Glyphosate Still Turning Up in Orange County Creeks Months After Spraying Stopped in Two Channels

Glyphosate Still Turning Up in Orange County Creeks More Than a Year After Spraying Stopped in Two Channels

Independent lab testing has turned up traces of glyphosate and its breakdown byproduct AMPA in Orange County creek water and sediment, more than a year after county officials said they stopped spraying the herbicide in two specific flood control channels.

Samples collected in May from Doheny State Beach and the Santa Ana River outlet showed the chemical residue is still there, according to the California Courier's reporting for the Daily Signal. Doheny soil contained 2.17 nanograms per gram of glyphosate and 2.73 ng/g of AMPA. Santa Ana River soil showed no detectable glyphosate but 2.59 ng/g of AMPA. Water at the river outlet had no detectable glyphosate but 0.04 parts per billion of AMPA.

For comparison, California's drinking-water limit for glyphosate is 700 parts per billion. Every reading found in this testing sits far below that threshold.

Glyphosate is the active ingredient in Roundup. When it breaks down, it becomes AMPA, which lingers in soil and sediment longer than the original chemical. These samples show the parent chemical mostly gone, its longer-lived byproduct still present.

Getting the samples tested wasn't simple. Both major commercial labs, Eurofins and Weck, declined to run the water and soil samples from the Santa Ana River and Doheny Beach, reportedly over concerns tied to their existing contracts with the county. The samples ended up going to the Health Research Institute in Iowa instead.

How this started

The scrutiny traces back to a resident group called Creek Team OC, founded by Brent Linas after he noticed a creek along San Juan Capistrano that would sometimes look alive and sometimes look completely dead. It took him about two years, he told ABC7's Jory Rand, to realize someone was deliberately spraying it.

Linas says the Santa Ana River alone gets hit with 30,000 to 50,000 gallons of Roundup-type herbicide annually, and that's the standard across the county. Biochemist Robert Beard, who goes by "Science Rob" and joined the group, put a bigger number on the scope: roughly 147 waterways sprayed per year, for at least the past decade, according to ABC7.

The group grew to include Bethany Nelms, now the organization's chief operating officer, who said she got involved as a mother whose three kids are in these waterways almost daily.

A partial win, then a stall

Orange County Supervisor Katrina Foley says she'd opposed this kind of spraying for decades and was still shocked by the scale once Creek Team OC laid it out for her, according to ABC7. In February, Foley told constituents that glyphosate had not been applied to the Trabuco or San Juan Creek flood control channels since January 2025, and that it wouldn't be applied there again. Her office said the county only uses State Water Board and EPA-approved herbicides in flood control channels, and framed the decision as balancing environmental concerns against flood risk to lives and property.

But that halt covers two channels. It's not a countywide ban. Foley brought a motion to the Board of Supervisors last month to begin phasing out herbicide use more broadly. Creek Team OC members waited seven hours for public comment. The motion failed.

Supervisor Don Wagner voted against it. His argument, laid out to ABC7: the state and federal government issue permits allowing use of these chemicals, and the volume of Roundup going into the rivers, based on the science the board reviewed, doesn't pose the risk these advocacy groups claim.

That's the crux of the disagreement. Wagner's position rests on existing state and federal permitting and the toxicology data regulators rely on. Creek Team OC and allied researchers argue the danger isn't necessarily acute poisoning at these concentrations, but cumulative, long-term exposure in an ecosystem where kids wade and residents jog daily alongside water that's sprayed repeatedly, year after year.

The Daily Signal's reporting raises a fair point worth weighing on its own. California's regulatory thresholds, including the 700 parts-per-billion drinking water limit, were built largely on toxicology studies submitted by the herbicide's manufacturers. That's standard practice in U.S. chemical regulation, not unique to glyphosate. It doesn't mean the limit is wrong, but it means the number didn't come from a fully independent third party. The Daily Signal report doesn't add contradicting toxicology of its own, so this is a fact about the regulatory process, not a proven flaw in the limit itself.

What's confirmed by both accounts: the two-channel halt Foley announced is real and appears to be holding. What's also confirmed: it left the other roughly 145 waterways Creek Team OC says get sprayed annually untouched, and the board just voted down a broader phaseout.

No additional testing dates or board votes on the issue have been scheduled as of this reporting. Creek Team OC has indicated it plans to keep pushing the county, and independent sampling beyond the May results has not yet been reported.