Aluminum Phosphide Poisoning, an Institutional Experience: Case Series.

BACKGROUND: The growing concern over pesticide use has been linked to self-harm and suicide especially in agricultural countries like Nepal.  Pesticides like organophosphorus and aluminum phosphide cause the majority of deaths. Although organophosphorus poisoning is common means for suicide, Aluminum phosphide poisoning is also encountered occasionally. Our case series aims to look after the intent of poisoning and the outcome of the patients following Aluminum phosphide poisoning. METHODS: This hospital record-based study includes Aluminum phosphide poisoning patients presenting to the emergency department of Scheer Memorial Adventist Hospital from first January 2017 to 31st December 2020. Data were analyzed using SPSS version-22. RESULTS:   Out of 25 total poisoning cases, most of them were female (60%) and married (56%).  The case fatality rate was 84% among which 20% cases were brought dead while 64% died in the hospital. All poisoning cases were suicidal in intent. CONCLUSIONS: Herein we report a case series on 25 Aluminum phosphide poisoning cases with high case fatality rate and all cases being suicidal in intent.

Analysis of the Distribution of Total Phosphine and the Characteristics of Phosphine Poisoning in 29 Victims.

OBJECTIVES: To study the distribution of total phosphine in phosphine poisoning victims and summarize the characteristics of phosphine poisoning cases. METHODS: The phosphine and its metabolites in the biological samples of 29 victims in 16 phosphine poisoning cases were qualified and quantified by headspace gas chromatography-mass spectrometry. RESULTS: Five victims among 29 were poisoned by ingestion of aluminium phosphide and 24 by inhalation of phosphine gas. Phosphine metabolites were detected in the biological samples of 23 victims, and the concentrations of total phosphine in blood ranged 0.5-34.0 µg/mL. The total concentration of phosphine in liver tissue was up to 71.0 µg/g. Phosphine was not detected in the blood of the other six survived victims, which may be related to the small amount of phosphine exposure and the delay in blood sampling. CONCLUSIONS: The total concentration of phosphine in blood and tissues caused by aluminum phosphine ingestion is higher than that caused by phosphine gas inhalation. The death cases of phosphine inhalation are characterized by long exposure time, repeated exposures and age susceptibility.

Analysis of the Distribution of Total Phosphine and the Characteristics of Phosphine Poisoning in 29 Victims / 法医学杂志

OBJECTIVES@#To study the distribution of total phosphine in phosphine poisoning victims and summarize the characteristics of phosphine poisoning cases.@*METHODS@#The phosphine and its metabolites in the biological samples of 29 victims in 16 phosphine poisoning cases were qualified and quantified by headspace gas chromatography-mass spectrometry.@*RESULTS@#Five victims among 29 were poisoned by ingestion of aluminium phosphide and 24 by inhalation of phosphine gas. Phosphine metabolites were detected in the biological samples of 23 victims, and the concentrations of total phosphine in blood ranged 0.5-34.0 μg/mL. The total concentration of phosphine in liver tissue was up to 71.0 μg/g. Phosphine was not detected in the blood of the other six survived victims, which may be related to the small amount of phosphine exposure and the delay in blood sampling.@*CONCLUSIONS@#The total concentration of phosphine in blood and tissues caused by aluminum phosphine ingestion is higher than that caused by phosphine gas inhalation. The death cases of phosphine inhalation are characterized by long exposure time, repeated exposures and age susceptibility.

Analysis of the characteristics of phosphine production by anaerobic digestion based on microbial community dynamics, metabolic pathways, and isolation of the phosphate-reducing strain.

Although phosphine is ubiquitously present in anaerobic environments, little is known regarding the microbial community dynamics and metabolic pathways associated with phosphine formation in an anaerobic digestion system. This study investigated the production of phosphine in anaerobic digestion, with results indicating that phosphine production mainly occurred during logarithmic microbial growth. Dehydrogenase and hydrogen promoted the production of phosphine, with a maximum phosphine concentration of 300 mg/m3. The abundance of Ruminococcaceae and Escherichia was observed to promote phosphine generation. The analysis of metabolic pathways based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) and the MetaCyc pathway database revealed the highest relative abundance of replication and repair in genetic information processing; further, the cofactor, prosthetic group, electron carrier, and vitamin biosynthesis were observed to be closely related to phosphine formation. A phylogenetic tree was reconstructed based on the neighbor-joining method. The results indicated the clear evolutionary position of the isolated Pseudescherichia sp. SFM4 strain, adjacent to Escherichia, with a stable phosphate-reducing ability for a maximum phosphine concentration of 26 mg/m3. The response surface experiment indicated that the initial optimal conditions for phosphine production by SFM4 could be achieved with nitrogen, carbon, and phosphorus loads of 6.17, 300, and 10 mg/L, respectively, at pH 7.47. These results provide comprehensive insights into the dynamic changes in the microbial structure, isolated single bacterial strain, and metabolic pathways associated with phosphine formation. They also provide information on the molecular biology associated with phosphorus recycling.

