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Question

Are there similar risks from consuming pesticidesherbicides to GMOs?

Submitted by: LINDSEY MORRILL


Answer

Expert response from Steve Savage

Consultant, Savage & Associates

Wednesday, 02/08/2017 18:50

The quick answer is that the food supply available today in the developed world involves no significant risk in terms of either pesticides or “GMOs.” That very positive profile is based on long-term and rigorous oversight by regulators, a history of investment in the development of new crop protection options, and careful compliance on the part of the growers as they use these technologies on their farms.

 

As consumers our risk associated with consuming pesticides is extremely low because as a society we employ the same two strategies we use to minimize our risk from electricity. There are forms of electricity that are definitely hazardous (e.g. the 110V AC power that powers many of our appliances and lights, high voltage transmission lines…), but we lower our risk using exposure-prevention strategies like insulated wires, GFI outlets, “child-proof” plugs, tall towers, or fences around transformers. We also enjoy other benefits of electricity with little risk because we power many of our favorite devices with low hazard forms of power (e.g. the low voltage DC current that runs your cell phone or blue tooth device).

 

Those same two strategies minimize our risk when it comes to consuming crops that have been protected with pesticides. For the pesticides that are hazardous to humans, we have rules in place to prevent people from being exposed to amounts that could cause harm. Increasingly we use pesticides that are selectively toxic to the target pests like weeds, insects or fungi and essentially non-toxic to us.  That is a low hazard approach analogous to the electricity for our cell phones.

 

Before the EPA approves the use of a pesticide it reviews required data about what happens to that material after it is applied to the crop. They look at how rapidly the chemical degrades, what the break-down products are, and what happens to those. Then, based on everything known about the toxicity of the chemical and its break down products, the EPA sets maximum use rates and a “Pre-Harvest Interval” or “PHI” designed to insure that by the time the crop is harvested, any residue will be below what is called a “tolerance” – a very conservative level below which there is no real risk to the consumer.  These tolerances that have been set for each pesticide for use on each approved crop.

 

Each year, the USDA scientists collect around 10,000 samples of food items from commercial channels, bring them back to their labs, and analyze them for pesticide residues. The chemists who run these tests are capable of detecting extremely small amounts of the pesticides. This effort is called the Pesticide Data Program or PDP.  What the USDA’s PDP shows year after year is that virtually all of the pesticide residues that can be detected on our food are below to far below those conservative “tolerance” levels.  Residues are found on both the samples from Organic farms and from conventional farms, but in both cases the levels are indicative that the system is working and that we consumers can safely enjoy our food supply.

 

When it comes to “GMO” crops that are connected in some way with pesticides, the same system is applied. If the crop is “herbicide tolerant” then studies are required to document what happens to the herbicide after it is applied to the crop. Once again an appropriate rate limit and PHI or Pre-harvest Interval are designed so that any residue remaining by harvest is below tolerance. Since most herbicides are applied early in the growing season the time to harvest is quite long anyway. When the USDA has looked at samples of herbicide tolerant crops as part of the PDP, it has found that residues, if present, are at non-hazardous levels.

 

Many “GMO” crops are resistant to insects because the plant has been engineered to produce a protein from a bacterium called “Bt” which is a very specific pesticide for control of the target insect. This same kind of bacterium has been used for decades as a spray-able pesticide. Farmers including organic farmers are allowed to spray Bt right up to the day of harvest if needed because that insecticidal protein represents no hazard to humans. That same no-hazard property extends to the GMO crops that have been modified to make the effective bacterial protein. 

 

Now as for risks to do with “GMO” crops that are not related to pesticides, there are approval processes and reviews that address any other potential issues. There is nothing to worry about in terms of consuming the DNA for the genes that might have been added or changed. Indeed we consume vastly more “foreign DNA” from the diverse microbiome of bacteria and fungi that normally live on and in plants.

 

If the GMO crop has been engineered to make any specific proteins (e.g. a modified version of one of its enzymes or the Bt protein) the review process considers whether that protein could possibly be an allergen or have any other undesired effect. Having considered such information, over 280 expert scientific panels around the world have confirmed that there are no special risks associated with any of the GMO crops that have been commercialized.

 

Both pesticides and crop biotechnology are important, complimentary tools that help farmers produce our food and fiber crops. In the developed world we can be confident that these tools are being used in ways that are safe for us as consumers. In parts of the developing world (where growers unfortunately still use pesticides long-banned in a country like the U.S.), something like a Bt version of a crop can significantly reduce the risk to consumers and farmers because the farmer does not need to apply those problematic old pesticides.