Discoveries in Charles Darwin’s laboratory led to modern herbicides. Darwin discovered the internal mechanism that directed plants to grow toward sunlight and sources of water. Scientists in Europe and America later ...Discoveries in Charles Darwin’s laboratory led to modern herbicides. Darwin discovered the internal mechanism that directed plants to grow toward sunlight and sources of water. Scientists in Europe and America later called this mechanism a plant’s hormone response system. Administrators and scientists, including Dr. Ezra J. Kraus, the Head of the Botany Department at the University of Chicago and a plant physiologist, suggested on the eve of WWII that weed killers had significant military value as chemical weapons. Dr. Kraus obtained access to a synthetic chemical, 2,4-D, and found that when the chemical was absorbed through the leaves of plants, it destroyed a plant’s hormones. After exposure, the plant experienced rapid and uncontrolled growth, and then the leaves shriveled, died and fell off. Dr. Kraus obtained funding for his Department of Botany research program from Department of Defense (DOD) during World War II (WWII). Camp Detrick (Biological Weapons Laboratory) scientists later obtained samples of newly created 2,4,5-T which contained unknown amounts of the by-product dioxin TCDD. In the 1950s and 1960s, Fort Detrick military scientists formulated the herbicide Agent Orange, which was a 50 - 50 mixture of 2,4-D and 2,4,5-T. These dual purpose herbicides were used by DOD and USDA. American and European farmers in the 1940s used 2,4-D and 2,4,5-T to eliminate weeds from pastureland and cropland. After WWII, synthetic herbicides (and pesticides) development continued in tandem with production of synthetic fertilizers and breeding of high-yield plant varieties. These new agricultural products were then shipped worldwide to increase crop yields, as part of the Green Revolution. This new system of agricultural technologies was intended to eliminate global starvation and increase food security by increasing field and farm crop yields. In contrast, the goal of military use of herbicides, as chemical weapons, was to defoliate jungle forests and destroy food crops as a strategy to win battles and wars. The primary objective of this research study is to describe how agricultural herbicides became tactical chemical weapons. A current assessment will address the environmental impacts of military and environmental chemical weapons on the United States and Vietnam ecosystems and need for additional dioxin TCDD hotspot clean-up efforts.展开更多
In this paper we highlight how the apparent double coverage of toxins and bioregulators by both the Biological and Toxin Weapons Convention(BTWC)and the Chemical Weapons Convention(CWC)in fact masks a regulatory gap t...In this paper we highlight how the apparent double coverage of toxins and bioregulators by both the Biological and Toxin Weapons Convention(BTWC)and the Chemical Weapons Convention(CWC)in fact masks a regulatory gap that has left such potentially dangerous agents neglected by both the control regimes during a period of rapid advances in relevant chemical,life and associated sciences and technologies.We first review what toxins,bioregulators and other mid-spectrum agents are and why they are of such concern and then examine how they are regulated under the BTWC and CWC.This paper then examines an illustrative range of contemporary chemical and life science research and associated activities of concern drawn from case study research on China,India,Iran,Russia,Syria and the United States,and assesses how the CWC and BTWC States Parties have inadequately addressed these threats.We then examine how both the CWC and BTWC Review Conferences failed to address these long-term challenges,and we end by providing a series of recommendations for how both regimes can be strengthened in this area.展开更多
During the last 60 years, the southern Vietnam environment and Vietnamese living in the Mekong Delta have bio-accumulated arsenic from natural and anthropic (Vietnam Civil War (1962-1965)) sources via their drinking w...During the last 60 years, the southern Vietnam environment and Vietnamese living in the Mekong Delta have bio-accumulated arsenic from natural and anthropic (Vietnam Civil War (1962-1965)) sources via their drinking water (groundwater from tube wells) and food supply leading to an increasing risk of chronic poisoning over time. A synthesis and analysis of publications and records is presented to document the Republic of Vietnam (RV), the official name of the South Vietnam Government, and United States (US) militaries contribution to arsenic levels and toxic spikes in the Vietnam Mekong Delta groundwater. During the Vietnam Civil War, Agent Blue, in powder form, was shipped to Port Saigon, via the Saigon River, and transported to the Tan Son Nhut Air Force base during the Vietnam Civil War. After the official start of the American-Vietnam War (1965-1973) the