I am new to newsgroups, and am attempting to respond to a note which I read
about the herbicide 2,4-d (commercially common as Roundup). The compound is
one of a class of phenoxychlorides (I probably am not remembering the absolute
correct spelling, and my books are unavailable, so forgive me please). These
molecules are essentially phenol rings connected by oxygen atoms, with
chloride radicals on the rings. They are very reactive. In plants, as pointed
out, they act much as growth hormone auxin, and in effect the plant grows
itself to death. Hence, the gnarled leaves which form on treated plants. I
believe that at least one effect of the compound is to interfere with the
photosynthetically driven electron transport chain.
These herbicides were commonly used in forestry applications, a notorious
example being 2,4,5-t, Agent Orange used in Vietnam, and a molecule related to
2,4-d. The numbers refer to the positions of chloride around the rings. An
unfortunate side-effect in forestry applications is the destruction of stream
life. It is true the compounds have a fairly rapid breakdown in soil (because
they are reactive!), but I certainly look for alternate control measures. I
find the smell of the stuff repugnant, especially on a lovely afternoon
pedalling my way home past a sea of chemically treated sod.
Personally, I don't trust data relative to the safety of 2,4-d. But
professionally I suppose I must reserve judgement. At least treat the stuff
respectfully if you need to use it, reading ALL SAFETY PRECAUTIONS, and
following proper disposal methods.
Thanks for listening to a "newbie",
(Dr.) Julie Gold