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Environmental impact indices: what do they reveal and not?

Environmental impact indices: what do they reveal and not?

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  • 1. DISCLAIMER: This presentation does not reflect the view of EFSA Environmental impact indices: what do they reveal and not? RR maize symposium: the European perspective 22-24 March 2010 22- Yann Devos (PhD) – Junior Scientific Officer GMO Unit – EFSA Yann.Devos@efsa.europa.eu
  • 2. 1. Introduction Aim – Assess and compare environmental impact of herbicide regimes applied in genetically modified herbicide tolerant (GMHT) maize with those used in its conventional counterpart Residual Residual + foliar Residual Residual + foliar GLY GLY Residual GLY Residual + GLY 2 sowing pre-emergence emergence 1 leaf stage; 2 leaf stage; 4 leaf stage; 5-6 leaf stage; 40 cm height 60 cm height 3-4 cm height 3-4 cm height 4-10 cm height 10-15 cm height
  • 3. 1. Introduction Environmental impact indices – Pesticide Occupational and Environmental Risk Indicator (POCER) → Vercruysse & Steurbaut (2002) • Maize: Devos et al (2008) – Environmental Impact Quotient (EIQ) → Kovach et al (1992) • Maize: Leroux et al (2006); Kleter et al (2007); Brookes & Barfoot (2008) • Soybean: Kleter et al (2007); Bonny (2008); Brookes & Barfoot (2008) • Cotton: Brookes & Barfoot (2008) • Oilseed rape: Brimner et al (2005); Kleter et al (2007); Brookes & Barfoot (2008) 3
  • 4. 2. POCER → Vercruysse & Steurbaut (2002) Pesticide Occupational and Environmental Risk Indicator (POCER) – modules – Annex VI of Directive 91/414/EEC • 3 modules for human health (non-dietary exposure) – Risk to pesticide operator – Risk to worker – Risk to bystander • 7 modules for the environment – Persistence in soil – Risk of ground water contamination – Acute risk to aquatic organisms – Acute risk to birds – Acute risk to bees – Acute risk to earthworms – Risk to beneficial arthropods 4
  • 5. 2. POCER → Vercruysse & Steurbaut (2002) Pesticide Occupational and Environmental Risk Indicator (POCER) – formula – For each module → risk is estimated via risk indices (RI) Risk index Estimated exposure / toxicity ratio Pesticide operator IE / AOEL [IE=internal exposure; AOEL=acceptable operator exposure level] Worker (DE x AbDE) / (AOEL x BW) [DE=dermal exposure; AbDE=dermal absorption factor; BW=body weight] Bystander (DE x AbDE + I x AbI) / (BW x AOEL) [I=inhalation exposure] Persistence 10[((DT50/90)-1) x 2] ) [DT50=half-life] Groundwater PEC / 0.1 [PEC=predicted environmental concentration in groundwater] Aquatic organisms PEC / MTC [MTC=maximum tolerable concentration] Birds (10 x PEC) / (LC50 x BW) Earthworms (10 x PEC) / LC50 Bees AR / (50 x LD50) [AR=application rate] 5 Beneficial arthropods (RC – 25) / (100 – 25) [RC=reduction of control capacity]
  • 6. 2. POCER → Vercruysse & Steurbaut (2002) Pesticide Occupational and Environmental Risk Indicator (POCER) – calculations – Integration of RI into total risk indicator • Describe extent to which a chosen trigger is exceeded as a numerical dimensionless value – Step 1 – define lower (LL) and upper limit (UL) for each RI – Step 2 – calculate relative RI, LL and UL & log-transform – Step 3 – determine exceedence factors (EF) » EF values ≤ 0 are scored as 0 → low risk » EF values ≥ 1 are scored as 1 → high risk » EF values between 0 and 1 → intermediate risk – Step 4 – calculate total risk = ∑ EF values ranging between 0 and 10 » Assumption: all components are equally important 6
  • 7. 2. POCER → Devos et al (2008) Herbicide regimes in conventional maize – 3 different strategies to control annual/perennial grasses and broadleaf weeds (abbreviated as CON) • Pre-emergence of crop • Early post-emergence, ideally in 2-4 leaf stage of maize • Sequentially, – where a combination of herbicides with soil (residual) activity is applied pre-emergence – followed by a mixture of post-emergence herbicides with foliar activity – Farmers use a combination of <3-4> active substances – 13 typical herbicide regimes (Flanders; Belgium) • Time of application; dose; activity; weed spectrum 7
  • 8. 2. POCER → Devos et al (2008) Herbicide regimes in RR maize – Different strategies to control annual/perennial grasses and broadleaf weeds (e.g., Dewar, 2009) • Single or sequential application of GLY only, without relying on pre-emergence herbicides • Use of GLY in combination with other herbicides, especially residual herbicides applied pre-emergence • Use of GLY in a single application in combination with other post-emergence herbicides with residual activity – 10 GLY-based herbicide regimes • Single vs. sequential application; dose; application timing; presence/absence of residual herbicide • RR composition = 360 g/l 8
