The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform

Wei Zheng - One of the best experts on this subject based on the ideXlab platform.

  • Short communication Determining breakthrough of the soil fumigant Chloropicrin from 120 mg XAD-4 sorbent tubes
    2020
    Co-Authors: Daniel J Ashworth, Wei Zheng
    Abstract:

    The emission to the atmosphere of soil fumigants such as Chloropicrin represents a potentially important human exposure pathway. Commonly, determining the air concentration of fumigants is carried out by pumping air through sorbent tubes which chemically retain the fumigant. In order to obtain an accurate measurement, it is essential that the fumigant does not break through the sorbent tubes, since this would result in an underestimation. Using a simple apparatus, we tested the potential for Chloropicrin breakthrough from 120 mg XAD-4 sorbent tubes. The effects of Chloropicrin loading (0.33 and 3.3 mg) and air flow rate (50 and 1000 mL min 1 ) on the transport of Chloropicrin through six XAD-4 tubes (connected in series) were examined over time periods ranging from 1 to 360 min. The higher flow rate led to rapid and high breakthrough of the Chloropicrin, especially at the longer time periods. At 360 min, all six tubes together retained only 46–54% (depending on initial loading) of the added Chloropicrin. At the lower flow rate, essentially all of the added Chloropicrin was always retained on the first two tubes. The effect of flow rate was greater than that of initial Chloropicrin loading and sampling time. It is concluded that when 120 mg XAD-4 tubes are used in soil fumigant emission studies, it should be at low flow rates only and always with at least one back-up tube. r 2008 Elsevier Ltd. All rights reserved.

  • effect of deep injection on field scale emissions of 1 3 dichloropropene and Chloropicrin from bare soil
    Atmospheric Environment, 2016
    Co-Authors: Scott R Yates, Daniel J Ashworth, Wei Zheng, J A Knuteson, I J Van Wesenbeeck
    Abstract:

    Abstract Fumigating soil is important for the production of many high-value vegetable, fruit, and tree crops, but fumigants are toxic pesticides with relatively high volatility, which can lead to significant atmospheric emissions. A field experiment was conducted to measure emissions and subsurface diffusion of a mixture of 1,3-dichloropropene (1,3-D) and Chloropicrin after shank injection to bare soil at 61 cm depth (i.e., deep injection). Three on-field methods, the aerodynamic (ADM), integrated horizontal flux (IHF), and theoretical profile shape (TPS) methods, were used to obtain fumigant flux density and cumulative emission values. Two air dispersion models (CALPUFF and ISCST3) were also used to back-calculate the flux density using air concentration measurements surrounding the fumigated field. Emissions were continuously measured for 16 days and the daily peak emission rates for the five methods ranged from 13 to 33 μg m−2 s−1 for 1,3-D and 0.22–3.2 μg m−2 s−1 for Chloropicrin. Total 1,3-D mass lost to the atmosphere was approximately 23–41 kg ha−1, or 15–27% of the applied active ingredient and total mass loss of Chloropicrin was

  • emissions of 1 3 dichloropropene and Chloropicrin after soil fumigation under field conditions
    Journal of Agricultural and Food Chemistry, 2015
    Co-Authors: Scott R Yates, Daniel J Ashworth, Wei Zheng, Qiaoping Zhang, J A Knuteson, Ian J Van Wessenbeeck
    Abstract:

    Soil fumigation is an important agronomic practice in the production of many high-value vegetable and fruit crops, but the use of chemical fumigants can lead to excessive atmospheric emissions. A large-scale (2.9 ha) field experiment was conducted to obtain volatilization and cumulative emission rates for two commonly used soil fumigants under typical agronomic practices: 1,3-dichloropropene (1,3-D) and Chloropicrin. The aerodynamic method and the indirect back-calculation method using ISCST3 and CALPUFF dispersion models were used to estimate flux loss from the treated field. Over the course of the experiment, the daily peak volatilization rates ranged from 12 to 30 μg m–2 s–1 for 1,3-D and from 0.7 to 2.6 μg m–2 s–1 for Chloropicrin. Depending on the method used for quantification, total emissions of 1,3-D and Chloropicrin, respectively, ranged from 16 to 35% and from 0.3 to 1.3% of the applied fumigant. A soil incubation study showed that the low volatilization rates measured for Chloropicrin were due ...

