ZT 轉基因，除草劑和公眾健康

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GMOs, Herbicides, and Public Health
轉基因，除草劑和公眾健康

Philip J. Landrigan, M.D., and Charles Benbrook, Ph.D.
N Engl J Med 2015; 373:693-695 August 20, 2015
作者：Philip J. Landrigan醫學博士和Charles Benbrook哲學博士
期刊和時間：N Engl J Med 2015; 373:693-695 August 20, 2015
翻譯：jrry86
原文鏈接：http://www.nejm.org/doi/full/10.1056/NEJMp1505660#t=article
 
Interview with Dr. Philip Landrigan on health concerns associated with genetically modified crops and the herbicides used on them.
Genetically modified organisms (GMOs) are not high on most physicians' worry lists. If we think at all about biotechnology, most of us probably focus on direct threats to human health, such as prospects for converting pathogens to biologic weapons or the implications of new technologies for editing the human germline. But while those debates simmer, the application of biotechnology to agriculture has been rapid and aggressive. The vast majority of the corn and soybeans grown in the United States are now genetically engineered. Foods produced from GM crops have become ubiquitous. And unlike regulatory bodies in 64 other countries, the Food and Drug Administration (FDA) does not require labeling of GM foods.
在大多數醫生的擔憂名單上，轉基因排名並不高。如果讓我們反思生物技術，大多數人可能會聚焦於給人類健康帶來的直接危害，例如將病原體轉變成生物武器的可能性，或者編輯人類種係的新技術所暗示的意義。但是當那些爭論還處於溫吞狀態之時，生物技術在農業上的應用卻迅猛和咄咄逼人。現在美國種植的玉米和大豆絕大部分都是轉基因的。用轉基因作物生產的食品無處不在。而與其它六十四個國家的管理機構不同，美國食品和藥物管理局（FDA）不要求標識轉基因食品。

Two recent developments are dramatically changing the GMO landscape. First, there have been sharp increases in the amounts and numbers of chemical herbicides applied to GM crops, and still further increases — the largest in a generation — are scheduled to occur in the next few years. Second, the International Agency for Research on Cancer (IARC) has classified glyphosate, the herbicide most widely used on GM crops, as a “probable human carcinogen”1 and classified a second herbicide, 2,4-dichlorophenoxyacetic acid (2,4-D), as a “possible human carcinogen.”2
最近的兩個進展戲劇性地改變了轉基因的形勢。首先，用於轉基因作物的化學除草劑的數量和種類劇烈增加，並且預計在今後若幹年會以最大幅度進一步增加。其次，國際癌症研究機構（IARC）將最廣泛用於轉基因作物的草甘膦歸類為“很可能對人類致癌”（1），並將另一個除草劑2,4-二氯苯氧基乙酸（2,4-D）歸類為“可能對人類致癌”（2）。

The application of genetic engineering to agriculture builds on the ancient practice of selective breeding. But unlike traditional selective breeding, genetic engineering vastly expands the range of traits that can be moved into plants and enables breeders to import DNA from virtually anywhere in the biosphere. Depending on the traits selected, genetically engineered crops can increase yields, thrive when irrigated with salty water, or produce fruits and vegetables resistant to mold and rot.
轉基因工程在農業上的應用建立在古代選擇育種實踐的基礎之上。但是與傳統選擇育種不同的是，基因技術將可以移入植物的性狀的範圍大大擴張，使得育種者在理論上可以轉移入生物圈內的任何DNA。取決於所選擇的性狀，轉基因作物可以增產，用鹽水灌溉也可以茁壯成長，或者長出可以抵抗黴菌和腐爛的蔬菜水果。

The National Academy of Sciences has twice reviewed the safety of GM crops — in 2000 and 2004.3 Those reviews, which focused almost entirely on the genetic aspects of biotechnology, concluded that GM crops pose no unique hazards to human health. They noted that genetic transformation has the potential to produce unanticipated allergens or toxins and might alter the nutritional quality of food. Both reports recommended development of new risk-assessment tools and postmarketing surveillance. Those recommendations have largely gone unheeded.
美國國家科學院在2000年和2004年兩次評審了轉基因作物的安全性（3）。這些評審幾乎完全集中於對生物技術的基因方麵的評估，並得出結論說轉基因作物對人類健康沒有特別的危害。他們注意到遺傳轉化有可能產生意料之外的過敏原或毒素，並可能改變食物的營養品質。兩個報告都推薦開發新的風險評估工具，加強上市後監管。可是這些建議基本上未得到重視。

