
| | - Laeticia Malingre
- University of Paris-Est, Scientific and Technical Center for Building (CSTB), Health and Comfort Department, French Indoor Air Quality Observatory (OQAI), 84 Avenue Jean Jaurès, Champs sur Marne, 77447, Marne La Vallée Cedex 2, France
| | - Olivier Ramalho
- University of Paris-Est, Scientific and Technical Center for Building (CSTB), Health and Comfort Department, French Indoor Air Quality Observatory (OQAI), 84 Avenue Jean Jaurès, Champs sur Marne, 77447, Marne La Vallée Cedex 2, France
| | - Corinne Mandin
- University of Paris-Est, Scientific and Technical Center for Building (CSTB), Health and Comfort Department, French Indoor Air Quality Observatory (OQAI), 84 Avenue Jean Jaurès, Champs sur Marne, 77447, Marne La Vallée Cedex 2, France
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Zhou Y, Guo J, Wang Z, Zhang B, Sun Z, Yun X, Zhang J. Levels and inhalation health risk of neonicotinoid insecticides in fine particulate matter (PM 2.5) in urban and rural areas of China. ENVIRONMENT INTERNATIONAL 2020; 142:105822. [PMID: 32497933 DOI: 10.1016/j.envint.2020.105822] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/16/2020] [Accepted: 05/18/2020] [Indexed: 05/27/2023]
Abstract
Neonicotinoid insecticide (NEO) concentrations in ambient fine particulate matter (PM2.5) and daily exposure via inhalation were investigated during spring and fall in an urban area in Beijing and in urban and rural areas of Zhengzhou, Henan Province, China. Four NEOs, including imidacloprid, acetamiprid, thiamethoxam and clothianidin, were assessed using a QuEChERS (quick, easy, cheap, effective, rugged, safe) extraction procedure coupled to liquid chromatography-tandem mass spectrometry. Of 64 PM2.5 samples, 100% contained at least two NEOs (imidacloprid and acetamiprid). Imidacloprid was detected at the highest levels, ranging from 4.33 to 1.13 × 102 pg m-3. A relative potency factor method that considered different toxicities was used to integrate the four NEO concentrations. The total NEO concentrations in air in the Zhengzhou rural area (mean: 80.86 pg m-3) were higher than those in urban areas. Differences between seasons were not significant (p > 0.05). The highest value for the total average daily dose via inhalation of four NEOs (ADDinh,total), 91.0 pg kg-1 day-1, was found in rural children <6 years old. The ADDinh,total of rural residents was significantly higher than that of urban residents when there was no intensive pesticide application. Although the ADDinh,total values were below the current chronic reference dose, when possible joint toxicity and the increasing use of NEOs are considered, a potential health risk via inhalation is evident. We believe this study is the first to characterize NEO levels in fine particulate matter and to evaluate inhalation exposure in urban and rural residents under nonoccupational scenarios in China. It will enhance our understanding of exposure to NEOs and provide a basis for risk management decisions.
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Affiliation(s)
- Ying Zhou
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Junyu Guo
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
| | - Zikuan Wang
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Boya Zhang
- Department of Epidemiology, University of Michigan, Ann Arbor, MI, USA
| | - Zhe Sun
- Centre for Atmospheric Science, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK
| | - Xiao Yun
- College of Urban and Environmental Sciences, Laboratory for Earth Surface Processes, Sino-French Institute for Earth System Science, Peking University, Beijing 100871, China
| | - Jianbo Zhang
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
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Quintano MM, Rodrigues GLS, Chagas MA, Rocha WR. Revisiting the Tropospheric OH-Initiated Unimolecular Decomposition of Chlorpyrifos and Chlorpyrifos-Methyl: A Theoretical Perspective. J Phys Chem A 2020; 124:4280-4289. [PMID: 32374604 DOI: 10.1021/acs.jpca.0c02006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Based on density functional theory (DFT) electronic structure calculations with dispersion correction, we propose new reaction pathways in which no extra reaction step is necessary to account for the formation of 3,5,6-trichloro-2-pyridynol (TCP) within the process of tropospheric OH-initiated unimolecular decomposition of chlorpyrifos (CLP) and chlorpyrifos-methyl (CLPM). Chlorpyrifos and its analogous compound are among the most used organophosphorus pesticides worldwide, and their unimolecular decomposition in the troposphere is a dominant process of removal in the gas phase. The reaction pathways that we put forward have turned out to be the most exergonic ones among the three possible routes for the attack of the hydroxyl radical to the thiophosphoryl (P═S) bond of both CLP and CLPM. The results showed that the reaction is thermodynamically controlled with the formation of P-bonded adducts via a six-membered ring. The unimolecular decomposition of such reactive intermediates takes place with small energy barriers (less than 3 kcal mol-1) and is distinguished by hydrogen transfer to the nitrogen atom of the aromatic ring, resulting in the formation of 3,5,6-trichloro-2-pyridinol (TCP) and dialkyl phosphate radical (DAP·) product complexes in a single step.
