Docket No. APHIS-2012-0019 Regulatory Analysis and Development, PPD, APHIS Station 3A-03.8 4700 River Road Unit 118 Riverdale, MD 20737- 1238 11 September 2012 Comments to USDA APHIS on Draft Environmental Assessment and Draft Plant Pest Risk Assessment for Dow AgroSciences Petition (09-349-01p) for Determination of Nonregulated Status of Event DAS-68416-4: 2,4-D- and glufosinate-resistant soybean Center for Food Safety, Science Comments By: Bill Freese, Science Policy Analyst and Martha L. Crouch, Ph.D, Science Consultant Table of Contents 1. Notes on science comments ...................................................................................................................... 3 2. The impact of approval of DAS-68416-4 soybean on herbicide use............................................ 3 a. Summary of herbicide use..................................................................................................................................... 3 b.Introduction................................................................................................................................................................ 4 c. DAS-68416-4 soybean will lead to sharply increased use of 2,4-D in American agriculture ......... 4 i. 2,4-D rates and EPA label restrictions................................................................................................................................5 ii. Projection by Mortensen et al. (2012) ..............................................................................................................................6 d. DAS-68416-4 soybean will lead to increased use of glufosinate in American agriculture ...........10 e. DAS-68416-4 will sharply increase overall herbicide use on soybeans..............................................11 f. Assessments of herbicide use as influenced by Roundup Ready crops ................................................14 g. Conclusions: Dow’s flawed herbicide use assessment has no merit and must not be relied upon by APHIS.........................................................................................................................................................................16 3. Herbicide-resistant weeds and approval of DAS-68416-4 soybean..........................................17 a. Summary ...................................................................................................................................................................17 ____________________________________________________________________________________________________________________________________________________ Main Office: 660 Pennsylvania Ave., S.E., Suite 302, Washington, D.C. 20003 • Phone: 202-547-9359 • Fax: 202-547-9429 California Office: 2601 Mission Street, Suite 803, San Francisco, CA 94110 • Phone: 415-826-2770 • Fax: 415-826-0507 Email: [email protected] • www.centerforfoodsafety.org • www.foodsafetynow.org Center for Food Safety – Science Comments – DAS-68416-4 Soybean 2 b. Weed management vs. weed eradication ......................................................................................................18 c. The high costs of herbicide-only weed control.............................................................................................19 d. Why herbicide-resistant crop systems promote rapid evolution of resistant weeds.....................21 e. Overview of glyphosate-resistant crops and weeds ...................................................................................24 f. Synthetic auxin-resistant crops and weeds....................................................................................................27 g. Multiple herbicide-resistant crops and weeds.............................................................................................29 i. Horseweed................................................................................................................................................................................... 29 ii. Waterhemp ................................................................................................................................................................................ 32 iii. Palmer amaranth.................................................................................................................................................................... 34 iv. Kochia.......................................................................................................................................................................................... 35 h. Potential for glufosinate resistant weeds......................................................................................................36 i. Stewardship ..............................................................................................................................................................37 j. Spread of weed resistance and tragedy of the commons...........................................................................38 k. Volunteer DAS-68416-4 soybean......................................................................................................................39 4. Crop injury from herbicide drift with approval of DAS-68416-4 soybean .............................43 5. Human health and approval of DAS-68416-4 soybean..................................................................45 a. Health risks to farmers and the general public from exposure to 2,4-D.............................................45 b. Health risks from exposure to glufosinate ....................................................................................................58 6. Transgenic contamination of conventional and organic soybean varieties by DAS-68416- 4 soybean ...........................................................................................................................................................59 7. Environmental impacts of DAS-68416-4 soybean approval........................................................61 a. Overview of environmental impacts................................................................................................................61 b. Herbicide resistant crops not responsible for increased conservation tillage.................................62 i. Correlation in question .......................................................................................................................................................... 63 ii. Conservation tillage leads to HR seeds, not vice versa ........................................................................................... 66 iii. Reductions in soil erosion come to an end during decade of herbicide-resistant crop adoption ...... 66 iv. Federal farm policy triggered sharp declines in soil erosion prior to HR crop adoption....................... 69 c. Environmental impacts of conservation tillage............................................................................................73 i. Soil and water............................................................................................................................................................................. 73 ii.Climate change........................................................................................................................................................................... 74 8. Environmental effects of increased herbicide use with approval of DAS-68416-4 soybean ...............................................................................................................................................................................76 a. Drift injury to plants and other non-target organisms ..............................................................................76 b. Herbicide use patterns w/ DAS-68416-4 soybean result in greater risk to non-target species .78 i. Timing of 2,4-D applications in the growing season ................................................................................................. 78 ii. Total use of 2,4-D at landscape level............................................................................................................................... 78 c. Increased ingestion of 2,4-D and glufoinate residues and metabolites...............................................79 d. Impacts to biodiversity ........................................................................................................................................79 i. Biodiversity in soybean fields ............................................................................................................................................. 79 e. Threatened and endangered species...............................................................................................................82 i. Increased herbicide use and listed species ................................................................................................................... 82 ii. Ingestion of DAS-68416-4 soybean by listed species.............................................................................................. 84 9. Impacts of the activity of AAD-12 enzyme in DAS-68416-4 soybean........................................84 a. Independent research shows that new, potentially toxic metabolites are formed in 2,4-D resistant plants............................................................................................................................................................86