  • determining breakthrough of the soil fumigant Chloropicrin from 120 mg xad 4 sorbent tubes
    Atmospheric Environment, 2008
    Co-Authors: Daniel J Ashworth, Wei Zheng, Scott R Yates
    Abstract:

    Abstract The emission to the atmosphere of soil fumigants such as Chloropicrin represents a potentially important human exposure pathway. Commonly, determining the air concentration of fumigants is carried out by pumping air through sorbent tubes which chemically retain the fumigant. In order to obtain an accurate measurement, it is essential that the fumigant does not break through the sorbent tubes, since this would result in an underestimation. Using a simple apparatus, we tested the potential for Chloropicrin breakthrough from 120 mg XAD-4 sorbent tubes. The effects of Chloropicrin loading (0.33 and 3.3 mg) and air flow rate (50 and 1000 mL min−1) on the transport of Chloropicrin through six XAD-4 tubes (connected in series) were examined over time periods ranging from 1 to 360 min. The higher flow rate led to rapid and high breakthrough of the Chloropicrin, especially at the longer time periods. At 360 min, all six tubes together retained only 46–54% (depending on initial loading) of the added Chloropicrin. At the lower flow rate, essentially all of the added Chloropicrin was always retained on the first two tubes. The effect of flow rate was greater than that of initial Chloropicrin loading and sampling time. It is concluded that when 120 mg XAD-4 tubes are used in soil fumigant emission studies, it should be at low flow rates only and always with at least one back-up tube.

  • dechlorination of Chloropicrin and 1 3 dichloropropene by hydrogen sulfide species redox and nucleophilic substitution reactions
    Journal of Agricultural and Food Chemistry, 2006
    Co-Authors: Wei Zheng, Scott R Yates, Sharon K Papiernik
    Abstract:

    The chlorinated fumigants Chloropicrin (trichloronitromethane) and 1,3-dichloropropene (1,3-D) are extensively used in agricultural production for the control of soilborne pests. The reaction of these two fumigants with hydrogen sulfide species (H2S and HS - ) was examined in well-defined anoxic aqueous solutions. Chloropicrin underwent an extremely rapid redox reaction in the hydrogen sulfide solution. Transformation products indicated reductive dechlorination of Chloropicrin by hydrogen sulfide species to produce dichloro- and chloronitromethane. The transformation of Chloropicrin in hydrogen sulfide solution significantly increased with increasing pH, indicating that H2S is less reactive toward Chloropicrin than HS - is. For both 1,3-D isomers, kinetics and transformation products analysis revealed that the reaction between 1,3-D and hydrogen sulfide species is an SN2 nucleophilic substitution process, in which the chlorine at C3 of 1,3-D is substituted by the sulfur nucleophile to form corresponding mercaptans. The 50% disappearance time (DT50) of 1,3-D decreased with increasing hydrogen sulfide species concentration at a constant pH. Transformation of 1,3-D was more rapid at high pH, suggesting that the reactivity of hydrogen sulfide species in the experimental system stems primarily from HS - . Because of the relatively low smell threshold values and potential environmental persistence of organic sulfur products yielded by the reaction of 1,3-D and HS - , the effects of reduced sulfide species should be considered in the development of alternative fumigation practices, especially in the integrated application of sulfur-containing fertilizers.

Scott R Yates - One of the best experts on this subject based on the ideXlab platform.

  • effect of deep injection on field scale emissions of 1 3 dichloropropene and Chloropicrin from bare soil
    Atmospheric Environment, 2016
    Co-Authors: Scott R Yates, Daniel J Ashworth, Wei Zheng, J A Knuteson, I J Van Wesenbeeck
    Abstract:

    Abstract Fumigating soil is important for the production of many high-value vegetable, fruit, and tree crops, but fumigants are toxic pesticides with relatively high volatility, which can lead to significant atmospheric emissions. A field experiment was conducted to measure emissions and subsurface diffusion of a mixture of 1,3-dichloropropene (1,3-D) and Chloropicrin after shank injection to bare soil at 61 cm depth (i.e., deep injection). Three on-field methods, the aerodynamic (ADM), integrated horizontal flux (IHF), and theoretical profile shape (TPS) methods, were used to obtain fumigant flux density and cumulative emission values. Two air dispersion models (CALPUFF and ISCST3) were also used to back-calculate the flux density using air concentration measurements surrounding the fumigated field. Emissions were continuously measured for 16 days and the daily peak emission rates for the five methods ranged from 13 to 33 μg m−2 s−1 for 1,3-D and 0.22–3.2 μg m−2 s−1 for Chloropicrin. Total 1,3-D mass lost to the atmosphere was approximately 23–41 kg ha−1, or 15–27% of the applied active ingredient and total mass loss of Chloropicrin was