Herbicide resistance is the main characteristic that the biotechnology industry has chosen to introduce into plants. Corn and soybeans with genetically engineered tolerance to glyphosate (Roundup) were first introduced in the mid-1990s. These “Roundup-Ready” crops now account for more than 90% of the corn and soybeans planted in the United States.4 Their advantage, especially in the first years after introduction, is that they greatly simplify weed management. Farmers can spray herbicide both before and during the growing season, leaving their crops unharmed.
對除草劑的抗性是生物技術工業所選擇的引入作物的主要性狀。通過基因工程手段而獲得對草甘膦（農達）抗性的玉米和大豆於1990年代中期首次引入。這些“抗農達”作物占了美國種植的玉米和大豆的90%以上（4）。其優勢在於可以大大簡化雜草管理，特別是在引入後的第一年。農民們在播種之前和作物生長過程中都可以噴灑除草劑，而作物本身不會受到傷害。

But widespread adoption of herbicide-resistant crops has led to overreliance on herbicides and, in particular, on glyphosate.5 In the United States, glyphosate use has increased by a factor of more than 250 — from 0.4 million kg in 1974 to 113 million kg in 2014. Global use has increased by a factor of more than 10. Not surprisingly, glyphosate-resistant weeds have emerged and are found today on nearly 100 million acres in 36 states. Fields must be now be treated with multiple herbicides, including 2,4-D, a component of the Agent Orange defoliant used in the Vietnam War.
但是廣泛采用抗除草劑作物導致了對除草劑（特別是草甘膦）的過分依賴（5）。在美國，草甘膦的使用增加了二百五十倍，從1974年的四十萬公斤增加到2014年的一億一千三百萬公斤。全球的使用量則增加了十倍以上。毫不奇怪，這導致了抗草甘膦的超級雜草的出現，在36個州近一億英畝土地上滋生。現在農田裏必須使用多種除草劑，包括2,4-D，後者是越戰中使用的橙劑落葉劑的組分之一。

The first of the two developments that raise fresh concerns about the safety of GM crops is a 2014 decision by the Environmental Protection Agency (EPA) to approve Enlist Duo, a new combination herbicide comprising glyphosate plus 2,4-D. Enlist Duo was formulated to combat herbicide resistance. It will be marketed in tandem with newly approved seeds genetically engineered to resist glyphosate, 2,4-D, and multiple other herbicides. The EPA anticipates that a 3-to-7-fold increase in 2,4-D use will result.
帶來對轉基因作物安全性新顧慮的兩個進展中的第一個，表現為2014年美國環保署（EPA）批準了Enlist Duo，它是由草甘膦和2,4-D組成的新型除草劑組合。Enlist Duo是被設計用來解決抗性雜草的問題的。它將與新近批準的抗草甘膦、2,4-D和多種其它除草劑的轉基因種子同步推向市場。EPA預計這將導致2,4-D的用量增加3到7倍。

In our view, the science and the risk assessment supporting the Enlist Duo decision are flawed. The science consisted solely of toxicologic studies commissioned by the herbicide manufacturers in the 1980s and 1990s and never published, not an uncommon practice in U.S. pesticide regulation. These studies predated current knowledge of low-dose, endocrine-mediated, and epigenetic effects and were not designed to detect them. The risk assessment gave little consideration to potential health effects in infants and children, thus contravening federal pesticide law. It failed to consider ecologic impact, such as effects on the monarch butterfly and other pollinators. It considered only pure glyphosate, despite studies showing that formulated glyphosate that contains surfactants and adjuvants is more toxic than the pure compound.
在我們看來，支撐Enlist Duo決策的科學和風險評估是有缺陷的。其所謂的科學僅僅包括除草劑生產商在1980和1990年代所做的毒理學研究，且從來沒有發表過，而這在美國農藥管理上並不是一個不同尋常的現象。這些研究遠早於現有的對低劑量、內分泌介導、和表觀遺傳效應等知識的認知，所以沒有作相應檢驗。這種風險評估很少考慮對嬰兒和兒童的潛在健康影響，因此違反了聯邦農藥法律。它也沒能考慮對生態的衝擊，例如對帝王蝶和其它授粉昆蟲的影響。它隻考察純草甘膦，而不顧多個研究顯示含有表麵活性劑和助劑的配方草甘膦比純化合物的毒性更大。

The second new development is the determination by the IARC in 2015 that glyphosate is a “probable human carcinogen”1 and 2,4-D a “possible human carcinogen.”2 These classifications were based on comprehensive assessments of the toxicologic and epidemiologic literature that linked both herbicides to dose-related increases in malignant tumors at multiple anatomical sites in animals and linked glyphosate to an increased incidence of non-Hodgkin's lymphoma in humans.
第二個新進展是2015年IARC認定草甘膦“對人類很可能致癌”（1），2,4-D“對人類可能致癌”（2）。這個歸類立足於對相關毒理學和流行病學文獻的完整評估，而這些文獻將這兩種除草劑與動物多個解剖學位置上的惡性腫瘤的與劑量相關的增加關聯了起來，也將草甘膦與人類的非霍奇金白血病的增加關聯了起來。

