Does the herbicide Roundup hurt fish in the Delta while killing off invasive plants?
A year ago, the active ingredient in Roundup, the nation’s most widely used weed-killing herbicide, was added to California’s official list of chemicals known to cause cancer.
The state’s warning about glyphosate followed a similar caution issued by the World Health Organization and coincided with hundreds of lawsuits across the country focused on the herbicide. The first jury trial to involve Roundup recently started in San Francisco — the plaintiff is a groundskeeper who believes he developed non-Hodgkin’s lymphoma by using the weedkiller on the job.
None of those alarm bells, however, have stopped the state Division of Boating and Waterways from spraying Roundup directly into the Sacramento-San Joaquin Delta, the nexus of California’s water system.
Since 2010, Boating and Waterways has put more than 14,000 gallons of Roundup into the Delta, according to a McClatchy review of data provided by the agency.
The Roundup treatments are part of a concerted effort to kill nonnative aquatic plants, which have become so pervasive in the Delta that NASA scientists can see them from space. State officials say the vegetation snarls boat propellers, blocks access to marinas and clogs drinking-water pipes. Officials also blame the weeds for damaging fish habitats and contributing to the precipitous declines of the Delta’s troubled fish populations.
“It’s a real conundrum,” said Jay Lund, director of the Center for Watershed Sciences at UC Davis. “It might be one of these cases where you have to poison the Delta to save it.”
Officials say the weed-killing program has been approved by a host of state and federal agencies, and that strict limits have been set on the use of Roundup and other herbicides in the West Coast’s largest estuary, which provides drinking water to 25 million Californians. A team of state scientists also monitors the treatment locations and water quality to ensure contamination levels don’t get too high or too close to drinking water intakes and Delta farmland.
“Everybody wants to make sure we’re taking care of the Delta and its natural resources and the drinking water as well,” said Gloria Sandoval, spokeswoman for the Division of Boating and Waterways.
But Roundup’s critics say it’s hypocritical for one state agency to say the herbicide is a likely cancer hazard while another sprays it into a place where drinking water is pulled.
“There is irony in one arm of the state acknowledging that the chemical is cancer causing while the other continues to use thousands of gallons of it in the hub of the state’s drinking water,” said Paul Towers, the Sacramento based organizing director and policy advocate for Pesticide Action Network North America. “At the very least, we need a deep assessment of whether or not the use of Roundup is the appropriate method for controlling or managing these invasive plants.”
The potential health effects of Roundup have been a subject of heated debate among scientists, regulators and others for more than 30 years.
Monsanto, the giant agrochemical and biotech company that makes Roundup, long has insisted its product is safe. It says claims to the contrary aren’t backed by scientific evidence.
The company, which was recently bought by German pharmaceutical company Bayer, took California to court to defend the Roundup brand after the state Office of Environmental Health Hazard Assessment listed glyphosate as a cancer-causing chemical under Proposition 65, the 1986 ballot initiative that requires warning labels for about 1,000 chemicals known to cause birth defects or cancer.
Responding to a lawsuit filed by Monsanto and a group of farming associations, a federal judge in Sacramento in February issued a preliminary injunction that blocked Monsanto from having to put cancer warning labels on Roundup. The judge said the warnings would mislead consumers because “almost all other regulators have concluded that there is insufficient evidence” that Roundup’s active ingredient, glyphosate, is carcinogenic.
Nevertheless, the chemical remains on the state’s Proposition 65 list (which does not ban or restrict its use). The state put it there because the International Agency for Research on Cancer, a branch of the United Nations World Health Organization, listed glyphosate as “probably carcinogenic” in 2015. The U.S. government and at least 18 states, including California, rely on the IARC’s expertise in carcinogen identification, the state said.
According the state, the IARC “found that glyphosate is an animal carcinogen and probable human carcinogen” based primarily on studies in which “rodents exposed to glyphosate developed tumors at higher rates than rodents not exposed glyphosate.”
However, several other government agencies, including the U.S. Environmental Protection Agency, have concluded there is no evidence that glyphosate causes cancer.
Following the international agency’s listing, hundreds of lawsuits alleging glyphosate causes cancer were filed in state and federal courts across the country.
San Francisco U.S. District Judge Vince Chhabria is presiding over more than 300 of those cases. Earlier this month, he called some plaintiff expert-witnesses’ testimony about the alleged cancer link “rather weak” and “shaky,” but he nonetheless let the cases move forward.
In the separate landmark jury trial that is underway, Benicia school groundskeeper DeWayne Johnson, 46, alleges his non-Hodgkin’s lymphoma — a blood cell cancer — was caused by being exposed to Roundup and other Monsanto chemicals over a two year period.