  • emissions of 1 3 dichloropropene and Chloropicrin after soil fumigation under field conditions
    Journal of Agricultural and Food Chemistry, 2015
    Co-Authors: Scott R Yates, Daniel J Ashworth, Wei Zheng, Qiaoping Zhang, J A Knuteson, Ian J Van Wessenbeeck
    Abstract:

    Soil fumigation is an important agronomic practice in the production of many high-value vegetable and fruit crops, but the use of chemical fumigants can lead to excessive atmospheric emissions. A large-scale (2.9 ha) field experiment was conducted to obtain volatilization and cumulative emission rates for two commonly used soil fumigants under typical agronomic practices: 1,3-dichloropropene (1,3-D) and Chloropicrin. The aerodynamic method and the indirect back-calculation method using ISCST3 and CALPUFF dispersion models were used to estimate flux loss from the treated field. Over the course of the experiment, the daily peak volatilization rates ranged from 12 to 30 μg m–2 s–1 for 1,3-D and from 0.7 to 2.6 μg m–2 s–1 for Chloropicrin. Depending on the method used for quantification, total emissions of 1,3-D and Chloropicrin, respectively, ranged from 16 to 35% and from 0.3 to 1.3% of the applied fumigant. A soil incubation study showed that the low volatilization rates measured for Chloropicrin were due ...

  • determining breakthrough of the soil fumigant Chloropicrin from 120 mg xad 4 sorbent tubes
    Atmospheric Environment, 2008
    Co-Authors: Daniel J Ashworth, Wei Zheng, Scott R Yates
    Abstract:

    Abstract The emission to the atmosphere of soil fumigants such as Chloropicrin represents a potentially important human exposure pathway. Commonly, determining the air concentration of fumigants is carried out by pumping air through sorbent tubes which chemically retain the fumigant. In order to obtain an accurate measurement, it is essential that the fumigant does not break through the sorbent tubes, since this would result in an underestimation. Using a simple apparatus, we tested the potential for Chloropicrin breakthrough from 120 mg XAD-4 sorbent tubes. The effects of Chloropicrin loading (0.33 and 3.3 mg) and air flow rate (50 and 1000 mL min−1) on the transport of Chloropicrin through six XAD-4 tubes (connected in series) were examined over time periods ranging from 1 to 360 min. The higher flow rate led to rapid and high breakthrough of the Chloropicrin, especially at the longer time periods. At 360 min, all six tubes together retained only 46–54% (depending on initial loading) of the added Chloropicrin. At the lower flow rate, essentially all of the added Chloropicrin was always retained on the first two tubes. The effect of flow rate was greater than that of initial Chloropicrin loading and sampling time. It is concluded that when 120 mg XAD-4 tubes are used in soil fumigant emission studies, it should be at low flow rates only and always with at least one back-up tube.

  • dechlorination of Chloropicrin and 1 3 dichloropropene by hydrogen sulfide species redox and nucleophilic substitution reactions
    Journal of Agricultural and Food Chemistry, 2006
    Co-Authors: Wei Zheng, Scott R Yates, Sharon K Papiernik
    Abstract:

    The chlorinated fumigants Chloropicrin (trichloronitromethane) and 1,3-dichloropropene (1,3-D) are extensively used in agricultural production for the control of soilborne pests. The reaction of these two fumigants with hydrogen sulfide species (H2S and HS - ) was examined in well-defined anoxic aqueous solutions. Chloropicrin underwent an extremely rapid redox reaction in the hydrogen sulfide solution. Transformation products indicated reductive dechlorination of Chloropicrin by hydrogen sulfide species to produce dichloro- and chloronitromethane. The transformation of Chloropicrin in hydrogen sulfide solution significantly increased with increasing pH, indicating that H2S is less reactive toward Chloropicrin than HS - is. For both 1,3-D isomers, kinetics and transformation products analysis revealed that the reaction between 1,3-D and hydrogen sulfide species is an SN2 nucleophilic substitution process, in which the chlorine at C3 of 1,3-D is substituted by the sulfur nucleophile to form corresponding mercaptans. The 50% disappearance time (DT50) of 1,3-D decreased with increasing hydrogen sulfide species concentration at a constant pH. Transformation of 1,3-D was more rapid at high pH, suggesting that the reactivity of hydrogen sulfide species in the experimental system stems primarily from HS - . Because of the relatively low smell threshold values and potential environmental persistence of organic sulfur products yielded by the reaction of 1,3-D and HS - , the effects of reduced sulfide species should be considered in the development of alternative fumigation practices, especially in the integrated application of sulfur-containing fertilizers.

