Alachlor
Alachlor·Affects liver, kidneys, reproductive
A widely-used corn and soybean herbicide that runs off agricultural fields into groundwater. EPA-regulated, classified as a probable human carcinogen.
Alachlor
EPA limit
0.002 mg/L (MCL)
Most at risk
Rural well-water households, Midwest corn-belt residents
Found in
City water · Well water
AquaOx filters
YesActivated coconut shell carbon
What it does to you
Health effects
Alachlor is classified by the EPA as a Group B2 probable human carcinogen. Animal studies show tumors in the liver, kidney, lung, and stomach at chronic exposure. The European Union banned it for agricultural use in 2006 specifically because of the contamination risk to drinking water.
Chronic exposure at elevated levels is linked to liver damage, kidney damage, and effects on the reproductive system. Studies of agricultural workers handling alachlor have shown an elevated incidence of certain cancers compared to non-exposed populations.
For most homeowners, the concern is not acute toxicity but the cumulative effect of long-term low-level exposure through drinking water.
Where it comes from
How it gets into your water
Alachlor is sprayed on millions of acres of US corn and soybean fields each spring. It does not bind tightly to soil and is moderately water-soluble, so a substantial fraction washes off during rainfall and snowmelt and ends up in nearby streams, rivers, and shallow groundwater.
The compound is most commonly detected in private wells across the Midwest corn belt (Iowa, Illinois, Indiana, Nebraska, Minnesota) and in city water systems that draw from agricultural-region rivers. Concentrations typically peak in late spring and early summer following application.
Corn and soybean fields
Pre-emergent herbicide application
Agricultural runoff
Storm water carries it into waterways
Shallow groundwater
Common in Midwest farming regions
Find out for yourself
Is it in your water?
Public water utilities in agricultural regions test for alachlor and report results in their annual Consumer Confidence Report. The EPA limit is set very low (2 ppb) precisely because of the carcinogenic concern.
Private well owners in farming regions should test for alachlor and related herbicides (atrazine, metolachlor, acetochlor) at least annually, ideally in late spring after the application season. State environmental quality offices and county extension services often offer subsidized testing.
The fix
How AquaOx filters it
Alachlor, like nearly all herbicides and pesticides, is filtered efficiently by activated carbon. The coconut shell carbon stage in The AquaOx adsorbs alachlor molecules as water passes through the bed, with independent testing showing reductions well above 90%.
For well-water households in agricultural regions, we recommend pairing The AquaOx with our FE Edition or RE Edition if iron or hydrogen sulfide is also present, and adding the under-sink RO for additional drinking-water polish.