Environmental Risk Assessment Process for Bt Crops Bt 农作物的环境风险评估过程

1. Environmental Risk Assessment Process for Bt CropsBt 农作物的环境风险评估过程 Tessa S. Milofsky, M.S. 泰莎. 米洛夫斯基, 硕士 U.S. Environmental Protection Agency Office of Pesticide Programs 美国环保局 杀虫剂项目办公室

2. Outline of presentation报告纲要 • Describe environmental risk assessment (ERA) process for insect-resistant Bt crops: 介绍抗虫Bt农作物环境风险评估(ERA)过程: • Terms 术语 • Conceptual framework 基本概念 • Data requirements 必要数据 • Tiering 阶段 • Summarize ERA for MON810 corn MON810玉米环境风险评估概述

3. Terms术语 • Risk - the probability of adverse effects resulting from exposure to an environmental agent or mixture of agents 风险 – 暴露于环境因素或混合因素所导致的负面影响的可能性 • Hazard - the inherent toxicity of the insecticidal protein 危害 –杀虫蛋白的内在毒性 • Exposure - the concentration of insecticidal protein encountered by an organism in the environment 暴露 – 某种生物在环境中接触到的杀虫蛋白的浓度 High risk 高风险 Hazard 危害 Low ris 低风险 Exposure 暴露

4. Terms (cont.) 术语 (续) • Risk Assessment - assessment of the probability that a harmful condition (hazard) will occur under a given set of conditions, using both hazard and exposure data • 风险评估 – 利用危害性数据和暴露数据评测在一系列给定条件下, 有害条件(危害性)发生的可能性.

5. Effects Characterization 效果描述 Hazard Measures of Effects Identification Risk Conclusion 风险结论 Risk Problem Formulation 问题建立 Characterization Exposure Assessment Exposure Characterization 暴露描述 Risk assessment process 风险评估过程 危害性识别 效果测试 风险描述 暴露评估

6. Problem formulation 问题建立 • Consider: 考虑 • Available information 可利用的信息 • Overall management goals 总体的管理目标 • Scientific and public concerns 科学和公众的考虑 • Identify: 识别 • Assessment endpoints 评估终点 • Test species 测试物种 • Test endpoints 测试终点 • Tiers required 必要的阶段

7. Effects Characterization 效果描述 Hazard Measures of Effects Identification Risk Conclusion 风险结论 Risk Problem Formulation 问题建立 Characterization Exposure Assessment Exposure Characterization 暴露描述 Risk assessment process 风险评估过程 危害性识别 效果测试 风险描述 暴露评估

8. Risk assessment at EPAEPA(美国环保局) 风险评估 • Assessment based on: • Data submitted to the Agency • Advisory panel recommendations • Consultations with scientific experts • Public comments • 评估基于: • 递交于环保局的数据 • 顾问团的建议 • 与学术专家的咨询 • 公众的意见

9. Data requirements必要的数据 • Product characterization 产品特征 • Human health 人类健康 • Toxicity 毒性 • Allergenicity 过敏性 • Environmental hazard 环境危害 • Insect resistance management (Bt crops only)昆虫抗药性管理(仅对Bt农作物)

10. Product characterization data requirements产品特征中的必要数据 • Molecular characterization • Characterization of inserted genes (active and inert) • Transformation system • Inheritance and stability of characteristics • Mode of action • 分子特征 • 插入基因的特征 (有活性的和无活性的) • 转录系统 • 遗传和稳定性特征 • 作用模式

11. Product characterization data requirements产品特征中的必要数据 • Test substance equivalence • Protein expression levels • Analytical methods • Verify presence of intended protein in plant • Check for cross reactivity • 测试物质的等效性 • 蛋白表达水平 • 分析方法 • 确认目标蛋白存在于植物中 • 验证杂交

12. Environmental hazard data requirements环境危害性中的必要数据 • Toxicity to nontarget wildlife: • Mammals • Birds • Fish • Terrestrial and aquatic invertebrates • Earthworms • Plants • 对非目标野生生物的毒性 • 哺乳动物 • 鸟类 • 鱼类 • 陆生水生无脊椎动物 • 蚯蚓 • 植物

13. Environmental hazard data requirements 环境危害性中的必要数据 • Fate in environment: • Soil fate • Horizontal gene transfer • Gene flow • Effect on threatened and endangered species • 在环境中的归趋: • 在土壤中的归趋 • 横向基因转移 • 基因流动 • 对濒临灭绝物种的影响

