FAO, PL:CP/15 WHO/Food Add./67.32 EVALUATION OF SOME PESTICIDE RESIDUES IN FOOD The content of this document is the result of the deliberations of the Joint Meeting of the FAO Working Party and the WHO Expert Committee on Pesticide Residues, which met in Geneva, 14-21 November 1966.1 1 Report of a Joint Meeting of the FAO Working Party and the WHO Expert Committee on Pesticide Residues, FAO Agricultural Studies, in press; Wld Hlth Org. techn. Rep. Ser., 1967, in press ETHYLENE DIBROMIDE IDENTITY Synonyms EDB, ethylene bromide Chemical name 1,2-dibromethane Formula CH2Br ' CH2Br BIOLOGICAL DATA AND TOXICOLOGICAL EVALUATION Biochemical aspects The fate of ethylene dibromide absorbed from the mammalian alimentary tract has apparently not been determined. After uptake by the pulmonary route, however, some of the compound is excreted through the lungs and some of it is changed in the body with the formation of organic bromides (von Oettingen, 1955). Acute toxicity Animal Route LD50 Reference mg/kg body-weight Mouse, female Oral 420 Rowe et al., 1952 Rat, male " 146 " Rat, female " 117 " Chick " 79 " Guinea-pig " 110 " Rabbit, female " 55 " A 43-year-old woman who took a single dose of ethylene dibromide amounting to 4.5 ml died 54 hours later after symptoms of vomiting, diarrhoea and anuria. At autopsy there was massive centro-lobular necrosis of the liver and proximal tubular damage in the kidney (Olmstead, 1960). Short-term studies A total of 19 rats and guinea-pigs was fed ethylene dibromide in oil or 50 per cent alcohol for about 4 months and there were no abnormal signs in those receiving about 40-50 mg/kg/day, but no pathological tests or autopsy examinations appear to have been undertaken (Aman et al., 1946). Fumigants in 50 per cent aqueous ethanol solution were administered directly into the crops of adult hens. Individually caged birds were given respectively 0.5, 1, 2, 4 and 20 mg ethylene dibromide/hen/day for 8 weeks. An additional group was given 8 mg/hen/day together with ethylene dichloride and carbon tetrachloride at levels which had no effect when given alone. At 8 mg/day (with other fumigants) and 20 mg/day both egg production and egg weight were decreased, whilst at 2 and 4 mg/day only egg weight was depressed. At 0.5 and 1.0 mg/day there were no differences from the controls. Haugh units of quality and shell thickness were also determined in this study, and the fumigant had no effect on these parameters (Fuller & Morris, 1962). In another experiment, groups of 24 pullets were treated for 12 weeks, rested for 8 weeks, and treated again for 12 weeks. Doses were 0, 0.5, 1, 2, 4 and 8 mg/bird/day. Egg production was depressed at 8 mg/day only. Egg weight was reported to be significantly decreased at all levels. However, the decrease at 0.5 and 1 mg/bird/day was very small. At necropsy, the birds receiving 8 mg/day and showing lowered productivity were found to have an excessive number of incompletely developed ovarian follicles, but no abnormalities in liver, brain or kidney. Effects on egg production and egg weight were comparable among two groups of hens treated at 7 and 18 months of age respectively (Fuller & Morris, 1962). Two-week-old chicks, in groups of 24, were fed for two weeks on a ration to which ethylene dibromide in ethanol and olive oil had been added at levels of 20, 40 and 80 ppm. Estimates made from chemical analyses suggested that these amounts would be reduced by evaporation and by conversion to inorganic bromide to somewhat less than 10, 20 and 40 ppm by the time the ration was consumed. At 10 and 20 ppm no change was observed in the chicks over the two weeks, but at 40 ppm there was retardation of growth rate, even when a correction was made for food intake (Morris & Fuller, 1963). Six-month-old pullets in groups of 10 were given ethylene dibromide either directly by injection into the crop, or indirectly in the diet after fumigation, daily intakes being 0.5, 1, 2, 4 and 8 mg per day. At 8 mg per day by both routes of administration, egg production was depressed, while egg weight was reduced at all levels down to 0.5 mg per bird, whether by crop or diet (Fuller & Morris, 1963). Four bull