Hi everyone,
I an assessing a QRA where the Consultant has used RBCA to calculate a
sstl for total TPH insoils and groundwater. The justifiaction for the
use of RBCA is that it allows for the claculation of a total rather than
individual TPH fractions.
A number of questions:
-- Can RBCA be used to calculate sstl's for individual fractions of
TPH.
--- Does P20 allow for calcualtion of sstl's for total TPH?
I'm not convinced that calculating a target level for total TPH is s
good idea. The level obtained is quite high7400mg/kg for soils and
270ug/L for groundwater. The aim is to leave materials that are lower
than this on site underneath a capping layer. I would say that if
individual fractions are not calculated then one has to presume that all
the TPH is light and aromatic and therefore potentially risky?
The reason given for calculating a total is that the contaminants found
are mainly C21-35 aliphatics. But there are other fractions that have
also been detected and these should be given consideration.
I'd value your thoughts and guidance.
Thanks,
Clare
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