Soil Guideline Values - SGV by decree


									What is a soil guideline value - SGV?

Soil guideline values (SGVs) have been produced by DEFRA and the
Environment Agency as indicators of potential unacceptable risk. They were
created using human toxicity data to estimate the amount of substance an
individual would take in as a result of exposure to soil.

SGVs are only designed to indicate whether further site-specific investigation is
needed. By exceeding this guideline value it does not necessarily mean that
there is a risk to health as the levels requiring further investigations are set very
low. As a result the SGV’s are as cautious as they possibly can be and take into
account the most vulnerable residents.

         residential with residential without                                 commerical/
substance                                      allotments
           plant uptake      plant uptake                                      industrial
Lead            450              450               450                            750
Selenium         35              260                35                           8000
Nickel           50               75                50                           5000
Mercury          8                15                8                             480
Chromium        130              200               130                           5000
           1,2,8 (for pH                      1,2,8 (for pH
 Cadmium                          30                                               1400
              6,7,8)                              6,7,8)
Arsenic          20               20                20                            500
          78 (1%SOM),      21900 (1%SOM),     80 (1%SOM),                   21900 (1%SOM),
  Phenol 150(2.5%SOM), 34400(2.5%SOM), 155(2.5%SOM),                       43000(2.5%SOM),
          280(5%SOM)        37300(5%SOM)      280(5%SOM)                     78100(5%SOM)

      All units are mg per kg which is equivalent to parts per million
      Residential with plant uptake is used for all properties with back gardens
      Residential without plant uptake is used for all properties with communal
       gardens or no garden areas
      Since there is no soil guideline value for open spaces, residential without
       plant uptake is commonly used
      SOM is soil organic matter

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