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PubMed2005

Potential use of essential oils from Cameroon applied as fumigant or contact insecticides against Sitophilus zeamais Motsch. (Coleoptera: Curculionidae).

Essential oils from seven plants species currently found in Cameroon were extracted by steam distillation and tested for their insecticidal activities against Sitophilus zeamats Motsch. Responses varied with the test applied and the plant species. For the contact toxicity, the acetone was used in order to dilute the pure essential oil. Formulations of 1% of essential oils of Xylopia aethiopica and Ocimum gratissimum were the most toxic and led to 96 and 98% of mortality respectively after 24 h. There was no death in control (0% of mortality). Fumigation test were done by applying 300 microl of pure essential oils in the bottom of closed 800 ml glass containers. In that case, the essential oil of Hyptis spicigera was the most toxic (fumigant) after 48 hours of fumigation followed by Annona seregalensis and Xylopia aethiopica 96 and 95% of mortality respectively. Some of the essential oils of plant species tested are promising for pest control in farmer granaries. However, further investigations are to be done on formulation and side effects.

Animals↗
PubMed2005

Life without methyl bromide: the Italian experience in replacing the fumigant.

Methyl bromide (MB) has been the most widely used chemical for the fumigation of soil, commodities, buildings and furniture for over seventy years. Since January 1st 2005, it has been phased-out in industrialized countries, where only critical uses are allowed, because of international regulatory measures designed to reduce substances that potentially deplete the stratospheric ozone layer. Italy ranked second in the world, after USA, in MB consumption, due to the importance of horticultural crop production. In order to replace the use of MB, research in Italy was aimed at: a) reducing the use of MB and its emission (short-term goal); b) developing alternative pest control methods, based on available technologies (mid-term goal); c) developing new MB alternatives (mid- and long-term goal). Italian growers switched to other fumigants, applied at reduced dosages, lowering their environmental impact and risk of worker exposure. Moreover, the adoption of non-chemical alternatives slowly but steadily increased as a result of the many activities (demonstration trials, seminars, etc.) carried out in the country. The gradual shift to MB alternatives over a 10 year period, as well as the use of half rates of MB under virtually impermeable plastic films (VIFs), has generally prevented the feared loss of competitiveness of Italian horticulture. Extension in cooperation with the fumigation companies was able to provide growers with a range of methods for soil disinfestation. The experience gained in Italy and how it can help developing countries to define strategies and training programmes needed to comply with the Montreal Protocol is discussed.

Crops, Agricultural↗
PubMed1962

Fumigation of jute bags with ethylene oxide and methyl bromide to eradicate potato ring rot bacteria.

In a series of full-scale tests, the effectiveness of various fumigant treatments for the eradication of potato ring rot bacteria from bulk lots of contaminated jute bags was evaluated. Survival of these bacteria on infested sample fibers located at various positions within and around a tightly wired bale was determined quantitatively from the growth lag in a liquid medium as indicated by the rate of turbidity development.Ethylene oxide, though highly toxic to Corynebacterium sepedonicum in laboratory tests, failed to penetrate the jute sufficiently to be effective in the interior of a bale. Methyl bromide showed better penetration, but was not sufficiently toxic at practical dosage levels. A mixture of 5% ethylene oxide and 10% methyl bromide achieved complete eradication throughout a bale in an 18-hr exposure period. On the basis of these results, eradication of ring rot bacteria from contaminated jute bags by fumigation with a combination of these two gases would appear to be feasible under commercial conditions.

Bacteria↗
PubMedDate not supplied

Fatal accident resulting from methyl bromide poisoning after fumigation of a neighbouring house; leakage through sewage pipes.