  • effect of combined application of methyl isothiocyanate and Chloropicrin on their transformation
    Journal of Environmental Quality, 2004
    Co-Authors: Wei Zheng, Scott R Yates, Sharon K Papiernik
    Abstract:

    Combining several soil fumigants to increase the broad spectrum of pest control is a common fumigation practice in current production agriculture. In this study, we investigated the effect of combined application of Chloropicrin and methyl isothiocyanate (MITC) on their transformations and persistence in the environment. In aqueous solution, no direct reaction between MITC and Chloropicrin occurred and relatively slow rates of hydrolysis of these compounds were observed in aquatic environments free of suspended solids. The transformation of Chloropicrin, however, was accelerated in aqueous solution with MITC because of a reduction reaction with bisulfide (HS ), which is a by-product of MITC hydrolysis. In soil, when fumigants were applied simultaneously, the degradation of MITC was suppressed under the bi-fumigant application due to the inhibition of soil microbial activity and a possible abiotic competition with Chloropicrin for a limited number of reaction sites on the surface of soil particles. However, the degradation rate of Chloropicrin was significantly enhanced in the bi-fumigant soil system, which was primarily attributed to the reaction of Chloropicrin and HS . Two sequential application approaches were developed to investigate the feasibility of the combined application of metam sodium (parent compound of MITC) and Chloropicrin in soil and assess their potential effects on environmental fate. For both application sequences, the degradation of Chloropicrin was accelerated and that of MITC, as a major breakdown product of metam sodium, was inhibited in soil.

Daniel J Ashworth - One of the best experts on this subject based on the ideXlab platform.

  • Short communication Determining breakthrough of the soil fumigant Chloropicrin from 120 mg XAD-4 sorbent tubes
    2020
    Co-Authors: Daniel J Ashworth, Wei Zheng
    Abstract:

    The emission to the atmosphere of soil fumigants such as Chloropicrin represents a potentially important human exposure pathway. Commonly, determining the air concentration of fumigants is carried out by pumping air through sorbent tubes which chemically retain the fumigant. In order to obtain an accurate measurement, it is essential that the fumigant does not break through the sorbent tubes, since this would result in an underestimation. Using a simple apparatus, we tested the potential for Chloropicrin breakthrough from 120 mg XAD-4 sorbent tubes. The effects of Chloropicrin loading (0.33 and 3.3 mg) and air flow rate (50 and 1000 mL min 1 ) on the transport of Chloropicrin through six XAD-4 tubes (connected in series) were examined over time periods ranging from 1 to 360 min. The higher flow rate led to rapid and high breakthrough of the Chloropicrin, especially at the longer time periods. At 360 min, all six tubes together retained only 46–54% (depending on initial loading) of the added Chloropicrin. At the lower flow rate, essentially all of the added Chloropicrin was always retained on the first two tubes. The effect of flow rate was greater than that of initial Chloropicrin loading and sampling time. It is concluded that when 120 mg XAD-4 tubes are used in soil fumigant emission studies, it should be at low flow rates only and always with at least one back-up tube. r 2008 Elsevier Ltd. All rights reserved.

  • effect of deep injection on field scale emissions of 1 3 dichloropropene and Chloropicrin from bare soil
    Atmospheric Environment, 2016
    Co-Authors: Scott R Yates, Daniel J Ashworth, Wei Zheng, J A Knuteson, I J Van Wesenbeeck
    Abstract:

    Abstract Fumigating soil is important for the production of many high-value vegetable, fruit, and tree crops, but fumigants are toxic pesticides with relatively high volatility, which can lead to significant atmospheric emissions. A field experiment was conducted to measure emissions and subsurface diffusion of a mixture of 1,3-dichloropropene (1,3-D) and Chloropicrin after shank injection to bare soil at 61 cm depth (i.e., deep injection). Three on-field methods, the aerodynamic (ADM), integrated horizontal flux (IHF), and theoretical profile shape (TPS) methods, were used to obtain fumigant flux density and cumulative emission values. Two air dispersion models (CALPUFF and ISCST3) were also used to back-calculate the flux density using air concentration measurements surrounding the fumigated field. Emissions were continuously measured for 16 days and the daily peak emission rates for the five methods ranged from 13 to 33 μg m−2 s−1 for 1,3-D and 0.22–3.2 μg m−2 s−1 for Chloropicrin. Total 1,3-D mass lost to the atmosphere was approximately 23–41 kg ha−1, or 15–27% of the applied active ingredient and total mass loss of Chloropicrin was