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Affiliation(s)
- Mateus M Quintano
- Laboratory of Computational Studies on Molecular Systems, eCsMolab Department of Chemistry, ICEx, Federal University of Minas Gerais Pampulha, Belo Horizonte 31270-901, MG, Brazil
| | - Gabriel L S Rodrigues
- Laboratory of Computational Studies on Molecular Systems, eCsMolab Department of Chemistry, ICEx, Federal University of Minas Gerais Pampulha, Belo Horizonte 31270-901, MG, Brazil
| | - Marcelo A Chagas
- Laboratory of Computational Studies on Molecular Systems, eCsMolab Department of Chemistry, ICEx, Federal University of Minas Gerais Pampulha, Belo Horizonte 31270-901, MG, Brazil
| | - Willian R Rocha
- Laboratory of Computational Studies on Molecular Systems, eCsMolab Department of Chemistry, ICEx, Federal University of Minas Gerais Pampulha, Belo Horizonte 31270-901, MG, Brazil
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Bustos N, Cruz-Alcalde A, Iriel A, Fernández Cirelli A, Sans C. Sunlight and UVC-254 irradiation induced photodegradation of organophosphorus pesticide dichlorvos in aqueous matrices. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 649:592-600. [PMID: 30176470 DOI: 10.1016/j.scitotenv.2018.08.254] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 07/24/2018] [Accepted: 08/04/2018] [Indexed: 06/08/2023]
Abstract
Dichlorvos (DDVP) is an organophosphorus pesticide that has been classified as highly hazardous chemical by the World Health organization. In this study, the fate of the pesticide DDVP in natural water compartments was examined under simulated sunlight. Moreover, the effect of UV-254 irradiation on DDVP depletion was also studied. In deionized water, DDVP was photodegraded only in the presence of dissolved molecular oxygen. The photodegradation during the first 6 h of sunlight irradiation occurred with pseudo first-order kinetics, and the rate constants were 0.040 h-1 at pH 7 and 0.064 h-1 at pH 3. A reaction mechanism for the generation of reactive oxygen species (ROS) via DDVP photoabsorption was proposed. Humic acids (HA) played a double role as photosensitizer and inhibitor, observing an enhancement on DDVP photodegradation at low HA concentration (TOC = 2 mg L-1). The depletion of DDVP under 254 nm UV irradiation was ascribed to direct photodegradation and oxygen mediated photoinduced reactions. Direct photodegradation of DDVP decreased with 254 nm irradiation reduction, highlighting the importance of radical mediated mechanisms at low irradiation doses. Based on LC/MS data, the main photoproducts under simulated solar light and UV-C irradiation were identified and potential reaction pathways were postulated. The three main identified products were o-methyl 2,2-dichlorovinyl phosphate, dichloroacetaldehyde and dimethylphosphate. Moreover, the toxicity of samples was evaluated along the irradiation exposure time using Microtox® assays. This study brings new insights into the role of oxygen in the photodegradation of DDVP and the induced and inhibition mechanisms involved in the presence of the humic acids in natural waters.
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Affiliation(s)
- Nahuel Bustos
- Centro de Estudios Transdisciplinarios del Agua/CETA (UBA), Instituto de Investigaciones en Producción Animal/INPA(CONICET-UBA), Facultad de Ciencias Veterinarias, Universidad de Buenos Aires, Av. Chorroarín 280, C1427CWO Buenos Aires, Argentina
| | - Alberto Cruz-Alcalde
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
| | - Analía Iriel
- Centro de Estudios Transdisciplinarios del Agua/CETA (UBA), Instituto de Investigaciones en Producción Animal/INPA(CONICET-UBA), Facultad de Ciencias Veterinarias, Universidad de Buenos Aires, Av. Chorroarín 280, C1427CWO Buenos Aires, Argentina
| | - Alicia Fernández Cirelli
- Centro de Estudios Transdisciplinarios del Agua/CETA (UBA), Instituto de Investigaciones en Producción Animal/INPA(CONICET-UBA), Facultad de Ciencias Veterinarias, Universidad de Buenos Aires, Av. Chorroarín 280, C1427CWO Buenos Aires, Argentina
| | - Carmen Sans
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain.
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Wei W, Mandin C, Ramalho O. Reactivity of Semivolatile Organic Compounds with Hydroxyl Radicals, Nitrate Radicals, and Ozone in Indoor Air. INT J CHEM KINET 2017. [DOI: 10.1002/kin.21093] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Wenjuan Wei
- University of Paris-Est; Scientific and Technical Center for Building (CSTB); Health and Comfort Department; French Indoor Air Quality Observatory (OQAI); 84 Avenue Jean Jaurès; Champs sur Marne 77447 Marne la Vallée Cedex 2 France
| | - Corinne Mandin
- University of Paris-Est; Scientific and Technical Center for Building (CSTB); Health and Comfort Department; French Indoor Air Quality Observatory (OQAI); 84 Avenue Jean Jaurès; Champs sur Marne 77447 Marne la Vallée Cedex 2 France
| | - Olivier Ramalho
- University of Paris-Est; Scientific and Technical Center for Building (CSTB); Health and Comfort Department; French Indoor Air Quality Observatory (OQAI); 84 Avenue Jean Jaurès; Champs sur Marne 77447 Marne la Vallée Cedex 2 France
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TD-M06-2X insights into the absorption and emission spectra of dichlorvos and its molecularly imprinted recognition by methacrylic acid. J Mol Model 2016; 22:282. [PMID: 27796784 DOI: 10.1007/s00894-016-3151-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 10/13/2016] [Indexed: 10/20/2022]
Abstract
The absorption and emission spectra of dichlorvos and the dichlorvos-MAA complex in methanol, water, and chloroform in the molecularly imprinted recognition were investigated systematically. The M06-2X results revealed that: 1) the hydroxyl groups in polar solvents such as methanol and water may markedly influence the weak interactions, and then alter the adsorption and emission spectra; 2) the electronic excitation in absorption spectra of dichlorvos is dominated by the configuration HOMO → LUMO, but in the most stable dichlorvos-MAA it becomes the ππ* excitation of HOMO → LUMO + 1; 3) Mulliken charges reveal that dichlorvos almost dissociates to Cl- and a cation in its S1 excitation state; 4) the phosphorescence spectra of dichlorvos-MAA are relatively weak. Graphical Abstract The absorption and emission spectra of dichlorvos and the dichlorvos-MAA complex in the molecularly imprinted recognition of dichlorvos were investigated systematically in methanol, water, and chloroform as solvents.
