Assessing the risk of GMOs

With the recent breakdown of discussions at the Biosafety Protocol negotiations in Cartagena and the concerns over genetically modified organisms (GMOs) reverberating once again, Topsy Jewell and Andy Stirling review the limitations and potential of a recent bid to apply the science of risk assessment in this field.

In 1995, the parties to the Convention on Biological Diversity called for an international protocol on biosafety based on the principles embodied in the Rio Declaration on Environment and Development and in particular the precautionary approach. In response to this call, the Edmonds Institute,  a public interest, non-profit organisation based in the US and a NGO observer at the Biosafety Protocol negotiations, invited a group of scientists from a range of biological disciplines to evaluate the potential impacts of GMOs and to develop a series of  biosafety assessment procedures. Their aim was to provide a means to assess in advance whether a particular GMO will yield the anticipated benefits and whether environmental or human health effects may result from any deliberate or inadvertent consequences of its release.

Bioassessment manual  
The result is a technical manual setting out a clear step-by-step bioassessment process. The manual is aimed at scientists, decision makers, regulators and manufacturers and was presented to delegates at the recent Biosafety Protocol negotiations in Cartagena. While all countries are vulnerable to unforeseen dangers of GMOs, some countries are more at risk-particularly those with insufficient scientific, financial or administrative capacities to establish a risk assessment programme. For these countries, the manual may prove a particularly useful tool. The user is guided through a series of questions presented in a set of flow diagrams. Each step is well annotated to aid decisions. The procedures can be applied to a variety of GMOs, including those created from viruses, bacteria, fungi, plants, and animals. The process identifies potential hazards and offers recommendations to minimise risks.

    The Edmonds Institute rightly recognises that uncertainty is a critical factor in the assessment of GMOs; that ecological systems and the behaviour of organisms are highly complex; and that efforts at prediction are extremely precarious. Yet it is here that the manual displays its greatest weakness, but one that is intrinsic to the task rather than to the efforts of the authors.
    Any attempt to apply an orthodox risk assessment approach to the problem of GMO releases-no matter how systematic and apparently comprehensive it may be-encounters a number of  serious practical and theoretical obstacles. GMOs are novel. The contexts for their application are diffuse, diverse and dynamic in nature. There are inherent limitations to the scientific understandings of the highly complex systems into which they are to be released. Taken together, these factors all serve to undermine the authority of the risk assessment calculus. The problem lies not only in estimating probabilities, but in characterising the possibilities themselves.
    The permutations of the possible effects of GMOs and their associated agricultural strategies are truly vast in number. As experience has shown repeatedly in the environmental domain, some of the most important impacts are intrinsically unforeseeable in nature. The early history of pesticides provides an example, as do more recent experiences with ozone depletion, BSE and hormone disrupting chemicals. The advent of GMOs raises the prospect of a host of potential threats of this sort: irreversible transformations in the genetic composition of established crops, wild plants or microbial life; the fostering of pest resistance, dependence on herbicides or antibiotic resistance; and the creation of new human food allergies, nutritional effects or toxic reactions. The potential for surprises in such areas  transcends even the notion of 'uncertainty' and places us firmly in the realm of 'ignorance'.
    Risk assessment methodology is used as the basis of 'sound science' in environmental appraisal, but there is a tendency in some quarters to regard risk assessment as both a necessary and sufficient condition for sound science in environmental appraisal. Yet the concept of 'ignorance' is just as well-founded in the science of probability as the concept of 'risk'. It simply refers to the condition under which we lack information both on the likelihoods of different possible outcomes and on the possible nature of some of the outcomes. Under these circumstances, the procedures of risk assessment are-even in their own terms-quite simply inapplicable. Precaution-rather than the narrow business of risk assessment- offers the most 'sound scientific' response.
    It is on this point that the biosafety assessment procedures, as presented in the  manual, fall well short of the precautionary approach.  Even the more technical aspects of appraisal, raise issues which require greater emphasis. For instance, the potential for cumulative, additive or synergistic effects involving different GMOs. 'Indirect' effects arising from the agricultural practices associated with GMOs (such as pesticide use) are also important. There are also crucial difficulties involved in the relative weighting of different aspects of the risk issue: balancing considerations such as biodiversity, occupational health and food safety.
    The most important issue concerns the role for wider consultation and deliberation involving stakeholders. The framing assumptions and priorities adopted in risk assessment are intrinsically subjective. For instance, appraisal is not just a matter of the case by case evaluation of individual GMOs, but of comparing a range of different agricultural and food strategies. Assessments of the importance of ignorance are also necessarily subjective. The systematic involvement of interested and affected parties in the appraisal process is therefore not just a matter of trust, expediency and democratic principles. It is also a matter of analytical rigour. How else can assumptions over the scope and framing of analysis and the presentation of results be verified and validated? The essential role of participatory deliberation in risk assessment is now acknowledged by bodies such as the US National Research Council and the UK Royal Commission on Environmental Pollution. There is no shortage of practical advice on the conduct of this increasingly important dimension in risk assessment. The details may lie beyond the scope of a technical manual but, the issues should be acknowledged.

Conclusion  
The carefully developed procedures clearly described in the Edmonds Institute manual will provide a useful source of prompting and quality control in the risk assessment of GMOs. However they do not offer a sufficient basis for the regulatory appraisal of these new technologies. Even in the terms of 'sound science' in the regulation of GMOs, the precautionary aims of the Biodiversity Convention require us to go beyond the limited framework of conventional risk assessment. And in the end the justification for the use of particular GMOs must, as with other risks, be grounded as much in the politics of credibility, legitimacy and accountability as in the inherently limited and imperfect science of risk assessment.

Manual for Assessing Ecological and Human Health Effects of Genetically Engineered Organisms Scientists Working Group on Biosafety, Edmonds Institute, Edmonds, Washington, US, 2 volumes, 245pp, 1998.

Topsy Jewell  is an environmental researchers. Andy Stirling is a lecturer at the Science Policy Research Unit, University of Sussex.

[This article first appeared in Pesticides News No. 43, March 1999, page 5]