Weeding Through the Thorny Debate on Glyphosate

January 23, 2020, Feature, by Richard J. Dolesh

2020 February Feature Weeding Through the Thorny Glyphosate Debate 410

How will your park agency kill weeds when glyphosate is banned?

A year or so ago, few people in the field of parks and recreation had ever heard the word “glyphosate,” much less knew that it is the active ingredient in the most widely used, non-selective herbicide in the world. Litigation, media attention and growing concerns for human safety have changed all that.

The Environmental Protection Agency (EPA) estimates that 280 million pounds per year of glyphosate are applied in the United States on agricultural fields, roadsides, businesses, industrial sites, homes and public parks. Farmers apply the vast majority of glyhposate-based herbicides (GBHs), but tens of millions of pounds of glyphosate are applied on public and private lands for purposes other than agriculture. “It’s been the go-to herbicide for park agencies for a long time,” says Patti Bakker, interim manager for the Seattle Parks and Recreation Department Natural Resource Unit.

Until a very short time ago, most park agencies considered Roundup an effective, benign and even safe herbicide. That belief is changing rapidly in light of new evidence that GBHs may be unsafe for humans and may cause cancer.

The link to human health and cancer may not be conclusive, but California juries ruled in 2019 that Roundup did contribute to developing non-Hodgkin’s lymphoma and awarded one couple $2 billion in damages. At this writing, there are more than 18,000 lawsuits filed against chemical giant Bayer, which bought Monsanto, the original developer of this herbicide.

These verdicts and publicity about glyphosate have awakened public concern about the safety of this widely used herbicide. More than 50 U.S. cities and individual park systems now have banned or restricted the use of herbicides containing glyphosate. It is likely that many other cities and counties will enact new bans in the coming year.

Bans Will Directly Affect Park and Recreation Agencies
Your city or park and recreation agency may not have yet banned glyphosate, but local actions to restrict or fully ban its use on public properties may be likely soon. Whether your agency, city or county enacts a ban on glyphosate or not, the health and safety of your workers and the public are of paramount importance with any continued use of GBHs. The threats to human health and to the environment are real, despite the EPA’s May 2019 declaration that the pesticide is safe for use if applied as instructed. The choices to use it or ban it are not simple and will have consequences no matter what actions local governments take.

What Is Glyphosate and What Does It Do?
Glyphosate is a non-selective systemic herbicide that kills plants down to the roots by blocking key enzymes that are essential to plant growth, causing plants to wither and die over a period of several days to a week. It is very effective on virtually all types of weeds and is relatively inexpensive.

Glyphosate, under the trade name Roundup, came on the market in 1974. It is now found in more than 750 products worldwide and approved for use on more than 100 crops in treatment of terrestrial and aquatic weeds. Its primary use is in conjunction with genetically modified (GMO) corn and soybean crops. This GMO seed stock withstands the pesticide and allows the crop to grow while weeds are killed. Today, as much as 92 percent of all U.S. corn and 94 percent of all soybean seeds are genetically modified to be “Roundup Ready.”

According to EPA, an average of 280 million pounds of glyphosate products are applied annually in the United States. While most GBHs are used for agriculture, they are also the primary herbicides for forestry, highways, rights-of-way, commercial and industrial areas, public parks, and other public and private lands. However, there are growing concerns about toxicity, persistence in the environment and the effects on wildlife and human health.

Health Impacts Disputed
While glyphosate systemically kills weeds relatively quickly, it also binds tightly to soils and can persist for months in the ground. Trace amounts of glyphosate are found in a variety of food products, wine, beer and even in breast milk. According to a U.S. Geological Survey study, glyphosate was found in 66 of 70 rivers and streams studied, as well as in 70 percent of rainfall samples.

In 2015, the International Association for Cancer Research of the World Health Organization issued a finding that glyphosate is “probably carcinogenic to humans.” Despite the finding, there was no change of policy or regulation in the United States, and the use of glyphosate continues to grow annually.

Diane Lewis, physician and founder of the Great Healthy Yard Project, says there is mounting evidence documented in medical literature that “glyphosate exposure is associated with increased risk of non-Hodgkin’s lymphoma and multiple myeloma.” She adds that there also is evidence that glyphosate-related herbicides “disrupt endocrine reproductive hormones [that] can lead to numerous health issues, including the abnormal growth of breast cancer cells that the body might have otherwise controlled without the exposure.” Small amounts of the chemicals in these herbicides can act cumulatively and can have more serious side effects, such as by acting as disruptors to hormonal systems, she says.

There is considerable dispute over research findings produced by the industry regarding the safety of GBHs. The actual ingredients and percentages of additional chemicals that boost the effectiveness of glyphosate are trade secrets. These adjuvants and surfactants that turbocharge the killing power of glyphosate may also increase the toxicity of these herbicides on humans, according to the National Institute of Environmental Health Sciences. One study cited showed that Roundup was at least twice as toxic as glyphosate alone. Most testing until now has been on glyphosate alone, not on the full herbicide formulation of products like Roundup.