calves were given a dose schedule averaging 2 mg/kg body-weight daily of ethylene dibromide from the age of four days. After 14-16 months, growth, health and libido of the treated bulls were comparable to the controls, but sperm density was low and motility poor. These changes were reversible (Amir & Volcani, 1965). Short-term studies with fumigated foodstuff When chickens were fed for five days, pigs for 12 days and heifers for one week on grain previously fumigated with a gaseous mixture containing 7.2 per cent ethylene dibromide none of them showed any deleterious effects (Rowe et al., 1954). Twenty-five adult hens, in groups of five, were given a ration made up of 50 per cent sorghum. In those groups receiving grain containing sorbed ethylene dibromide in amounts ranging from 50 to 320 ppm, there was a decrease in egg weight proportional to the level of the fumigant. Moreover, in those receiving the highest amount, egg laying ceased completely in six-and-a-half weeks, and in those receiving 200 ppm it ceased within eight weeks. Even as little as 50 ppm had a depressive effect on egg size within three weeks. Further, those hens in which laying was arrested failed to resume when returned to a normal ration (Bondi et al., 1955). In another experiment with six-month-old hens in groups of 24 the sorghum, making up 50 per cent of the grain fed, contained 10-15 ppm ethylene dibromide and 20 ppm residual bromide, 20-30 ppm ethylene dibromide and 50 ppm residual bromide and no free ethylene dibromide but 120 ppm residual bromide. The fourth group was a control. Over 16 weeks the group receiving only the residual bromide behaved the same as the controls, but those receiving ethylene dibromide showed a decrease in egg size proportional to dose. But when these birds were returned to a normal diet the egg size was regained (Bondi et al., 1955). In an experiment carried out with two groups each of five hens, all of which were laying small eggs (40 per cent below normal) by being fed grain containing ethylene dibromide, the administration to one group of follicle stimulating hormone intravenously led to a partial recovery in egg size. Moreover, there was no reaction between ethylene dibromide and follicle stimulating hormone in sorghum. It is therefore postulated that the ethylene dibromide acts on the formation or release of pituitary follicle stimulating hormone (Olomucki, 1957). A group of laying hens that was fed for 23 days with oats fumigated with ethylene dibromide several months previously showed some diminution of egg size compared with controls and when the grain had been treated the day before with Dowfume EB5 (containing 63.6 per cent carbon tetrachloride, 29.2 per cent ethylene dichloride and 7.2 per cent ethylene dibromide by weight) at 10 times the recommended dose, egg output and size declined rapidly in 10 days (Bierer & Vickers, 1959). Five groups, each of 16 pullets six months of age, were fed for 19 days on: (i) a protein laying ration, plus non-fumigated oats; (ii) a protein laying ration, plus oats fumigated at the rate of 1.1 ml/kg; (iii) a protein laying ration, plus oats fumigated at the rate of 3.3 ml/kg; (iv) a commercial, all-mash ration, non-fumigated; (v) a commercial, all-mash ration, the corn component of which had been fumigated previously at the rate of 1.1 ml/kg. The fumigant was a commercial mixture containing carbon tetrachloride 64 per cent, ethylene dichloride 29 per cent and ethylene dibromide 7 per cent. After fumigation the grain was allowed to air for two weeks. In those groups which received fumigated oats, egg size was seriously and significantly depressed, more so at the heavy dosage (when production was totally arrested) than at the lower dosage. A smaller but still significant depression of egg production was observed in the birds on the mash ration containing fumigated oats subsequently ground (Caylor & Laurent, 1960). Comments When ethylene dibromide is used as a fumigant on food products a small amount of the compound may be converted to inorganic bromide by reaction with the foodstuff, but the major part remains adsorbed to the food in the unchanged form for some time. There is