  • emissions of 1 3 dichloropropene and Chloropicrin after soil fumigation under field conditions
    Journal of Agricultural and Food Chemistry, 2015
    Co-Authors: Scott R Yates, Daniel J Ashworth, Wei Zheng, Qiaoping Zhang, J A Knuteson, Ian J Van Wessenbeeck
    Abstract:

    Soil fumigation is an important agronomic practice in the production of many high-value vegetable and fruit crops, but the use of chemical fumigants can lead to excessive atmospheric emissions. A large-scale (2.9 ha) field experiment was conducted to obtain volatilization and cumulative emission rates for two commonly used soil fumigants under typical agronomic practices: 1,3-dichloropropene (1,3-D) and Chloropicrin. The aerodynamic method and the indirect back-calculation method using ISCST3 and CALPUFF dispersion models were used to estimate flux loss from the treated field. Over the course of the experiment, the daily peak volatilization rates ranged from 12 to 30 μg m–2 s–1 for 1,3-D and from 0.7 to 2.6 μg m–2 s–1 for Chloropicrin. Depending on the method used for quantification, total emissions of 1,3-D and Chloropicrin, respectively, ranged from 16 to 35% and from 0.3 to 1.3% of the applied fumigant. A soil incubation study showed that the low volatilization rates measured for Chloropicrin were due ...

  • determining breakthrough of the soil fumigant Chloropicrin from 120 mg xad 4 sorbent tubes
    Atmospheric Environment, 2008
    Co-Authors: Daniel J Ashworth, Wei Zheng, Scott R Yates
    Abstract:

    Abstract The emission to the atmosphere of soil fumigants such as Chloropicrin represents a potentially important human exposure pathway. Commonly, determining the air concentration of fumigants is carried out by pumping air through sorbent tubes which chemically retain the fumigant. In order to obtain an accurate measurement, it is essential that the fumigant does not break through the sorbent tubes, since this would result in an underestimation. Using a simple apparatus, we tested the potential for Chloropicrin breakthrough from 120 mg XAD-4 sorbent tubes. The effects of Chloropicrin loading (0.33 and 3.3 mg) and air flow rate (50 and 1000 mL min−1) on the transport of Chloropicrin through six XAD-4 tubes (connected in series) were examined over time periods ranging from 1 to 360 min. The higher flow rate led to rapid and high breakthrough of the Chloropicrin, especially at the longer time periods. At 360 min, all six tubes together retained only 46–54% (depending on initial loading) of the added Chloropicrin. At the lower flow rate, essentially all of the added Chloropicrin was always retained on the first two tubes. The effect of flow rate was greater than that of initial Chloropicrin loading and sampling time. It is concluded that when 120 mg XAD-4 tubes are used in soil fumigant emission studies, it should be at low flow rates only and always with at least one back-up tube.

Maija Pesonen - One of the best experts on this subject based on the ideXlab platform.

  • Chloropicrin-induced toxicity in the respiratory system.
    Toxicology Letters, 2020
    Co-Authors: Maija Pesonen, Kirsi Vahakangas
    Abstract:

    Abstract Chloropicrin is a volatile and reactive chemical that has been utilized as a warfare agent and a pesticide to fumigate soil against insects, fungi and nematodes. It poses a health risk to humans and animals if inhaled. The main source of Chloropicrin exposure is occupational and occurs during its manufacture, transport and fumigation. Chloropicrin is toxic via all routes of exposure but the main route of systemic exposure is inhalation of the ambient air. Thus, the toxicity mainly affects the respiratory system. After a low level exposure, the first sign is irritation of the upper respiratory tract and eyes. Irritation is mediated by the sensory nerve fibers, which coordinate further activation of various protective reflexes. Chloropicrin-induced irritation is generally reversible but can alter airway responsiveness to other inhalation toxicants. Severe exposures cause injuries in the respiratory tract, inflammation, and even life-threatening edema. Much of the Chloropicrin-caused symptoms and toxicity in the respiratory system displays similarities with those evoked by chlorine, which is also a breakdown product of Chloropicrin. This review summarizes the latest information on Chloropicrin with emphasis on the toxicity in the respiratory system. The data indicates that oxidative stress, modification of macromolecules, mutations, dysfunctions of cell organelles and cell death are involved in acute Chloropicrin-induced toxicity in the respiratory system.