  • 9. 2. POCER → Devos et al (2008) Herbicide regimes in RR maize – 3 regimes: • Single application of GLY only (abbreviated as GLY) • Application dose rates (g/ha): – 720 → medium efficacy (Soukup et al, 2008) – 900 → medium efficacy (Leroux et al, 2006) – 1080 → medium efficacy (Phipps and Park, 2002) – 4 regimes: • Sequential application of GLY only (abbreviated as GLY) • Application dose rates (g/ha) – 900 + 450 = 1350 → high efficacy (Leroux et al, 2006) – 720 + 720 = 1440 → high efficacy (Monsanto) – 900 + 900 = 1800 → high efficacy (Leroux et al, 2006; Monsanto) – 1080 + 1080 = 2160 → high efficacy (Soukup et al, 2008; Monsanto) 9
  • 10. 2. POCER → Devos et al (2008) Herbicide regimes in RR maize – 3 regimes: • Single application of GLY in combination with herbicides with residual activity (abbreviated as GLY+) • Application dose rate (g/ha) – GLY (1080) + acetochlor (2100) → high efficacy (Soukup et al, 2008; Monsanto) – GLY (1080) + herbicide with residual activity (full dose rate) » S-metolachlor » Terbuthylazin » Dimethenamid-P 10
  • 11. 2. POCER → Devos et al (2008) Results – human health – 3 modules • Risk to pesticide operator – EF CON = [1.00] – EF GLY = [0.54-0.78] – EF GLY+ = [1.00] • Risk to worker – EF CON/GLY/GLY+ = [0.00-0.37] • Risk to bystander – EF CON/GLY/GLY+ = [0.00] – If used alone, GLY has lower impact on pesticide operator than other herbicide regimes tested – Risk to worker and bystander is low and transient 11
  • 12. 2. POCER → Devos et al (2008) Results – environment – 7 modules • Persistence in soil – EF CON/GLY/GLY+ = [0.00-0.03] – Half lives ≤ 90 days considered low • Risk of ground water contamination – EF CON/GLY/GLY+ = [0.18-0.33] – Risk of ground water contamination low due to rapid adsorption in soil of GLY • Acute risk to aquatic organisms – EF CON = [0.47-1.00] – EF GLY = [0.00] – EF GLY+ = [0.38-1.00] – GLY has low acute toxicity to fish, Daphnia and algae 12
  • 13. 2. POCER → Devos et al (2008) Results – environment – Acute risk to birds / bees / earthworms / beneficial arthropods • EF CON/GLY/GLY+ = [0.00] • Low acute toxicity to birds, bees, earthworms and beneficial arthropods Overall conclusion 3,0 Exceedence factor (EF) POCER modules 2,5 2,0 CON values GLY 1,5 GLY+ 1,0 0,5 0,0 13 Human health Environment Total
  • 14. 3. EIQ → Kovach et al (1992) Environmental Impact Quotient (EIQ) – components and calculations 14
  • 15. 3. EIQ → Leroux et al (2006) EIQ-methodology applied to RR maize in Canada (Québec) 15
  • 16. 3. EIQ → Kleter et al (2007) EIQ-methodology applied to GMHT crops in US – 2004; pesticide use survey data of National Center for Food and Agricultural Policy (NCFAP); percent change – Proportional EIQ/ha reduction of 39% in maize Soybean Ecology impact, EI/A Maize Consumer impact, EI/A Cotton Farmworker impact, EI/A Total impact, EI/A Canola Pesticide use, lbs ai/A 0 20 40 60 80 % decrease GM vs. conventional 16
  • 17. 3. EIQ → Brookes & Barfoot (2008) EIQ-methodology applied to GMHT maize globally – 1997-2006; pesticide use survey data from US, Canada, South Africa & Argentina 17
  • 18. 3. EIQ → Bonny (2008) EIQ-methodology applied to GMHT soybean in US – 1990-2006; pesticide use survey data of US Department of Agriculture (USDA) Period Field EIQ 1994-1996 29.2 2001 20.4 2002 23.8 2006 25.7 18
  • 19. 3. EIQ → Brookes & Barfoot (2008) EIQ-methodology applied to GMHT soybean in Romania – 2000-2003; data from Brookes (2005) 19
  • 20. 4. What environmental impact indices do not reveal? – (see e.g., Cerdeira & Duke, 2006, 2010; Dewar, 2009, for comprehensive reviews) • Weed control efficacy & weed management flexibility • Impact due to the adoption of conservation tillage practices • Impact on human health due to pesticide residues • Impact of GLY metabolites (e.g., AMPA) • Risk to mammals • Weed resistance evolution to GLY • Weed spectrum shifts • Impact on farmland biodiversity • Impact on microorganisms and soil functions • … 20
  • 21. 5. What environmental impact indices do reveal? Useful tools – as indicators of environmental impact of pesticides – to compare/rank pesticides based on environmental impact Herbicide regimes in maize cropping systems – GLY-based herbicides have a better environmental profile compared to those applied in conventional maize – Addition of herbicides other than GLY in RR maize reduces/cancels beneficial effect, depending on application dose rate of additional herbicide 21
  • 22. 6. Thank YOU for your attention! Acknowledgments – Dirk Reheul & Mathias Cougnon & Robert Bulcke • University of Ghent; Department of Plant Production – Sofie Vergucht & Walter Steurbaut • University of Ghent; Department of Crop Protection – Geert Haesaert • University College of Ghent; Department of Plant Production – Gijs Kleter • RIKILT; Institute of Food Safety; Wageningen University and Research Center 22