little reason to believe that the limited changes brought about chemically in the foodstuff by the action of ethylene dibromide on its components are responsible for any significant changes in its food value or for the production of any toxic substances. The deleterious effects observed experimentally with the feeding of fumigated rations to animals can be attributed, in all probability, to the residue of unchanged ethylene dibromide. The feeding studies carried out with ethylene dibromide, either fed directly or as a residue after fumigation, were principally done with poultry. This species seems particularly sensitive to the compound, since experiments on other animals, though limited, give little indication of toxicity. This action of ethylene dibromide on poultry may be due to interference with the hormonal balance. TOXICOLOGICAL EVALUATION The minimum pharmacologically effective dosage in the human adult has been generally stated to be about 900 mg of KBr, equivalent to 600 mg of bromide ion daily. Assuming an adult weight of 60 kg, this dosage in man is about 10 mg/kg body-weight per day. In the light of available toxicological information obtained from the extensive therapeutic use in man, an acceptable daily intake for man of inorganic bromide from all food sources can be estimated. Estimate of acceptable daily intake for man of inorganic bromide 0-1.0 mg/kg body-weight. On the available toxicological evidence, ethylene dibromide should be used for fumigation of food only on the condition that no residue of the unchanged compound will reach the consumer. Further work required for unchanged ethylene dibromide Further investigation of the effect of processing and cooking on residual ethylene dibromide in food. Short-term feeding studies in two mammalian species. Reproduction studies for three generations in at least two species. Results of the above work should be made available not later than three years after the publication of this report, when a re-evaluation of this compound will be made. RESIDUES IN FOOD AND THEIR EVALUATION Use pattern (a) Pre-harvest treatment Ethylene dibromide has a fairly high phytotoxicity. Its pre-harvest uses are confined to the treatment of soil before planting and to certain, usually dormant, plants for quarantine purposes. Any residues in food derived from such uses are likely to be minute and to occur as inorganic bromide. (b) Post-harvest treatment Ethylene dibromide is rarely used by itself. In a few countries it is so used for stacked cereals in bags. It is used in many countries for treating cereals, in mixtures with other liquid fumigants such an ethylene dichloride and carbon tetrachloride. These mixtures are usually applied to the surface of grain standing in bins or in holds of ships. Ethylene dibromide is readily sorbed by individual grains but, when poured on to grain it only penetrates a short distance. This also pertains even when mixtures are used in this manner, since separation of the constituents rapidly occurs (Berck, 1961; Berck & Solomon, 1962). This chemical therefore is used sometimes in liquid grain fumigants to ensure an adequate treatment of the surface layers, where the highest concentrations of insects are frequently found. When such mixtures are applied to the surface of a bulk, the proportion of the grain present which comes into contact with ethylene dibromide is usually quite small; furthermore, samples carefully taken from surface layers may have high residues whereas the main volume of grain present may not contain any fumigant. Mixtures are also used for the "spot fumigation" of individual items of machinery in milling plants. Ethylene dibromide is used on fresh fruit such as citrus, mainly as a quarantine measure against fruit fly. It is also sometimes used in a mixture with other fumigants, such as ethylene dichloride and carbon disulfide, on some other stored foods, such as pulses, and on various non-edible products. Fresh fruits may sorb some fumigant but with thick-skinned fruits such as citrus, these residues appear to be concentrated in the skins and penetration into the flesh of undamaged fruit appears to be small (Page & Blackith, 1956; Grierson & Hayward, 1959; Coggiola & Huelin, 1964). Ethylene dibromide is also used for the fumigation of empty wagons. Tolerances There are no tolerances for residues of unchanged ethylene dibromide. For inorganic bromide derived from fumigation there are tolerances of 50 ppm in Brazil, Germany, India, the Netherlands, USA and Canada; there is a tolerance of 20 ppm in Czechoslovakia and New Zealand. Residues resulting from supervised trials The fumigant is sorbed very readily by cereals or cereal products during exposure period (Whitney & Kenaga, 1960; Heuser, 1964). Although nearly all of the fumigant taken up by the cereals appears to be physically sorbed and can be removed by airing, this is a very slow process by comparison with the removal of methyl bromide. Therefore there is a greater chance of unchanged fumigant remaining in food. When whole or ground wheat was fumigated experimentally at 8 g/m3 or 16 g/m3 for 24 hours, more than 95 per cent of the ethylene dibromide could be recovered unchanged after 10 days; most of it was retained in the bran. Very little was converted to ionized bromide. Residues in milled samples after 35 days amounted to 4.5 ppm (Sinclair, Lindgren & Forbes, 1962). The very small proportion of the sorbed fumigant which combines appears to react mainly with the protein, or to change into inorganic bromide. This may result in a very slight change in the nature of the food protein itself, probably in its methionine component (Bridges, 1956). Coggiola & Heulin (1964) found the uptake of ethylene dibromide by treated oranges during treatment to increase with the period of storage of the fruit before fumigation. These authors also found that the losses of residue after treatment were greater with longer periods of pre-fumigation storage. One hundred and fifty gram oranges stored one to 25 days before fumigation absorbed from approximately 30 mg to 35 mg (respectively) of ethylene dibromide per orange; subsequent loss of residue varied from about zero up to over 5 mg per orange after 30 days. Getzendaner (1965) has investigated the residues of various mixed commercial fumigants based on ethylene dibromide in milled wheat products following spot-fumigant treatment of mill machinery. For a mixture of 59 per cent ethylene dibromide with 32 per cent carbon tetrachloride and nine per cent ethylene dichloride residues up to 1000 ppm of organic bromide were found immediately following fumigation, but giving way to pre-fumigation levels (10-20 ppm total Br. 0-4 ppm organic Br.) fairly quickly. 20.4 per cent ethylene dibromide with 57 per cent carbon tetrachloride, 19.6 per cent ethylene dichloride gave somewhat lower bromide residues in the flour immediately after fumigation (200-300 ppm) falling quickly to pre-fumigation levels. Getzandaner (1965a) has also shown that poultry meat and eggs from hens fed diets containing up to 400 ppm bromide residues contain at equilibrium no more bromide residue than the diet. Bär (1964) showed that the feeding of fumigated cereals to cattle may lead to bromide residues in milk. Lynn (1963) found 20 ppm bromide in milk from cows fed a diet containing 43 ppm bromide. Berck (1965) has shown that under laboratory conditions the uptake of ethylene dibromide by wheat increases significantly with increase of moisture content from nine to 18.5 per cent; the same is true of ethylene dichloride but not of carbon tetrachloride. Comminution, as in milling, greatly increased the uptake. The chromatographic characteristics of 51 different cereals (or cereal products) towards mixed fumigants was also studied. Residues in food moving in commerce Duggan, Barry & Johnson (1966) reported total bromide levels of up to 200 ppm in various defined food groups in total diet studies; the findings are summarized in Table I; but Heywood (1966) pointed out that not all of this bromide could be attributed to the use of fumigants since some occurs naturally in food. TABLE 1. BROMIDE RESIDUES IN TOTAL DIET STUDIES Foods Bromide range ppm Number of samples (out of 18) Dairy products 1.1 to 31.7 17 Meat, fish 2.3 to 35.5 16 TABLE 1. (cont'd) Foods Bromide range ppm Number of samples (out of 18) Grain 4.4 