Development and validation of a methodology for quantifying parts-per-billion levels of arsine and phosphine in nitrogen, hydrogen and liquefied petroleum gas using a variable pressure sampler coupled to gas chromatography-mass spectrometry.

The reliable determination of arsine (AsH3) and phosphine (PH3) in hydrogen (H2), nitrogen (N2) and liquefied petroleum gas (LPG) is of great importance because of its drastic effects on the efficiency of catalysts, as well as the strict regulations associated with health, safety and environmental issues. It is challenging for an analyst to determine the parts per billion of AsH3 and PH3 in H2, N2, and LPG at low and high pressures without collection procedures using adsorption, desorption, and dissolution techniques. To overcome this analytical need an analytical methodology was developed, employing a variable pressure sampler (VPS) coupled to a gas chromatograph (GC) with mass spectrometry (MS) for the identification and quantification of traces of AsH3 and PH3. The instrumentation, tubing and accessories of the VPS were made of passivated steel to avoid losses from absorption of AsH3 and PH3 in the steel which would generate significant analytical problems. The VPS had a homogeneous heating block that prevented analyte losses from condensation. With the VPS, 24 AsH3 and PH3 standards were prepared between 0.005 and 0.1 mg kg-1 in balance of H2, N2 and LPG. The separation and quantification of the analytes was achieved with an improved GC with 4 valves and 5 columns in series that guaranteed the elimination of impurities. The proposed method was optimized in VPS and GC-MS and then validated showing highly accaptable linearity (r2 > 0.9999), detection limits (<0.0009 mg kg-1), limits of quantification (<0.003 mg kg-1), intra-day and inter-day precision and accuracy (<1.14% and ≤3.0% respectively), recovery for the standard addition (86-109%), P values> 0.05 for the test Student's t paired who evaluated the effect of the matrix on pressure and concentration. The speed of analysis was high (<5.2 min). The method was applied to real samples, showing values between 0.005 and 0.1 mg kg-1 and an effect on the efficiency of the Ziegler Natta catalyst between 5 and 56%.

Equilibrium and site selective analysis for DNA threading intercalation of a new phosphine copper(I) complex: Insights from X-ray analysis, spectroscopic and molecular modeling studies.

To clarify the interaction of phosphine copper(I) complex with DNA, our study reports the synthesis of a new phosphine copper(I) complex, along with a detailed analysis of the geometry characterization and its interaction with double-stranded DNA. The triclinic phase Cu(PPh3)2(L)(I) with a tetrahedral geometry was identified as the product of the reaction of copper(I) iodide with (E,E)-N,N'-1,2-Ethanediylbis[1-(3-pyridinyl)methanimine] ligand and triphenylphosphine by single-crystal X-ray analysis. Molecular interaction of the synthesized complex with the calf thymus deoxyribonucleic acid (ct-DNA) was investigated in the physiological buffer (pH 7.4) by multi-spectroscopic approaches associated with a competitive displacement towards Hoechst 33258 and methylene blue (MB) as groove and intercalator probes. The fluorescence and UV/Vis results detected the formation of a complex-DNA adduct in the ground-state with a binding affinity in order of 104 M-1, which is in keeping with both groove binders and intercalators. The thermodynamic parameters, ΔS0 = -200.31 ± 0.08 cal/mol·K and ΔH0 = -63.11 ± 0.24 kcal/mol, confirmed that the van der Waals interaction is the main driving force for the binding process. Moreover, the ionic strength and pH effect experiments demonstrated the electrostatic interactions between the complex and DNA is negligible. Analysis of the molecular docking simulation declared the flat (E,E)-N,N'-1,2-Ethanediylbis[1-(3-pyridinyl)methanimine] part of the complex was inserted between the sequential A…T/A…T base pairs, while the phosphine substituents were located in the groove, i.e. threading intercalation. Besides, the cytotoxicity of the complex against the MCF-7 human breast cancer cells was detected at IC50 = 10 µg/mL.