An intoxication after using methyl bromide (CH3Br) in fumigation is reported. The accident resulted in the death of a newborn infant within 12-13 h after exposure, as well as clinical intoxication of the infant's parents. The concentration of bromide ion in the infant's blood was 170 mg l-1 and in the parents blood it was 130 and 110 mg l-1. Autopsy showed that the cause of death was acute pneumonia due to aspiration, most likely resulting from vomiting and aspiration after inhalation of CH3Br. The clinical symptoms of the parents are reported, as well as a brief survey on the kinetics and CH3Br toxicity in animals and humans. Reconstruction of the events prior to the intoxication revealed that the sewage pipes serving the two houses had been sucked empty only 1-2 h prior to the start of fumigation, resulting in an open sewage connection between the houses and permitting CH3Br to leak from the treated house into the house of the affected family.

Female↗
PubMed2006

Physical, chemical and environmental properties of selected chemical alternatives for the pre-plant use of methyl bromide as soil fumigant.

Production and use of methyl bromide, a soil fumigant, are being restricted because of this chemical's deleterious effects on stratospheric ozone concentrations. Several products, some of which are currently used as soil fumigants, are being considered as possible replacements for methyl bromide, alone and in various combinations. Among these, 1,3-dichloropropene, methyl isothiocyanate generators such as metam-sodium, and chloropicrin are currently registered, while others such as methyl iodide and sodium azide are at different stages of the registration process. This review examines physicochemical properties, environmental fate, and metabolism of the various potential methyl bromide replacement products.

Agriculture↗
PubMed2005

Effectiveness of allyl acetate as a fumigant against five stored grain beetle pests.

Five esters, butyl acetate, allyl acetate, ethyl acetoacetate, isopropyl acetate and propyl acetate, were screened as fumigants in the laboratory for 24 h at 27 (+/-2) degrees C against the adults of Rhyzopertha dominica (F), Sitophilus oryzae (L) and Tribolium castaneum (Herbst). Of the compounds tested, allyl acetate was the most toxic, with LD(99) values of 7.56, 12.81 and 11.42 mg litre(-1) against R dominica, S oryzae and T castaneum, respectively. Tests with allyl acetate against mixed-age cultures of Cryptolestes ferrugineus (Stephens), Oryzaephilus surinamensis (L), R dominica, S oryzae and T castaneum revealed that doses of 50-150 mg litre(-1) with 24-120-h exposures were necessary to achieve 100% mortality of all life stages. Cryptolestes ferrugineus was the most tolerant insect tested, whilst R dominica was highly susceptible. The insect toxicity data indicates that allyl acetate has potential as a fumigant of stored food grains.

Acetates↗
PubMed1981

Dangerous concentrations of methyl bromide used as a fumigant in Belgian greenhouses.

In the disinfection of soil in greenhouses, methyl bromide can be applied to the soil by injection or by fumigation on the surface. The concentrations of methyl bromide in the air are measured, and the differences between each technique discussed. Concentrations during injection vary between 100 and 1,000 ppm with peaks up to 3,000 (10,000 in one case) ppm, but drop below 200 ppm if preventive measures are taken. During fumigation concentrations remain between 100 and 1,000 ppm. Large variations occur within a technique depending on the quality both of the material and operator.

Air Pollutants, Occupational↗
PubMed1984

[A semiempirical mathematical model for assessment of PH3 residues as exemplified by phosphine-fumigated hazelnuts].

A mathematical model for the calculation of residues of PH3 in fumigated hazelnuts in dependence on dosage, fumigation- and storage time is discussed. The model is based on the physical process of the diffusion of a gas out of a sphere. An empirical dependence of the diffusion coefficient on the residue levels can be observed. Adequate agreement is obtained between calculated and experimental values.

Food Contamination↗
PubMed1993

A two-generation reproduction study in rats with methyl bromide-fumigated diets.