to 111.0 17 Potatoes 1.5 to 38.0 15 Leafy vegetables 1.1 to 16.3 16 Legumes 0.9 to 17.9 14 Root vegetables 2.6 to 22.1 14 Salad fruit 1.7 to 18.9 15 Fruit 0.7 to 31.4 12 Oils, fats 1.1 to 261.0 16 Sugar etc. 0.7 to 55.1 18 Beverages 0.9 to 17.0 10 An examination of 227 grain shipments to the Netherlands from all parts of the world in the period May 1964 to September 1961, showed inorganic bromide residues to be present in only 12 of these. Methods for the measurement of unchanged residues of ethylene dibromide are still being developed but preliminary observations on these shipment: showed unchanged ethylene dibromide to be present in one sample only (approximately 0.5 ppm). Although results are available from a number of pilot scale trials using commercial sale, handling and milling facilities (e.g. Lynn & Vorkes, 1957), very few data are available for commercially marketed cereals. Because of the manner in which the fumigant separates out when liquid fumigant mixtures are applied to the surfaces of grain standing in tins, measurable residues may only be found in the surface layer of the grain present: reports on residues found should therefore give details of the sampling method used. Fate of residues In plants and animals Little work appears to have been done on mechanisms by which ethylene dibromide produces toxic effects in plants and animals or on its fate when it has been absorbed. Residues of "apparent organo bromine compounds" reported by Gunther & Spenger (1966) were said to be due to the extraction of inorganic bromide by organic solvents in the presence of lecithin-type complexing agents present in vegetable tissues and the results (some of which are reproduced on page 121) probably reflect naturally occurring bromide in the various plants. In storage and processing Ethylene dibromide in wheat and wheat products is very resistant to dispersion by airing. Toxic effects on animals, particularly poultry, have resulted from consumption of food treated with this fumigant. These effects have usually followed feeding relatively soon after a treatment, bearing in mind the low rate of dispersion, and seem to be attributable to the presence of free ethylene dibromide. Almost all traces of ethylene dibromide appear to be lost by volatilization on heating as in baking (Senger & Mapes, 1957; Munsey, Mills & Klein, 1957) but according to Bridges (1956) some breaks down to produce minute amounts of ethylene glycol which may react with the - SCH3 of the methionine in the wheat protein. The joint meeting of the FAO Committee on Pesticides in Agriculture and the WHO Expert Committee on Pesticide Residues (FAO/WHO, 1965) recommended that the effects of processing and particularly of cooking on the residues of ethylene dibromide in foods should be further investigated. Methods of residue analysis In sampling cereals for ethylene dibromide residue analysis, special attention must be paid to the extent to which the sample is representative of the bulk. Analysis of residues of ethylene dibromide in cereals, which are mostly present in the unchanged organic form, is usually based on the measurement of total organic and inorganic bromine, measured as bromide. For this, there are a number of well established methods based on the hydrolysis of ethylene dibromide with alkali to inorganic bromide, evaporation to dryness of the resultant mixture, removal of the organic matter by controlled ignition, extraction by dilute acid of the total bromide from the resultant ash, oxidation to bromate, the liberation by this of iodine from acid potassium iodide and the determination of the iodine titrimetrically with sodium thiosulfate (Mapes & Shrader, 1957; Heuser, 1961). The inorganic bromide residue alone may similarly be determined after removal of unchanged ethylene dibromide by aeration (Heuser, 1961.). Unchanged ethylene dibromide can then be calculated by difference. The limit of detection by this procedure is of the order of 1 ppm as bromide. Berck (1965) has published details of a gas chromatograph method for the detection and measurement of some 34 fumigant vapours, including ethylene dibromide. This general technique has recently been