tactical herbicides were re-routed to Bien Hoa Air Force base (1965 to 1971). Approximately 3.2 million liters of Agent Blue (468,008 kg As) was sprayed or dumped by the RV military with the assistance and support of the Central Intelligence (CIA), US Army and US Navy, during the 1962-1965 Khai Huang (Hamlet) Program. A portion of an additional 4.6 million liters of Agent Blue (664,392 kg of As) was sprayed between 1962 and 1965 by the US Air Force as part of Operation Ranch Hand and prior to the official start of the American-Vietnam War in August 1964. Operation Rand Hand began in 1962 and ended in 1971. The Institute of Medicine estimated a total of 7.8 million liters (1,132,400 kg As) of Agent Blue was applied to southern Vietnam landscape from 1962 to 1971. This total includes both the 1962 to 1965 RV Khai Huang program with the assistance of the CIA, US Army and US Navy, and the total Agent Blue applied by US Air Force Operation Ranch Hand from 1962 to 1971. The primary objective of this study was to document how Agent Blue, the arsenic-based herbicide, became a secret US military and environmental chemical weapon used by the RV and US militaries in southern Vietnam during the Vietnam Civil War years (1962-1965). This assessment found that the anthropic arsenic, including Agent Blue, added a toxic burden to the Mekong Delta soils, surface water, groundwater, drinking water, food supply, and human health. However, there are missing details regarding political decisions and a full accounting of the geographic locations sprayed and amount of Agent Blue used. Vietnam War Archives have paper correspondence and RV herbicide spray records that shed greater light on this period. These records are over 50 years old and need to be electronically scanned, stored, and made available for additional historical analyses.展开更多
Recent publications reveal the disturbing information that a minor edit to an algorithm being used for designing legitimate drug candidates redirected the program in a way that resulted in the surprising design of nov...Recent publications reveal the disturbing information that a minor edit to an algorithm being used for designing legitimate drug candidates redirected the program in a way that resulted in the surprising design of novel chemical warfare agent candidates. Although this outcome was not the result of nefarious intent, and appropriate chemical defense authorities were notified, the potential implications of some misapplication of a drug-design algorithm for nefarious purposes are clear. This Commentary summarizes how otherwise benign Artificial Intelligence (AI) algorithms used for drug discovery can be easily reversed to design novel chemical warfare agents for which no effective antidote will be available, or perhaps even envisioned.展开更多
Though blessed to be born in a peaceful era, Chi Shuai, a 17-year-old high school student in Qiqihar, northeast China’s Hei-longjiang Province, was unfortunate to fall victim to the Japanese invasion his grandparents...Though blessed to be born in a peaceful era, Chi Shuai, a 17-year-old high school student in Qiqihar, northeast China’s Hei-longjiang Province, was unfortunate to fall victim to the Japanese invasion his grandparents witnessed in the 1930s and 1940s. On August 4, 2003, the boy and 43 others were poisoned by mustard gas leaked from five tanks dug out at a construction site. The five metal tanks were later proved to be left by Japanese invaders in 1945. Li Guizhen, a rag picker who carried away and incised the tanks, died despite all the medical efforts to save his life. The youngest victim in this incident was only eight years old.展开更多
N,N-dialkylaminoethane-2-sulfonic acids are environmental marker compounds of V type nerve agents,hence analysis of them is very important for verification of the chemical weapons convention(CWC).In this article,liqui...N,N-dialkylaminoethane-2-sulfonic acids are environmental marker compounds of V type nerve agents,hence analysis of them is very important for verification of the chemical weapons convention(CWC).In this article,liquid chromatography-high resolution time of flight mass spectrometry coupled with accurate mass measurement were used to discriminate N,N-disopropyl aminoethane-2-sulfonic acid and a CWC non-related compound 3-(N-Morpholino)propanesulfonic acid in Water.The method was fast,simple and accurate,proving that high resolution mass spectrometry is a good technique for the analysis of unknown toxicant.展开更多
