With regards to the last slide in RB NWBR presentation.
There are other ways to view the impact of remediation to 5 mg/kg instead of to 1 mg/kg.
Using the numbers presented by RB, exposure to:
5 mg/kg BaP = 10 additional cancers per million population (over lifetime)
1 mg/kg BaP = 2 additional cancers per million population (over lifetime)
So having 5 mg/kg instead of 1 mg/kg = 8 additional cancers per million population
Applied across UK Population of 63M, this policy approach could theoretical add c. 500 cancers into the UK... (dodgy calc I know, but gives a nice population wide upper bound)
(but also need to be remember that increasing BaP soil loading, will also increases other PAH soil loading, so cancers due to other PAHs could also be increased by a factor of 5)
Other factors to consider: c. 330,000 new cancer cases per year in UK (cancer research UK).
So say over 50 years = 16.5 Million cases
Or using the 1/3 get cancer rule of thumb = 31M lifetime cancer cases in snap shot of population
So country wide 5 mg/kg versus 1 mg/kg BaP would add max 0.002% cancers to the mix...
Devils Advocate: So if we continue the RB thought process to its logical conclusion, there really is a strong case for not worrying about any cancer inducing contaminants in soil in the greater scheme of things as it is a drop in the ocean..: so how about a RB land contamination regime based on: "if it looks like a soil, it will be fine, any potential impact to health are not really worth worrying about in the greater scene of things" ...
.... playing with numbers is a dangerous thing. 'Careful with That Calculator, Eugene". (some of you might get that).
Chris Dainton
Peak Environmental Solutions
http://peakenvironmentalsolutions.com/
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