applied by Bielorai & Alumot (1965) to the measurement of residues of unchanged ethylene dibromide in experimentally fumigated animal feeds: its application to the determination of such residues in commercially fumigated foods is most desirable. The method for the determination of total and inorganic bromide derived from the use of ethylene dibromide on cereals based on that of Heuser (1961) is in the meantime suggested. Details are set out in Appendix A(1) of the (Extract) Report of the Second Session of the FAO Working Party on Pesticide Residues (PL/1965/12). RECOMMENDATION FOR TOLERANCES On the basis of an acceptable daily intake of 1 mg/kg of inorganic bromide, a tolerance of 50 ppm for inorganic bromide residues in cereals and flour resulting from the use of ethylene dibromide and other fumigants can be recommended. This recommendation is also consistent with tolerance for dried eggs, processed herbs and spices at 400 ppm, various fresh fruits at 200 ppm, citrus at 230 ppm, raisins and dates at 100 ppm, and various other fruits, including certain dried fruits, at from 50 ppm to 20 ppm, which are residues which have been found after responsible use of the fumigant and which are as follows: Dried eggs, spices, herbs 400 Cereals 50 Dried figs 250 Avocados 75 Dried raisins, dates 100 Dried peaches 50 Dried prunes 20 Other dried fruits 30 Citrus, strawberries 30 Other fresh fruit 20 In the absence of a recommendation for an acceptable daily intake for unchanged ethylene dibromide and as there appear to be no very strong practical or economic reasons for accepting such residues, no recommendations are made for a tolerance for residues of this compound. The joint FAO/WHO Expert Committee on Food Additives (FAO/WHO, 1964), when considering the presence of bromide in bread due to the addition of bromate conditioner to flour, gave estimates of acceptable levels for treatment for flour to be consumed by man as: Unconditional 0-20 ppm Conditional (for special purposes) 20-75 ppm The recommendation of 50 ppm in cereals and flour resulting from fumigation is in accordance with this estimate because cereals and cereal products are treated with the fumigant to deal with specific outbreaks and not as a routine, during milling or other manufacture, as are flour conditioners. Further work or information Further data are needed on the occurrence of residues in raw and processed foods after use of the fumigant under practical conditions. Measurement of residues in foods resulting from the use of mixed fumigants, including ethylene dibromide, is desirable. Gas-liquid chromatographic methods should be particularly useful for the determination of residues of unchanged ethylene dibromide in cereals. The method offers the prospect of increased sensitivity and a means for the simultaneous determination of other fumigants which may be present. It should now be possible to develop a rapid, selective, quantitative technique for traces of halogenated fumigants, together with suitable desorption techniques, and to combine these into a single method for the determination of residues in treated foods and the Working Party recommends accordingly. Figures for the levels of any unchanged ethylene dibromide in commercially treated materials particularly those which have a relatively high oil or fat content, would also be useful. REFERENCES PERTINENT TO BIOLOGICAL DATA Aman, J., Farkas, L. & Ben-Shamai, M. H. (1946) Ann. appl. Biol., 33, 389 Amir, D. & Volcani, B. (1965) Nature, 206, 99 Bierer, B. W. & Vickers, C. L. (1959) J. Amer. vet. med. Ass., 134, 452 Bondi, A., Olomucki, E. & Calderon, M. (1955) J. Sci. Food Agr., 6, 600 Caylor, J. F. & Laurent, C. K. (1960) Poultry Sci., 39, 216 Fuller, H. L. & Morris, G. K. (1962) Poultry Sci., 41, 645 Fuller, H. L. & Morris, G. K. (1963) Poultry Sci., 42, 508 Morris, G. K. & Fuller, H. L. (1963) Poultry Sci., 42, 15 von Oettingen, W. F. (1955) Public Health Service Publ. No. 414 Olmstead, E. V. (1960) Arch. environm. Hlth, 21, 525 Olomucki, E. (1957) Nature (Lond.), 180, 1358 Rowe, V. K., Hollingsworth, R. L. & McCollister, D. D. (1954) J. Agr. Food Chem., 2, 1318 