Rapid destruction of stockpiles of sarin and other chemical weapon agents(CWA)requires understanding and quantitative description of the relevant chemical reactions.Rapid reactions at elevated temperatures are of part...Rapid destruction of stockpiles of sarin and other chemical weapon agents(CWA)requires understanding and quantitative description of the relevant chemical reactions.Rapid reactions at elevated temperatures are of particular interest for prompt agent defeat scenarios.Diisopropyl methylphosphonate(DIMP)is a sarin surrogate particularly well suited to model sarin thermal decomposition and is often used in experiments.This article is a review of different experimental methods addressing decomposition of gasified DIMP,respective results and their interpretations.Major early decomposition products are propene,methylphosphonic acid,methyl(oxo)phosphoniumolate,and isopropanol.Early computational work using available kinetic data for fluorine and the phosphorus-fluorine bond predicted the decomposition under incineration conditions.Experiments using an isothermal flow reactor operated at 700-800 K were used to model DIMP decomposition as unimolecular reaction with results that were consistent with the earlier theoretical work.Decomposition in dynamic environments was studied using DIMP supported on rapidly heated substrates.The results showed different decomposition products and product sequences forming at different heating rates,suggesting the need for revised reaction kinetics.However,species quantification in such experiments is difficult because of inherent large temperature gradients.Plasma produced in a corona discharge was also reported to lead to rapid DIMP decomposition at low temperatures.Decomposition products were distinct from those observed at high temperatures.Shock tube experiments may be well suited to study decomposition of organophosphorus compounds like DIMP following their rapid heating in diverse environments.However,presently,only sarin surrogates other than DIMP have been investigated,and no intermediate reaction products,important for developing a validated mechanism,could be detected.展开更多
Chemical warfare agents(CWA)are stockpiled in large quantities across the globe.Agents stored in inaccessible facilities need to be destroyed rapidly without dispersing the compounds to surrounding areas.Metal-based e...Chemical warfare agents(CWA)are stockpiled in large quantities across the globe.Agents stored in inaccessible facilities need to be destroyed rapidly without dispersing the compounds to surrounding areas.Metal-based energetic formulations are used in such prompt defeat applications to rapidly decompose the CWA by generating a high temperature environment.An alternate,and possibly a more effective decomposition pathway could be provided by chemicidal action of aerosolized condensed combustion products,which typically consist of metal oxides.Toxic fumes that escape the high temperature blast zone can be neutralized by smoke generated during combustion,depending on the particle size,surface characteristics,chemical properties,and concentration of this smoke.This review considers relevant experimental and modeling studies quantifying decomposition of CWA comprising organophosphorus compounds and their surrogates on the surface of various metal oxides.Dimethyl methylphosphonate(DMMP),a sarine surrogate,was used most commonly for such experiments.Many reported efforts focused on the mechanisms of adsorption of DMMP to various metal oxides and initial reaction steps cleaving various bonds from the chemisorbed molecules.For selected oxides,these experiments were supported by quantum-mechanical calculations.In other studies,the capacity of oxide surfaces to adsorb and decompose DMMP was quantified.In most cases,porous catalysts were used although limited experimental data are available for aerosolized nonporous oxide particles.The reported experimental data applicable to scenarios involving prompt decomposition of CWA are summarized.It is noted that information is lacking describing respective heterogeneous reaction kinetics.Preliminary estimates of aerosolized smoke particle concentrations required to destroy CWA are made considering gas phase diffusion rates and reported values of the oxide capacity to decompose CWA or their surrogates.展开更多
Diphenylarsinic acid (DPAA) is formed during the leakage of aromatic arsenic chemical weapons in soils, is persistent in nature, and results in arsenic contamination in the field. The adsorption and desorption chara...Diphenylarsinic acid (DPAA) is formed during the leakage of aromatic arsenic chemical weapons in soils, is persistent in nature, and results in arsenic contamination in the field. The adsorption and desorption characteristics of DPAA were investigated in two typical Chinese soils, an Acrisol (a variable-charge soil) and a Phaeozem (a constant-charge soil). Their thermodynamics and some of the factors influencing them (i.e., initial pH value, ionic strength and phosphate) were also evaluated using the batch method in order to understand the environmental fate of DPAA in soils. The results indicate that Acrisol had a stronger adsorption capacity for DPAA than Phaeozem. Soil DPAA adsorption was a spontaneous and endothermic process and the amount of DPAA adsorbed was affected significantly by variation in soil pH and phosphate. In contrast, soil organic matter and ionic strength had no significant effect on adsorption. This suggests that DPAA adsorption may be due to specific adsorption on soil mineral surfaces. Therefore, monitoring the fate of DPAA in soils is recommended in areas contaminated by leakage from chemical weapons.展开更多
