A case of fatal methyl bromide poisoning

A case of preventable fatality and a nearly greater disaster as a result of methyl bromide fumigation of a restaurant is presented. Methyl bromide is a nearly odorless, volatile hydrocarbon used as a fumigant in the food industry. As a result of this episode, recommendations are made for worker and community notification of the hazards involved whenever fumigation takes place. Addition of a mucosal irritant or olfactory stimulant is recommended to provide warning for methyl bromide exposure.

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.

Postharvest-applied agrochemicals and their residues in fresh fruits and vegetables

Many agrochemicals are applied postharvest on fruits and vegetables to extend their lives and preserve quality during storage, transport, and marketing. Persistence and distribution of residues on the edible portions of produce have been reported for citrus fruits, pome fruits, stone fruits, mangos, strawberries, bananas, kiwi fruits, avocados, some minor fruit commodities, and bell peppers and tomatoes. Data on the persistance and residues of the fungicides benomyl, biphenyl, sec-butylamine, captan, carbendazim, dicloran, fosetyl-aluminum, guazatine, imazalli, iprodione, metalaxyl, o-phenylphenol, prochloraz, thiabendazole, thiophanate-methyl, triadimeton, and vinclozolin, the fumigants ethylene dibromide, methyl bromide, and sulfur dioxide, the insecticides dimethoate and fenthion, the antiscald compounds diphenylamine and ethoxyquin, and the growth regulators 2,4-D and daminozide are presented and discussed.

Evaluation of methyl bromide exposure on the plant quarantine fumigators by environmental and biological monitoring

The study was undertaken to assess the potential risk of exposure to methyl bromide (MB) gas of plant quarantine fumigators who wore full facepiece gas masks with respirator canisters. The mean ambient concentrations of MB determined by a personal sampling device exceeded the TLV-ACGIH level of 5 ppm in the degassing processes at three fumigation sites except at the silos. The mean urinary bromine concentration of 379 non-MB workers was 6.3 +/- 2.5 mg/l with 95% confidence limits of 10 mg/l. There were 44.6% of 251 MB workers whose urinary bromine levels exceeded the 10 mg/l. There was a significantly positive correlation between the urinary bromine concentrations of the MB workers and the ambient MB concentrations in the degassing process. The MB levels in the workers' exhalation were positive in the degassing process, while those were below the detection limit in the dispersion process. Three possible routes through which the workers are exposed to MB gas are considered to exist: leakage through the interstice between the facepiece of a gas mask and the wearer's face, breakthrough of MB gas in the respirator canister, and percutaneous absorption of MB gas. Biological monitoring of urinary bromine and exhalatory MB as well as environmental monitoring of the ambient MB provided useful information for evaluating exposure of workers to MB.

Preparation for human study of pesticide applicators: sister chromatid exchanges and chromosome aberrations in cultured human lymphocytes exposed to selected fumigants

In preparation for a human study of worker exposure to grain fumigants and pesticides, we decided to screen commonly used fumigants for genotoxic effects in vitro. This research strategy was employed to test the possibility that structurally simple chemicals might have similar genotoxic properties in vivo and in vitro. As a first step, we designed our in vitro protocol to mimic to the extent possible, a single in vivo exposure of lymphocytes to fumigants. Go lymphocytes were treated with different doses of carbon tetrachloride, carbon disulfide, methyl bromide, chloropicrin, and melathion with and without addition of rat liver homogenate for 1/2 hour, washed free of toxicant, and stimulated with PHA. After culture, the prepared slides were studied for chromosome aberrations and SCEs. Malathion, methyl bromide, and chloropicrin significantly induced SCEs without S-9. Carbon disulfide alone required S-9 for significant SCE induction. Chromosome aberrations were significantly increased by malathion and methyl bromide. Carbon tetrachloride failed to induce SCEs or chromosome aberrations with or without S-9. We concluded from these preliminary studies and other comparable work that the fumigants studied here may be less likely to express genotoxicity in terms of SCEs or chromosome aberrations than ethylene oxide or phosphine given a single short-term in vivo exposure. The final design of our human study was altered to focus on seasonal worker exposure rather than on a single exposure event.

Toxicology and hazard evaluation of cyanide fumigation powders

Studies were conducted to assess potential handling hazards from the pesticidal use of HCN-liberating "cyanide fumigation powders". Simulations were conducted in enclosed chambers on the release of HCN vapor from wetted powder containing 40% NaCN/60% kaolin at application rates of 1 g powder/m3 of space (usual rate) and 5 g/m3 (overuse condition). With the overuse situation, HCN vapor concentrations may be rapidly attained that produce serious or lethal toxicity; with the lower application rate minor signs and symptoms of HCN vapor exposure toxicity may develop. The acute peroral LD50 (rat and rabbit) of fumigant formulation is reduced in proportion to the kaolin content, but kaolin does not modify the inherent toxicity of NaCN. A typical cyanide hazard exists from swallowing cyanide fumigant powder formulations. Lethal systemic toxicity was produced by contamination of the eye (rabbit) with powder formulation, which also caused a rapid onset of moderately severe conjunctivitis and keratitis. Applied to dry intact skin (rabbit) neither NaCN nor its kaolin formulation produced systemic toxicity. However, on moistened intact skin lethal amounts of cyanide were absorbed; but the kaolin content reduced the hazard in comparison with NaCN-alone applied to moist skin. With abraded dry skin there was no difference in lethal toxicity between NaCN-alone and its formulation; also, the toxicity of the formulation on abraded skin was three times that on intact moist skin. These finds indicate that the use of cyanide fumigant powder formulations may be hazardous by contact of powder with moist or abraded skin, contamination of the eye, swallowing, and inhalation of evolved HCN. There is a clear need for respiratory, cutaneous, and ocular protection when handling cyanide fumigant powder formulations.