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Borrás E, Tortajada-Genaro LA, Ródenas M, Vera T, Coscollá C, Yusá V, Muñoz A. Gas-phase and particulate products from the atmospheric degradation of the organothiophosphorus insecticide chlorpyrifos-methyl. CHEMOSPHERE 2015; 138:888-894. [PMID: 25548033 DOI: 10.1016/j.chemosphere.2014.11.067] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 11/13/2014] [Accepted: 11/28/2014] [Indexed: 06/04/2023]
Abstract
The phosphorothioate structure is highly present in several organophosphorus pesticides. However, there is insufficient information about its degradation process after the release to the atmosphere and the secondary pollutants formed. Herein, the atmospheric reaction of chlorpyrifos-methyl (o,o-dimethyl o-(3,5,6-trichloropyridin-2-yl) phosphorothioate), is described for semi-urban or rural locations. The photo-oxidation under low NOx conditions (5-55 ppbV) was reproduced in a large outdoor simulation chamber, observing a rapid degradation (lifetime<3.5 h). The formation of gaseous products and particulate matter (aerosol yield 2-8%) was monitored. The chemical composition of minor products (gaseous and particulate) was studied, identifying 15 multi-oxygenated derivatives. The most abundant products were ring-retaining molecules such as o,o-dimethyl o-(3,5,6-trichloropyridin-2-yl) phosphorothioate, dimethyl 3,5,6-trichloropyridin-2-yl phosphate, o-methyl o-(3,5,6-trichloropyridin-2-yl) hydrogen phosphorothioate, 3,5,6-trichloropyridin-2-yl dihydrogen phosphate, 3,5,6-trichloropyridin-2-ol, and 3,5,6-trichloropyridine-2,4-diol. An atmospheric degradation mechanism has been proposed based on an oxidation started with OH-nucleophilic attack to P=S bond. The results have been extrapolated to other organothiophosphorus molecules, such as malathion, parathion, diazinon and methidathion, among many others, to estimate their photo-oxidative degradation and the expected products.
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Affiliation(s)
- Esther Borrás
- Centro de Estudios Ambientales del Mediterráneo (Fundación CEAM), Spain; Atmospheric Pesticide Research Group of Valencia, Valencia, Spain
| | - Luis Antonio Tortajada-Genaro
- Instituto de Reconocimiento Molecular y Desarrollo Tecnológico-Departamento Química, Universitat Politècnica de València, Spain
| | - Milagros Ródenas
- Centro de Estudios Ambientales del Mediterráneo (Fundación CEAM), Spain; Atmospheric Pesticide Research Group of Valencia, Valencia, Spain
| | - Teresa Vera
- Centro de Estudios Ambientales del Mediterráneo (Fundación CEAM), Spain; Atmospheric Pesticide Research Group of Valencia, Valencia, Spain
| | - Clara Coscollá
- Public Health Laboratory of Valencia-FISABIO, 21, Avenida Catalunya, 46020 Valencia, Spain; Atmospheric Pesticide Research Group of Valencia, Valencia, Spain
| | - Vicent Yusá
- Public Health Laboratory of Valencia-FISABIO, 21, Avenida Catalunya, 46020 Valencia, Spain; Atmospheric Pesticide Research Group of Valencia, Valencia, Spain
| | - Amalia Muñoz
- Centro de Estudios Ambientales del Mediterráneo (Fundación CEAM), Spain; Atmospheric Pesticide Research Group of Valencia, Valencia, Spain.