After the Egyptian military toppled the Muslim Brotherhood regime,the situation in Egypt can hardly be stabilized.The Syrian chemical weapons crisis was resolved,but the political solution staggered.The Palestine-Isra...After the Egyptian military toppled the Muslim Brotherhood regime,the situation in Egypt can hardly be stabilized.The Syrian chemical weapons crisis was resolved,but the political solution staggered.The Palestine-Israel peace talks were restarted,but it is still difficult to make a breakthrough.The US-Iran relations were eased and the Iranian nuclear negotiation achieved initial progress.US ability to dominate in the Middle East is weakened.The Arab countries face a long-term and difficult transformation.The rise of Islamism has been thwarted.展开更多
As social media becomes increasingly ubiquitous,many events are recorded and released on social media platforms,including chemical weapon attacks.We develop an objective tool in order to evaluate brief and unstructure...As social media becomes increasingly ubiquitous,many events are recorded and released on social media platforms,including chemical weapon attacks.We develop an objective tool in order to evaluate brief and unstructured social media videos for analysing sarin exposure from a civilian medical pathology perspective.We developed and validated this new questionnaire using a standardized procedure that includes content domain specification,item pool generation,content validity evaluation,a pilot study,and assessment of reliability and validity.In total,51 sarin attacks and 48 matched videos were analysed.Cronbach’s a for all 20 items was 0.75,which indicates adequate internal reliability.The test–retest reliability was 0.96,which indicates good internal reliability.The inter-observer intraclass correlation coefficient was 0.97.After verifying sampling adequacy with the Kaiser–Meyer–Olkin measure and the factorability of the items with Barlett’s test of sphericity,a factor analysis was performed.According to the principal axis factoring,a six-factor solution explained 51.86%of the total variance.The receiver-operating characteristic curve analysis showed that the Video Score Questionnaire has a sensitivity of 0.817,a specificity of 0.478,and an efficiency of 65.3.Therefore,the Video Score Questionnaire is reliable and valid for evaluating sarin attacks from brief and unstructured social media videos.展开更多
文摘Discoveries in Charles Darwin’s laboratory led to modern herbicides. Darwin discovered the internal mechanism that directed plants to grow toward sunlight and sources of water. Scientists in Europe and America later called this mechanism a plant’s hormone response system. Administrators and scientists, including Dr. Ezra J. Kraus, the Head of the Botany Department at the University of Chicago and a plant physiologist, suggested on the eve of WWII that weed killers had significant military value as chemical weapons. Dr. Kraus obtained access to a synthetic chemical, 2,4-D, and found that when the chemical was absorbed through the leaves of plants, it destroyed a plant’s hormones. After exposure, the plant experienced rapid and uncontrolled growth, and then the leaves shriveled, died and fell off. Dr. Kraus obtained funding for his Department of Botany research program from Department of Defense (DOD) during World War II (WWII). Camp Detrick (Biological Weapons Laboratory) scientists later obtained samples of newly created 2,4,5-T which contained unknown amounts of the by-product dioxin TCDD. In the 1950s and 1960s, Fort Detrick military scientists formulated the herbicide Agent Orange, which was a 50 - 50 mixture of 2,4-D and 2,4,5-T. These dual purpose herbicides were used by DOD and USDA. American and European farmers in the 1940s used 2,4-D and 2,4,5-T to eliminate weeds from pastureland and cropland. After WWII, synthetic herbicides (and pesticides) development continued in tandem with production of synthetic fertilizers and breeding of high-yield plant varieties. These new agricultural products were then shipped worldwide to increase crop yields, as part of the Green Revolution. This new system of agricultural technologies was intended to eliminate global starvation and increase food security by increasing field and farm crop yields. In contrast, the goal of military use of herbicides, as chemical weapons, was to defoliate jungle forests and destroy food crops as a strategy to win battles and wars. The primary objective of this research study is to describe how agricultural herbicides became tactical chemical weapons. A current assessment will address the environmental impacts of military and environmental chemical weapons on the United States and Vietnam ecosystems and need for additional dioxin TCDD hotspot clean-up efforts.