EPA Reaffirms Assessment That Glyphosate Is Not a Cancer Risk
According to a May 2019 EPA press release, “EPA continues to find that there are no risks to public health when glyphosate is used in accordance with its current label and that glyphosate is not a carcinogen.”

However, other countries do not consider GBHs to be as benign as the United States does. Many already have enacted bans or have issued statements of intent to ban or restrict its use. In 2017, the European Union (EU) controversially voted to re-license glyphosate for a period of five years. Many expect that the EU will approve a partial or full ban when the license expires in 2022.

Why Should Park Agencies Be Concerned?
The vast majority of public park and recreation agencies have used GBHs as the preferred weed killer for landscaped areas, golf courses, roadsides, overgrown areas and, most recently, the establishment of pollinator meadows. If GBHs are prohibited, park agencies have few alternative choices except to use herbicides like 2,4-D, “the most dangerous pesticide you’ve never heard of,” according to Natural Resources Defense Council. While it may be just as or more toxic than glyphosate, 2,4-D could be the next likely choice for many park agencies that no longer can use glyphosate as an herbicide to control aggressive weeds and invasive plant species.

Safety Considerations for Park Workers
One of the most important considerations regarding the use of GBHs is the safety of the public and park workers who apply it. In practice, park and recreation employees who intend to apply pesticides must become certified pesticide applicators under the classification of “public agency applicators.” To become certified, employees must first be registered with state departments of agriculture, complete a training program, and then work under already certified applicators for a year. Maintaining certified status requires annual testing and annual recertification.

The burden for day-to-day employee safety mainly falls on the agency to practice safe storing and handling of herbicides and to provide safety training under individual certified applicators within agencies to train and monitor those working under their certification. This is a critical agency responsibility since the least trained and experienced applicators at park and rec agencies may often be those most at risk of exposure to harmful pesticides. One supervisor interviewed says that it can be difficult to ensure that all employees applying GBHs use all appropriate personal protection equipment when they are out on a 90-degree day, hiking through invasive vegetation using a backpack sprayer. “Education is the best way to minimize risks,” Lewis says. “If you are employing the person who uses the chemical, you have a responsibility for giving employees the education and equipment on how to use it safely.” Some lawsuits have been brought against institutions [that] gave employees the duty to apply GBHs and then left them untrained and, therefore, unprotected, she says.

Can Organic Herbicides and Other Measures Replace Glyphosate?
Agencies looking for alternatives to GBHs are trying a variety of alternatives, including organic herbicides. Grace Dietsch, a biologist at Five Rivers MetroParks in Dayton, Ohio, says that their horticulture team uses orange oil, a weed torch and horticultural-grade vinegar to kill weeds in landscape beds and indoor plant displays. Bakker says Seattle Parks and Recreation have tried horticultural-grade vinegar herbicides, but they are harsh on equipment and unpleasant for applicators due to the fumes.

Park and rec maintenance supervisors point out that weed control without glyphosate will be much more expensive, less effective and require greater commitments of staff time. Many also fear an inability to contain invasive weed species that are destroying native landscapes and crowding out native wildflowers essential to pollinators and ecosystem health. Most agree, however, that nothing beats using volunteers to pull up weeds manually in spot locations, but it depends on the number and willingness of your volunteers.

Weed control scientists are exploring promising new technology, which includes the use of drones to precisely locate and map noxious weeds in fields, autonomous vehicles that can provide microdoses of herbicides in spot applications, electrocuting weeds with a zap of electricity and laser-pulse treatments on roadside weeds. None of these technologies, however, are ready to bring to scale yet.

Every agency takes pride in the appearance of its parks, and there are often high expectations by the public on what a “beautiful park” should look like. In a future without GBHs, there is no question that parks will look different, and our perceptions of what constitutes beauty will need to evolve. Managing expectations will be a challenge, but creating healthier, safer parks is a goal that the public and every park and recreation employee can support wholeheartedly.

Seven Steps Your Agency Should Take Now

  1. Commit to a system-wide re-evaluation of your entire weed control and landscape maintenance program.
  2. Develop an agency-wide or intergovernmental procedure to evaluate your current applications of glyphosate-based herbicides (GBHs) and alternative methods to control weeds in your park landscapes. 
  3. Review your internal safety training program, giving special attention to your protections for workers who apply GBHs. Perform spot inspections to improve your training program.
  4. Look at alternatives to glyphosate and test safer, less toxic methods. These can include flame, hot foam, organic herbicides, manual and mechanical control, and, seriously, goats. 
  5. Evaluate the circumstances and occasions that you need to use glyphosate as a last resort and justify such uses.
  6. Consult with peer agencies, such as public works and transportation departments, to evaluate alternative methods. 
  7. Look to the future. The time may come, sooner than you think, when your governing body, mayor or city council institutes a ban on the use of glyphosate. Are you prepared?

Richard J. Dolesh