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Muñoz A, Vera T, Ródenas M, Borrás E, Mellouki A, Treacy J, Sidebottom H. Gas-phase degradation of the herbicide ethalfluralin under atmospheric conditions. CHEMOSPHERE 2014; 95:395-401. [PMID: 24139158 DOI: 10.1016/j.chemosphere.2013.09.053] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 09/06/2013] [Accepted: 09/16/2013] [Indexed: 06/02/2023]
Abstract
The gas-phase degradation of ethalfluralin, N-ethyl-α,α,α-trifluoro-N-(2-methylallyl)-2,6-dinitro-p-toluidine, a widely used herbicide, was investigated under atmospheric conditions at the large outdoor European simulation chamber (EUPHORE) in Valencia, Spain. The photolysis of ethalfluralin was investigated under solar radiation and the mean photolysis rate coefficient was determined: J(ethalfluralin)=(1.3±0.2)×10(-3) s(-1) (JNO2=8×10(-3) s(-1)). The rate coefficients for the reactions of hydroxyl radicals and ozone with ethalfluralin in the dark were also measured under atmospheric conditions using the relative rate and the absolute rate technique, respectively. The rate coefficients values for the reactions of kOH(ethalfluralin)=(3.5±0.9)×10(-11)cm(3)molecule(-1)s(-1), and kO3(ethalfluralin)=(1.6±0.4)×10(-17) cm(3) molecule(-1) s(-1) were determined at 300±5 K and atmospheric pressure. The results show that removal of ethalfluralin from the atmosphere by reactions with OH radicals (τ ~ 4 h) or ozone (τ ~ 25 h) is slow compared to loss by photolysis. The available kinetic data suggest that the gas-phase tropospheric degradation of ethalfluralin will be controlled mainly by photolysis and provide an estimate for the tropospheric lifetime of approximately 12 min. The atmospheric implications of using ethalfluralin as a herbicide are discussed.
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Affiliation(s)
- Amalia Muñoz
- Instituto Universitario UMH-CEAM, C/Charles R. Darwin, 14, Parque Tecnológico, 46980 Paterna, Valencia, Spain.
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12
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Aschmann SM, Atkinson R. Atmospheric chemistry of methyl and ethyl N,N,N',N'-tetramethylphosphorodiamidate and O,S-dimethyl methylphosphonothioate. J Phys Chem A 2013; 117:11038-48. [PMID: 24134801 DOI: 10.1021/jp407702w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Rate constants for the reactions of OH radicals with methyl N,N,N',N'-tetramethylphosphorodiamidate [CH3OP(O)[N(CH3)2]2; MTMPDA], ethyl N,N,N',N'-tetramethylphosphorodiamidate [C2H5OP(O)[N(CH3)2]2; ETMPDA], and O,S-dimethyl methylphosphonothioate [CH3OP(O)(CH3)SCH3; OSDMMP] have been measured over the temperature range 281-349 K at atmospheric pressure of air using a relative rate method. The rate expressions obtained were 4.96 × 10(-12) e((1058±71)/T) cm(3) molecule(-1) s(-1) (1.73 × 10(-10) cm(3) molecule(-1) s(-1) at 298 K) for OH + MTMPDA, 4.46 × 10(-12) e((1144±95)/T) cm(3) molecule(-1) s(-1) (2.07 × 10(-10) cm(3) molecule(-1) s(-1) at 298 K) for OH + ETMPDA, and 1.31 × 10(-13) e((1370±229)/T) cm(3) molecule(-1) s(-1) (1.30 × 10(-11) cm(3) molecule(-1) s(-1) at 298 K) for OH + OSDMMP. The rate constant for OH + OSDMMP was independent of O2 content over the range 2.1-71% O2 at 296 ± 2 K. In addition, rate constants for the reactions of NO3 radicals and O3 with MTMPDA, of (1.4 ± 0.1) × 10(-12) cm(3) molecule(-1) s(-1) and <3.5 × 10(-19) cm(3) molecule(-1) s(-1), respectively, were measured at 297 ± 2 K. Products of the OH radical- and, for MTMPDA, NO3 radical-initiated reactions were investigated using gas chromatography and in situ atmospheric pressure ionization mass spectrometry. A product of molecular weight 180 was observed from the OH and NO3 radical-initiated reactions of MTMPDA, and this is attributed to CH3OP(O)[N(CH3)2]N(CH3)CHO. Similarly, a product of molecular weight 194 was observed from the OH + ETMPDA reaction and attributed to C2H5OP(O)[N(CH3)2]N(CH3)CHO. Possible reaction mechanisms are discussed.
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Affiliation(s)
- Sara M Aschmann
- Air Pollution Research Center, University of California , Riverside, California 92521, United States
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Tortajada-Genaro LA, Borrás E, Muñoz A. Gas-phase and particulate products from the atmospheric degradation of an isoxazole fungicide. CHEMOSPHERE 2013; 92:1035-1041. [PMID: 23602658 DOI: 10.1016/j.chemosphere.2013.03.041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 03/12/2013] [Accepted: 03/17/2013] [Indexed: 06/02/2023]
Abstract
The isoxazole structure is present in several pesticides. However, there is a lack of information about its degradation products after the release to the atmosphere. The main atmospheric reactions of hymexazol (5-methylisoxazol-3-ol), selected as representative model, were investigated at a large outdoor simulation chamber. The predominant products of atmospheric degradations were gaseous nitrogen derivates (nitric acid, nitrogen dioxide, nitrogen oxide, nitrous acid, and peroxyacetylnitrate), ozone, and small oxygenated compounds (formic acid, formaldehyde, and methylglyoxal). The aerosol yields were lower than 5%, and an OH rate-dependence was observed in the nucleation, particle growth, and size distribution. Also, the chemical composition of minor multi-oxygenated products was studied for OH-photo-oxidations. More than 20 products were detected in the gas or particulate phase. The most abundant were heterocyclic cleavage products with C4-chain and oxygenated moieties at positions 1 and 3, such as 3,4-dioxobutanoic acid, 3-oxobutanoic acid, and 3-oxobutanal. The suggested reaction pathway is the opening of heterocycle ring by the cleavage of N-O bond and C-N bond, releasing nitrogen oxides.