Phosphine fumigation - Time dependent changes in the volatile profile of table grapes.

Industrial and agricultural goods are fumigated in transport containers in order to control pest infestations and to avoid the transmission of alien species. Phosphine is increasingly used prior to the export as fumigant for table grapes, fruit cultures and dried fruits to control active table grapevine insect pests. Less knowledge exists for fumigants about the desorption time of toxic gases and factors that affect the composition of the fumigated good. Therefore, red and white table grapes (´Thompson seedless´, ´Scarlotta´ and ´Flame seedless´) were chosen to represent the allowed group of phosphine fumigated foods and were treated with a concentration of 2000 vpm phosphine (PH3) at different temperatures. In the present study, sorption and desorption behavior of PH3 by table grapes and possible changes in their VOC (volatile organic compounds) profiles were investigated. The PH3 concentration was monitored before and after the fumigation process and was determined under the maximum residue level 0.005 ppm after 35 days. The adsorbed amount of PH3 was not influenced by fumigation parameters. For analysis of the influences on the volatile profile after fumigation, a headspace solid-phase micro-extraction coupled to gas chromatography mass spectrometry (HS-SPME-GC/MS) was used. Small differences in volatile profiles of fumigated and subsequently outgassed table grapes compared to non-fumigated table grapes could be observed. A slight influence on the aldehyde group directly after fumigation could be perceived by a decrease of hex-2-en-1-ol and 1- hexanol in PH3-treated table grapes. The concentrations of both compounds increase again after completion of the desorption process. On the other hand terpenes are not significantly influenced by the fumigation process. Overall these changes are likely to affect table grape aroma characteristics directly after a treatment with PH3 and it could be demonstrated that phosphine alters the volatile profile of fumigated table grapes qualitatively and quantitatively.

Phosphine detection in veterinary samples using headspace gas chromatography/tandem mass spectrometry with multiple reaction monitoring.

RATIONALE: Determination of phosphine exposure from zinc or aluminum phosphide fumigants continues to be a routine analytical requirement in veterinary forensic toxicology. There is a need for a more reliable and specific method than simple gas chromatography/mass spectrometry (GC/MS) analysis of sample solvent extracts, as GC/MS of extracts on capillary columns used for general screens involves significant interference from air peaks. METHODS: GC/MS/MS headspace analysis of acid-generated phosphine gas enabled study of the feasibility of devising multiple reaction monitoring (MRM) approaches to the determination of phosphine with greater specificity. RESULTS: Collision-induced dissociation in GC/MS/MS showed that phosphine generated m/z 34 → 31, 32 and 33 ion transitions by sequential proton release as well as minor transitions m/z 34 → 47, 34 → 63 and 63 → 31.5 by intermolecular collisions and double charging. Study of the formation of these product ions enabled development of MRM settings for a highly useful headspace method for phosphine detection. CONCLUSIONS: The method was validated over a working range of 5-100 ppm of phosphide generating phosphine gas which enabled retention of regular screen capillary columns without necessitating separation from air components. The method should have adequate sensitivity and reliability for veterinary toxicology laboratories confronting specimens from animals poisoned by crop fumigants.

Phosphine as a Biosignature Gas in Exoplanet Atmospheres.

A long-term goal of exoplanet studies is the identification and detection of biosignature gases. Beyond the most discussed biosignature gas O2, only a handful of gases have been considered in detail. In this study, we evaluate phosphine (PH3). On Earth, PH3 is associated with anaerobic ecosystems, and as such, it is a potential biosignature gas in anoxic exoplanets. We simulate the atmospheres of habitable terrestrial planets with CO2- and H2-dominated atmospheres and find that PH3 can accumulate to detectable concentrations on planets with surface production fluxes of 1010 to 1014 cm-2 s-1 (corresponding to surface concentrations of 10s of ppb to 100s of ppm), depending on atmospheric composition and ultraviolet (UV) irradiation. While high, the surface flux values are comparable to the global terrestrial production rate of methane or CH4 (1011 cm-2 s-1) and below the maximum local terrestrial PH3 production rate (1014 cm-2 s-1). As with other gases, PH3 can more readily accumulate on low-UV planets, for example, planets orbiting quiet M dwarfs or with a photochemically generated UV shield. PH3 has three strong spectral features such that in any atmosphere scenario one of the three will be unique compared with other dominant spectroscopic molecules. Phosphine's weakness as a biosignature gas is its high reactivity, requiring high outgassing rates for detectability. We calculate that tens of hours of JWST (James Webb Space Telescope) time are required for a potential detection of PH3. Yet, because PH3 is spectrally active in the same wavelength regions as other atmospherically important molecules (such as H2O and CH4), searches for PH3 can be carried out at no additional observational cost to searches for other molecular species relevant to characterizing exoplanet habitability. Phosphine is a promising biosignature gas, as it has no known abiotic false positives on terrestrial planets from any source that could generate the high fluxes required for detection.

