Picloram
Tordon·Affects liver, reproductive
A broadleaf herbicide sold as Tordon, used on pastures, rangeland, and rights-of-way. Highly persistent and mobile in groundwater.
Tordon
EPA limit
0.5 mg/L (MCL)
Most at risk
Rural well-water households near treated rangeland, pastures, or roadside spray zones
Found in
City water · Well water
AquaOx filters
YesActivated coconut shell carbon
What it does to you
Health effects
Picloram primarily targets the liver. Chronic exposure in animal studies produces increased liver weight, enzyme changes, and histopathological liver damage. The EPA sets the MCL to protect against liver and reproductive effects over a lifetime of exposure.
Picloram is not classified as a likely human carcinogen by the EPA, but technical-grade product has historically contained trace hexachlorobenzene as a manufacturing impurity, which raises additional concern at contaminated sites.
Acute toxicity is relatively low, but the compound's extreme persistence in soil and water means chronic low-dose exposure is the realistic risk for well-water households.
Where it comes from
How it gets into your water
Picloram is one of the most persistent and mobile herbicides in widespread use. It does not bind well to soil and resists breakdown by sunlight and microbes, with half-lives in groundwater measured in months to years.
The compound is used heavily on pastures, rangeland, roadsides, utility rights-of-way, and to control invasive woody plants. Runoff and leaching from treated areas regularly contaminate nearby surface water and shallow groundwater, especially in the West and Mountain West where rangeland use is concentrated.
Pastures and rangeland
Broadcast application for broadleaf weed control
Rights-of-way and roadsides
Utility and highway vegetation management
Shallow groundwater
High mobility and persistence
Surface water
Detected in rivers downstream of treated areas
Find out for yourself
Is it in your water?
Public utilities in agricultural and ranching regions test for picloram and report results in the annual Consumer Confidence Report. Detections at low ppb levels are documented in USGS National Water-Quality Assessment data, particularly in the Plains and Mountain West.
Private well owners on or near treated pasture, rangeland, or right-of-way should test for picloram and related herbicides (2,4-D, dicamba, triclopyr) at least annually. State extension services often offer subsidized testing.
The fix
How AquaOx filters it
Picloram is filtered efficiently by activated carbon. The coconut shell carbon stage in The AquaOx adsorbs picloram and related chlorinated herbicides as water passes through the bed, with independent testing showing reductions well above 90%.
For well-water households in ranching country, we recommend pairing The AquaOx with our FE or RE Edition if iron or hydrogen sulfide is also present, and adding the under-sink RO for additional drinking-water polish.