Ethephon and Jackfruit (1)

Introduction - Regulatory Aspects All pesticides sold or distributed in the United States (US) must be registered with the EPA (US Environmental Protection Agency) for the intended uses and must have safety data to show that they can be used without posing unreasonable risks to humans and the environment. Ethephon (2-chloroethylphosphonic acid) is classified as an organophosphate pesticide. It is registered with the EPA since 1973 as a plant growth regulator used to promote fruit repening and flower induction and has approved applications in food, feed and nonfood crops, greenhouse nursery, outdoor residential ornamental plants, and mostly in cotton....
Nội dung trích xuất từ tài liệu:
Ethephon and Jackfruit (1) Ethephon and Jackfruit (1) Introduction - Regulatory Aspects All pesticides sold or distributed in the United States (US) must beregistered with the EPA (US Environmental Protection Agency) for theintended uses and must have safety data to show that the y can be usedwithout posing unreasonable risks to humans and the environment. Ethephon(2-chloroethylphosphonic acid) is classified as an organophosphatepesticide. It is registered with the EPA since 1973 as a plant growthregulator used to promote fruit repening and flower induction and hasapproved applications in food, feed and nonfood crops, greenhouse nursery,outdoor residential ornamental plants, and mostly in cotton. Toxicology – Summary As an organophosphate, Ethephon is expected to inhibit plas macholisterase in humans. Indeed, in studies involving laboratory animals orhumans, Ethephon inhibits primarily plasma butyrylcholinesterase. Theresults of those studies also suggest that Ethephon is a very weak inhibitor ofcholinesterase. Ethephon is irritant to the skin or the eyes but it is not a skinsensitizer. Ethephon is not a carcinogen and is classified by IARC(International Agency for Research on Cancer – a WHO organization) asGroup D (not carcinogenic to humans). Ethephon is not a developme ntaltoxicant and does not appear to induce adverse reproductive effects.Although Ethephon is an organophosphate, it does not appear to causedelayed neurotoxicity in laboratory animals. In 2000, the World HealthOrganization has classified Ethephon as “unlikely to present an acute hazardin normal use” Human Exposure Humans are exposed to Ethephon through the diet or via occupationalexposures (handlers, pesticide sprayers, etc.). Tolerances or maximumresidue limits have been established for Ethephon in many raw agriculturalcommodities, processed foods and feeds. Several International CodexMaximum Residue Limits (MRLs) have been established for Ethephon inapples, strawberries, cherries, pineapples tomatoes and walnuts. Human Risk Assessment Ethephon has the potential to cause severe skin and eye irritation uponcontact. As an organophosphate, it has the potential to cause cholinesteraseinhibition leading to adverse neurotoxic effects. Consequently, infantsencounter the greatest exposure and risk as a result of ingesting Ethephonfrom foods and crops. Ecological Effects Risk Assessment Ethephon is expected to have minimal effects on birds and mammalsas well as on fish, freshwater invertebrates, and marine and estuarineorganisms. Dietary Risk Assessment The Joint Meeting on Pesticide Residues (JMPR; an unit of FAO)established a maximum Allowable Daily Intake (ADI) for Ethephon at 0.05mg/kg body weight/day based on a 16-day study in humans treated orally. Inthis study, male and female volunteers received Ethephon orally by capsuleat 0.5 mg/kg bw/day for 16 days. Plasma cholinesterase was significantlyinhibited but no gross symptoms or changes in hematological, clinicalchemistry or urine endpoints were associated with treatment. Risk Characterization Based on surveys of residues of Ethephon in food commodities, EPAhas determined that the current intake of Ethephon from food crops is safe ifthe daily intake does not exceed the ADI of 0.05 mg/kg body weight. Usingan average human body weight of 60 kg , then the total permissible intake ofEthephon for the general population is 3 mg/day. Conclusion Ethephon is an organophosphate pesticide registered for many foodand feed uses. The EPA has concluded that the use of currently registered productscontaining Ethephon in accordance with approved labelling will not poseunreasonable risks or adverse effects to humans or the environment. From a toxicological standpoint, Ethephon does not pose risks ofsystemic, carcinogenic, reproductive or genotoxic effects. However, it doespose risks of severe skin and eye irritation and has the potential to inhibitcholinesterase (albeit weak inhibitor). 1. For short term exposure, as long as the daily intake of Ethephon isless than 3 mg, then it is considered as safe without foreseeable risk. Careshould be taken when handling jackfruit treated with Ethephon due to itsirritant properties. Infants should not be exposed to Ethephon due to itscholinesterase inhibitor potential. 2. For long term exposure, then the cholinesterase inhibition propertyof Ethephon must be taken into consideration especially for people withexisting neurological disorders. 3. For pregnant women, exposure to cholinesterase inhibitor should beavoided although there is no evidence to suggest that Ethephon is areproductive or developmental toxicant Ts Bùi Quốc Quang Palo Alto, CA July 4, 2007 Ethephon trong quả mít (2) Tác giả: Ts Bùi-Quốc-Quang, chuyên viên độc chất học ở PaloAlto, California Người dịch : Ds Lê-văn-Nhân Dẫn nhập và luật lệ: Tất cả chất diệt côn trùng bán hay phân phối tại Hoa-kỳ phải đượcđăng ký với cơ quan bảo vệ sinh thái (EPA) với mục đích sử dụng và phải códữ liệu an toàn cho thấy có thể dùng mà không gây những nguy cơ vô lý chongười và sinh thái. Ethephon (2-chloroethylphosphoric acid) được xếp vàoloại thuốc diệt côn trùng phosphat hữu cơ. Chất này được ghi tên với cơquan bảo vệ sinh thái từ năm 1973 như là chất điều hòa tăng trưởng thực vậtđể kích thích trái cây chín và cảm ứng ra hoa và được chấp thuận áp dụngcho hoa màu dùng trong thức ăn người, súc vật hay không phải thực phẩm,trại ươm cây trong bóng dim, cây dùng để trang trí ngoài trời và phần lớntrong bông vải. Tóm tắt độc chất học: Là một phosphat hữu cơ, Ethephon được cho rằng sẽ ức ...