Can't help you with Benzene constant :(. A charming Russian (I've
met him) called Zygvantsiev (probably wrong spelling but I don't have my
refs with me) carried out work on soils donkeys years ago and stated
that less than 1% of soil bacteria were in the soil solution. Rest were
glued down. This as near as you can get to a bit of soil microbiology
carved in stone as I have not come across ANY other work that is quoted
as often. It is the best figure that we have which is a pity. (Please
some-one tell me different !).
Peter Harris,Soil Microbiology, University of Reading, UK.
AKA <P.J.Harris at reading.ac.uk>