#3535: Philadelphia Ash : Pilling comments

[Robert Corbett <bcorbett@netcom.com>]

From: John Pilling <jldjk@gis.net>

From:  jldjk@gis.net

The seeming disparity between the previous "hazardous" test results
obtained by the British lab and the current proclamation that the ash is
now "clean" at the very least raises the question of how the samples
were collected, what type of analyses were conducted, and which
standards were consulted when the differing conclusions were made.  Were
the different samples collected all truly representative of the ash
pile?  Was there variability within the ash pile?  There are many
apparently unanswered variables which could lead to vastly differing
results such as what appears to be happening now.  The U.S. has
standards for hazardous materials present in waste streams (which the
incinerator ash would be considered-a waste stream that is).  These
standards can only be referred to provided a certain type of analysis is
conducted (US EPA TCLP Method).  The British may have a different set of
standards and a different set of analytical procedures-does anyone know
what the British system consists of?  This could potentially result in
the differing conclusions we are reading about.  Another set of test
methods measures what are called total metals (lead, cadmium, chromium,
etc.) concentrations in a waste stream. These results are typically used
to assess exposure risks to people who may come into contact with the
ash, as well as, potential health effects which may occur once these
contaminants have migrated to other media (such as soil and
groundwater).  If the results of the various testing parties were
available, they could be reviewed as to their meaning in light of waste
characterization and risk to human health.  It is very important,
however, to understand that one set of testing results cannot typically
be used to assess both waste characterization and risk to human health
at the same time.  Different types of tests would need to be conducted
on the same material.  Does anyone have addditional information on the
actual test results.  That could shed new light on the situation.

John Pilling