Where It Comes From
Formed when alachlor degrades in soil and water; these degradates (OA, ESA) are mobile and persistent, and found in groundwater [3].
How You Are Exposed
Mostly by drinking contaminated private well water; less often from public water. Workers handling alachlor may also be exposed. Related metabolites can be measured in urine [1][4].
Why It Matters
Alachlor can irritate eyes/skin and caused tumors in animal studies; EPA’s drinking water limit for alachlor is 2 ppb. OA itself is less studied but indicates alachlor use and possible co-occurrence of other degradates [1][2][3].
Who Is at Risk
People using untreated wells in agricultural areas; farmers and applicators; infants, children, and pregnant people may be more susceptible to effects [1].
How to Lower Your Exposure
Test well water for alachlor and degradates. Use NSF/ANSI-certified activated carbon or reverse osmosis devices verified for herbicides. Follow label and PPE if applying pesticides; use alternate water for infant formula until results are safe [2][5].
References
- [1]ATSDR. ToxFAQs for Alachlor. https://www.atsdr.cdc.gov/toxfaqs/tfacts3.html
- [2]EPA. National Primary Drinking Water Regulations (Alachlor MCL = 0.002 mg/L). https://www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations
- [3]EPA. Reregistration Eligibility Decision (RED) for Alachlor. EPA 738-R-98-020, 1998.
- [4]CDC. Biomonitoring Summary: Alachlor and Metabolites. https://www.cdc.gov/biomonitoring/Alachlor_BiomonitoringSummary.html
- [5]EPA. Drinking Water Treatability Database: Alachlor. https://tdb.epa.gov/tdb/contaminant/787/alachlor