14. Terms (术语) • Estimated environmental concentration (EEC) – estimated concentration within the ecosystem (usually used to describe concentrations in soil or water) 环境浓度估计值(EEC) – 在生态系统中浓度的估计值(通常用来描述在土壤和水中的浓度) • High end exposure estimate (HEEE) - measured or estimated 90th percentile of possible exposure concentrations (usually used to describe levels of expression in the insect-resistant plant) 高端暴露估计值(HEEE) – 百分之九十可能暴露的测量或估计浓度(通常用来描述在抗虫作物中的表达水平) • Maximum hazard dose (MHD) – the dose chosen to represent an extreme exposure scenario, calculated using the EEC or HEEE and incorporating an additional safety factor 最大危害剂量(MHD) – 用来表达极端暴露的剂量,由EEC或HEEE和另外一个合并的安全因素来计算.

15. Tier IV 第四级 Tier III 第三级 Tier II 第二级 Tier I 第一级 Tiered progression 阶梯状过程 Worst case scenario 最差案例设想 Field conditions 田间条件 Effects seen at screening level? 检测水平上的结果

16. Tier IV Tier III Tier II Tier I Tiered progression • Semi-field test in green • or screen house • Long-term (full-life cycle) • Plant material • Actual field exposure • (1x EEC/HEEE) • Screening level test • Laboratory test • Short-term (30-day) • Microbe-derived protein with artificial diet • Uses representative NTOs • Exposure of 10x EEC/HEEE • Full-field test • Long-term • Plant material • Actual field exposure • (1x EEC/HEEE) • May have multiple locations • Census or look at sentinel orgs. • Laboratory test • Plant material alone or mixed with artificial diet • Exposure of 1-5x EEC/HEEE

17. 第四级 第三级 第二级 第一级 阶梯状过程 • 温室中的半田间测试 • 长期 (完整生命周期) • 植物材料 • 暴露于 • (1x EEC/HEEE) • 检测水平测试 • 实验室测试 • 短期 (30-天) • 由人工食物培育的微生物起源的蛋白 • 使用有代表性的NTO • 暴露于10x EEC/HEEE • 完整田间测试 • 长期 • 植物材料 • 暴露于 • (1x EEC/HEEE) • 不同地点 • 普查或在一些机构查询 • 实验室测试 • 单独植物材料或人工混合食物 • 暴露于 1-5x EEC/HEEE

18. Tiering: an important message阶梯过程: 重要的信息 Adverse effect at maximum hazard dose (MHD) 最大危害剂量(MHD)的副作用 ≠ Unreasonable effect 不合理作用 Adverse effect at estimated environmental concentration (EEC) or high end exposure estimate (HEEE) 环境浓度估计值(EEC)或高端暴露估计值(HEEE)表现的副作用 = Potential for unreasonable effect 潜在的不合理作用

19. An example: MON810 corn例子: MON810 玉米 • Pesticide:Cry1Ab protein • cry1Ab gene derived from Bacillus thuringiensis kurstaki • Activity against European corn borer, southwestern corn borer, and corn earworm • Source of test substance: • Plant material • Bacteria-produced purified protein • 杀虫剂: Cry1Ab 蛋白 • cry1Ab 基因由Bacillus thuringiensis kurstaki 得来 • 可抗欧洲玉米螟, 西南玉米螟,和玉米田棉铃虫 • 测试物质来源 • 植物材料 • 细菌产生的纯蛋白

20. MON810 environmental toxicity data summary

21. MON810 环境毒性数据概述

22. MON810 environmental toxicity data summary (cont.)

23. MON810环境毒性数据概述(续)

24. Other environmental toxicity issues其他环境毒性问题

25. Other environmental toxicity issues其他环境毒性问题

26. Effects Characterization 效果描述 Hazard Measures of Effects Identification Risk Conclusion 风险结论 Risk Problem Formulation 问题建立 Characterization Exposure Assessment Exposure Characterization 暴露描述 Risk assessment process 风险评估过程 危害性识别 效果测试 风险描述 暴露评估

27. Risk characterization风险描述 • Low probability of harm due to source of toxin and history of safe use • No adverse effects at Tier I and Tier II test levels • Low probability of risk to endangered species, due to pest biology, distribution, and exposure potential • No observed adverse effects on population abundance in field census • 低危害率归因于毒素的来源和安全使用的历史. • 第一第二测试阶段没有副作用. • 对濒危物种的低风险率归因于害虫的生物学特性,害虫分布和害虫的暴露潜在可能性. • 在田间普查中没有观察到对种群的丰度有负面作用.

