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Petaluma looking at alternatives to Roundup weed killer


Both the city of Petaluma and the area’s largest school district have largely suspended the use of a common yet increasingly controversial herbicide while evaluating the effectiveness of various alternatives, following an outpouring of public concern.

City parks staff and their counterparts at Petaluma City Schools said they have spent several months experimenting with products marketed as a more natural option than glyphosate-based weed killers like Roundup, which both said was in use only on a limited basis across their grounds. Applying the herbicide has been a standard practice for decades, but has come under fire in recent years by some groups who argue it comes at a cost to public health and the environment.

The ongoing trial has already offered up some complex considerations in Petaluma, ranging from the significantly higher cost of the alternative herbicides to the increased frequency of their use.

“We’re not under a moratorium, but we’re doing this internally so we can have some data to bring to people to consider,” said Ron DeNicola, parks and landscape manager for the city of Petaluma.

Swapping notes with some other cities that have sought alternatives to glyphosate-based weed killers, Petaluma parks staff switched to using so-called herbicidal soaps in March.

While glyphosate kills the root of the weed, the new products, under the brands Finalsan and Suppress, use naturally occurring fatty acids that damage the exposed part of the plant.

Petaluma City Schools is also experimenting with Suppress, as well as another brand called Avenger, said Joe DeCarlo, the district’s director of maintenance. The district has long avoided using glyphosate at elementary schools.

“We’re not entirely happy, we’re not entirely unhappy” with the products, said DeCarlo, who began the informal trial after hearing from a handful of community members concerned over herbicide use “about five or six months ago.”

Petaluma’s Recreation, Parks and Music Commission fielded similar testimony during a meeting in January, when a group of area residents expressed their concern over the city’s use of glyphosate-based herbicides. The city stopped using those herbicides while starting their trial in March, though DeNicola noted that a contractor who maintains landscaping in Petaluma’s medians still uses a glyphosate-based weed killer.

“At that point, I thought, why don’t we just be proactive and try some alternative products and see how well they work?” he said.

Among the clearest differences is the price — a 140-gallon mix of Roundup and water costs $62, while a similar mix of Finalsan, which requires more of the product in the mixture, costs $1,136, DeNicola said. A mixture of Suppress requires around half of the volume of product but, since it is pricer, costs $1,001.

Having used the alternative herbicides over the past two months, DeNicola said crews have needed to apply the treatments more often to achieve similar results. The plants are also likely to regrow, since the root remains alive underground.

The treatments are also said to be extremely pungent during application, with several workers complaining of eye irritation and one experiencing respiratory problems, DeNicola said. Those attributes have required the use of new protective equipment, something that was not required with Roundup.

“It’s frustrating being out there using something labeled as organic, but you have to be out there in a bodysuit and a respirator,” he said.

It’s not the first time Petaluma has experimented with alternatives to glyphosate — several years ago, the city also used citrus oil, clove oil and industrial-strength vinegar on an experimental basis. Yet weed and pest control chemicals are under tight federal regulations, and only approved herbicides, including those currently under trial in Petaluma, are allowed as part of an ongoing maintenance program, DeNicola said.

Members of Petaluma’s Parks Commission recently toured several sites where staff have been using the treatments, seeing first-hand how the trial is playing out in the real world.

Councilwoman Kathy Miller, who currently serves as a liaison to the commission, noted that the method seemed to show mixed results. Areas where mulch was applied after herbicide use seemed devoid of weeds, while the treatment appeared less effective in areas where weeds emerged from cracks in concrete.

“I know people don’t want to use Roundup – I don’t really want to use Roundup, either,” said Miller, who described her usage of vinegar to control weeds along the walkway in front of her home. “I’d love to hear if there’s an alternative that doesn’t break the bank, and that actually kills the plant.”

Miller said she saw it as likely that the topic would eventually wind its way to the City Council agenda.

Among those who brought their concerns to the Parks Commission in January, Tiffany Renée, a former councilwoman and current head of the Petaluma Grange, was critical of the city’s informal approach.

She called on elected officials to define their parameters for herbicide use as a matter of public policy, rather than a process that begins at the staff level.

“They’re letting staff test these products and determine what they like best, rather than saying, ‘These are the chemicals we don’t want to be using in our community,’” she said.

DeNicola, the city’s parks manager, said Petaluma traditionally has used herbicide sparingly, amounting to about 50 gallons of glyphosate product every year.

The city also leans on other methods like mulching and manual removal, and generally avoids spraying in sensitive spots like playgrounds and picnic areas.

While testing is ongoing, DeNicola pointed to an approach by the city of Davis as one that might make sense for Petaluma.

That city has developed an extremely fine-detail map showing levels of human activity in various areas, along with a list of landscaping products and techniques approved for those locations.

The map also includes an activity log that is easily available for public review.

Other cities have taken a more dramatic approach, including the city of Richmond, where a closely watched, year-long review of herbicide use recently resulted in an outright ban and a move to completely manual methods, he said.

Yet such an approach would be difficult to sustain in Petaluma, where reductions in staffing levels after the recent recession have put pressure on many city departments.

Still, Parks Commission Chairwoman Beverly Schor said an all-manual method would have some perks and would be better for the environment.

“I think if we went to a more intensive manual process, everybody would get what they wanted. The parks could look good, and there wouldn’t be any exposure, nor would there be any impact on the water table,” she said.

Trials at both Petaluma city parks and the grounds of Petaluma City Schools are expected to continue for several months, but no defined timeline has been set.

DeNicola stressed that regardless of the outcome, safety was a major priority.

“One of my biggest tasks as a park manager is to provide safe and beautiful places for people to recreate,” he said.

(Contact Eric Gneckow at eric.gneckow@arguscourier.com. On Twitter @Eric_Reports.)