CONTAMINANT MASS

[Aimee Houghton <aimeeh@igc.org>]

From: Aimee Houghton <aimeeh@igc.org>

CONTAMINANT MASS

The State of California (Department of Toxic Substance Control, 
Office of Military Facilities) has published a paper describing the 
preliminary results of its innovative Contaminant Inventory Project. 
Instead of relying upon the poorly defined "number of sites" with 
particular forms of contamination, Peter Wood and David Wang used 
existing data to estimate the contaminant mass, by type, of soil 
contamination at 13 closing military bases in northern California.

At eight Navy installations in the San Francisco Bay Area, they found 
that TPH contamination (total petroleum hydrocarbons) accounted for 54%
of the total mass of contamination, much more than their 22% share of 
contaminated sites. Inorganics, principally iron, lead, copper, zinc, 
and antimony, accounted for 29% of the contaminant mass, even 
though they represented 68% of the sites. Iron made up 22% of the 
inorganic contaminant mass (that is, 22% of 29%), even though found 
at only one site, while arsenic represented only .57% of the mass, 
even though it was listed at 13% of the inorganic contamination sites.

Three Bay Area Army sites, including Fort Ord, showed inorganics at 
51% (led by lead at 46% of the 51%) of contaminant mass and TPH at 
21%. Explosives were counted at .0002%, but that obviously doesn't 
include the UXO and other explosive wastes at the Fort Ord impact 
range. A fourth Army base - the Sacramento Army (Signal) Depot - 
showed inorganics at 68% and solvents at 25% of contaminant mass. 
Lead represented 97% of the inorganics.

Mather Air Force Base, the only Air Force facility analyzed, showed 
TPH at 90% of the contaminant mass. Gasoline accounted for nearly 
6% more.

The data compiled by this project, as well as further analysis of other 
facilities, provide a tool to "prioritize resource allocation, evaluate 
cleanup progress, and help focus cleanup technology research and 
development efforts that maximize risk reduction."

This methodology appears to be a relatively inexpensive new tool for 
analyzing cleanup requirements and accomplishments, but as the 
report acknowledges, the authors have not yet come up with a 
systematic way to integrate risk and risk reduction data.