“I would have never sprayed that product on school grounds ... if I knew it would cause harm,” he testified in court July 23.
‘Dissipates pretty quickly’
If Roundup is so controversial, why use it in the Delta at all?
Because it’s effective, and the relatively small amounts sprayed there pose little risk to the water supply, said John Madsen, a U.S. Department of Agriculture biologist based at the Weed Research and Information Center at UC Davis.
Billions of gallons of water flow through the estuary each year as the Sacramento and San Joaquin rivers converge before washing out to the ocean. A portion of those flows are used by local farms and cities, and some is pumped to the southern half of the state to drink and irrigate fields.
“Water is constantly moving in the Delta so whatever herbicide they use dissipates pretty quickly,” said Madsen, whose agency works with the state on its herbicide program.
In addition, the custom blend of Roundup the state uses for aquatic weeds “is absorbed by the plants,” Madsen said. ““Glyphosate has no activity in the water itself. It’s only active when it’s on the foliage of the plants.”
Madsen and other scientists say the herbicide treatments will never completely remove the weeds, but they’re critical for keeping water flowing through the Delta’s 60,000-acre spiderweb of sloughs and river channels stretching from south of Sacramento and west of Stockton to the San Francisco Bay.
At any given time, as many as a third of those waterways are choked with invasive plants, such as the flowering water primrose and hyacinth, brought to California for use in aquariums and decorative ponds.
“That’s approximately doubled over the past 10 years,” said Ted Sommer, the lead scientist with the state Department of Water Resources. “We’ve seen this huge ramp-up that occurred during the drought. ... There are entire channels that are completely choked and closed because of the weeds.“
Between 2013 and 2016, marinas and various government agencies spent about $46 million on Delta weed control, according to a UC Davis study.
The state sometimes removes a few acres of the weeds with mechanical harvesters, but officials say that method is impractical on a large scale.
Chopping up the plants can harm native species while spreading seeds and other debris that can re-establish the plant elsewhere. In addition, few land owners are willing to have thousands of tons of soggy, decomposing weeds dumped on their properties.
State officials say that gives them few options other than using Roundup and other types of herbicides to control the eight primary invasive weed species that have invaded the Delta.
Clear channels for boats and water deliveries aren’t the only reasons for the herbicide treatments.
Gov. Jerry Brown’s Natural Resources Agency in 2016 called for more weed control to improve the plight of the nearly extinct Delta smelt. State biologists also say reducing the weeds helps the Delta’s struggling salmon species. The native fish need cold, free-flowing, murky water in the Delta to thrive.
Biologists say fish are harmed by the nonnative weeds because they clog up Delta’s natural flows and make the water clearer and warmer. The warm, languid currents and the dense stands of plants also are ideal habitat for bass and other nonnative fish that prey on native fish.
“Instead of providing good rearing habitat (for young fish), we’ve just got predator habitat,” said Sommer, the Department of Water Resources scientist.
Madsen, the U.S. Department of Agriculture biologist, said the treatments appear to be helping fish habitats. For instance, in the shallow 3,300-acre open waterway known as Franks Tract, the herbicides have removed infestations of underwater Brazilian waterweed that used to plague the area. Madsen said native vegetation has grown back.
Roundup only is used on plants such as hyacinth that float on the surface. To kill underwater plants like the waterweed, the state uses sinking pellets containing the herbicide fluridone. Last year, the state applied 198,100 pounds of it, said Sandoval, the Boating and Waterways spokeswoman.
To ensure the public is aware of where the treatments are taking place, the Division of Boating and Waterways publicizes on its website where its fleet of 29 herbicide boats plans to spray.
Some Delta anglers, however, aren’t convinced the spraying is as benign as officials claim.
Mike Birch has been fishing on the Delta several times a week for the past decade. He’s used to occasionally seeing state-owned boats cruising the estuary’s sloughs and channels, spraying herbicides. This year, Birch and his fellow anglers have watched with growing alarm as state boats visited their favorite bass fishing spots, sometimes multiple times a week.
“I said, ‘What in the heck is going on this year?’” Birch said. “You’re not supposed to nuke everything.”
Birch and others began sounding the alarm on Facebook fishing pages, and Delta anglers soon began blaming the herbicides for dead fish and other deceased wildlife spotted in the estuary.
Sandoval said her agency has forwarded the reports of dead animals to the state’s wildlife agency, but there’s no evidence the spraying is harming wildlife.
“There has been a very extensive amount of toxicity studies on these chemicals,” said Madsen, the USDA scientist. “The rates that they’re using are not going to cause any fish kills. There are lots of things that can cause fish kills besides the pesticides.”