The result of herbicide resistant GM crops is that more herbicide is sprayed, and that greater residues end up in our soils, food and groundwater.
A new report published today examines the dangers of the pesticide 2,4-D - an ingredient of Vietnam's Agent Orange - and the steady increase of applications for genetically modified (GM) herbicide resistant plants for import into the EU.
This reflects an increased interest in the cultivation of plants with resistance against the 2,4-D and other related herbicides in the world's major cash crop regions such as the US, Brazil and Argentina.
If GM crops engineered for 2,4-D herbicide resistance are permitted for import to the EU, the danger is that resdidues will enter the human food chain via animal feeds.
Glyphosate resistance - only the beginning
Over a decade into the large-scale cultivation of genetically engineered plants resistant to glyphosate, we are seeing a strong increase in the number of crops varieties with glyphosate resistance - and in the annual volume in which the herbicide is sprayed.
There are also strong indications of an increase in residues from spraying in the plants.
And now an examination of applications for genetically engineered plants currently pending in the EU and other parts of the world shows that GMO crop varieties are being engineered to be resistant to more and more herbicides.
Many of the plants are engineered to be resistant to glyphosate, but we are also seeing applications for plants that are being made resistant to eight other herbicides or groups of herbicides.
Toxic herbicide residues are set to increase
These include glufosinate, AOPPs (also known as FOPs), dicamba, ALS inhibitors, imidazolinone, isoxaflutole, mesotrione and 2,4-D. Some of these herbicides are known to be toxic, for instance, glufosinate, quizalofop (group of AOPPs) and isoxaflutole.
Some plants have been engineered to be resistant to several herbicides at once, for example SmartStax corn, which combines glyphosate and glufosinate resistance.
As a result, we can expect to see an increase in the load of residues in the food chain. The usage of dicamba in genetically engineered plants, for instance, requires higher maximum residue levels in the crop.
It will also increase the load of carcinogenic substances like formaldehyde - is one of the metabolites of dicamba.
Dioxins - coming soon in your food?
2,4-D is notorious from its use as an ingredient (together with 2,4,5-T) of Agent Orange in the Vietnam War. At that time, the most visible detrimental effects on human health were caused by dioxin, which is a highly toxic byproduct of manufacture.
Dioxin was listed as a human carcinogen in 1997 by IARC after a long campaign by industry to stop its classification. It is also capable of causing reproductive problems and damaging the immune system.
The result of herbicide resistant GM crops is that more herbicide is sprayed, and that greater residues end up in our soils, food and groundwater.
As our report shows, high levels of dioxin can still be found in some 2,4-D mixtures. Furthermore, independent research is creating concerns about the risks of the active ingredient of 2,4-D for causing adverse effects in embryo development8, birth defects and endocrine disruption.
The EU approval of 2,4-D is currently being revised and the food authority, EFSA, is carrying out a peer review of the summary dossier prepared by German authorities. The DG SANCO standing committee will then decide on an extended approval.
Occupational exposure - the farmers will suffer
There are particular concerns for users (such as farmers), rural communities and ecology in those regions where these plants are grown and sprayed with 2,4-D:
- Currently the use of 2,4-D is restricted to certain applications. In future, much larger areas will be sprayed with this herbicide, especially if 2,4-D herbicide resistant plants are grown. It is known that 2,4-D (as well as dicamba) are highly volatile and will drift by wind to other fields.
- There are many mixtures of 2,4-D that can be applied, but only some of these mixtures were investigated for risks to the environment and human health. There are strong indications that the risks of several formulations have been underestimated.
- Dermal absorption after direct contact with 2,4-D (such as sprayers) is a matter of serious concern, being underestimated so far.
- Despite relevant findings, there is insufficient investigation into the effects of 2,4-D salts and esters on the potential endocrine effect on aquatic insects and the potential negative effects on human male fertility.
- Adverse effects for users (such as farmers) and the environment caused by contamination with dioxin cannot be excluded.
Stronger safeguards are needed
In the light of these findings, we demand that EU regulators:
- Stop extending the use of herbicide resistant plants in agriculture. Existing applications must be thoroughly reassessed for their impact on sustainable agriculture, environment and food production.
- Reject applications for commercial large-scale cultivation of plants resistant to 2,4-D because these plants will strongly increase the use of 2,4 D and therefore increase risks for farmers, rural communities and the environment.
- Suspend permits for 2,4-D, specifically 2,4-DMA products, until there has been a re-assessment of dermal absorption and exposure under realistic worst case scenarios (like backpack sprayer)
- Impose a legal requirement that all pesticides should be dioxin-free (below the limits of detections, LOD). A representative number of products from all production facilities must be checked and information made available about where the samples were taken. All results must be publicly available.
- Evaluate all 2,4-D salts and esters regarding potential endocrine effects on aquatic insects.
- Evaluate of potential negative effects on human male fertility using suitable methods.
- Perform detailed a investigation of risks of 2,4-D for embryo development, birth defects and endocrine disruption in humans.
- Require defined crop rotations for arable cropping systems to reduce weed and pest pressure.
- Bring about a shift from agricultural subsidies for unsustainable conventional agriculture, to more organic agriculture and promotion of non-chemical weed control methods
The alternative is simple. We already know, from our experience of glyphosate resistance, that the result of herbicide resistant GM crops is that more herbicide is sprayed, and that greater residues end up in our soils, food and groundwater. The madness must be stopped.
Christoph Then, Helen Wallace & Hans Muilerman are co-authors of the introduction to today's report: The risks of the herbicide 2,4-D.
The report itself is written by Lars Neumeister, an independent pesticide expert. It is a joint publication of Testbiotech, GeneWatch UK and Pesticides Action Network (PAN) Europe, in association with TestBiotech.
