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Hi Matt,
You have summed it up at the end with why choose an exposure model for allotments when the site is for a residential end use? In my opinion they are being overly conservative and are costing the developer money as 600mm cover is unlikely
to be necessary [based on the facts given]. To be honest a large part of me thinks tough..let the developer spend unnecessary money on this as they should procure services on a quality/cost basis not just cost…the old adage “you pay for what you get” comes
to mind!
So your options are [1] approve as the site will be suitable for use or [2] knock back the report as it isn’t considered best scientific practice but basically you will be telling them to be less conservative! Or [3] tell them to not
practice con land and to take up something less taxing on the old grey matter and that 600mm is not necessary..I like [3] but I wouldn’t recommend it..
It is tough one and this issue has been raised on the forum before i.e. What should we do as regulators when faced with too much conservatism and potentially unnecessary remediation?
Kind regards
Dave
David Jackson
Land Quality Officer
Wakefield Council
Regeneration & Economic Growth | Environmental Health
Wakefield One | P.O Box 700 | Burton Street | Wakefield | WF1 2EB
t 0345 8506506 [Contact Centre]
m
07810152565
w www.wakefield.gov.uk/landquality
-----Original Message-----
From: Contaminated Land Management Discussion List [mailto:[log in to unmask]] On Behalf Of Matthew Axton
Sent: 23 November 2016 9:58 AM
To: [log in to unmask]
Subject: Lead - Using allotments “low” risk criteria as a “minimal” risk criteria for residential
Hi All,
Following on from the conversations around RMS last week -
I have a consultant submitting reports in my LA area who is quoting the S4ULs and C4SLs in their reports as usual, but, when nothing exceeds the usual screening values, they state the following - "One of the samples tested was above
the most conservative associated UK criteria for lead but was below the C4SL criteria for residential land use." - max value was 130mg/kg. They made a similar statement for BaP - "One of the samples tested was above the most conservative associated UK criteria
for benzo(a)pyrene but was below the LQM and C4SL criteria for residential land use." max value was 0.94mg/kg. There are also very low levels of Total TPH in a couple of locations (maximum 97mg/kg). I should say that the site is residential, 11 samples
were tested in total, and the consultant has recommended site wide remediation and 600mm clean cover.
When I asked for clarification on these "most conservative associated UK criteria", I was told that: "We have adopted the C4SL allotments “low” risk criteria of 80 mg/kg in soil as the “minimal” risk level criteria for residential, which
represents a precautionary approach". No clarification was received on the BaP.
I've not seen any other consultant take this approach and I personally think that it is scientifically flawed as the exposure pathways to calculate the allotment and residential settings are not directly transferable. I thought I would
see what the industry thinks before I respond...
Thanks in advance,
Matt