  • molecular targets of Chloropicrin in human airway epithelial cells
    Toxicology in Vitro, 2017
    Co-Authors: Maija Pesonen, Kirsi Rilla, Markku Pasanen, Markus Storvik, Jaana Rysa, Kirsi Vahakangas
    Abstract:

    Abstract Chloropicrin is a vaporizing, irritating compound that causes complications in the respiratory system when inhaled. In this study, we examined the effects of exposure to Chloropicrin for 24 h on ultrastructure and global gene expression in primary human bronchial epithelial cells. The treatment increased the number of round and shrunken cells, which detached from culture plates more readily than the untreated control cells. Transmission electron microscopy revealed some swollen mitochondria and the appearance of autophagy/lysosome type of vacuoles in the treated cells. However, the main alteration in the ultrastructure of the treated cells was the presence of aggregated and slightly deformed cytoskeleton structures. Furthermore, confocal microscopy and immunoblotting indicated that cytoskeletal β-tubulin protein is a probable target of Chloropicrin exposure. Ingenuity Pathway Analysis (IPA) of differentially expressed microarray data (fold change > ± 2 compared to controls considered) revealed that the top molecular functions were cell growth and proliferation. The main enriched top canonical pathways identified by IPA were associated with EIF2-signalling, protein ubiquitination pathway, glycolysis and mitochondrial dysfunction. Furthermore, the main upstream regulators and their target genes were involved in cell growth and proliferation and cytoskeletal organization. The alterations found here can be the core components of toxicity involved in the lung complications after Chloropicrin exposure.

  • analysis of nitromethane from samples exposed in vitro to Chloropicrin by stable isotope dilution headspace gas chromatography with mass spectrometry
    IEEE Journal of Solid-state Circuits, 2015
    Co-Authors: Mia Halme, Maija Pesonen, Markku Pasanen, Kirsi Vahakangas, Toni Grandell, Matti Kuula, Paula Vanninen
    Abstract:

    Chloropicrin (trichloronitromethane) is a widely used soil fumigant and an old chemical warfare agent. The metabolism of Chloropicrin is not well known in mammals but nitromethane has been shown to be one of its main metabolites. Here, a fast and simple headspace gas chromatography with mass spectrometry method was applied for the measurement of nitromethane from aqueous samples. The analytical method was validated using stable isotope labeled internal standard and a small sample volume of 260 μL. No conventional sample preparation steps were needed. The method was accurate (relative standard deviations ≤1.5%) and linear (R(2) = 0.9996) within the concentration range of 0.1-6.0 μg/mL. This method was used to measure nitromethane in in vitro incubations with human and pig liver cell fractions containing enzymes for xenobiotic metabolism, exposed to Chloropicrin. The results indicate that the presence of glutathione is necessary for the formation of nitromethane from Chloropicrin. Also, nitromethane was formed mostly in liver cytosol fractions, but not in microsomal fractions after the incubation with Chloropicrin. Our results suggest that although nitromethane is not the unequivocal biomarker of Chloropicrin exposure, this method could be applied for screening the elevated levels in humans after Chloropicrin exposure.

  • transcriptomic analysis of human primary bronchial epithelial cells after Chloropicrin treatment
    Chemical Research in Toxicology, 2015
    Co-Authors: Maija Pesonen, Kirsi Vahakangas, Markus Storvik, Tarja Kokkola, Jaana Rysa, Markku Pasanen
    Abstract:

    Chloropicrin is a vaporizing toxic irritant that poses a risk to human health if inhaled, but the mechanism of its toxicity in the respiratory tract is poorly understood. Here, we exposed human primary bronchial epithelial cells (HBEpC) to two concentrations of Chloropicrin (10–50 μM) for 6 or 48 h and used genomic microarray, flow cytometry, and TEM-analysis to monitor cellular responses to the exposures. The overall number of differentially expressed transcripts with a fold-change > ± 2 compared to controls increased with longer exposure times. The initial response was activation of genes with a higher number of up- (512 by 10 μM and 408 by 40 μM Chloropicrin) rather than down-regulated transcripts (40 by 10 μM and 215 by 40 μM Chloropicrin) at 6 h seen with both exposure concentrations. The number of down-regulated transcripts, however, increased with the exposure time. The differentially regulated transcripts were further examined for enriched Gene Ontology Terms (GO) and KEGG-pathways. According to t...