Optimization and Validation of HS-SPME-GCMS Method for Determination of Multifumigant Residues in Grain, Oilseeds, Nuts, and Dry Fruit.

Background: Fumigants are approved in many countries and used to treat food, feed, and seed. The amount of residue that remains in fumigated materials is measured and reported. Objective: The optimization and validation of a high-sensitivity headspace solid-phase microextraction gas chromatograph mass spectrometer (HS-SPME-GCMS) method for determination of eight fumigant residues-phosphine, methyl bromide, cyanogen, sulfuryl fluoride, ethylene oxide, propylene oxide, ethyl bromide and ethyl formate-in a range of food matrices were developed. The food matrices included grain, oilseed, dried fruit, and nut. Methods: The new method was used to determine residue levels from a fumigant complex in food matrices by monitoring the change of the absorption of spiked standards and desorption of fumigant from fumigated samples. Results: Based on the observation, the process of physical sorption and chemisorption was defined. The equilibrium time of the sample analysis was chosen at 5 hours. The LODs of the fumigants were in the range of 0.03 to 1.99 ng/g. Response to a range of diluted authentic standards gave significant linear regressions (r² > 0.9983), and the RSDs were ≤8.7% at the 3 ng/g level of aged spiking standard, except for sulfuryl fluoride, for which the LOD was 1.99 ng/g and the RSD value was 39.7% (6.64 ng/g). Conclusions: The performance of the HS-SPME-GCMS method was more sensitive than the use of a gas syringe, except for sulfuryl fluoride. Highlights: An innovative multifumigant residue detection method based on HS-SPME sampling technology with gas chromatograph-mass selective detection (GC-MSD) analysis was established, including phosphine, methyl bromide, cyanogen, sulfuryl fluoride, ethylene oxide, propylene oxide, ethyl bromide, and ethyl formate; The first report of a sorption study of the process of physical sorption and chemisorption of residual fumigant in fruit and food matrices by an HS-SPME-GCMS method; Consider the effect of time on fumigant behavior in dried fruit, grain, and nut; The LODs of the fumigants were in the range of 0.03 to 1.99 ng/g.

Physical, chemical and biological behaviour of fumigants on cottonseed.

Fumigation is required to protect cottonseed in storage and pre-shipment from insect pests and/or microorganisms. Fumigation of cottonseed with carbon disulphide (CS2), carbonyl sulphide (COS), ethanedinitrile (C2N2), ethyl formate (EF), methyl bromide (MB) and phosphine (PH3) showed that >85% of the fumigants disappeared within 5 h of exposure. COS maintained >20 mg L-1 for 24 h. After 1 day of aeration, 75%-85% of the absorbed COS and MB and 20%-40% of the absorbed CS2, EF and PH3 were released from treated cottonseed. The fumigant residues were reduced by 80% for COS, 50% for EF or MB and 25% for CS2 after 1 day of aeration. After 13 days of aeration, fumigant residues were reduced by 95% for MB, 65% for EF, 55% for CS2 and to natural levels in the COS residue. Carbon disulphide, COS, PH3, EF and C2N2 had no effect on the germination of cottonseed, but germination was reduced to 50% by MB. COS has potential as a fumigant for control of insect pests in cottonseed because it dissipates quickly and does not negatively impact germination. On the other hand, MB appears to strongly absorb and requires an extended period for residues to dissipate, and it negatively impacts germination.

Lucigenin-Tris(2-carboxyethyl)phosphine Chemiluminescence for Selective and Sensitive Detection of TCEP, Superoxide Dismutase, Mercury(II), and Dopamine.

