Methoxychlor
Methoxychlor·Affects brain, reproductive, liver
An organochlorine insecticide once marketed as a safer substitute for DDT. Used on crops, livestock, and home gardens until the EPA cancelled all uses in 2003 over endocrine and reproductive concerns.
Methoxychlor
EPA limit
0.04 mg/L (MCL)
Most at risk
Rural well-water households in former application regions, women of reproductive age, children
Found in
City water · Well water
AquaOx filters
YesActivated coconut shell carbon
What it does to you
Health effects
Methoxychlor was promoted as a safer DDT alternative because it does not bioaccumulate as aggressively, but it carries its own significant health risks. The EPA cancelled all registered uses in 2003 after concluding that the endocrine and reproductive risks could not be controlled at registered use rates.
The compound is a documented endocrine disruptor with estrogenic activity. Animal studies show effects on ovarian function, sperm production, and embryonic development at exposures comparable to environmental contamination. Chronic exposure also damages the central nervous system and liver.
The EPA does not currently classify methoxychlor as a carcinogen, but the IARC lists it as possibly carcinogenic based on limited evidence. Of greater concern is the reproductive and developmental toxicity profile, which is the basis for the very conservative drinking water standard.
Where it comes from
How it gets into your water
Methoxychlor was applied to fruits, vegetables, alfalfa, livestock, and residential gardens from the 1940s through 2003. It binds tightly to soil and degrades slowly, though not as slowly as DDT or chlordane, with a half-life measured in months to years.
Legacy contamination from past agricultural use continues to produce occasional low-level detections in groundwater and surface water. Erosion of treated soil into rivers and reservoirs is a continuing input.
No new applications are permitted in the United States, so all current detections are from legacy contamination.
Legacy fruit and vegetable fields
Pre-2003 applications still in soil
Legacy livestock applications
Dipping and spray treatments
Shallow groundwater
Migrates from contaminated soil
Find out for yourself
Is it in your water?
Public utilities test for methoxychlor and report results in their annual Consumer Confidence Report. Detections in city water are now uncommon.
Private well owners in regions with historical agricultural use should consider testing for methoxychlor as part of a broader organochlorine panel. These compounds (methoxychlor, chlordane, heptachlor, lindane, endrin) tend to occur together because they were applied for overlapping purposes.
The fix
How AquaOx filters it
Methoxychlor is filtered efficiently by activated carbon. The coconut shell carbon stage in The AquaOx adsorbs methoxychlor molecules as water passes through, with independent testing showing reductions above 95%.
For well-water households in regions with historical use, 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.