To get rid of pesky pesticides, San Francisco must be diligent

On Saturday, about 70 volunteers gathered at the Officer’s Club in the Presidio to participate in the 2018 Nature Challenge. Using the iNaturalist app, these citizen scientists took pictures of long garter snakes, delicate purple Douglas irises and fat yellow-faced bumblebees.

Jonah Benningfield was excited to see swifts overhead. Although the 15-year-old regularly bird-watches in the Presidio, spotting the fast-flying birds was a rare site. “It’s really fun finding out bits of information about what’s unique to this area,” he told me. Access to nature has fueled Benningfield’s passion to save shorebirds from extinction.

Last month, San Francisco’s unique natural habitats received additional protections. The Board of Supervisors established biodiversity as a citywide priority. Now, all departments have a standard framework to share best practices, hone goals and ensure The City’s diverse array of flora and fauna continues to inspire San Franciscans.

But a group of activists frequently opposes biodiversity efforts. They are concerned habitat restoration increases pesticide use. The Recreation and Park Department, for example, can use Monsanto’s Roundup to kill species that threaten native plants and habitats. Through monthly records requests, Rupa Bose, a citizen watchdog, determined that Rec and Park used 112 percent more Roundup between 2016 and 2017.

San Francisco hasn’t yet figured out how to care for the nature Benningfield loves without the toxic chemicals Bose tracks. Although it would be cheaper and easier to pull the plug, city officials determine every year that limited pesticide use as a last resort is necessary for our native ecosystem to survive. How can we move closer to a healthier future for the birds and humans that call San Francisco home?

Jonah Benningfield participates in the 2018 Nature Challenge on Saturday. (Robyn Purchia/Special to S.F. Examiner)

“The City takes this issue seriously,” Charles Sheehan of the Department of Environment, which oversees San Francisco’s pesticide use, told me.

Rec and Park has decreased the amount of Roundup and other hazardous products it uses overall by 97 percent and in natural areas by 64 percent since 2010. Now, it primarily relies on nonchemical methods, like lizards to combat pests in the Conservatory of Flowers, goats to munch weeds on Glen Park and Potrero Hill and raptors to control rodent populations. Volunteers have also logged more than 200,000 hours mostly pulling weeds.

But city departments are authorized to use Roundup in limited circumstances to combat invasive species. This raises concerns, especially after the World Health Organization’s cancer agency found in 2015 that Roundup’s active ingredient, glyphosate, is probably carcinogenic.

“I have been getting pesticide usage reports monthly for a number of years now,” Bose told me. “A lot of people are really interested in going to pesticide-free parks.”

Bose’s data suggests The City increased its use of pesticides last year. In 2016, the Rec and Park used 56 fluid ounces of Roundup. In 2017, it used 120 fluid ounces, an increase of 112 percent. While The City still used less Roundup in 2017 than it did from 2010 to 2015, any increase is alarming.

Public data available on the Department of Environment’s website also indicates an increase in the volume of glyphosate between 2016 and 2017, but it’s explainable, according to city officials.

“There’s a natural oscillation year by year,” explained Dr. Chris Geiger, The City’s Municipal Toxics Reduction Senior Coordinator. “When the wet season starts, you get bumps because that’s when weeds grow. It wasn’t a surprise to see a bump last year because it was very wet.”

It’s clear San Francisco is reducing pesticide use and making the process transparent and explainable to the public. Further measures prohibiting hazardous chemicals in playgrounds, on blackberry fruits and within 15 feet of park trails also protect San Franciscans.

But with a reduction of only 64 percent in natural areas, there’s room for improvement.

District 2 supervisor candidate Nick Josefowitz, who brought the increase in pesticide use to my attention, believes The City can enact additional creative programs and push manufacturers to develop better products.

“If we set a target to transition away from the most dangerous pesticides over a reasonable period of time, it will spur innovation in the private and public sectors to meet the goal,” he told me.

More San Franciscans like Benningfield and Bose could also make pesticide-free native habitats more possible. We shouldn’t rely entirely on The City to protect our natural heritage and our health. More volunteers caring for nature, pulling weeds and planting pollinator-friendly flowers and shrubs on their private property can help the ecosystem survive without chemicals.

As Dr. Seuss wrote, “Unless someone like you cares a whole awful lot, nothing is going to get better. It’s not.”


“My wife insists that we group plastic bags, be they from packaging, food, etc., into one larger plastic bag before putting that bag into the bag lining the recycling receptacle in the kitchen. This seems like a ridiculous “bag-ception” to me — isn’t it enough to have all recycling in one big plastic trash bag?” — Dubious in Dolores Heights

Listen to your wife, Dolores. To recycle plastic bags and other clean, dry film or flimsy plastic, Recology asks residents to put the items in a clear, plastic bag about the size of a soccer ball and tie the top. Loose plastic jams the sorting equipment.

But it’s still possible to avoid the ridiculous bag-ception you identified. Ditch the bag lining your receptacle. Putting bottles, cans and plastic inside bags creates extra waste and makes it very difficult for workers to recycle. If containers are clean and dry before you toss them, it should eliminate the need for a liner.

Glad to add a bit of clarity to your dubious debris. Email more sorting questions to

Robyn Purchia is an environmental attorney, environmental blogger and environmental activist who hikes, gardens and tree hugs in her spare time. Check her out at

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