We have recently analyzed the data for herbicide use in the full year 2017 for San Francisco’s so-called “Natural Resources Department” (NRD – formerly Natural Areas Program). It’s up 57% from the previous year.
NRD is a department of San Francisco Recreation and Parks Department (SFRPD). We were greatly encouraged when NRD started reducing herbicide use in 2014. Before that, pesticide use had increased sharply from 2009 onwards. (You can read an article about that here: SF’s Natural Areas Program – more pesticide in 2013.) Another sharp reduction in 2016 was even more encouraging – though it’s never come down to 2008 or 2009 levels. (The graph above shows annual NRD herbicide usage in fluid ounces of active ingredient.)
But this year, it’s up again, almost to 2015 levels. We have been hoping that SFRPD is working to eliminate all Tier I and Tier II herbicides, with leadership from the Department of the Environment (SF Environment).
For the rest of SFRPD (excluding Harding Golf Course, which is managed under a PGA contract), they have actually reduced usage. They use a greater variety of herbicides than NRD, of which more later. But they are using less – across all their parks and golf courses – than the NRD is. NRD forms a quarter of the area of SFRPD.
WHAT’S WRONG WITH THESE HERBICIDES?
NRD uses four herbicides: Two that SF Environment classifies as Tier I (“Most Hazardous”) and two classified as Tier II (“More Hazardous”). The Tier I herbicides are Roundup/ Aquamaster (glyphosate) and Garlon 4 Ultra (triclopyr); and Stalker/ Polaris/ Habitat (imazapyr) and Milestone VM (Aminopyralid) are Tier II. (In the first picture, with the white dog, the sign posted on Mount Davidson indicates they are using Aquamaster, Garlon, and Milestone in March 2018.)
These hazard rankings can change: Roundup/ Aquamaster (glyphosate) was reclassified from Tier II to Tier I when the World Health Organization found it was a probable human carcinogen. Milestone (Aminopyralid) was reclassified from Tier I to Tier II, despite the fact that it is extremely persistent and mobile in the environment.
THE FEARSOME FOUR
As you research these herbicides, you may find – as we did – that much of the research originates with the companies that produce them. It may be unbiased, but the evidence is that it often is not. So we looked for other sources, which are easier to find for well-established herbicides like glyphosate (Roundup or Aquamaster). It doesn’t mean the others are innocuous.
ROUNDUP or AQUAMASTER (Glyphosate)
- Carcinogenic. In April 2015, the World Health Organization determined glyphosate was a “probably carcinogenic.” EPA scientist Dr Marion Copley sent a letter before her death saying it was essentially certain that glyphosate causes cancer. She also said that as a chelater, it was likely an endocrine disruptor.
- Associated with birth defects. It’s been associated with birth-defects, especially around the head, brain and neural tube — defects like microcephaly (tiny head); microphthalmia (tiny undeveloped eyes); impairment of hindbrain development; cyclopia (also called cyclocephaly – a single eye in the middle of the forehead).
- Bad for the soil. Research indicates it kills beneficial soil fungi while allowing dangerous ones to grow.
It binds to the soil, and acts as a “chelating agent” – trapping elements like magnesium that plants need to grow and thus impoverishing the soil.
- Bad for other living things. It’s very dangerous to frogs and other amphibians, and quite dangerous to fish.
- Garlon is even more hazardous than Roundup. It’s been classified as Tier I for at least as as long as we have been monitoring pesticide use in San Francisco.
- Garlon “causes severe birth defects in rats at relatively low levels of exposure.” Baby rats were born with brains outside their skulls, or no eyelids. Exposed adult females rats also had more failed pregnancies.
- Rat and dog studies showed damage to the kidneys, the liver, and the blood.
- About 1-2% of Garlon falling on human skin is absorbed within a day. For rodents, its absorbed twelve times as fast. It’s unclear what happens to predators such as hawks that eat the affected rodents.
- Dogs may be particularly vulnerable; their kidneys may not be able to handle Garlon as well as rats or humans. Dow Chemical objected when the Environmental Protection agency noted decreased red-dye excretion as an adverse effect, so now it’s just listed as an “effect.”
- It very probably alters soil biology. “Garlon 4 can inhibit growth in the mycorrhizal fungi…” ( soil funguses that help plant nutrition.)
- It’s particularly dangerous to aquatic creatures: fish (particularly salmon); invertebrates; and aquatic plants.
- Garlon can persist for up to two years in dead vegetation .
The NRD uses Garlon extensively against oxalis. If it terminated its war on oxalis, it could stop using Garlon altogether.
POLARIS, HABITAT, STALKER (Imazapyr)
This is a relatively new pesticide, and not much is known about it — except that it’s very persistent. In Sweden, it was found in the soil 8 years after a single application. It not only doesn’t degrade, some plants excrete it through their roots so it travels through the environment.
It can cause irreversible damage to the eyes, and irritate the skin and mucosa. As early as 1996, the Journal of Pesticide Reform noted that a major breakdown product is quinolic acid, which is “irritating to eyes, the respiratory system and skin. It is also a neurotoxin, causing nerve lesions and symptoms similar to Huntington’s disease.”
It’s prohibited in the European Union countries, since 2002; and in Norway since December 2001 because of groundwater concerns.
Milestone is a Dow product that kills broadleaf plants while ignoring most grasses. This is even more problematically persistent than Imazapyr; a computer search yielded warnings of poisoned compost.
It seems that this chemical is so persistent that if it’s sprayed on plants, and animals eat those plants, it still doesn’t break down. They excrete the stuff in their droppings. If those are composted — it still doesn’t break down the chemical. So now the compost’s got weedkiller in it, and it doesn’t nourish the plants fertilized with the compost, it kills them.
The manufacturer sees this as a benefit. “Because of its residual activity, control can last all season long, or into the season after application on certain weed species,” says the Dow AgroSciences FAQ sheet.
Nevertheless, after an outcry and problems, Dow AgroSciences stopped selling Milestone in the UK for a number of years. It’s also prohibited for use in New York.
IT’S TIME TO STOP
There’s growing evidence that herbicides are more dangerous, more mobile, and more persistent than their manufacturers claim. Glyphosate, for instance, is widely found in all water sources, in the soil – and in people. A UCSF study of glyphosate in urine found: “Glyphosate residues were observed in 93% of urine samples in voluntary public testing in the U.S. general population; this is higher than the frequency observed in Europe using GC-MS (43.9%)” and “exposure is likely due to dietary intake or environmental exposure.”
With endocrine disruptors, the old theory “the dose makes the poison” doesn’t work. They are potent at very low levels.
These are parks that we visit with our families, including kids and pets. Kids are particularly vulnerable to pesticides because of their low body weight and rapid growth. These are the watersheds that feed chemicals into our groundwater (which is also now being added to our domestic water supply).
The San Francisco Forest Alliance stands for No Pesticides in our Parks.
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