Rowe, V. K., Spencer, H. C., McCollister, D. D., Hollingsworth, R. L. & Adams, E. M. (1952) Arch. Industr. Hyg., 6, 158 REFERENCES PERTINENT TO AGRICULTURAL DATA Bär, F. (1964) Methylbromide zür Schädlingsbekämpfung Bundesgesundheitsblatt, 7: 113 Berck, B. (1961) Distribution and persistence of methyl bromide, ethylene dibromide and carbon tetrachloride applied in grain fumigant mixtures, Canada Dept. Agr. Publ. No. 1104 Berck, B. & Solomon, J. (1962) Wheat as a chromatographic column toward methyl bromide, ethylene dibromide, acrylonitrile, and carbon tetrachloride in the vapour phase. J. Agric. Food Chem., 10, 163-7 Berck, B. (1965a) Sorption of ethylene dibromide, ethylene dichloride, and carbon tetrachloride by cereal products. J. Agric. Food Chem., 13 (3): 248-254 Berck, B. (1965b) Determination of fumigant gases by gas chromatography. J. Agric. Food Chem., 13 (4): 373-377 Bielbrai, R. & Alumot, E. (1965) Determination of ethylene dibromide in fumigated feeds and foods by gas liquid chromatography. J. Sci. Fd. Agric., 16: 594-596 Bridges, R. G. (1956) The fate of labelled insecticide residues in food products. V. The nature and significance of ethylene dibromide residues in fumigated wheat. J. Sci. Fd. Agric., 7: 305-13 Coggiola, J. M. & Huelin, F. S. (1964) The absorption of 1,2-dibromoethane by oranges and by materials used in their fumigation. J. Agric. Fd. Chem. 12: 192-196 Duggan, R. E., Barry, H. C. & Johnson, L. Y. (1966) - Pesticide residues by total-diet samples. Science, 151 (3706): 101-104 FAO/WHO (1964) Specifications for the identity and purity of food additives and their toxicological evaluation: emulsifiers, stabilizers, bleaching and maturing agents. Rome. FAO Nutrition Meeting Rept. Ser., 35: 167 FAO/WHO (1965) Evaluation of the hazards to consumers resulting from the use of fumigants in the protection of food. Rome. FAO Meeting Rept. FL/1965/10/2. 71 p. Getzendander, M.E. (1965a) Residues in milled wheat products resulting from spot fumigation of mill machinery with halogenated liquid fumigants. J. Agric. Fd. Chem., 13: (5) 455-458 Getzendaner, M. E. (1965b) Fumigant residues. Bromide residues in chicken tissues and eggs from ingestion of methyl bromide - fumigated feed. J. Agric. Fd. Chem., 13: 349-352 Grierson, W. & Hayward, F. W. (1959) Fumigation of Florida citrus fruit with ethylene dibromide. Proc. Amer. Hort. Sci., 73: 267-77 Gunther, F. A. & Spenger, R. E. (1966) Apparent organobromide compounds in higher plants by neutron activation analysis. Bull. Environ. Contam. Toxicol., 1: 121 Heuser, S. G. (1961) Residues in wheat and wheat products after fumigation with ethylene dibromide. J. Sci. Fd. Agr., 12: 103-15 Heuser, S. G. (1964) Behaviour of components of an ethylene dibromide-methyl bromide mixture during fumigation of flour. J. Sci. Fd. Agr., 15: 114-9 Heywood, B. J. (1966) Pesticide residues in total diet samples. bromine content Science, 152 (3727): 1408 Lynn, G. E. & Vorkes, F. A., eds. (1957) Residues in foods and feeds resulting from fumigation of grains with the commoner liquid formulations of carbon disulfide, carbon tetrachloride, ethylene dichloride and ethylene dibromide. [Symposium] J. Ass. Off. Agr. Chem. 40: 163-209 Mapes, D. A. & Shrader, S. A. Determination of total and inorganic bromide residues in fumigated product. [In: Lynn & Vorkes, 1957] J. Ass. Off. Agr. Chem., 40, 189-96 Page, A. B. P. & Blackith, R. E. (1956) Developments in fumigation practice. Rep. Progr. Appl. Chem., 41: 535-45 Sinclair, W. B., Lindgren, D. L. & Forbes, R. (1962) Recovery of ethylene dibromide residues from fumigated whole kernel and milled wheat fractions. J. Econ. Ent., 55: 836-42 Stenger, V. A. & Mapes D. A. (1957) Effect of baking on ethylene dibromide and total bromide residues. [In: Lynn & Vorkes, 1957] J. Ass. Off. Agr. Chem., 40: 196-201 Whitney, W. K. & Kenaga, E. E. (1960) Distribution and sorption of liquid fumigants applied to wheat by recirculation. J. Econ. Ent., 53: 259-261
See Also: Toxicological Abbreviations Ethylene dibromide (ICSC) Ethylene dibromide (FAO Meeting Report PL/1965/10/2) Ethylene dibromide (FAO/PL:1967/M/11/1) Ethylene dibromide (FAO/PL:1968/M/9/1) Ethylene Dibromide (IARC Summary & Evaluation, Volume 71, 1999)