基金supported by an Emeritus Fellowship from the Leverhulme Trust(EM-2018-005/10)to Professor Malcolm Dando.
文摘In this paper we highlight how the apparent double coverage of toxins and bioregulators by both the Biological and Toxin Weapons Convention(BTWC)and the Chemical Weapons Convention(CWC)in fact masks a regulatory gap that has left such potentially dangerous agents neglected by both the control regimes during a period of rapid advances in relevant chemical,life and associated sciences and technologies.We first review what toxins,bioregulators and other mid-spectrum agents are and why they are of such concern and then examine how they are regulated under the BTWC and CWC.This paper then examines an illustrative range of contemporary chemical and life science research and associated activities of concern drawn from case study research on China,India,Iran,Russia,Syria and the United States,and assesses how the CWC and BTWC States Parties have inadequately addressed these threats.We then examine how both the CWC and BTWC Review Conferences failed to address these long-term challenges,and we end by providing a series of recommendations for how both regimes can be strengthened in this area.
文摘During the last 60 years, the southern Vietnam environment and Vietnamese living in the Mekong Delta have bio-accumulated arsenic from natural and anthropic (Vietnam Civil War (1962-1965)) sources via their drinking water (groundwater from tube wells) and food supply leading to an increasing risk of chronic poisoning over time. A synthesis and analysis of publications and records is presented to document the Republic of Vietnam (RV), the official name of the South Vietnam Government, and United States (US) militaries contribution to arsenic levels and toxic spikes in the Vietnam Mekong Delta groundwater. During the Vietnam Civil War, Agent Blue, in powder form, was shipped to Port Saigon, via the Saigon River, and transported to the Tan Son Nhut Air Force base during the Vietnam Civil War. After the official start of the American-Vietnam War (1965-1973) the tactical herbicides were re-routed to Bien Hoa Air Force base (1965 to 1971). Approximately 3.2 million liters of Agent Blue (468,008 kg As) was sprayed or dumped by the RV military with the assistance and support of the Central Intelligence (CIA), US Army and US Navy, during the 1962-1965 Khai Huang (Hamlet) Program. A portion of an additional 4.6 million liters of Agent Blue (664,392 kg of As) was sprayed between 1962 and 1965 by the US Air Force as part of Operation Ranch Hand and prior to the official start of the American-Vietnam War in August 1964. Operation Rand Hand began in 1962 and ended in 1971. The Institute of Medicine estimated a total of 7.8 million liters (1,132,400 kg As) of Agent Blue was applied to southern Vietnam landscape from 1962 to 1971. This total includes both the 1962 to 1965 RV Khai Huang program with the assistance of the CIA, US Army and US Navy, and the total Agent Blue applied by US Air Force Operation Ranch Hand from 1962 to 1971. The primary objective of this study was to document how Agent Blue, the arsenic-based herbicide, became a secret US military and environmental chemical weapon used by the RV and US militaries in southern Vietnam during the Vietnam Civil War years (1962-1965). This assessment found that the anthropic arsenic, including Agent Blue, added a toxic burden to the Mekong Delta soils, surface water, groundwater, drinking water, food supply, and human health. However, there are missing details regarding political decisions and a full accounting of the geographic locations sprayed and amount of Agent Blue used. Vietnam War Archives have paper correspondence and RV herbicide spray records that shed greater light on this period. These records are over 50 years old and need to be electronically scanned, stored, and made available for additional historical analyses.