Crj:CD(SD) rats were fed basal (control) diet or methyl bromide-fumigated diet containing 80, 200 or 500 ppm total bromine for two successive generations (18 wk for each generation). Compared with controls, food consumption was significantly lower in F1 parental females of the 500-ppm group during the second half of the dosing period, and F2 female pups of the 500-ppm group showed lower body weights throughout the lactation period. No other treatment-related changes were found at any dietary level of total bromine in either parental animals (F0, F1) or their offspring (F1, F2) for any of the parameters studied (i.e. clinical signs, oestrous cycle, sperm count and morphology, mating, fertility, gestation, parturition, litter size, pup viability, organ weights, and gross or histopathological examination). It was concluded that residues of 200 and 500 ppm total bromine in diets fumigated with methyl bromide are the no-observed-effect level and the minimum toxic level, respectively, for both parental rats and their offspring, and that bromine residues do not affect reproductive performance at dietary levels of up to 500 ppm.

Administration, Oral↗
PubMed2003

Predicting regional emissions and near-field air concentrations of soil fumigants using modest numerical algorithms: a case study using 1,3-dichloropropene.

Soil fumigants, used to control nematodes and crop disease, can volatilize from the soil application zone and into the atmosphere to create the potential for human inhalation exposure. An objective for this work is to illustrate the ability of simple numerical models to correctly predict pesticide volatilization rates from agricultural fields and to expand emission predictions to nearby air concentrations for use in the exposure component of a risk assessment. This work focuses on a numerical system using two U.S. EPA models (PRZM3 and ISCST3) to predict regional volatilization and nearby air concentrations for the soil fumigant 1,3-dichloropropene. New approaches deal with links to regional databases, seamless coupling of emission and dispersion models, incorporation of Monte Carlo sampling techniques to account for parametric uncertainty, and model input sensitivity analysis. Predicted volatility flux profiles of 1,3-dichloropropene (1,3-D) from soil for tarped and untarped fields were compared against field data and used as source terms for ISCST3. PRZM3 can successfully estimate correct order of magnitude regional soil volatilization losses of 1,3-D when representative regional input parameters are used (soil, weather, chemical, and management practices). Estimated 1,3-D emission losses and resulting air concentrations were investigated for five geographically diverse regions. Air concentrations (15-day averages) are compared with the current U.S. EPA's criteria for human exposure and risk assessment to determine appropriate setback distances from treated fields. Sensitive input parameters for volatility losses were functions of the region being simulated.

Air↗
PubMed2005

Fumigant activity of plant essential oils and components from garlic (Allium sativum) and clove bud (Eugenia caryophyllata) oils against the Japanese termite (Reticulitermes speratus Kolbe).

Plant essential oils from 29 plant species were tested for their insecticidal activities against the Japanese termite, Reticulitermes speratus Kolbe, using a fumigation bioassay. Responses varied with plant material, exposure time, and concentration. Good insecticidal activity against the Japanese termite was achived with essential oils of Melaleuca dissitiflora, Melaleuca uncinata, Eucalyptus citriodora, Eucalyptus polybractea, Eucalyptus radiata, Eucalyptus dives, Eucalyptus globulus, Orixa japonica, Cinnamomum cassia, Allium cepa, Illicium verum, Evodia officinalis, Schizonepeta tenuifolia, Cacalia roborowskii, Juniperus chinensis var. horizontalis, Juniperus chinensis var. kaizuka, clove bud, and garlic applied at 7.6 microL/L of air. Over 90% mortality after 3 days was achieved with O. japonica essential oil at 3.5 microL/L of air. E. citriodora, C. cassia, A. cepa, I. verum, S. tenuifolia, C. roborowskii, clove bud, and garlic oils at 3.5 microL/L of air were highly toxic 1 day after treatment. At 2.0 microL/L of air concentration, essential oils of I. verum, C. roborowskik, S. tenuifolia, A. cepa, clove bud, and garlic gave 100% mortality within 2 days of treatment. Clove bud and garlic oils showed the most potent antitermitic activity among the plant essential oils. Garlic and clove bud oils produced 100% mortality at 0.5 microL/L of air, but this decreased to 42 and 67% after 3 days of treatment at 0.25 microL/L of air, respectively. Analysis by gas chromatography-mass spectrometry led to the identification of three major compounds from garlic oil and two from clove bud oils. These five compounds from two essential oils were tested individually for their insecticidal activities against Japanese termites. Responses varied with compound and dose. Diallyl trisulfide was the most toxic, followed by diallyl disulfide, eugenol, diallyl sulfide, and beta-caryophyllene. The essential oils described herein merit further study as potential fumigants for termite control.

