ZT 转基因，除草剂和公众健康

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GMOs, Herbicides, and Public Health
转基因，除草剂和公众健康

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医学博士和Charles Benbrook哲学博士
期刊和时间：N Engl J Med 2015; 373:693-695 August 20, 2015
翻译：jrry86
原文链接：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.
在大多数医生的担忧名单上，转基因排名并不高。如果让我们反思生物技术，大多数人可能会聚焦于给人类健康带来的直接危害，例如将病原体转变成生物武器的可能性，或者编辑人类种系的新技术所暗示的意义。但是当那些争论还处于温吞状态之时，生物技术在农业上的应用却迅猛和咄咄逼人。现在美国种植的玉米和大豆绝大部分都是转基因的。用转基因作物生产的食品无处不在。而与其它六十四个国家的管理机构不同，美国食品和药物管理局（FDA）不要求标识转基因食品。

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
最近的两个进展戏剧性地改变了转基因的形势。首先，用于转基因作物的化学除草剂的数量和种类剧烈增加，并且预计在今后若干年会以最大幅度进一步增加。其次，国际癌症研究机构（IARC）将最广泛用于转基因作物的草甘膦归类为“很可能对人类致癌”（1），并将另一个除草剂2,4-二氯苯氧基乙酸（2,4-D）归类为“可能对人类致癌”（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.
转基因工程在农业上的应用建立在古代选择育种实践的基础之上。但是与传统选择育种不同的是，基因技术将可以移入植物的性状的范围大大扩张，使得育种者在理论上可以转移入生物圈内的任何DNA。取决于所选择的性状，转基因作物可以增产，用盐水灌溉也可以茁壮成长，或者长出可以抵抗霉菌和腐烂的蔬菜水果。

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.
美国国家科学院在2000年和2004年两次评审了转基因作物的安全性（3）。这些评审几乎完全集中于对生物技术的基因方面的评估，并得出结论说转基因作物对人类健康没有特别的危害。他们注意到遗传转化有可能产生意料之外的过敏原或毒素，并可能改变食物的营养品质。两个报告都推荐开发新的风险评估工具，加强上市后监管。可是这些建议基本上未得到重视。

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.
对除草剂的抗性是生物技术工业所选择的引入作物的主要性状。通过基因工程手段而获得对草甘膦（农达）抗性的玉米和大豆于1990年代中期首次引入。这些“抗农达”作物占了美国种植的玉米和大豆的90%以上（4）。其优势在于可以大大简化杂草管理，特别是在引入后的第一年。农民们在播种之前和作物生长过程中都可以喷洒除草剂，而作物本身不会受到伤害。

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.
但是广泛采用抗除草剂作物导致了对除草剂（特别是草甘膦）的过分依赖（5）。在美国，草甘膦的使用增加了二百五十倍，从1974年的四十万公斤增加到2014年的一亿一千三百万公斤。全球的使用量则增加了十倍以上。毫不奇怪，这导致了抗草甘膦的超级杂草的出现，在36个州近一亿英亩土地上滋生。现在农田里必须使用多种除草剂，包括2,4-D，后者是越战中使用的橙剂落叶剂的组分之一。

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.
带来对转基因作物安全性新顾虑的两个进展中的第一个，表现为2014年美国环保署（EPA）批准了Enlist Duo，它是由草甘膦和2,4-D组成的新型除草剂组合。Enlist Duo是被设计用来解决抗性杂草的问题的。它将与新近批准的抗草甘膦、2,4-D和多种其它除草剂的转基因种子同步推向市场。EPA预计这将导致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.
在我们看来，支撑Enlist Duo决策的科学和风险评估是有缺陷的。其所谓的科学仅仅包括除草剂生产商在1980和1990年代所做的毒理学研究，且从来没有发表过，而这在美国农药管理上并不是一个不同寻常的现象。这些研究远早于现有的对低剂量、内分泌介导、和表观遗传效应等知识的认知，所以没有作相应检验。这种风险评估很少考虑对婴儿和儿童的潜在健康影响，因此违反了联邦农药法律。它也没能考虑对生态的冲击，例如对帝王蝶和其它授粉昆虫的影响。它只考察纯草甘膦，而不顾多个研究显示含有表面活性剂和助剂的配方草甘膦比纯化合物的毒性更大。

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.
第二个新进展是2015年IARC认定草甘膦“对人类很可能致癌”（1），2,4-D“对人类可能致癌”（2）。这个归类立足于对相关毒理学和流行病学文献的完整评估，而这些文献将这两种除草剂与动物多个解剖学位置上的恶性肿瘤的与剂量相关的增加关联了起来，也将草甘膦与人类的非霍奇金白血病的增加关联了起来。

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.
这些新进展说明转基因食品以及用于其上的除草剂对人类健康带来危害，这在以前的评估中都没有得到审视。因此我们相信现在是时候重新彻底考察植物生物技术安全性的方方面面了。美国国家科学院已经召集了一个新的委员会来重新评估转基因作物对社会、经济、环境和人类健康的影响。我们对这个新动向表示欢迎，但是该委员会的报告至少在2016年前还不能出炉。

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.
同时，我们也提出两个建议。首先，我们相信环保署（EPA）应该推迟实施它所作出的允许Enlist Duo应用的决定。该决定的作出是很草率的；它建立在设计拙劣且过时的研究的基础上，没能完整评估其对人类接触和环境造成的影响；它本来应该更深入的参考独立经费资助并发表在同行评议杂志上的研究；而且该决定是在IARC最近将草甘膦和2,4-D重新定性之前作出的。其次，美国国家毒理学规划处应紧急评估纯草甘膦、配方草甘膦以及草甘膦和其它除草剂混合物的毒理。

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.
最后，我们相信是时候重新审视美国对标识转基因食品的不情愿政策。标识会带来若干好处。它是追踪新出现的食品过敏原和评估用于转基因作物的化学除草剂的影响所必须的。它也尊重了越来越多消费者的愿望，他们坚持认为有权了解所购买的食物及其是如何生产的。那些认为基因重组没有什么新奇之处的观点，忽视了当今转基因作物是最大量使用了除草剂后的农产品，这其中的两种除草剂可能带来癌症风险。我们希望，根据这些新的信息，FDA会重新考虑标识转基因食品，同时提供足够经费作好其上市后的长期监控。
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来自纽约西奈山Icahn医学院预防医学系；C.B.来自华盛顿州立大学作物和土壤科学系。
 

References（参考文献，翻译从略）

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    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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