Letter to Boulder city manager Jane Brautigam and members of the Boulder City Council, May 18, 2010 (slightly edited)
Dear Ms. Brautigam and members of the Boulder City Council,
Please don’t approve the herbicides Tenacity and Barricade for use in city parks and playing fields. To do so would put people and pets—and especially children—at risk. And it would be a huge step backward for the city.
I’m the mother of an 11-year-old daughter. I also have an academic background in human biology, plant ecology, and human genetics (which includes the study of environmental factors that contribute to problems in fetal development).
I appreciate the city’s attempts to go with “less-toxic” products, but I believe the subcommittee’s recommendations are based on a number of misperceptions. I also believe the city’s IPM process itself is basically flawed.
Misperception: Safer weed control in turf is all about finding safer herbicides.
Reality: Safer weed control in turf is primarily about horticultural techniques.
There’s a basic flaw in the process the IPM committee went through to make its recommendation. The report “Evaluation of New Products for the City of Boulder’s Approved Pesticide List” is all about pesticide products. The process does not appear to include other alternatives.
The bigger picture, however, includes strategies that are not products. Organic weed-management strategies for lawns include
- Letting grass grow taller so it shades out weed seedlings.
- Encouraging deep grass roots—for example, by adding organic matter to the soil to improve its structure and by watering infrequently and deeply.
- Letting the top layer of soil dry out between waterings so that weed seedlings dry up (while your grass is drinking from lower layers of soil with its deep roots).
- Creating healthy soil with a thriving population of microbes so you get healthy grass that crowds out weeds.
The least-toxic product is not same as the least-toxic solution!
Misperception: Killings weeds is the solution to your weed problem.
Reality: Pulling or killing a weed creates the perfect little habitat for a new weed.
Even when you spray, dandelions and other weeds come back year after year. You haven’t solved the problem at its root cause, so to speak. A more basic solution is to create conditions under which weeds are less likely to grow.
Misperception: The herbicides recommended by the committee are safe.
Reality: The products described in the report are less acutely toxic than other products on the market. But they are still toxic. And acute toxicity is not the only health risk that pesticides present.
I quote from the city’s own report:
“Tenacity may … be neurotoxic to fetuses, babies and children. … Expectant mothers, infants and children should not come into contact with or have any exposure to Tenacity.”
Barricade’s active ingredient, prodiamine, “is a suspected endocrine disruptor,” …
“is a possible carcinogen,” … and presents a “potential risk to aquatic systems.”
When you do a Medline search on “mesotrione” (Medline is where you search for articles in medical journals), you get 32 entries. On quick inspection, the only article related to health risks was on the metabolism of mesotrione in rats and mice.
A Medline search on “prodiamine” turns up only two entries. One is titled “Mode of Carcinogenic Action of Pesticides Inducing Thyroid Follicular Cell Tumors in Rodents.” It states, “prodiamine … seem[s] to enhance the hepatic [liver] metabolism and excretion of thyroid hormone.” Thyroid hormone is extremely important during human development. (The other study was not on health effects.)
Where is the evidence that these products are safe?
Misperception: The active ingredient in Tenacity, mesotrione, is a natural compound.
Reality: Tenacity’s main ingredient is chemically related to a compound from the bottle brush plant, but it’s not the same chemical.
Of course, compounds can be natural and still be toxic (think poison hemlock). But is mesotrione even natural? Here’s from Syngenta’s website
Many scientific discoveries occur due to a mixture of curiosity and observation. CALLISTO is the result of such a find. In 1977, a US scientist noticed that few weeds were growing under a bottle brush plant in his garden. After analyzing a soil sample, it was discovered that the Callistemon plant naturally secretes a herbicidal compound known as leptospermone that suppresses the development of other plants. This has since been chemically improved to make mesotrione. (my italics) (source)
Presumably, “chemically improved” means that mesotrione is more toxic and/or more persistent than the naturally occurring compound, leptospermone. Looks like this is a bit of greenwashing.
Misperception: You just need to wait until the product dries to go back onto the grass. In any case, the products will be all gone in a few days.
Reality: The products remain in the soil for weeks or months.
I looked up the half-lives in the soil of the two products the subcommittee recommended. (The half-life of a chemical is the amount of time it takes for half the product to break down.)
- The half-life in the soil of Tenacity's active ingredient is five to 15 days. (source)
- The half-life of Barricade's active ingredient is two months! (source)
Misperception: Reading the research about each herbicide gives you a good idea of the risks of using it.
Reality: We’re not exposed to these products in isolation.
Herbicides contain more than just their active ingredients. Sometimes the “inert” ingredients are also toxic, or they effectively increase the toxicity of the active ingredient.
Also, in the real world, we’re exposed to many products on a regular basis—for example, pesticides, personal care products, cleaning products, building materials, and furnishings. The additive and synergistic effects of our exposures to multiple chemicals have barely been studied.
Misperception: Organic lawns are ugly.
Reality: With proper training and implementation, you can maintain attractive and functional turf organically.
Training in organic lawn care for landscape professionals is available right now. Chip Osborne, Grassroots Environmental Information, or Boulder County’s own Tim Gilpin could train city staff. (See http://pesticideboulder.org/professionals.aspx for links.)
Public education can be part of an organic lawn program as well, so the public understands the city’s priorities and what techniques the city is using.
Misperception: We need to keep our lawns looking as good as those of nearby cities.
Reality: We don’t need to give into peer pressure to have a lawn with a certain appearance. Organic turf care can produce an attractive lawn.
Just as styles change when it comes to body type (think Marilyn Monroe versus Twiggy), styles change when it comes to lawns. For example, people used to put clover seed in lawn mixes. The clover would fix nitrogen for the grass. That practice ended sometime after WWII. Companies developed herbicides that would kill broadleaf weeds but not grass, and the the companies started marketing those herbicides.
What if I gave this advice to my daughter: “Honey, the style these days is to be skinny. You’d better fit in so other people approve of you. And you’re looking a little chunky right now. Anorexia isn’t such a good idea, but how about you binge and purge to maintain your weight? That’s a little less unhealthy. You could even ‘purge’ by exercising a lot. That might be even a bit less unhealthy.”
Looking like a slender prepubescent girl is not natural or sustainable for most of us. Likewise, the current style of lawn—a monoculture of grass—is not natural or sustainable either.
If we’re going to compete with other cities, how about we compete to have the safest and most environmentally friendly lawns? This as an opportunity for Boulder not to give in to peer pressure, but instead to courageously lead!
Misperception: Organic lawn care costs too much.
Reality: Organic lawn care doesn’t have to be that expensive. Even if it costs more at first, costs decrease over time. You can save on water bills in the long run as well.
Once you’ve improved the soil and encouraged healthy populations of soil microorganisms, they do a lot of the work for you. And when your soil has good tilth and your grass has deep roots, you can save on water bills.
One study, prepared by a nonprofit group (Grassroots Environment Education) for New York State’s legislature, found that, after a couple of years, the annual cost of maintaining a school athletic field using natural products and techniques is as much as 25 percent lower than the cost of conventional programs that use chemical fertilizers and pesticides. The study is here: http://www.beyondpesticides.org/dailynewsblog/?p=3318.
Misperception: It’s just about lawn care.
Reality: It’s about values.
What do we value more? Is it the health of our children and other vulnerable members of the population? Or is it the appearance of our lawns? Seems like a no-brainer to me.
More information and links are at www.pesticideboulder.org. You can also follow Citizens for Pesticide Reform on Facebook at www.facebook.com/CitizensforPesticideReform.
Thank you.
Kathleen Christensen