GENETICALLY MODIFIED CROPS & FOODS: HOW BAD CAN THEY REALLY BE?
However, despite the extensive market and consumption of genetically modified foods, there is growing concern for the personal and environmental safeness of growing and eating genetically modified foods. While some species benefit from biotechnology, non-target organisms may accidently suffer; for example, pollen from Bt corn caused high mortality rates in monarch butterfly caterpillars[8] and caddisflies, relatives of the targeted Bt pests, died or had reduced function from eating Bt plant parts.[9] Unintentional gene transfer may also occur between target and non-target species, which may cause unpredictable effects on the non-target organisms and the food web.[10] Growing crops that are resistant to specific pests can also reduce the effectiveness of pesticides and force farmers who are using pesticides to continually invest in new pesticides.[11] These “stronger and better” crops that contain foreign genes are then put on the market and incorporated into our foods, possibly endangering human health by creating allergens and causing unexpected and negative effects as little is still known about the impact of genetically modified foods on our health.[12] Agriculturists may also take advantage of these “stronger and better” crops to maximize their profits, which may result in a few companies dominating the world food production and increase developing countries’ dependence on industrialized nations for food as new advances are skewed to the interests of richer nations that can afford to invest in research and in the industry.[13] There are also ethical concerns about the ethicality of modifying genes; some believe biotechnology violates organisms' intrinsic values and humans should not manipulate nature to fulfill their needs while others object to consuming animal genes in plants and plant genes in animals.[14] As more research is being done to investigate the effects of genetically modified crops on the environment and health and as more people learn of the risks of persistently growing and using genetically modified crops, the joy over its benefits dwindle and people are advocating for stricter regulation or elimination of genetically modified crops.
Genetically modified corn was grown for the first time in the United States in 1997 and since then, genetically modified corn production has extended worldwide.[15] About 80% of the corn produce in the United States is genetically modified to express herbicide tolerance and insect resistance.[16] Bt corn, the poster child of plant biotechnology, contains a gene from a bacteria, Bacillus thuringiensis (Bt), that encodes for a protein that is deadly to many pests, such as European corn borers which destroy corn stems.[17] While this modification has been proven to be effective against its intended pests, there is great concern over Bt corn's potential negative effects on non-target insect species, such as Monarch caterpillars. Milkweed, the exclusive diet of Monarch caterpillars, grows in regions surrounding cornfields and wind can carry the corn pollen onto the surfaces of nearby plants, such as the milkweed; should the larvae feed on milkweed leaves coated in Bt corn pollen, they may suffer a decline in fitness.[18] However, the group of scientists that investigated this detrimental effect in 1997 used conditions that may not be applicable to conditions outside of the laboratory setting; for example, they only gave the larvae the sole option of feeding on milkweed leaves that had pollen grains on them. In order for the pollen to be toxic, monarch larvae must be exposed to pollen levels that are greater than 1000 grains/cm2 and the average pollen level on milkweed leaves is about 170 pollen grains/cm2.[19] While the effects of Bt corn on non-target species may not be as severe as the Cornell study exhibited, there is no doubt that Bt corn, and all genetically modified foods, have the potential to be extremely dangerous. Many people assume the effects of Bt corn are limited to just the organisms that live on the cornfield, however, one study shows it can also affect aquatic ecosystems and streams nearby. Todd V. Royer, an Indiana University professor, conducted a study that investigated whether byproducts of Bt corn, such as pollen, leaf stem, and cob litter, enter streams by surface runoff and wind, and if so, how the byproducts might affect non-target insect species that live in the streams.[20] The research team analyzed 217 streams in Indiana to determine the amount of corn byproducts in the water.[21] They found 86% of the sites contained corn byproducts and during storms, these byproducts travel can travel even farther and flow into larger bodies of water.[22] 13% of the sites contained detectable amounts of insecticidal proteins and they were all located within 500 meters of a corn field.[23] After harvest, discarded plant material is often left behind on the fields, which minimizes soil erosion, but increases the likelihood of corn byproducts entering nearby streams. Royer and his team also did laboratory feeding experiments with caddisflies, typical stream insects that are relatives of moths, which are targeted Bt pests. One group of caddisflies was fed Bt corn leave and another group was fed non-Bt corn leaves; their data revealed that caddisflies fed Bt corn leaves had 50% slower growth rates compared to the control and they concluded feeding on Bt corn litter in streams “may negatively impact fitness because adult size of aquatic insects is directly related to fecundity.”[24] The lower growth rates and increased mortality can “potentially reduce secondary production and consequently the prey biomass available to stream and riparian predators.”[25] Caddisflies are an essential part of fish and amphibians’ diets and if Bt corn byproducts continue to spread and spread more extensively and increase in concentration, a domino effect may occur as the reduced caddisfly population could cause predator populations to decrease, which in turn can hurt human populations.[26] While the effects of Bt corn seen in laboratory settings may not necessarily be the same as those in nature, we can conclude that Bt corn has the potential to have unforeseen effects on habitat, food webs, and ecosystems. |
[8] Whitman.
[9] The Nature Institute, "Byproducts from Bt maize enter streams, and in feeding experiments affected stream insects," 2007. [10] Human Genome Project, "Genetically Modified Foods and Organisms," U.S. Department of Energy Genome Program's Biological and Environmental Research Information System, 2008. [11] Whitman. [12] Ibid. [13] HGP. [14] Ibid. [15] GMO Compass. [16] Ibid. [17] Hardy Hall, "Bt Corn: Is It Worth the Risk?," The Science Creative Quarterly, 2005. [18] Rogene M. Eichler West, "Killer Corn." Sciencentral, 2005. [19] Agricultural Research Service, "Q&A: Bt Corn and Monarch Butterflies," United States Department of Agriculture, 2004. [20] Nature Institute. [21] Ibid. [22] Ibid. [23] Steve Connor, "GM maize 'has polluted rivers across the United States'," The Independent, Sept 2010. [24] Nature Institute. [25] Ibid. [26] Ibid. |