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Affiliation(s)
- Luis Antonio Tortajada-Genaro
- Instituto de Reconocimiento Molecular y Desarrollo Tecnológico, Departamento Química, Universitat Politècnica de València, Spain.
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14
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Al Rashidi MJ, Chakir A, Roth E. Heterogeneous Ozonolysis of Folpet and Dimethomorph: A Kinetic and Mechanistic Study. J Phys Chem A 2013; 117:2908-15. [DOI: 10.1021/jp3114896] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Mariam J. Al Rashidi
- Groupe de Spectrométrie Moléculaire et
Atmosphérique, Unité Mixte de Recherche CNRS 7331, and
UFR Sciences Exactes et Naturelles Moulin de la Housse, Université de Reims Champagne Ardenne, B.P.
1039, 51687 Reims, France
| | - Abdelkhaleq Chakir
- Groupe de Spectrométrie Moléculaire et
Atmosphérique, Unité Mixte de Recherche CNRS 7331, and
UFR Sciences Exactes et Naturelles Moulin de la Housse, Université de Reims Champagne Ardenne, B.P.
1039, 51687 Reims, France
| | - Estelle Roth
- Groupe de Spectrométrie Moléculaire et
Atmosphérique, Unité Mixte de Recherche CNRS 7331, and
UFR Sciences Exactes et Naturelles Moulin de la Housse, Université de Reims Champagne Ardenne, B.P.
1039, 51687 Reims, France
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15
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Muñoz A, Person AL, Calvé SL, Mellouki A, Borrás E, Daële V, Vera T. Studies on atmospheric degradation of diazinon in the EUPHORE simulation chamber. CHEMOSPHERE 2011; 85:724-730. [PMID: 21733545 DOI: 10.1016/j.chemosphere.2011.06.044] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 06/03/2011] [Accepted: 06/07/2011] [Indexed: 05/31/2023]
Abstract
The gas phase atmospheric degradation of diazinon has been investigated at the large outdoor European Photoreactor (EUPHORE) in Valencia, Spain. The rate constant for reaction of diazinon with OH radicals was measured using a conventional relative rate method with di-n-buthylether as reference compound being k = (3.5 ± 1.2) × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹ at 302 ± 10 K and atmospheric pressure. The available evidence indicates that tropospheric degradation of diazinon is mainly controlled by reaction with OH radicals, and that the tropospheric lifetime with respect to the OH reaction is estimated to be around 4h whereas its lifetime with respect to the photolysis is higher than 1d under our conditions. Significant aerosol formation was observed following the reaction of diazinon with OH radicals, and the main carbon-containing products detected in the particle phase were hydroxydiazinon, hydroxydiazoxon and 2-isopropyl-6-methyl-pyrimidinyl-4-ol.
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Affiliation(s)
- Amalia Muñoz
- Instituto Universitario CEAM-UMH, C/Charles R. Darwin 14, Parque Tecnológico, 46980 Paterna, Valencia, Spain.
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16
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Aschmann SM, Tuazon EC, Long WD, Atkinson R. Atmospheric chemistry of dichlorvos. J Phys Chem A 2011; 115:2756-64. [PMID: 21405039 DOI: 10.1021/jp112019s] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dichlorvos [2,2-dichlorovinyl dimethyl phosphate, (CH(3)O)(2)P(O)OCH═CCl(2)] is a relatively volatile in-use insecticide. Rate constants for its reaction with OH radicals have been measured over the temperature range 296-348 K and atmospheric pressure of air using a relative rate method. The rate expression obtained was 3.53 × 10(-13) e((1367±239)/T) cm(3) molecule(-1) s(-1), with a 298 K rate constant of (3.5 ± 0.7) × 10(-11) cm(3) molecule(-1) s(-1), where the error in the 298 K rate constant is the estimated overall uncertainty. In addition, rate constants for the reactions of NO(3) radicals and O(3) with dichlorvos, of (2.5 ± 0.5) × 10(-13) cm(3) molecule(-1) s(-1) and (1.7 ± 1.0) × 10(-19) cm(3) molecule(-1) s(-1), respectively, were measured at 296 ± 2 K. Products of the OH and NO(3) radical-initiated reactions were investigated using in situ atmospheric pressure ionization mass spectrometry (API-MS) and (OH radical reaction only) in situ Fourier transform infrared (FT-IR) spectroscopy. For the OH radical reaction, the major initial products were CO, phosgene [C(O)Cl(2)] and dimethyl phosphate [(CH(3)O)(2)P(O)OH], with equal (to within ±10%) formation yields of CO and C(O)Cl(2). The API-MS analyses were consistent with formation of (CH(3)O)(2)P(O)OH from both the OH and NO(3) radical-initiated reactions. In the atmosphere, the dominant chemical loss processes for dichlorvos will be daytime reaction with OH radicals and nighttime reaction with NO(3) radicals, with an estimated lifetime of a few hours.