Animals↗
PubMed2003

Estimating methyl bromide exposure due to offgassing from fumigated commodities.

Methyl bromide (MB) is used to fumigate diverse commodities. During fumigation, the commodity can sorb a substantial mass of MB, which does not chemically react and is termed a residue. During subsequent commodity handling, the residue offgasses and can lead to MB inhalation exposure among processing workers. Although MB has a low 1 ppm 8-hr TLV-TWA as recommended by the American Conference of Governmental Industrial Hygienists (ACGIH(R)) and is considered a potential occupational carcinogen by the National Institute for Occupational Safety and Health, the recent industrial hygiene literature contains no pertinent exposure data. Limited measurements made in 1992 by the California Department of Pesticide Regulation are summarized here, but associated information on exposure determinants is lacking. In this article, mathematical models are used to integrate data on MB residue offgassing with several processing scenarios to estimate potential exposure levels. The main finding is that if a large volume of commodity rapidly offgasses MB and is handled under conditions of low ventilation, the potential exists for MB exposures above the 1 ppm TLV-TWA value. However, the combination of handling a smaller commodity volume and less rapid offgassing may be the more typical scenario. It is recommended that a pilot study be conducted to measure current MB exposure levels, test the validity of the mathematical models, and collect industry-wide data on exposure determinants. By using the latter data as inputs for validated models, public health scientists could estimate the distribution of MB exposure levels across the commodity processing industry.

Agrochemicals↗
PubMed1980

On site determination of Sulfotep air levels in a fumigating greenhouse.

Sulfotep air levels in a greenhouse were monitored continuously in real time, for 4-40 hours after fumigation, using a trace atmospheric gas analyzer system. Sulfotep air levels were below the threshold limit value of 15 ppb following overnight ventilation but, when ventilation was stopped to conserve heat, the Sulfotep air levels exceeded the threshold limit value. This study also showed that worker activity in the greenhouse significantly increased Sulfotep air levels. It is recommended, therefore, that ventilation of a greenhouse following Sulfotep fumigation should continue during the entire day and workers exposed to such conditions should wear appropriate protective equipment.

Air Pollutants↗
PubMed2004

Sorption of the fumigant 1,3-dichloropropene on soil.

The fumigant 1,3-dichloropropene (1,3-D) is considered a major replacement to methyl bromide, which is to be phased out of use in the United States by 2005. The main purpose of this study was to evaluate soil-water partitioning of 1,3-D in two California agricultural soils (Salinas clay loam and Arlington sandy loam). The partition coefficients (Kd and Kf) were determined by directly measuring the concentration of 1,3-D in the solid phase (Cs) and aqueous phase (Cw) after batch equilibration. In the Salinas clay loam, the Kf of cis-1,3-D in adsorption and desorption isotherms was 0.47 and 0.54, respectively, with respective values of 0.39 and 0.49 for trans-1,3-D. This slight hysteric effect suggests that a different range of forces are involved in the adsorption and desorption process. Since n was near unity in the Freundlich equation, the Freundlich isotherms can also be approximated using the liner isotherm. At 25 degrees C, the Kd of the 1,3-D isomers in both soils ranged from 0.46 to 0.56, and the Koc (organic matter partition coefficient) ranged from 58 to 70. The relatively low Kd values and a Koc that falls within the range of 50-150, suggests that 1,3-D is weakly sorbed and highly mobile in these soils. Understanding the sorption behavior of 1,3-D in soil is important when developing fumigation practices to reduce the movement of 1,3-D to the air and groundwater.

Adsorption↗
PubMed1977

Terminal disinfection of calf houses by formaldehyde fumigation.