28. Risk conclusion风险结论 • This assessment finds no hazard to the environment from cultivation of MON810 corn for a time-limited registration period • Supplemental long term effects studies would provide added weight to support the Agency’s conclusions • 这一评估在一定的注册时间期限内并没有发现MON810玉米的耕作对环境有危害作用. • 补充的长期效果研究将对环保局的结论提供更加有力的支持.

29. Post-registration data requirements for MON810 • Long-term soil fate study (Tier II) • Used to evaluate potential adverse effects on soil organisms • Long-term field study (Tier IV) • Used to evaluate potential adverse effects on nontarget invertebrates in a corn agroecosystem

30. 注册期限后MON810的必需数据 • 长期土壤归趋研究 (阶段 II) • 用来评价对土壤中生物的潜在毒副作用 • 长期农田实验 (阶段 IV) • 用来评价对玉米田农业生态系统中的非目标生物的潜在毒副作用

31. Why have we required field studies for Bt crops?为什么需要Bt农作物的田间研究? • Advisory panels have stated the following: • Field evaluations should be conducted to determine the impact of insect-resistant crops on nontarget organisms • Field studies (are) the most direct way to assess nontarget impact • Community-level interactions cannot be easily measured in laboratory experiment • Laboratory tests may not fully represent the level or form of harm that may occur in the field • 顾问团有如下声明: • 田间评价应可确定抗虫作物对非目标生物的影响. • 田间研究是评价这种影响的最直接的方法. • 实验室中的实验很难测出群落水平的相互影响. • 实验室测试不能完全代表农田中发生的危害水平或危害形式.

32. Limitations of Tier IV full-field studies第四阶段田间实验的局限性 • Full-field studies (census) may result in significant within-plot variation 田间研究(普查)会导致显著的土地内变化 • Difficult to: 很难 • identify useful hypothesis 鉴别有用的假设 • prove hypotheses 证明假设 • compare/contrast treatments with meaningful controls in field 对比处理组和对照组

33. Tier IV full-field study: sampling canopy-dwelling invertebrates第四阶段-田间实验: 林间生活的无脊椎动物取样 Flying insect trap 飞虫捕捉器 Whole plant survey 全植物调查

34. Tier IV full-field study: sampling surface-dwelling invertebrates第四阶段-田间实验: 地表生活的无脊椎动物取样 Pitfall trap for ground-dwelling invertebrates 土地上生活的无脊椎动物陷阱 Carabid beetle 步行虫 Rove beetle 隐翅虫

35. What are the alternatives?其他选择 • Follow the tier progression: I→II→ III→IV • Require higher-tier (Tiers III & IV) testing only when lower-tier tests indicate potential risk • If higher-tier testing is required, investigate Tier III semi-field level alternatives • 按着阶梯状过程: I→II→ III→IV • 仅当低阶段测试表明有潜在的风险时,才需进行高阶段(第三第四阶段)测试. • 如果高阶段测试是必须的,那么第三阶段半田间调查是可选择的

36. Why might Tier III semi-field tests be a better option than Tier IV full-field tests?为什么第三阶段半田间测试相对于第四阶段田间测试可能是更好的选择? • Guaranteed exposure • Higher likelihood of measuring effects, because test system is confined • Can readily relate results to those obtained in laboratory • Can introduce laboratory-reared, or field-collected individuals • Can regulate number of pests • 暴露是有保证的 • 由于测试系统是有限的,所以得到结果的可能性更高 • 可以更好的和实验室得到的结果联系起来 • 可以引进实验室缺少的或只能在田间收集的个体 • 可以更好的控制害虫的数目

37. Why might Tier III semi-field tests be a better option than Tier IV full-field tests?为什么第三阶段半田间测试相对于第四阶段田间测试可能是更好的选择? • Greater number of replicates possible • Can be compared with other treatments • Con of Tier III tests • Difficult to design • 繁殖的可能性更高 • 可以和其他实验组比较 • 第三阶段的缺陷 • 很难设计

38. Tier III semi-field study: litter bag method第三阶段半田间实验: 小袋法

39. A take-home message重点总结 Risk assessment is always a dynamic process 风险评估往往是个动态的过程.