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Affiliation(s)
- Sara M Aschmann
- Air Pollution Research Center, University of California, Riverside, California 92521, United States
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17
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Aschmann SM, Tuazon EC, Long WD, Atkinson R. Atmospheric Chemistry of Isopropyl Methyl Methylphosphonate and Dimethyl N,N-Dimethylphosphoroamidate. J Phys Chem A 2010; 114:3523-32. [DOI: 10.1021/jp911668h] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sara M. Aschmann
- Air Pollution Research Center, Department of Environmental Sciences, and Department of Chemistry, University of California, Riverside, California 92521
| | - Ernesto C. Tuazon
- Air Pollution Research Center, Department of Environmental Sciences, and Department of Chemistry, University of California, Riverside, California 92521
| | - William D. Long
- Air Pollution Research Center, Department of Environmental Sciences, and Department of Chemistry, University of California, Riverside, California 92521
| | - Roger Atkinson
- Air Pollution Research Center, Department of Environmental Sciences, and Department of Chemistry, University of California, Riverside, California 92521
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18
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Coleman BK, Wells JR, Nazaroff WW. Investigating ozone-induced decomposition of surface-bound permethrin for conditions in aircraft cabins. INDOOR AIR 2010; 20:61-71. [PMID: 20028435 DOI: 10.1111/j.1600-0668.2009.00627.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
UNLABELLED The reaction of ozone with permethrin can potentially form phosgene. Published evidence on ozone levels and permethrin surface concentrations in aircraft cabins indicated that significant phosgene formation might occur in this setting. A derivatization technique was developed to detect phosgene with a lower limit of detection of 2 ppb. Chamber experiments were conducted with permethrin-coated materials (glass, carpet, seat fabric, and plastic) exposed to ozone under cabin-relevant conditions (150 ppb O(3), 4.5/h air exchange rate, <1% relative humidity, 1700 ng/cm(2) of permethrin). Phosgene was not detected in these experiments. Reaction of ozone with permethrin appears to be hindered by the electron-withdrawing chlorine atoms adjacent to the double bond in permethrin. Experimental results indicate that the upper limit on the reaction probability of ozone with surface-bound permethrin is approximately 10(-7). Extrapolation by means of material-balance modeling indicates that the upper limit on the phosgene level in aircraft cabins resulting from this chemistry is approximately 1 microg/m(3) or approximately 0.3 ppb. It was thus determined that phosgene formation, if it occurs in aircraft cabins, is not likely to exceed relevant, health-based phosgene exposure guidelines. PRACTICAL IMPLICATIONS Phosgene formation from ozone-initiated oxidation of permethrin in the aircraft cabin environment, if it occurs, is estimated to generate levels below the California Office of Environmental Health Hazard Assessment acute reference exposure level of 4 microg/m(3) or approximately 1 ppb.
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Affiliation(s)
- B K Coleman
- Department of Civil and Environmental Engineering, University of California-Berkeley, CA 94720-1710,USA
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19
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Segal-Rosenheimer M, Dubowski Y. Photolysis of methyl-parathion thin films: Products, kinetics and quantum yields under different atmospheric conditions. J Photochem Photobiol A Chem 2010. [DOI: 10.1016/j.jphotochem.2009.11.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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20
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Cáceres T, Megharaj M, Venkateswarlu K, Sethunathan N, Naidu R. Fenamiphos and related organophosphorus pesticides: environmental fate and toxicology. REVIEWS OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2010; 205:117-162. [PMID: 20044796 DOI: 10.1007/978-1-4419-5623-1_3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In this review, we emphasize recent research on the fate, transport, and metabolism of tree selected organophosphorus pesticides (fenamiphos, isofenphos, and coumaphos) in soil an water environments. This review is also concerned with the side effects of these pesticides on nontarget organisms. Despite the fact that fenamiphos is not very mobile, its oxides have been detected in the groundwaters of Western Australia. Most organophosphorus pesticides generally are chemically unstable and underfo microbial degradation in soil and water environments. Enhanced biodegradation of many organophosphorus pesticides upon their repeted applications to soil and water is well established. Myriads of soil microorganisms, bacteria in particular, exhibit an exceptional capacity to transform many organophosphorus pesticides. Fenamiphos can undergo rapid microbially mediated degradation via oxidation to its oxides (sulfoxide and sulfone) and eventually to CO2 and water in soils, or via hydrolysis, in cultures of the soil bacterium, Brevinbacterium sp. There is evidence for enhanced biodegradation of (i) isofenphos in soils with a long history of use and (ii) coumaphos in cattle dip by bacterial cultures to chlorferon and diethylthiophosphoric acid.