Trials were carried out to investigate the effectiveness of various methods of formaldehyde fumigation as a means of disinfecting calf houses. Houses were cleaned by the farmer, sealed and then fumigated. A significant reduction in bacterial numbers was obtained when the gas was produced by heating paraformaldehyde, mixing formalin with potassium permanganate or boiling formalin in calf houses that could be effectively sealed. Aerosol generators did not give satisfactory results. Efficient pre-cleaning and sealing of the houses were of paramount importance; relative humidity and temperature were less important.

Animals↗
PubMed1992

Microbiologically monitored fumigation of a newly built SPF laboratory rodent facility.

The initial sanitization and sterilization of a newly built animal facility for the breeding and holding of specific pathogen free (SPF) rats and mice is described. The fumigation programme was started with methyl bromide treatment directed primarily against arthropods, followed by ammonia spray to kill coccidial oocysts and concluded by three formaldehyde treatments with fog and spray against bacteria and viruses. The practicalities and problems involved are described in detail and the rationale and purpose of the programme and its monitoring are discussed. The report is expected to contribute towards the establishment of a rational, efficient and standardized fumigation programme for SPF animal facilities, under increasing constraints of safety and environmental considerations concerning pollution with toxic and corrosive agents.

Animals↗
PubMed2006

Comparative toxicity of fumigants and a phosphine synergist using a novel containment chamber for the safe generation of concentrated phosphine gas.

BACKGROUND: With the phasing out of ozone-depleting substances in accordance with the United Nations Montreal Protocol, phosphine remains as the only economically viable fumigant for widespread use. However the development of high-level resistance in several pest insects threatens the future usage of phosphine; yet research into phosphine resistance mechanisms has been limited due to the potential for human poisoning in enclosed laboratory environments. PRINCIPAL FINDINGS: Here we describe a custom-designed chamber for safely containing phosphine gas generated from aluminium phosphide tablets. In an improvement on previous generation systems, this chamber can be completely sealed to control the escape of phosphine. The device has been utilised in a screening program with C. elegans that has identified a phosphine synergist, and quantified the efficacy of a new fumigant against that of phosphine. The phosphine-induced mortality at 20 degrees C has been determined with an LC(50) of 732 ppm. This result was contrasted with the efficacy of a potential new botanical pesticide dimethyl disulphide, which for a 24 hour exposure at 20 degrees C is 600 times more potent than phosphine (LC(50) 1.24 ppm). We also found that co-administration of the glutathione depletor diethyl maleate (DEM) with a sublethal dose of phosphine (70 ppm, <LC(5)), results in a doubling of mortality in C. elegans relative to DEM alone. CONCLUSIONS: The prohibitive danger associated with the generation, containment, and use of phosphine in a laboratory environment has now been substantially reduced by the implementation of our novel gas generation chamber. We have also identified a novel phosphine synergist, the glutathione depletor DEM, suggesting an effective pathway to be targeted in future synergist research; as well as quantifying the efficacy of a potential alternative to phosphine, dimethyl disulphide.

Animals↗
PubMed1992

[Efficacy of ozone fumigation for laboratory animal sanitation].

Ozone resistance of spores of 2 strains of Bacillus isolated from laboratory animals was examined. Each of 0.02 ml of phosphate-buffered saline at pH 7.0 containing 10(6) Bacillus spores was dropped onto sterilized filter strips, wood chip bedding, pellets of diet, cloth pieces and stainless steel plates. After drying at room temperature, the test materials were exposed to ozone gas of different concentrations at 90% RH. Exposure to 200ppm ozone for 6 hours was sufficient to kill spores in filter strips, but a little higher concentration or a little longer period of ozone fumigation was necessary for sterilization of wood chips, cotton cloth pieces and steel plates. The present results indicated that 600ppm ozone fumigation for 6 hours might be effective for routine sterilization of cages, wood bedding, working clothes and other materials used in laboratory animal facilities. However, exposure to ozone gas of 500 or 1,000 ppm for 6 hours or 200 ppm for 24 hours could not kill spores in pellets of diet, suggesting that dietary protein inhibited the bactericidal activity of ozone.

Animals↗