文摘Recent publications reveal the disturbing information that a minor edit to an algorithm being used for designing legitimate drug candidates redirected the program in a way that resulted in the surprising design of novel chemical warfare agent candidates. Although this outcome was not the result of nefarious intent, and appropriate chemical defense authorities were notified, the potential implications of some misapplication of a drug-design algorithm for nefarious purposes are clear. This Commentary summarizes how otherwise benign Artificial Intelligence (AI) algorithms used for drug discovery can be easily reversed to design novel chemical warfare agents for which no effective antidote will be available, or perhaps even envisioned.
文摘Though blessed to be born in a peaceful era, Chi Shuai, a 17-year-old high school student in Qiqihar, northeast China’s Hei-longjiang Province, was unfortunate to fall victim to the Japanese invasion his grandparents witnessed in the 1930s and 1940s. On August 4, 2003, the boy and 43 others were poisoned by mustard gas leaked from five tanks dug out at a construction site. The five metal tanks were later proved to be left by Japanese invaders in 1945. Li Guizhen, a rag picker who carried away and incised the tanks, died despite all the medical efforts to save his life. The youngest victim in this incident was only eight years old.
文摘N,N-dialkylaminoethane-2-sulfonic acids are environmental marker compounds of V type nerve agents,hence analysis of them is very important for verification of the chemical weapons convention(CWC).In this article,liquid chromatography-high resolution time of flight mass spectrometry coupled with accurate mass measurement were used to discriminate N,N-disopropyl aminoethane-2-sulfonic acid and a CWC non-related compound 3-(N-Morpholino)propanesulfonic acid in Water.The method was fast,simple and accurate,proving that high resolution mass spectrometry is a good technique for the analysis of unknown toxicant.
基金supported by the US Defense Threat Reduction Agency,Award HDTRA1-19-1-0023。
文摘Rapid destruction of stockpiles of sarin and other chemical weapon agents(CWA)requires understanding and quantitative description of the relevant chemical reactions.Rapid reactions at elevated temperatures are of particular interest for prompt agent defeat scenarios.Diisopropyl methylphosphonate(DIMP)is a sarin surrogate particularly well suited to model sarin thermal decomposition and is often used in experiments.This article is a review of different experimental methods addressing decomposition of gasified DIMP,respective results and their interpretations.Major early decomposition products are propene,methylphosphonic acid,methyl(oxo)phosphoniumolate,and isopropanol.Early computational work using available kinetic data for fluorine and the phosphorus-fluorine bond predicted the decomposition under incineration conditions.Experiments using an isothermal flow reactor operated at 700-800 K were used to model DIMP decomposition as unimolecular reaction with results that were consistent with the earlier theoretical work.Decomposition in dynamic environments was studied using DIMP supported on rapidly heated substrates.The results showed different decomposition products and product sequences forming at different heating rates,suggesting the need for revised reaction kinetics.However,species quantification in such experiments is difficult because of inherent large temperature gradients.Plasma produced in a corona discharge was also reported to lead to rapid DIMP decomposition at low temperatures.Decomposition products were distinct from those observed at high temperatures.Shock tube experiments may be well suited to study decomposition of organophosphorus compounds like DIMP following their rapid heating in diverse environments.However,presently,only sarin surrogates other than DIMP have been investigated,and no intermediate reaction products,important for developing a validated mechanism,could be detected.
基金This work was supported by the US Defense Threat Reduction Agency,DTRAGrant HDTRA1-19-1-0023.