Respiratory exposure of grain inspection workers to carbon tetrachloride fumigant

Carbon tetrachloride (often mixed with carbon disulfide or ethylene dichloride) is a common constituent of liquid grain fumigants. Applied as liquids, these mixtures volatilize and achieve vapor concentrations sufficient to control insect infestations in stored grains. Absorbed grain desorbs fumigant components after the fumigation period, and it then becomes a source of exposure to workers who handle fumigated grain. Carbon tetrachloride meets the EPA's risk criteria for hepatotoxicity, nephrotoxicity and oncogenicity, and it has been under regulatory review since 15 October 1980. Present OSHA standards for CCl4 are a time-weighted average (TWA) of 10 ppm and an acceptable ceiling of 25 ppm. ACGIH and NIOSH have recommended lowering the OSHA standard. The point at which peak exposure occurs during the grain inspection process has been identified as the off odor test in which the inspector smells the grain sample for rancidity, sourness, etc. Ambient concentrations of CCl4 in 7750 grain samples submitted for inspection were determined by colorimetric tube, and these concentrations were an estimate of peak grain inspector exposure to CCl4. The average ambient concentration of CCl4 per grain sample was 1.69 ppm +/- 8.35. Approximately 380 TWA CCl4 exposures for grain inspection workers were determined by using passive dosimeters. All TWA exposures were less than 2 ppm. Variables are examined, such as location of work, grain type, time of year and grain transportation vehicle--all of which are known to the sampler or inspector before performing their job functions and which affect potential exposure.

Semen quality in papaya workers with long term exposure to ethylene dibromide

To examine whether long term occupational exposure to ethylene dibromide (EDB) affects semen quality a cross sectional study of semen quality was conducted among 46 men employed in the papaya fumigation industry in Hawaii, with an average duration of exposure of five years and a geometric mean breathing zone exposure to airborne EDB of 88 ppb (eight hour time weighted average) and peak exposures of up to 262 ppb. The comparison group consisted of 43 unexposed men from a nearby sugar refinery. Statistically significant decreases in sperm count per ejaculate, the percentage of viable and motile sperm, and increases in the proportion of sperm with specific morphological abnormalities (tapered heads, absent heads, and abnormal tails) were observed among exposed men by comparison with controls after consideration of smoking, caffeine and alcohol consumption, subject's age, abstinence, history of urogenital disorders, and other potentially confounding variables. No effect of exposure to EDB on sperm velocity, the overall proportion of sperm with normal morphology, or YFF bodies was observed. These data strongly suggest that EDB may increase the risk of reproductive impairment in workers at exposure levels near the National Institute for Occupational Safety and Health recommended limit of 45 ppb (as an eight hour time weighted average) and far below the current standard of the Occupational Safety and Health Administration of 20 ppm.

[Changes in the vitamin content of various cereals during storage]

Thiamine and niacin losses were studied in various cereals (grinding millet, non-grinding oatmeal, fine-ground corn, grinding rice, wheat Poltavskaya, buckwheat, pearl-barley, and grinding pea) stored in sacks at store-houses in two different climatic areas of the USSR - with a temperate and with a dry hot climate, as well as at a constant temperature of 10 degrees C, during 6-29 months. Vitamin losses in grinding millet, non-grinding oatmeal and grinding rice were evaluated considering their treatment with methyl bromide and cereal cooking. It was found that during the storage under conditions of a dry hot climate thiamine and niacin losses comprised 37.8, after methyl bromide treatment - 44.0, and after cooking - 28.6%. Lower vitamin losses were recorded after the cereals storage at a constant temperature of 10 degrees C.

Nutritional and toxicological effects of long-term ingestion of phosphine-fumigated diet by the rat

The fumigation of stored foodstuffs with phosphine (PH3) is likely to become widely used in the future because of its technological efficiency and the rapid desorption of the fumigant. In a long-term feeding study of a phosphine-fumigated diet, rats were monitored for weight gain, food intake, plasma chemistry, haematology and urinary changes. Histopathological studies, including organ-weight determinations, were carried out after treatment of the rats for 1 and 2 yr. The results show that ingestion of a phosphine-fumigated diet by the rat for 2 yr does not cause any marked modification of growth, food intake, nitrogen balance, body composition, functional behaviour or the incidence or type of tumours.