| Literature DB >> 23193357 |
S Ravi Rajan1, Deborah K Letourneau.
Abstract
The risks of genetically modified organisms (GMOs) are evaluated traditionally by combining hazard identification and exposure estimates to provide decision support for regulatory agencies. We question the utility of the classical risk paradigm and discuss its evolution in GMO risk assessment. First, we consider the problem of uncertainty, by comparing risk assessment for environmental toxins in the public health domain with genetically modified organisms in the environment; we use the specific comparison of an insecticide to a transgenic, insecticidal food crop. Next, we examine normal accident theory (NAT) as a heuristic to consider runaway effects of GMOs, such as negative community level consequences of gene flow from transgenic, insecticidal crops. These examples illustrate how risk assessments are made more complex and contentious by both their inherent uncertainty and the inevitability of failure beyond expectation in complex systems. We emphasize the value of conducting decision-support research, embracing uncertainty, increasing transparency, and building interdisciplinary institutions that can address the complex interactions between ecosystems and society. In particular, we argue against black boxing risk analysis, and for a program to educate policy makers about uncertainty and complexity, so that eventually, decision making is not the burden that falls upon scientists but is assumed by the public at large.Entities:
Mesh:
Year: 2012 PMID: 23193357 PMCID: PMC3502034 DOI: 10.1155/2012/203093
Source DB: PubMed Journal: J Biomed Biotechnol ISSN: 1110-7243
Figure 1Modified from Douglas and Wildavsky's “Four Problems of Risk” to include examples potentially relevant to GMO risk assessments [12].
Fundamental sources of uncertainty identified in the literature on public health risk assessments with hypothetical examples for human exposure to pesticides and environmental exposure to plant-incorporated pesticides.
| Source of uncertainty | Risk of human illness due to insecticide exposure (examples) | Risk of nontarget insect mortality from transgenic insecticidal plants (examples) |
|---|---|---|
| Body's past exposures and synergistic effects | Prior exposure to common household cleaning agents not recorded or simultaneous exposure to so-called inert ingredients not available, but these substances could increase sensitivity to the toxin in question. | No prior exposure to secondary plant compounds when testing for the susceptibility of clean-cultured, non-target insects, reared on a diet with purified proteins, but substances in food derived from plants or herbivores could increase negative effects of the novel proteins [ |
| Dose-Response Relationships | Insecticides such as DDT are stored in the body fat, and thus are more likely to have cumulative effects than are organophosphates, which cause acute illness, and tend to have nonlinear, threshold level toxicity. | Dosages needed to cause lethal effects on non-targets are measured in standard tests on a small number of indicator species (e.g., [ |
| Etiological Uncertainty | Farm workers with exposure to low doses of an insecticidal nerve toxin experience respiratory distress that is over three times as severe when applying fungicides. It is difficult, if not impossible, to document conclusively that a specific disease is caused by exposure to a specific environmental effluent. | The rise in acreage of transgenic insecticidal crops accompanied the rise in colony collapse syndrome in honeybees, but so has the use of neonicotinoid insecticides, the number of cell phone towers, incidence of bee mites, virus infection, the distance commercial pollination hives were transported, and many other confounding factors [ |