Residual free methyl bromide in fumigated commodities

The extent to which methyl bromide was retained by fumigated material after treatment was followed in laboratory studies on a range of commodities exposed to the vapour at atmospheric pressure. Amounts of methyl bromide, recovered by solvent extraction and determined using gas-liquid chromatography, were related to the temperature, moisture content and manner of post-treatment storage. Immediately after exposure, the initial amount of free methyl bromide present was more dependent on the gas concentration used than on the time of exposure. Under the experimental conditions of exposure, the residual free methyl bromide in all commodities fumigated at 25°, except cocoa beans and groundnuts, fell to below 1 ppm within a few days when they were held at that temperature, whether spread in thin layers on trays or kept sealed in glass bottles. At lower temperatures, the rate of loss was slower, small amounts of methyl bromide being extracted from several commodities one month after treatment. The disappearance of fumigant from wheat and sultanas was more rapid from samples with higher moisture contents. A mathematical treatment of the data is presented, to assist in prediction of the behaviour of residual fumigant under storage conditions before processing. It is concluded that the risk of ingestion of harmful quantities of free methyl bromide by the consumer is small and that the occasions when relatively high residues might occur can be predicted.     

Selective determination of ionised bromide and organic bromides in Foodstuffs by gas-liquid chromatography with special reference to fumigant residues

A number of methods in common use for determining amounts of bromine-containing compounds occurring as residues in foodstuffs, primarily as a result of commodity or soil fumigation, do not distinguish between bromide ion and organically bound bromine. Although such compounds may differ widely in their toxicity, national and international schedules have included tolerances for total bromide determined as ‘inorganic bromide’. A method is described in which ionised bromide in foodstuffs is quantitatively converted to 2-brompethanol (ethylene bromohydrin) by reaction with ethylene oxide in an acid medium. The 2-bromoethanol produced is determined in processed extracts by gas-liquid chromatography. Residual methyl bromide and ethylene dibromide (1,2-dibromoethane), neither of which react with ethylene oxide under the conditions prescribed, are separated and determined concurrently. With foodstuffs which did not contain organo-bromine compounds, good agreement was observed between results obtained by the gas chromatographic method and by total bromide determination involving alkali digestion, controlled ashing, extraction of ash and wet oxidation. In the light of the more specific methods of determination now available, some clarification in tolerance schedules for residual bromine compounds in foodstuffs is suggested.     

International recommendations for training future toxicologic pathologists participating in regulatory-type, nonclinical toxicity studies

The International Federation of Societies of Toxicologic Pathologists (IFSTP) proposes a common global framework for training future toxicologic pathologists who will support regulatory-type nonclinical toxicology studies. Trainees optimally should undertake a scientific curriculum of at least 5 years at an accredited institution leading to a clinical degree (veterinary medicine or medicine). Trainees should then obtain 4 or more years of intensive pathology practice during a residency and/or on-the-job "apprenticeship," at least 2 years of which must be focused on regulatory-type toxicologic pathology topics. Possession of a recognized pathology qualification (i.e., certification) is highly recommended. A non-clinical pathway (e.g., a graduate degree in medical biology or pathology) may be possible if medically trained pathologists are scarce, but this option is not optimal. Regular, lifelong continuing education (peer review of nonclinical studies, professional meetings, reading, short courses) will be necessary to maintain and enhance one's understanding of current toxicologic pathology knowledge, skills, and tools. This framework should provide a rigorous yet flexible way to reliably train future toxicologic pathologists to generate, interpret, integrate, and communicate data in regulatory-type, nonclinical toxicology studies.     

Residues of carbon tetrachloride and 1,2-dibromoethane in cereals and processed foods after liquid fumigant grain treatment for pest control

Residues of halogenated hydrocarbon ‘liquid’ fumigants occurring in cereals and their products as a result of use for insect control continue to be of concern in technologically advanced as well as developing countries. Carbon tetrachloride and ethylene dibromide residues remaining in wheat, maize, barley and sorghum shortly after fumigation, during storage for periods of up to 1 year and after processing have been determined, with the fumigants applied either as liquids or vapours. Amounts of residues occurring in bread made from wheat containing residual fumigants were also measured. Current methods of use of these fumigants are discussed with reference to the results of these experiments and interim recommendations are made for post- treatment handling of cereals.     

Canine hypertrophic osteoarthropathy associated with a malignant Sertoli cell tumour

A 15-year-old crossbred dog was presented with a severe cough of acute onset and an enlarged right testis. Symptomatic treatment for presumed 'kennel cough' failed to produce any improvement and at re-examination the dog had developed a swollen right forelimb. Radiographic examination suggested a diagnosis of hypertrophic pulmonary osteoarthropathy (Marie's disease) associated with pulmonary metastases from a testicular tumour. The dog was re-presented five days later with acute-onset severe vomiting and the owner elected for euthanasia. Necropsy was performed and histopathological assessment confirmed the presence of a Sertoli cell tumour in the right testis with multiple pulmonary and renal metastases. Hypertrophic pulmonary osteoarthropathy is a rare complication of metastatic canine Sertoli cell tumour. The authors know of no previously reported cases.     

Ethylene oxide and its persistent reaction products in wheat flour and other commodities: Residues from fumigation or sterilisation,and effects of processing

The effects of dosage, temperature, moisture content and conditions of storage on the retention of ethylene oxide by a range of commodities after exposure to the vapour were studied in laboratory tests at treatment levels normal for sterilisation and for insect control. The extent of reaction of ethylene oxide with inorganic halides and water to form halohydrins and glycols was investigated with reference to amounts of inorganic chloride and bromide present, moisture content and acidity of the commodity, and storage temperature. Residual compounds were determined by gas-liquid chromatography of acetone-water extracts during a period of up to a year after treatment. When commodities were kept at 25°c, either under air-tight storage conditions or freely aired, residual ethylene oxide usually fell to below 1 ppm within 14 days, but in flour kept under air-tight conditions after treatment at sterilisation level, 50–100 ppm remained at this time and traces were found after 90 days. At lower temperatures ethylene oxide disappeared more slowly. Levels of ethylene chlorohydrin produced during and after exposure to ethylene oxide ranged from zero in groundnuts and cocoa beans at fumigation dosage to thousands of parts per million in sterilised curry powder and turmeric. Ethylene chlorohydrin, ethylene bromohydrin, ethylene glycol and diethylene glycol persisted in some commodities after treatment but the halohydrins disappeared from finely divided products under the influence of air movement and ethylene bromohydrin slowly decomposed under sealed conditions. In the preparation of baked and steamed products from flour containing ethylene chlorohydrin and ethylene bromohydrin, from 20 to 100% of the original residue was lost, depending on the alkalinity of the conditions used. It is concluded that residual amounts of ethylene oxide and glycols produced in foodstuffs by such treatments are unlikely to constitute a toxic hazard, and that in ethylene chlorohydrin formed otherwise significant amounts may partly disappear during storage and cooking. The presence of glycols or halohydrins in treated commodities could be interpreted as an indication that other changes in chemical composition may have taken place, the overall effects of which might best be determined by long-term animal feeding trials.     

Intestinal leiomyosarcoma in a cat

Intramural ileocaecocolic leiomyosarcoma is described in an elderly neutered male domestic shorthaired cat with poor appetite and weight loss. Histological examination of the resected lesion revealed a poorly differentiated soft tissue sarcoma and a diagnosis of leiomyosarcoma was confirmed by positive immunohistochemical staining for vimentin and a-smooth muscle actin. Postoperative survival time was 102 days before local recurrence justified euthanasia.