Derryl wrote:

Paraquat has arsenic in it and it can sterilize the soil it is used
for clearing lanes and sidewalks.

This is complete and utter ********. Paraquat is a fast acting knock
down contact weedkiller of the bipyridine family. It is most notable for
the tendency of would be suicides to drink it (a horrible way to go).

There are far better formulations like "Pathclear" for clearing paths
that include a long acting pre-emergent herbicide like Simazine.

Paraquat binds strongly to clays and is inactive by physical adsorbption
on most soils. I cannot offhand think of any modern herbicide that
contains arsenic. Glyphosate is usually preferable on toxicity grounds
though especially if you have small children or pets.

Most weedkillers are ineffective in the kind of weather you have in the
UK at the moment. they all need active growth of the weeds to work.

The thing it demonstrates ever so clearly is that the average user
cannot be trusted to RTFM with potentially dangerous garden chemicals.

Regards,
Martin Brown