Environmental Risk of GMOs: Comparing Two Studies

Introduction

The environmental risk of genetically modified organisms (GMOs) is a controversial topic that has been addressed in peer-reviewed journals by researchers, some of whom claim there is a high risk (Seralini et al., 2012) and some of whom claim there is no discernible risk (Tien & Huy, 2013). This paper compares and contrasts the two risk perceptions presented in these two articles, identifies the environmental stressors related to GMO risk, and concludes with a discussion of the author's own risk perception of GMOs.

Seralini et al.: High Environmental Risk of GMO

The risk perception of GMOs on the environment is high according to the study by Seralini et al. (2012), which presents results from a two-year study of rats fed Roundup-tolerant genetically modified maize. The study indicated a direct link between the GM corn and death: "In females, all treated groups died 2–3 times more than controls, and more rapidly" (Seralini et al., 2012, p. 4221). Male rats fed GM corn were four times more likely to develop "large palpable tumors than controls, which occurred up to 600 days earlier" (Seralini et al., 2012, p. 4221).

The study also found a link between a diet of genetically modified organisms and chronic kidney failure in both sexes of rats. It concluded that the Roundup-resistant corn severely disrupted the endocrine system, and that the rats also suffered from an "overexpression of the transgene in the GMO and its metabolic consequences" (Seralini et al., 2012, p. 4221). Seralini et al. thus argued that genetically modified foods pose a direct environmental health threat to consumers, asserting that GMO poisoning could be likened to "environmental pollution" (p. 4222).

Seralini et al. clearly identify the environmental stressor in their study as the genetically manipulated maize. However, in a follow-up analysis of the study, Tien and Huy (2013) emphasize an altogether different set of stressors and draw a different conclusion — namely, that GMO carries a low environmental risk.

Tien and Huy: Methodological Critique and Low-Risk Claim

Tien and Huy (2013) argued that one stressor was the "rat strain" used by Seralini et al., which they claimed compromised the findings and rendered them illegitimate. They asserted that the rat strain "has been known to be prone to cancer during their lifetime, especially when they get aged … thus, the use of this rat strain had made the comparison of tumor occurrence in aged rats difficult and unclear" (p. 443). In other words, Tien and Huy contended that the test subjects were defective from the outset and prone to cancer, a condition that would skew the study and make its results self-fulfilling.

Secondly, Tien and Huy stated that the Seralini et al. study suffered from too small a control group — another stressor. They indicated that the study should have had a control "to figure out which factors cause tumor and deaths in the experimental rats" (p. 443), and claimed that the control size used by the researchers was insufficient to establish any legitimate connection between GMO and consumer health outcomes.

Tien and Huy (2013) also argued that the evidence given by Seralini et al. contradicted itself, in that some rats lived longer on higher doses of Roundup-resistant GMO than those who consumed lower doses (p. 444). They also noted that a separate study conducted by Snell et al. in 2012 showed that GMO had no such dangerous effects. After presenting these arguments, Tien and Huy called for the journal editor to issue a retraction of the Seralini study.

Conclusion

The issue of whether GMO poses a high or low level of environmental risk has been examined at length by opposing sides, and ultimately it is the side that views GMO as carrying a high risk level that makes the stronger case. The study conducted by Seralini et al. (2012) presents substantial evidence that has not been sufficiently refuted. The analysis by Tien and Huy (2013) did little to demonstrate why GMO poses no risk to the environment; instead, it made targeted attacks on the methodology of Seralini et al. without offering real evidence of its own. Therefore, the Seralini study remains more compelling in showing why the environmental risk of GMO should be a primary concern for individuals and policymakers alike.

References

Seralini, G., Clair, E., Mesnage, R., et al. (2012). Long-term toxicity of a Roundup herbicide and a Roundup-tolerant genetically modified maize. Food and Chemical Toxicology, 50(11), 4221–4231.

Tien, D., & Huy, H. (2013). Comments on 'Long-term toxicity of a Roundup herbicide and a Roundup-tolerant genetically modified maize.' Food and Chemical Toxicology, 53(3), 443–444.