Why is the site specific standard for lead contamination at the site, more than double the default state, non-residential lead standard?

The approach used to calculate the SSS for lead was to use the updated Adult Lead Model recommended by the USEPA. The previous calculations used by the PADEP were outdated; therefore, the PADEP recently used the same Adult Lead model to develop an updated non-residential lead direct contact MSC that reflects the current state of the science for lead.  The new calculated proposed direct contact standard for lead is in line with the site-specific standard that was calculated in 2015 for the site.  The site-specific standard was calculated using the updated Adult Lead Model and exposure assumptions recommended by the USEPA and the PADEP and has been shown to be protective of site personnel. If the PADEP changes their assumptions related to lead, Evergreen will update the SSS accordingly.