Heptachlor
Heptachlor·Affects liver, reproductive
A persistent organochlorine insecticide used heavily on corn, citrus, and around homes for termite control until banned in 1988. Breaks down into the more persistent heptachlor epoxide.
Heptachlor
EPA limit
0.0004 mg/L (MCL)
Most at risk
Residents of pre-1988 termite-treated homes, rural well-water households in former corn-belt application areas
Found in
City water · Well water
AquaOx filters
YesActivated coconut shell carbon
What it does to you
Health effects
Heptachlor is classified by the EPA as a probable human carcinogen. Long-term animal studies show liver tumors at moderate exposures, and epidemiological studies of exposed workers have associated chronic exposure with elevated rates of lymphoma and other cancers.
The compound bioaccumulates in fatty tissue and is excreted in breast milk. Chronic exposure damages the liver, disrupts reproductive hormones, and is linked to developmental effects in animals exposed in utero. Heptachlor crosses the placenta, so the fetus is exposed when the mother carries body burden from past exposure.
In the body, heptachlor is metabolized to heptachlor epoxide, which is more persistent and the focus of long-term health concerns. The EPA regulates both compounds separately because the epoxide builds up over time even after exposure to the parent compound stops.
Where it comes from
How it gets into your water
Heptachlor was used on corn, citrus, and a range of other crops from the 1950s, then almost exclusively as a termite treatment around home foundations from 1978 until the EPA cancelled all uses in 1988. The compound binds very tightly to soil and degrades extremely slowly.
Homes treated for termites before 1988 often still have measurable heptachlor and heptachlor epoxide in foundation soil. The contamination can leach into shallow wells and migrate into basement and crawlspace air. Agricultural fields treated decades ago can also still contribute to runoff.
All current detections in water are from legacy contamination working through the hydrologic cycle.
Termite-treated foundations
Pre-1988 applications still in soil
Legacy corn and citrus fields
Persistent in former-use soil
Shallow groundwater
Migrates from contaminated soil
Find out for yourself
Is it in your water?
Public utilities test for heptachlor and report results in their annual Consumer Confidence Report. Detections in city water are now rare.
If your home was built before 1988 and treated for termites, or if your well is near a foundation treated in that era, you should test for both heptachlor and heptachlor epoxide. The cyclodiene insecticides (heptachlor, chlordane, aldrin, dieldrin) tend to occur together because they were applied for similar purposes.
The fix
How AquaOx filters it
Heptachlor is filtered efficiently by activated carbon. The coconut shell carbon stage in The AquaOx adsorbs heptachlor molecules as water passes through, with independent testing showing reductions above 95%.
For well-water households near former application sites, 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.