  • Chloropicrin induced toxic responses in human lung epithelial cells
    Toxicology Letters, 2014
    Co-Authors: Maija Pesonen, Merja R Hakkinen, Kirsi Rilla, Risto O Juvonen, Tapio Kuitunen, Markku Pasanen, Kirsi Vahakangas
    Abstract:

    Abstract Chloropicrin is a slowly evaporating toxic irritant that is known to cause damage in the respiratory system. Here we used a lung epithelial cell line (A549) to study the molecular responses underlying Chloropicrin toxicity. Glutathione (GSH), synthetic peptide and 2′-deoxyguanosine were used as in vitro trapping agents to identify early markers of Chloropicrin toxicity. Microscopy of the cells revealed massive vacuolization by Chloropicrin exposure (80–100 μM). The number of apoptotic cells increased with the Chloropicrin concentration as assessed by flow cytometry. Immunoblotting analysis revealed increases in the amount of four proteins (p53, p21, p27 and phospho-Erk1/2) that are involved in DNA-damage, cell cycle regulation and apoptosis. Chloropicrin evoked a dose-dependent increase in levels of reactive oxygen species within one hour of exposure. The treatment triggered also the formation of disulphide bonds between the model thiol-containing peptides as analysed by LC/MS. Chloropicrin did not form stable adducts with the model peptides or 2′-deoxyguanosine. N-acetyl-cysteine (1 mM NAC) fully prevented the vacuoles and Chloropicrin-induced cytotoxicity. The results suggest that an oxidative insult, particularly modification of free sulfhydryl groups in proteins is involved in the acute toxicity evoked by Chloropicrin in airway epithelial cells. The protective effect of NAC as a potential antidote in Chloropicrin intoxication will require further investigation.

Kirsi Vahakangas - One of the best experts on this subject based on the ideXlab platform.

  • Chloropicrin-induced toxicity in the respiratory system.
    Toxicology Letters, 2020
    Co-Authors: Maija Pesonen, Kirsi Vahakangas
    Abstract:

    Abstract Chloropicrin is a volatile and reactive chemical that has been utilized as a warfare agent and a pesticide to fumigate soil against insects, fungi and nematodes. It poses a health risk to humans and animals if inhaled. The main source of Chloropicrin exposure is occupational and occurs during its manufacture, transport and fumigation. Chloropicrin is toxic via all routes of exposure but the main route of systemic exposure is inhalation of the ambient air. Thus, the toxicity mainly affects the respiratory system. After a low level exposure, the first sign is irritation of the upper respiratory tract and eyes. Irritation is mediated by the sensory nerve fibers, which coordinate further activation of various protective reflexes. Chloropicrin-induced irritation is generally reversible but can alter airway responsiveness to other inhalation toxicants. Severe exposures cause injuries in the respiratory tract, inflammation, and even life-threatening edema. Much of the Chloropicrin-caused symptoms and toxicity in the respiratory system displays similarities with those evoked by chlorine, which is also a breakdown product of Chloropicrin. This review summarizes the latest information on Chloropicrin with emphasis on the toxicity in the respiratory system. The data indicates that oxidative stress, modification of macromolecules, mutations, dysfunctions of cell organelles and cell death are involved in acute Chloropicrin-induced toxicity in the respiratory system.

  • molecular targets of Chloropicrin in human airway epithelial cells
    Toxicology in Vitro, 2017
    Co-Authors: Maija Pesonen, Kirsi Rilla, Markku Pasanen, Markus Storvik, Jaana Rysa, Kirsi Vahakangas
    Abstract:

    Abstract Chloropicrin is a vaporizing, irritating compound that causes complications in the respiratory system when inhaled. In this study, we examined the effects of exposure to Chloropicrin for 24 h on ultrastructure and global gene expression in primary human bronchial epithelial cells. The treatment increased the number of round and shrunken cells, which detached from culture plates more readily than the untreated control cells. Transmission electron microscopy revealed some swollen mitochondria and the appearance of autophagy/lysosome type of vacuoles in the treated cells. However, the main alteration in the ultrastructure of the treated cells was the presence of aggregated and slightly deformed cytoskeleton structures. Furthermore, confocal microscopy and immunoblotting indicated that cytoskeletal β-tubulin protein is a probable target of Chloropicrin exposure. Ingenuity Pathway Analysis (IPA) of differentially expressed microarray data (fold change > ± 2 compared to controls considered) revealed that the top molecular functions were cell growth and proliferation. The main enriched top canonical pathways identified by IPA were associated with EIF2-signalling, protein ubiquitination pathway, glycolysis and mitochondrial dysfunction. Furthermore, the main upstream regulators and their target genes were involved in cell growth and proliferation and cytoskeletal organization. The alterations found here can be the core components of toxicity involved in the lung complications after Chloropicrin exposure.

