cience Forum

:rfl Hun run

Detection of Toxicantfs^ on Building Surfaces following Chemical Attack

Human

Exposure Issue:

Monitoring toxic compounds on
building surfaces after a chemical
attack is a critical step to ensure
safe reoccupation.

Many toxicant(s), including
readily available pesticides, may
be used as chemical weapons
by potential terrorists.

Protocols for surface sampling
will be developed that are similar

to methods produced
within ORD.

	 Craig Bernard, Jeffrey Morgan, and Lisa Melnyk

Office of Research and Development, National Exposure Research Laboratory, Microbiology and Chemical Exposure Assessment Research Division, Cincinnati, OH

Homeland

Scientific Approach

Test Compounds &
Surfaces:

• Industrial chemicals, including

organophosphate and carbamate insecticides,
will be tested on walls, floors, ceilings, office
furniture, and duct work to ensure the protocol
is applicable to different types of building
surfaces.

Surface Contamination &
Sampling:

•	A customized spray chamber will be used to
apply the chemicals to each surface.

•	Each surface will be dried.

•	The surfaces will be wiped with moistened
gauze pads across a defined sampling area.

Sample Preparation for
Analysis:

•	Gauze pads from surface wipes will be
inserted into an Accelerated Solvent
Extractor cell for extraction of toxicant(s).

•	The extract volume is reduced under
inert nitrogen gas to increase the overall
method sensitivity.

Sample Analysis:

•	Flexible analytical instrumentation will be
used to address the diversity of compounds
that may be encountered in a chemical attack.

•	This is achieved using liquid (LC) and gas
chromatography (GC) systems with mass
spectrometric (MS/MS) and pulsed flame
photometric detectors. (PFPD).

GC or LC Column

Liquid Solvent (LCI or Carrier Gas (GCl

Previous Surface Monitoring:

Results from previous testing demonstrated that surface wipes with gauze pads were effective at removing pesticides from hard indoor surfaces (Figures 1 -3) including surface wipes on ceramic
tile, vinyl tile, and hardwood flooring contaminated with an aqueous pesticide spray solution containing chemicals commonly used and/or found in homes. The efficiency of surface wipes was
determined by comparing them to surface loading levels.

Figure 1. Ceramic tile

Figure 2. Vinyl tile

Figure 3. Hardwood flooring

Relevance:
•	

This project is being conducted under the Homeland Security Safe Building Initiative for the
detection of contaminants on building surfaces. The study provides a critical link between
building decontamination processes and building reoccupation by providing a rapid and
sensitive method for monitoring toxicant(s) at low levels on surfaces in order to protect
public safety.

Products:

Protocols will be developed for conducting surface sampling of toxicant(s) on contaminated building
surfaces including:

•	Procedures for performing surface wipes with gauze pads.

•	Procedures for sample handling and preparation for analysis.

•	Analytical procedures for detection and quantitation of compounds captured in the
surface wipes by LC/MS/MS & GC/MS/MS-PFPD.

These protocols and analytical procedures will be available for use by EPA and its partners in an
emergency response to chemical terrorism.

PRO"^

Partnering to Protect Human Health and the Environment


-------