These developments suggest that GM foods and the herbicides applied to them may pose hazards to human health that were not examined in previous assessments. We believe that the time has therefore come to thoroughly reconsider all aspects of the safety of plant biotechnology. The National Academy of Sciences has convened a new committee to reassess the social, economic, environmental, and human health effects of GM crops. This development is welcome, but the committee's report is not expected until at least 2016.
這些新進展說明轉基因食品以及用於其上的除草劑對人類健康帶來危害，這在以前的評估中都沒有得到審視。因此我們相信現在是時候重新徹底考察植物生物技術安全性的方方麵麵了。美國國家科學院已經召集了一個新的委員會來重新評估轉基因作物對社會、經濟、環境和人類健康的影響。我們對這個新動向表示歡迎，但是該委員會的報告至少在2016年前還不能出爐。

In the meantime, we offer two recommendations. First, we believe the EPA should delay implementation of its decision to permit use of Enlist Duo. This decision was made in haste. It was based on poorly designed and outdated studies and on an incomplete assessment of human exposure and environmental effects. It would have benefited from deeper consideration of independently funded studies published in the peer-reviewed literature. And it preceded the recent IARC determinations on glyphosate and 2,4-D. Second, the National Toxicology Program should urgently assess the toxicology of pure glyphosate, formulated glyphosate, and mixtures of glyphosate and other herbicides.
同時，我們也提出兩個建議。首先，我們相信環保署（EPA）應該推遲實施它所作出的允許Enlist Duo應用的決定。該決定的作出是很草率的；它建立在設計拙劣且過時的研究的基礎上，沒能完整評估其對人類接觸和環境造成的影響；它本來應該更深入的參考獨立經費資助並發表在同行評議雜誌上的研究；而且該決定是在IARC最近將草甘膦和2,4-D重新定性之前作出的。其次，美國國家毒理學規劃處應緊急評估純草甘膦、配方草甘膦以及草甘膦和其它除草劑混合物的毒理。

Finally, we believe the time has come to revisit the United States' reluctance to label GM foods. Labeling will deliver multiple benefits. It is essential for tracking emergence of novel food allergies and assessing effects of chemical herbicides applied to GM crops. It would respect the wishes of a growing number of consumers who insist they have a right to know what foods they are buying and how they were produced. And the argument that there is nothing new about genetic rearrangement misses the point that GM crops are now the agricultural products most heavily treated with herbicides and that two of these herbicides may pose risks of cancer. We hope, in light of this new information, that the FDA will reconsider labeling of GM foods and couple it with adequately funded, long-term postmarketing surveillance.
最後，我們相信是時候重新審視美國對標識轉基因食品的不情願政策。標識會帶來若幹好處。它是追蹤新出現的食品過敏原和評估用於轉基因作物的化學除草劑的影響所必須的。它也尊重了越來越多消費者的願望，他們堅持認為有權了解所購買的食物及其是如何生產的。那些認為基因重組沒有什麽新奇之處的觀點，忽視了當今轉基因作物是最大量使用了除草劑後的農產品，這其中的兩種除草劑可能帶來癌症風險。我們希望，根據這些新的信息，FDA會重新考慮標識轉基因食品，同時提供足夠經費作好其上市後的長期監控。
SOURCE INFORMATION
From the Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York (P.J.L.); and the Department of Crops and Soil Sciences, Washington State University, Pullman, WA (C.B.).
作者信息
P.J.L來自紐約西奈山Icahn醫學院預防醫學係；C.B.來自華盛頓州立大學作物和土壤科學係。
 

References（參考文獻，翻譯從略）

  1. Guyton KZ, Loomis D, Grosse Y, et al. Carcinogenicity of tetrachlorvinphos, parathion, malathion, diazinon, and glyphosate. Lancet Oncol 2015;16:490-491
    CrossRef | Web of Science | Medline

  2. Loomis D, Guyton K, Grosse Y, et al. Carcinogenicity of lindane, DDT, and 2,4-dichlorophenoxyacetic acid. Lancet Oncol 2015 June 22 (Epub ahead of print).

  3. National Research Council, Committee on Identifying and Assessing Unintended Effects of Genetically Engineered Foods on Human Health. Safety of genetically engineered foods: approaches to assessing unintended health effects. Washington, DC: National Academies Press, 2004.

  4. Adoption of genetically engineered crops in the U.S. Washington, DC: Department of Agriculture, Economic Research Service (http://www.ers.usda.gov/data-products/adoption-of-genetically-engineered-crops-in-the-us.aspx).

  5. Duke SO. Perspectives on transgenic, herbicide-resistant crops in the United States almost 20 years after introduction. Pest Manag Sci 2015;71:652-657

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