  • analysis of nitromethane from samples exposed in vitro to Chloropicrin by stable isotope dilution headspace gas chromatography with mass spectrometry
    IEEE Journal of Solid-state Circuits, 2015
    Co-Authors: Mia Halme, Maija Pesonen, Markku Pasanen, Kirsi Vahakangas, Toni Grandell, Matti Kuula, Paula Vanninen
    Abstract:

    Chloropicrin (trichloronitromethane) is a widely used soil fumigant and an old chemical warfare agent. The metabolism of Chloropicrin is not well known in mammals but nitromethane has been shown to be one of its main metabolites. Here, a fast and simple headspace gas chromatography with mass spectrometry method was applied for the measurement of nitromethane from aqueous samples. The analytical method was validated using stable isotope labeled internal standard and a small sample volume of 260 μL. No conventional sample preparation steps were needed. The method was accurate (relative standard deviations ≤1.5%) and linear (R(2) = 0.9996) within the concentration range of 0.1-6.0 μg/mL. This method was used to measure nitromethane in in vitro incubations with human and pig liver cell fractions containing enzymes for xenobiotic metabolism, exposed to Chloropicrin. The results indicate that the presence of glutathione is necessary for the formation of nitromethane from Chloropicrin. Also, nitromethane was formed mostly in liver cytosol fractions, but not in microsomal fractions after the incubation with Chloropicrin. Our results suggest that although nitromethane is not the unequivocal biomarker of Chloropicrin exposure, this method could be applied for screening the elevated levels in humans after Chloropicrin exposure.

  • transcriptomic analysis of human primary bronchial epithelial cells after Chloropicrin treatment
    Chemical Research in Toxicology, 2015
    Co-Authors: Maija Pesonen, Kirsi Vahakangas, Markus Storvik, Tarja Kokkola, Jaana Rysa, Markku Pasanen
    Abstract:

    Chloropicrin is a vaporizing toxic irritant that poses a risk to human health if inhaled, but the mechanism of its toxicity in the respiratory tract is poorly understood. Here, we exposed human primary bronchial epithelial cells (HBEpC) to two concentrations of Chloropicrin (10–50 μM) for 6 or 48 h and used genomic microarray, flow cytometry, and TEM-analysis to monitor cellular responses to the exposures. The overall number of differentially expressed transcripts with a fold-change > ± 2 compared to controls increased with longer exposure times. The initial response was activation of genes with a higher number of up- (512 by 10 μM and 408 by 40 μM Chloropicrin) rather than down-regulated transcripts (40 by 10 μM and 215 by 40 μM Chloropicrin) at 6 h seen with both exposure concentrations. The number of down-regulated transcripts, however, increased with the exposure time. The differentially regulated transcripts were further examined for enriched Gene Ontology Terms (GO) and KEGG-pathways. According to t...

  • Chloropicrin induced toxic responses in human lung epithelial cells
    Toxicology Letters, 2014
    Co-Authors: Maija Pesonen, Merja R Hakkinen, Kirsi Rilla, Risto O Juvonen, Tapio Kuitunen, Markku Pasanen, Kirsi Vahakangas
    Abstract:

    Abstract Chloropicrin is a slowly evaporating toxic irritant that is known to cause damage in the respiratory system. Here we used a lung epithelial cell line (A549) to study the molecular responses underlying Chloropicrin toxicity. Glutathione (GSH), synthetic peptide and 2′-deoxyguanosine were used as in vitro trapping agents to identify early markers of Chloropicrin toxicity. Microscopy of the cells revealed massive vacuolization by Chloropicrin exposure (80–100 μM). The number of apoptotic cells increased with the Chloropicrin concentration as assessed by flow cytometry. Immunoblotting analysis revealed increases in the amount of four proteins (p53, p21, p27 and phospho-Erk1/2) that are involved in DNA-damage, cell cycle regulation and apoptosis. Chloropicrin evoked a dose-dependent increase in levels of reactive oxygen species within one hour of exposure. The treatment triggered also the formation of disulphide bonds between the model thiol-containing peptides as analysed by LC/MS. Chloropicrin did not form stable adducts with the model peptides or 2′-deoxyguanosine. N-acetyl-cysteine (1 mM NAC) fully prevented the vacuoles and Chloropicrin-induced cytotoxicity. The results suggest that an oxidative insult, particularly modification of free sulfhydryl groups in proteins is involved in the acute toxicity evoked by Chloropicrin in airway epithelial cells. The protective effect of NAC as a potential antidote in Chloropicrin intoxication will require further investigation.