In article , Franz Heymann
"Philip Eden" philipATweatherHYPHENukDOTcom wrote in message
Although she realised her error within an hour and
subsequently sprayed them with water, naturally
they all shrivelled and died within 24 hours. However,
there were dozens and dozens of ripening tomatoes
on the plants which she has since harvested and put
in the sun to finish the ripening process.
The weedkiller was glyphosate, and it says on the
can that it's safe to use around children and pets,
and that it breaks down quickly in the soil after use.
The question is: are the tomatoes safe to eat?
It does not seem to me to be worth the risk of trying.
The ld50 for glyphosate is measured in grams per kilo - about 4 iIrc. At
spray concentration she'd need to drink gallons to be at significant risk.
(In the days when farm quantities were sold without additives the reps used
to drink some of the mix to show how safe it was.)
The surfactants (used to make sure the spray sticks to the leaves) are more
harmful to humans than the active ingredient.
So give them a wash and tell her that at that dose rate it'll take a century
or so of repeated mistakes before she notices adverse reactions.