The persistence of methyl bromide residues in rice, dried fruit, seeds and nuts following laboratory fumigation

Abstract

The persistence of methyl bromide (MB) in white rice, brown rice, sultanas, raisins, pumpkin seeds, brazil nuts, groundnuts and walnuts was monitored following laboratory fumigations at different concentration time products and temperatures. A sensitive automated headspace gas chromatographic method with a limit of quantitation of 0.005 mg kg−1 was used to determine MB residues. Nuts and seeds sorbed the highest amounts of MB followed by rice and dried fruit. Measurable MB residues were shown to persist in nuts and seeds for 10 weeks and in dried fruit for four weeks following a fumigation with recommended concentration time products. The data presented suggest MB residues may persist in unprocessed nuts, seeds or dried fruit at the point of consumption using recommended fumigation practices, or particularly following overdosing or multiple fumigations. Crown copyright © 2000 Reproduced with the permission of Her Majesty's Stationery Office

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

“…Air samples may be trapped in charcoal tubes and then desorbed with appropriate organic solvents followed by gas chromatography with electron capture detection. Similar approaches have been reported for residue determination in foods 25–28…”

Robust colorimetric detection based on the anti-aggregation of gold nanoparticles for bromide in rice samples

“…Methyl bromide (CH 3 Br) is a fumigant that is oen used for controlling a variety of pests such as insects, mites, moulds, nematodes, weeds, viruses and bacteria, as well as being used in soil disinfection and as a postharvest treatment for stored and dried foodstuffs including rice, tobacco, fresh fruits and vegetables. [1][2][3] It is dominant over other fumigants due to the fact it is a colorless, odorless (at low concentrations) and non-ammable gas with a high rate of penetration. [2][3][4] Its toxic effects on human health are (following short-term exposure) headache, dizziness, nausea, vomiting, blurred vision, slurred speech and convulsions.…”

“…9 Aer food commodities are fumigated, methylated products and inorganic bromide are formed as a result of chemical reactions with some of the constituents of the treated foodstuffs or the breakdown products of methyl bromide. [1][2][3]10,11 Inorganic bromide has been detected in rice and glutinous rice in the ranges 0.13-11.93 mg kg À1 and 0.20-1.37 mg kg À1 , respectively, and its concentration in all samples were within the Codex maximum residue limit value of 50 mg kg À1 . 2 Methyl bromide residues can persist in nuts and seeds for 10 weeks and in dried fruit for 4 weeks.…”

“…2 Methyl bromide residues can persist in nuts and seeds for 10 weeks and in dried fruit for 4 weeks. 1 Cova et al reported that higher concentrations of bromide ions were detected in fumigated pastas with eggs, pastas with eggs and spinach, and rice compared to in those that were unfumigated. 11 Thailand, as the world's leading rice producer and also one of the largest rice consumers, imported an average of 357.69 and 103.85 tons per year of methyl bromide and a mixture between methyl bromide and chloropicrin, respectively, to eliminate undesired pests before commercializing their products between 2007 and 2012.…”

“…In most cases, bromide ion contamination in rice has been found when food commodities are fumigated with either low or high concentrations of methyl bromide, and are particularly over the limit when they have been fumigated with methyl bromide multiple times. [1][2][3]11,14,15 Many studies have also focused on inorganic bromide in food in order to assess the daily intake of bromide ions from food and water into the human body. 10,16,17 Therefore, bromide ions are the main target analyte for this work, whether from the accumulation of bromide ions from the environment or from the transformation of methyl bromide.…”