Environmental Engineering Reference
In-Depth Information
lyzed to minimize worker exposure, ensure proper
treatment and disposal, and meet cleanup criteria for
closure. Finally, as is typical at any industrial facility,
operations at each disposal site will entail a variety of
maintenance and repair activities capable of generating
contamination by various SOPCs. These include clean-
ing and degreasing with volatile solvent emissions and
welding or machine operations with organic and metal
emissions. Emissions from these routine industrial op-
erations may have to be monitored on an episodic basis
to validate industrial hygiene practices for controlling
and minimizing worker exposures.
The sites at Aberdeen, Maryland, and Newport, In-
diana, have only one agent each (HD at Aberdeen and
VX at Newport) stored in bulk containers. These sites
will use hot aqueous hydrolysis (hot aqueous caustic
hydrolysis in the case of VX) as the first step in agent
destruction. Batch analyses of liquid hydrolysates will
be necessary at both sites to ensure that the defined
degree of agent destruction (99.9999 percent) is met
prior to secondary treatment.
Five of the stockpile sites that store (or have stored)
chemical agents configured in a variety of weapons
(e.g., rockets, bombs, artillery shells, mortar rounds,
and mines) have used, currently use, or will use incin-
eration as the means of disposal. Requirements for
these disposal facilities include techniques for moni-
toring products of incomplete combustion, acid gases,
and heavy metals that may elude exhaust pollution
abatement systems and be emitted with exhaust gases
through the common stacks.
The emphasis at the two operating baseline sites has
(properly) been on gas-phase monitoring for agents
because of their toxicity and the potential of airborne
transport and inhalation. However, with the imminent
start-up of sites using alternative liquid processing
technologies and the upcoming plant closures (begin-
ning with the closure of JACADS in 2001), monitoring
for agents in liquid and solid media will become much
more important.
system designed to provide a “near-real-time” alarm
(currently ~3 to 8 minutes) if agent vapors are present;
and (2) the depot area air monitoring system
(DAAMS), a passive sampling system that draws air
through adsorption tubes that are collected periodically
for desorption and analysis in on-site laboratories.
Short descriptions of these systems are provided below.
More extensive descriptions can be found in the
committee's report, Review of Monitoring Activities
Within the Army Chemical Stockpile Disposal Program
(NRC, 1994b), and the Army's Monitoring Concept
Plan (U.S. Army, 1997a).
ACAMS monitors are composed of an automated
air sampling system that supplies gaseous samples to a
gas chromatograph that separates agent or agent-de-
rived compounds and detects characteristic phospho-
rus or sulfur chemiluminescence with flame photomet-
ric detectors. ACAMS monitors can also be deployed
with higher alarm levels in areas subject to operational
contamination to monitor contamination levels, as well
as to monitor progress during decontamination opera-
tions. ACAMS monitors are also deployed at several
points in the pollution abatement system (PAS) and in
the common stack for exhaust gas emissions from
baseline system incinerators. Some ACAMS monitors
are arranged in tandem to cut analysis cycle times in
half. Alarms triggered by ACAMS monitors on the
common stack automatically shut off the feed to the
liquid agent incinerator to minimize potential emission
of agents into the atmosphere.
DAAMS monitors contain adsorption tubes that col-
lect chemicals from ambient air, usually over a period
of several hours. These monitors are deployed in con-
junction with most ACAMS monitors to provide a ca-
pability for confirming or negating an ACAMS alarm.
This is important because ACAMS monitors operating
at their lowest detection levels have a significant fre-
quency of false positive alarms (NRC, 1994b, 1999a).
DAAMS monitors are also deployed as perimeter
monitors at disposal facility fence lines to detect any
ground-level transport of agent outside the facility.
Even in the absence of ACAMS alarms, DAAMS ad-
sorption tubes are periodically collected and taken to
the facility's laboratory for desorption and quantitative
analysis on a research-grade gas chromatograph with
flame photometric detection. A gas chromatograph
with mass spectrometric detection is also available in
each laboratory to help identify compounds that lead to
false positive ACAMS alarms or otherwise interfere
with the quantification of agents or agent derivatives.
MONITORING FOR AIRBORNE AGENT
Description
Monitoring for airborne chemical agent is a major
activity at each chemical agent disposal facility. Two
systems are currently being used: (1) the automatic con-
tinuous air monitoring system (ACAMS), an active
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