Re new USEPA Region IX Preliminary Remediation Goals

[zweifel@nexus.chapman.edu]

From: Don Zweifel <zweifel@nexus.chapman.edu>
Subject: Re new USEPA Region IX Preliminary Remediation Goals

To all interested parties:

Regarding Dichloro-difluoromethane or Freon-12 fluorocarbon: 
This chemical is suspected of causing global-warming due to its
ozone-depleting propensity's within the stratosphere..

As of 1 August 1996 USEPA Region IX gives residential Preliminary
Remediation Goals (PRGs) of 94 milligrams per kilogram concentration in
soil and 390 micro-grams per liter in water. These are based on an oral
reference dose (RfDo) of 2 micro-grams per kg per day ingestion and an
inhalation reference dose (RfD1) of 0.57 micro-gram per kg per day
exposure rate.

Regarding 2 Butanone or methyl ethyl ketone:
This chemical is an industrial solvent utilized primarily for cleaning
aircraft and aircraft parts.

As of 1 August 1996, USEPA Region IX gives residential PRGs of 7,100 mg/kg
in soil and 1,900 micro-grams/liter in water. These are based on an RfDo
of 0.6 mg/kg per day and an RfD1 of 0.6 mg/kg per day ingestion factor.

Regarding 2-Hexanone or methyl-n-butyl ketone: 

No PRGs or refernce doses are published for this chemical. However
n-hexane is metabolized in mammals primarily as 2-Hexanone then to the
neurotoxic 2,5-hexanedi-one.

Therefore n-hexane is an adequate surrogate compound ("For transference,
perhaps mutagenically") D.Z.

As of 1 August 1996, USEPA Region IX gives residential PRGs for n-hexane
of 110 mg/kg in soil and 350 micro-grams in water. The PRG in soil is the
saturating concentration, while the PRG for tap water is based on an RfDo
of 0.6 micro-grams/kg per day and an RfD1 of 0.57 micro-grams per day
exposure factor.

Source: CalEPA's Department of Toxic Substances Control

Note: Consider searching your particular base's documentation on
contaminant levels to ascertain as to whether this data may have an impact
on risk to human health in the area of concern (AOC). 
 
 Don Zweifel
 CalEPA DTSC Adv Grp Mil Base Closure