文摘Chemical warfare agents(CWA)are stockpiled in large quantities across the globe.Agents stored in inaccessible facilities need to be destroyed rapidly without dispersing the compounds to surrounding areas.Metal-based energetic formulations are used in such prompt defeat applications to rapidly decompose the CWA by generating a high temperature environment.An alternate,and possibly a more effective decomposition pathway could be provided by chemicidal action of aerosolized condensed combustion products,which typically consist of metal oxides.Toxic fumes that escape the high temperature blast zone can be neutralized by smoke generated during combustion,depending on the particle size,surface characteristics,chemical properties,and concentration of this smoke.This review considers relevant experimental and modeling studies quantifying decomposition of CWA comprising organophosphorus compounds and their surrogates on the surface of various metal oxides.Dimethyl methylphosphonate(DMMP),a sarine surrogate,was used most commonly for such experiments.Many reported efforts focused on the mechanisms of adsorption of DMMP to various metal oxides and initial reaction steps cleaving various bonds from the chemisorbed molecules.For selected oxides,these experiments were supported by quantum-mechanical calculations.In other studies,the capacity of oxide surfaces to adsorb and decompose DMMP was quantified.In most cases,porous catalysts were used although limited experimental data are available for aerosolized nonporous oxide particles.The reported experimental data applicable to scenarios involving prompt decomposition of CWA are summarized.It is noted that information is lacking describing respective heterogeneous reaction kinetics.Preliminary estimates of aerosolized smoke particle concentrations required to destroy CWA are made considering gas phase diffusion rates and reported values of the oxide capacity to decompose CWA or their surrogates.
基金supported by the National Natural Science Foundation of China (No. 41171248,40810180)the Ministry of Environmental Protection Special Funds for Scientific Research on Public Causes (No. 2010467016)
文摘Diphenylarsinic acid (DPAA) is formed during the leakage of aromatic arsenic chemical weapons in soils, is persistent in nature, and results in arsenic contamination in the field. The adsorption and desorption characteristics of DPAA were investigated in two typical Chinese soils, an Acrisol (a variable-charge soil) and a Phaeozem (a constant-charge soil). Their thermodynamics and some of the factors influencing them (i.e., initial pH value, ionic strength and phosphate) were also evaluated using the batch method in order to understand the environmental fate of DPAA in soils. The results indicate that Acrisol had a stronger adsorption capacity for DPAA than Phaeozem. Soil DPAA adsorption was a spontaneous and endothermic process and the amount of DPAA adsorbed was affected significantly by variation in soil pH and phosphate. In contrast, soil organic matter and ionic strength had no significant effect on adsorption. This suggests that DPAA adsorption may be due to specific adsorption on soil mineral surfaces. Therefore, monitoring the fate of DPAA in soils is recommended in areas contaminated by leakage from chemical weapons.
文摘After the Egyptian military toppled the Muslim Brotherhood regime,the situation in Egypt can hardly be stabilized.The Syrian chemical weapons crisis was resolved,but the political solution staggered.The Palestine-Israel peace talks were restarted,but it is still difficult to make a breakthrough.The US-Iran relations were eased and the Iranian nuclear negotiation achieved initial progress.US ability to dominate in the Middle East is weakened.The Arab countries face a long-term and difficult transformation.The rise of Islamism has been thwarted.
基金This work was supported by the Spiez Laboratory(Federal Office for Civil Protection),Switzerland[grant number 354012624].
文摘As social media becomes increasingly ubiquitous,many events are recorded and released on social media platforms,including chemical weapon attacks.We develop an objective tool in order to evaluate brief and unstructured social media videos for analysing sarin exposure from a civilian medical pathology perspective.We developed and validated this new questionnaire using a standardized procedure that includes content domain specification,item pool generation,content validity evaluation,a pilot study,and assessment of reliability and validity.In total,51 sarin attacks and 48 matched videos were analysed.Cronbach’s a for all 20 items was 0.75,which indicates adequate internal reliability.The test–retest reliability was 0.96,which indicates good internal reliability.The inter-observer intraclass correlation coefficient was 0.97.After verifying sampling adequacy with the Kaiser–Meyer–Olkin measure and the factorability of the items with Barlett’s test of sphericity,a factor analysis was performed.According to the principal axis factoring,a six-factor solution explained 51.86%of the total variance.The receiver-operating characteristic curve analysis showed that the Video Score Questionnaire has a sensitivity of 0.817,a specificity of 0.478,and an efficiency of 65.3.Therefore,the Video Score Questionnaire is reliable and valid for evaluating sarin attacks from brief and unstructured social media videos.