Problem Formulation in Environmental Risk Assessment for Genetically Modified Crops Alan Gray Centre for Ecology and Hydrology UK The genetic basis of unintended effects in modified plants Ottawa, 14-15 January 2014
In this talk: Take-home messages Problem Formulation Unintended environmental effects Disclaimer: Any views expressed in this presentation are mine and not necessarily shared by any organisation with which I am, or have been, associated
Take-home messages (1) * Because ERA for GM crops deals almost exclusively with the phenotype it considers all traits altered by transformation * Traits have been characterised during growing trials and product development * ERA thus embraces both intended and unintended effects of transformation
Main traits of interest in multi-site trials of GM plant and comparator Regeneration niche traits seed development /yield, shattering, dormancy, germination rates Competitiveness traits seedling vigour, growth rate, days to flowering, plant height/yield, plant-insect/disease interactions, etc
Data from plant characterisation trials can be used to test several general hypotheses e.g. will the modified crop be more weedy or invasive than its non-modified counterpart Further data will be required to test hypotheses relating to intended effects (e.g. novel protein expression, effects on NTOs etc)
Take-home messages (2) * ERA considers the collateral effects of cultivating a GM crop on a large scale * Problem Formulation aims to identify which effects may cause harm and to devise a plan to analyse the risk of the harm being realised * Some outcomes of large-scale cultivation, negative or beneficial, GM or non-gm, may be unintended Problem Formulation is designed to capture the potentially harmful ones
Common components of ERA frameworks (after Hill 2005) 1 HAZARD IDENTIFICATION The what could go wrong step 2 EXPOSURE ASSESSMENT The how likely is it to happen step 4 RISK CHARACTERISATION The what is the risk step 3 CONSEQUENCES ASSESSMENT The would it be a problem step
Simple schematic of ERA (after US EPA) PROBLEM FORMULATION (includes identification of assessment endpoints, risk hypotheses and analysis plan) EXPOSURE ASSESSMENT (levels and likelihood of exposure) RISK CHARACTERISATION HAZARD ASSESSMENT (effects testing or consequences assessment)
Problem context PROBLEM FORMULATION The ILSI framework (Wolt et al 2010) Problem definition Communication and consultation Risk characterization Likelihood of exposure Risk evaluation conclusions RISK ASSESSMENT Risk treatment Consequence of exposure Monitoring and review Problem context develops the parameters and identifies constraints for the ERA Problem definition shapes the ERA into a tractable form for analysis mitigation options & actions
Problem Formulation starts with the identification of protection goals (environmental objectives defined by policy, law, statutes or guidelines) From these we derive assessment endpoints (explicit expressions of the environmental value to be protected a valued ecological entity and its attributes e.g. beneficial insect abundance
Protection goal conservation of insect pollinators Assessment endpoint the abundance of bumblebees Protection goal weed-free crops Assessment endpoint the abundance of in-field weeds
We then generate an exposure scenario or pathway to harm (describing the link between the GM crop and the assessment endpoint, enabling characterisation of risk) This pathway can be expressed as a set of risk hypotheses (tentative explanations taken to be true for the purpose of argument e.g. GMHT canola will not be a worse volunteer weed than conventional canola) The process can be aided by conceptual models
..which may be simple PATHWAY TO HARM RISK HYPOTHESES HT soybean produces seed Seed disperses to natural habitats HT soybean establishes in natural habitats HT soybean persists and spreads more than non-ht counterpart HT soybean displaces species or reduces valued species HT soybean does not produce seed Seed does not disperse to natural habitats HT soybean does not establish in natural habitats HT soybean does not persist and spread more than non-ht soybean HT soybean does not displace species or reduce valued species ANAYSIS PLAN Assess comparative performance of HT and non-ht soybean for unintended effects during product development (e.g. weedy traits)
Bt Corn Production and Distribution Pollen Characterization Bt expression Pollen Shed Timing, Duration, Intensity Environmental Dispersal or more complex Monarch Occurrence & Distribution Region Landscape Habitat Behavior Oviposition Feeding Environmental Exposure Milkweed Occurrence and Distribution Region Landscape Habitat Sears et al. PNAS 98: 11937 11942, 2001. Monarch Effect Lethal Sub lethal Risk
For definition of terms, framework etc. Wolt JD, Keese P, Raybould AF, Fitzpatrick JW, Burachik M, Gray AJ, Olin SS, Schiemann J, Sears M & Wu F (2010) Problem formulation in the environmental risk assessment for genetically modified plants. Transgenic Research 19:425-436 Also Raybould AF (2011) The bucket and the searchlight: Formulating and testing risk hypotheses about the weediness and invasive potential of transgenic crops, Environmental Biosafety Research 9:123-133
The steps in Problem Formulation can be expressed as four questions * 1 What do we not want to see harmed? What must be protected? 2 Can we envision a way in which they could be harmed? 3 How can we assess whether they are likely to be harmed? 4 Does it matter? *Gray AJ (2012) Collection of Biosafety Reviews http://www.icgeb.org/biosafety/publications/collections.html
Problem formulation in ERA for GM crops QUESTION PROBLEM FORMULATION 1 What do we not want to see harmed? What must be protected? 2 Can we envision a way in which they could be harmed? 3 How can we assess whether they are likely to be harmed? Identify assessment endpoints from protection goals Trace pathways to harm and develop conceptual models Formulate risk hypotheses and devise analysis plans 4 Does it matter? Decide regulatory context
For application and worked examples.. Gray AJ (2012) Problem Formulation in Environmental Risk Assessment for genetically modified crops: a practitioner s approach. Collection of Biosafety Reviews 6:10-65 Also Tepfer M, Racovita M & Craig W (2013) Putting problem formulation at the forefront of GMO risk analysis. GM Crops and Food: Biotechnology in Agriculture and the Food Chain 4:1-6
Unintended environmental effects * Large-scale cultivation of novel crops is likely to have novel effects, arising from new varieties and/or changes in management * Some effects will be unintended sensu unplanned but not unforeseen (e.g. evolution of pest resistance) and form part of the ERA * Others may be unintended sensu unexpected * Problem Formulation aims to identify possible harmful effects, providing a tool for decision making about the cultivation of the crop
The challenge for ecology is to improve our understanding of the effects of agricultural changes For example the huge changes in grassland management in the UK (haystacks->bales-> silage ; permanent pasture -> temporary leys)
.and in cereal and other arable farming (e,g. harvesting methods, spring-> winter crops).and in dairy and beef production
..have been accompanied by declines in biodiversity (as indicated for example by a huge decline in some farmland bird species) But agri-environment schemes are indicating species need specific management to reverse these declines (e.g. Hicks et al (2013) Aspects of Applied Biology 121 Rethinking Agricultural Systems in the UK, pp 219-20)
Not all unexpected effects are harmful - changes in cultivation of Canadian canola with increase in HT varieties 1996 2006 Conventional Conservation No-till Source: Statistics Canada, Census of Agriculture 1996-2006 (with thanks to Phil Macdonald)