"Bob S." wrote:
....
Years ago I had a neighbor who sprayed his yard for weeds with "a
herbicide he brought back from Viet Nam." He didn't have a green
anything in his yard for 5 years!

Wasn't 2,4-D or 2,4,5-T then. Both are broadleaf selective and they
breakdown in the soil or water within 2-3 weeks at most. Found the
following quickly for 2,4,5-T and my recollection is 2,4-D is similar in
nature.


"Fate
2,4,5-T on the soil may be degraded chemically or biologically,
volatilized, absorbed in the soil, or leached beyond the depth of plant
roots. 2,4,5-T is moderately mobile in sandy and clay soils. Half-life
on grass is 8-17 days, in soils 21-24 days. Normally, only small
amounts enter water, where it does not persist as it is absorbed by clay
or biota within a few days,. Esters of 2,4,5-T are usually hydrolysed
within a few days. There is no significant bioaccumulation."

Extracted from

Rotterdam Convention - Operation of the Prior Informed Consent
Procedure for Banned or Severely Restricted Chemicals

Decision Guidance Documents

2,4,5-T and its salts and esters



BTW, as an aside, the prime toxicological effect supporting the ban was
listed as the dioxin contaminant as another poster noted.