Development of simple and effective chemiluminescence (CL) systems for multiple sensing applications is significantly important but still a challenge. Until now, the majority of CL systems primarily utilized hydrogen peroxide (H2O2) as coreactant, which is limited in its stability and selectivity due to the easy decomposition of H2O2 in the presence of several ions. In this study, we develop a new and intense CL system by combined use of tris(2-carboxyethyl)phosphine (TCEP), a highly solution stable and pH-tolerant tertiary phosphine, with lucigenin for the first time. The effective pairing leads to a significant ∼23 times CL enhancement over classic the lucigenin-H2O2 system without employing additional catalysts. By virtue of this fascinating platform, a sensitive CL method has been developed for the multiple detection of TCEP (LOD = 70 nM), lucigenin (LOD = 4.0 nM), superoxide dismutase (LOD = 0.8 ng/mL), Hg2+(LOD = 0.3 nM), and dopamine (LOD = 3.0 nM), with a linear range of 0.1-320 µM, 0.01-55 µM, 0.005-0.5 µg/mL, 1.0-600 nM, and 0.01-0.8 µM, respectively. Remarkably, this CL method exhibited superior selectivity over several potential interferents. Moreover, the proposed method achieved excellent recoveries in the range of 94.0-102.3% for both Hg2+ detection in lake water and dopamine detection in human serum real samples. We envision that broad applications of TCEP may lead to construct new CL systems, pushing forward for efficient detection of various analytes.

New environmental model for thermodynamic ecology of biological phosphine production.

We present a new model for the biological production of phosphine (PH3). Phosphine is found globally, in trace amounts, in the Earth's atmosphere. It has been suggested as a key molecule in the phosphorus cycle, linking atmospheric, lithospheric and biological phosphorus chemistry. Phosphine's production is strongly associated with marshes, swamps and other sites of anaerobic biology. However the mechanism of phosphine's biological production has remained controversial, because it has been believed that reduction of phosphate to phosphine is endergonic. In this paper we show through thermodynamic calculations that, in specific environments, the combined action of phosphate reducing and phosphite disproportionating bacteria can produce phosphine. Phosphate-reducing bacteria can capture energy from the reduction of phosphate to phosphite through coupling phosphate reduction to NADH oxidation. Our hypothesis describes how the phosphate chemistry in an environmental niche is coupled to phosphite generation in ground water, which in turn is coupled to the phosphine production in water and atmosphere, driven by a specific microbial ecology. Our hypothesis provides clear predictions on specific complex environments where biological phosphine production could be widespread. We propose tests of our hypothesis in fieldwork.

Phosphine production in anaerobic wastewater treatment under tetracycline antibiotic pressure.

The influence of tetracycline (TC) antibiotics on phosphine (PH3) production in the anaerobic wastewater treatment was studied. A lab-scale anaerobic baffled reactor with three compartments was employed to simulate this process. The reactor was operated in a TC-absence wastewater and 250µg/L TC-presence wastewater for three months after a start-up period, respectively. The responses of pH, oxidation-reduction potential (ORP), chemical oxygen demand (COD), total phosphorus (TP), enzymes activity (dehydrogenase and acid phosphatase), and microbial community were investigated to reveal the effect of TC on PH3 production. Results suggested that the dehydrogenase (DH) activity, acid phosphatase (ACP) activity and COD have positive relationship with PH3 production, while pH, ORP level and the TP in liquid phase have negative relationship with PH3 production. With prolonged TC exposure, decrease in pH and increase in DH activity are beneficial to PH3 production, while decrease in COD and ACP activity are not the limiting factors for PH3 production.

Phosphine Analysis in Postmortem Specimens Following Inhalation of Phosphine: Fatal Aluminum Phosphide Poisoning in Children.

Phosphine is an insecticide for the fumigation of grains, animal feed, and leaf-stored tobacco, and it was used as a rodenticide in bulk grain stores. Phosphine poisoning may occur after accidental inhalation of phosphine, sometimes leading to death. Analysis of phosphine and its metabolites in postmortem specimens from seven fatal cases was conducted in this study, as well as postmortem specimens collected from rabbits exposed to phosphine. The total phosphine in postmortem specimens was analyzed by headspace gas chromatography coupled with mass spectrometry. Diagnosis of aluminum phosphide poisoning was made after postmortem toxicological analysis and confirmed by police investigation. The deaths of the children occurred after inhalation of phosphine generated from aluminum phosphide contacting moisture in the air in all seven fatal cases. The concentration of total phosphine in the biological fluids and tissues of victims ranged from 0.2 to 4.7 µg/mL (µg/g). Animal experiments demonstrated that the phosphine generated from aluminum phosphide could rapidly cause death. The toxicological analysis of postmortem specimens provides useful information in diagnosis of aluminum phosphide poisoning in forensic science. As an important fumigation pesticide, aluminum phosphide deserves special attention, especially since there is no specific antidote and there is a high fatality rate.