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Affiliation(s)
- Tanya Cáceres
- Centre for Environmental Risk Assessment and Remediation, Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, University of South Australia, Mawson Lakes, 5095 SA, Australia
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21
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Yusà V, Coscollà C, Mellouki W, Pastor A, de la Guardia M. Sampling and analysis of pesticides in ambient air. J Chromatogr A 2009; 1216:2972-83. [DOI: 10.1016/j.chroma.2009.02.019] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Revised: 02/05/2009] [Accepted: 02/09/2009] [Indexed: 11/26/2022]
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22
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Sauret N, Wortham H, Strekowski R, Herckès P, Nieto LI. Comparison of annual dry and wet deposition fluxes of selected pesticides in Strasbourg, France. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2009; 157:303-312. [PMID: 18676073 DOI: 10.1016/j.envpol.2008.06.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2008] [Revised: 06/19/2008] [Accepted: 06/22/2008] [Indexed: 05/26/2023]
Abstract
This work summarizes the results of a study of atmospheric wet and dry deposition fluxes of Deisopropyl-atrazine (DEA), Desethyl-atrazine (DET), Atrazine, Terbuthylazine, Alachlor, Metolachlor, Diflufenican, Fenoxaprop-p-ethyl, Iprodione, Isoproturon and Cymoxanil pesticides conducted in Strasbourg, France, from August 2000 through August 2001. The primary objective of this work was to calculate the total atmospheric pesticide deposition fluxes induced by atmospheric particles. To do this, a modified one-dimensional cloud water deposition model was used. All precipitation and deposition samples were collected at an urban forested park environment setting away from any direct point pesticide sources. The obtained deposition fluxes induced by atmospheric particles over a forested area showed that the dry deposition flux strongly contributes to the total deposition flux. The dry particle deposition fluxes are shown to contribute from 4% (DET) to 60% (cymoxanil) to the total deposition flux (wet+dry).
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Affiliation(s)
- Nathalie Sauret
- Marseilles University, Laboratoire Chimie Provence-UMR 6264, Campus Saint Charles, Case 29, 3 Place Victor Hugo, 13331 Marseilles Cedex 03, France
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23
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Aschmann SM, Long WD, Atkinson R. Rate Constants for the Gas-Phase Reactions of OH Radicals with Dimethyl Phosphonate over the Temperature Range of 278−351 K and for a Series of Other Organophosphorus Compounds at ∼280 K. J Phys Chem A 2008; 112:4793-9. [DOI: 10.1021/jp800899y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sara M. Aschmann
- Air Pollution Research Center, University of California, Riverside, California 92521
| | - William D. Long
- Air Pollution Research Center, University of California, Riverside, California 92521
| | - Roger Atkinson
- Air Pollution Research Center, University of California, Riverside, California 92521
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24
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Sleiman M, Ferronato C, Chovelon JM. Photocatalytic removal of pesticide dichlorvos from indoor air: a study of reaction parameters, intermediates and mineralization. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:3018-3024. [PMID: 18497160 DOI: 10.1021/es702425q] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
This paper presents for the first time the investigation of TiO2 photocatalysis for the removal of pesticides in gas phase. Dichlorvos was used as a model pesticide, and experiments were carried out using both static and dynamic reaction systems to explore the different aspects of the process. Thus, adsorption, reaction kinetics, and the influence of several operational parameters such as relative humidity (RH), inlet concentration, flow rate, and association of TiO2 with activated carbon (AC) were all examined in detail. Furthermore, a special attention was devoted to the analysis of reaction products by means of various analytical techniques such as Fourier transform infrared spectroscopy, automated thermal desorption technique coupled to gas chromatography-mass spectrometry instrument, gas chromatography equipped with a pulse discharge helium photoionization detector, and ion chromatography. The results showed an immediate and total removal of dichlorvos at ppbv levels (50-350 ppbv) along with a high mineralization extent (50-85%) into harmless final products (CO2, HCl, PO43-). Moreover, RH was found to significantly affectthe mineralization extent and the formation of reaction intermediates. On the basis of identification data, direct charge transfer and chlorine radical (Cl*) attack were shown to play a key role in the reaction mechanism at low RH, whereas at high RH, HO* radicals were the predominant active species.
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Affiliation(s)
- Mohamad Sleiman
- Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), UMR 5256 CNRS/ Université de Lyon 1, 2 Avenue Albert Einstein, F-69626 Villeurbanne, France.
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25
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Zhang Q, Qu X, Wang W. Mechanism of OH-initiated atmospheric photooxidation of dichlorvos: a quantum mechanical study. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2007; 41:6109-6116. [PMID: 17937289 DOI: 10.1021/es0628001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Dichlorvos (2,2-dichlorovinyl phosphate, DDVP) is a widely used organophosphorus insecticide. DDVP may be released into the atmosphere, where it may be transported for long distances and undergo chemical transformations. The mechanisms of the atmospheric reactions of DDVP have not been fully understood because of the short lifetime of its oxidized radical intermediates and the extreme difficulty in the detection of these species experimentally. In this paper, we carried out molecular orbital theory calculations for the OH-initiated atmospheric photooxidation of DDVP. The profile of the potential energy surface was constructed, and the possible channels involved in the reaction are discussed. Several energetically favorable reaction pathways are revealed for the first time. The calculated results were compared with the available experimental observations. Four product pathways are energetically feasible for DDVP degradation initiated by OH radicals in the atmosphere and are consistent with the experimentally observed products CCl2O and CO, but the additional products CCl2CHO, (CH3O)2P(O)OH, HO2, and a closed-shell organophosphorus compound denoted P10 are also predicted.
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Affiliation(s)
- Qingzhu Zhang
- Environment Research Institute, Shandong University, Jinan 250100, PR China
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26
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Le Person A, Mellouki A, Muñoz A, Borras E, Martin-Reviejo M, Wirtz K. Trifluralin: photolysis under sunlight conditions and reaction with HO* radicals. CHEMOSPHERE 2007; 67:376-83. [PMID: 17166544 DOI: 10.1016/j.chemosphere.2006.09.023] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2006] [Revised: 09/08/2006] [Accepted: 09/13/2006] [Indexed: 05/13/2023]
Abstract
The gas phase atmospheric degradation of trifluralin (a widely used herbicide) has been investigated at the EUPHORE facility. Its photolysis has been studied under sunlight conditions and its reaction rate constant with HO() radicals was measured using the relative rate method. Using 1,3,5-trimethylbenzene as reference compound, the rate constant of HO() reaction with trifluralin was obtained to be [formula: see text] The mean photolysis rate measured under solar radiation was [formula: see text] . The photolysis of trifluralin was found to generate organic aerosols with a yield of (20 +/-10)%. The data obtained enabled us to discuss the atmospheric fate of trifluralin in the gas phase.
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Affiliation(s)
- A Le Person
- LCSR-CNRS, 1C Avenue de la Recherche scientifique, 45071 Orléans cedex 02, France
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27
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Tuazon EC, Aschmann SM, Atkinson R. Products of the Gas-Phase Reactions of OH Radicals with (C2H5O)2P(S)CH3 and (C2H5O)3PS. J Phys Chem A 2007; 111:916-24. [PMID: 17266233 DOI: 10.1021/jp067274e] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Products of the gas-phase reactions of OH radicals with O,O-diethyl methylphosphonothioate [(C2H5O)2P(S)CH3, DEMPT] and O,O,O-triethyl phosphorothioate [(C2H5O)3PS, TEPT] have been investigated at room temperature and atmospheric pressure of air using in situ atmospheric pressure ionization mass spectrometry (API-MS) and, for the TEPT reaction, gas chromatography and in situ Fourier transform infrared (FT-IR) spectroscopy. Combined with products quantified previously by gas chromatography, the products observed were: from the DEMPT reaction, (C2H5O)2P(O)CH3 (21+/-4% yield) and C2H5OP(S)(CH3)OH or C2H5OP(O)(CH3)SH (presumed to be C2H5OP(O)(CH3)SH by analogy with the TEPT reaction); and from the TEPT reaction, (C2H5O)3PO (54-62% yield), SO2 (67+/-10% yield), CH3CHO (22-40% yield) and, tentatively, (C2H5O)2P(O)SH. The FT-IR analyses showed that the formation yields of HCHO, CO, CO2, peroxyacetyl nitrate [CH3C(O)OONO2], organic nitrates, and acetates from the TEPT reaction were <5%, 3+/-1%, <7%, <2%, 5+/-3%, and 3+/-2%, respectively. Possible reaction mechanisms are discussed.
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Affiliation(s)
- Ernesto C Tuazon
- Air Pollution Research Center, University of California, Riverside, California 92521, USA
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28
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Aschmann SM, Atkinson R. Kinetic and Product Study of the Gas-Phase Reactions of OH Radicals, NO3 Radicals, and O3 with (C2H5O)2P(S)CH3 and (C2H5O)3PS. J Phys Chem A 2006; 110:13029-35. [PMID: 17134163 DOI: 10.1021/jp065382v] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Rate constants for the reactions of OH radicals and NO3 radicals with O,O-diethyl methylphosphonothioate [(C(2)H(5)O)(2)P(S)CH(3); DEMPT] and O,O,O-triethyl phosphorothioate [(C(2)H(5)O)(3)PS; TEPT] have been measured using relative rate methods at atmospheric pressure of air over the temperature range 296-348 K for the OH radical reactions and at 296 +/- 2 K for the NO(3) radical reactions. At 296 +/- 2 K, the rate constants obtained for the OH radical reactions (in units of 10(-11) cm(3) molecule(-1) s(-1)) were 20.4 +/- 0.8 and 7.92 +/- 0.27 for DEMPT and TEPT, respectively, and those for the NO(3) radical reactions (in units of 10(-15) cm(3) molecule(-1) s(-1)) were 2.01 +/- 0.20 and 1.03 +/- 0.10, respectively. Upper limits to the rate constants for the reactions of O(3) with DEMPT and TEPT of <6 x 10(-20) cm(3) molecule(-1) s(-1) were determined in each case. Rate constants for the OH radical reactions, measured relative to k(OH + alpha-pinene) = 1.21 x 10(-11) e(436/T) cm(3) molecule(-1) s(-1), resulted in the Arrhenius expressions k(OH + DEMPT) = 1.08 x 10(-11) e(871+/-25)/T cm(3) molecule(-1) s(-1) and k(OH + TEPT) = 8.21 x 10(-13) e(1353+/-49)/T cm(3) molecule(-1) s(-1) over the temperature range 296-348 K, where the indicated errors are two least-squares standard deviations and do not include the uncertainties in the reference rate constant. Diethyl methylphosphonate was identified and quantified from the OH radical and NO(3) radical reactions with DEMPT, with formation yields of 21 +/- 4%, independent of temperature, from the OH radical reaction and 62 +/- 11% from the NO(3) radical reaction at 296 +/- 2 K. Similarly, triethyl phosphate was identified and quantified from the OH radical and NO(3) radical reactions with TEPT, with formation yields of 56 +/- 9%, independent of temperature, from the OH radical reaction and 78 +/- 15% from the NO(3) radical reaction at 296 +/- 2 K.
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Affiliation(s)
- Sara M Aschmann
- Air Pollution Research Center, Department of Environmental Sciences, and Department of Chemistry, University of California, Riverside, California 92521, USA
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