Physical Sciences, Inc.
land Business Center, Andover, MA 01810
' vw.psicorp.com
DESCRIPTION OF THE TECHNOLOGY
With support from the Environmental Protection Agency's
(EPA) Small Business Innovation Research (SBIR) Pro-
gram, Physical Sciences Inc. (PSI), has developed a
prototype monitor for the onsite characterization of soil
using spark-induced breakdown spectroscopy (SIBS). This
device determines the elemental composition of soil by
emission spectroscopy, including dangerous heavy metal
pollutants, using an electrically generated pulsed plasma
as an excitation source.
The PSI prototype metals monitor is based on the excita-
tion of a sample with a large, robust electric spark.
Following the excitation, the elements in the sample emit
light. These emissions provide the basis for the detection:
the energy of the radiated light identifies the element
and the intensity of the light indicates the concentration
of the element in the matrix. The use of a small spec-
trometer enables simultaneous multi-metal deter-
minations. Analytical methodology is based on the use of
standard additions to the sample and normalization to
persistent iron lines. Detection limits for lead (Pb), chro-
mium (Cr), cadmium (Cd), mercury (Hg), and barium
(Ba) have been determined to be near 25 mg metal/kg
soil, and determination times of a few minutes are pos-
sible.
SIGNIFICANCE OF THE TECHNOLOGY
Metals are a ubiquitous waste material present in soils
and sediments at sites across the United States. Contami-
nation levels range from individual species present at low
concentrations to multiple class mixtures present in parts
per thousand quantities. These sites are the result of years
of disposal of chemicals into the environment. Prior to
the 1970s, disposal of hazardous material into unlined
shallow pits was a common practice. This method mini-
mized costs associated with waste disposal, and the general
public was mostly ignorant of the dangers caused by the
disposed chemicals. Moreover, it was generally assumed,
even more recently, that metals buried in soils remained
in the top few centimeters of soil. This is now known not
to be the case. Hazardous wastes spilled or disposed on
land migrate through the surface and subsurface soils
under certain conditions, and can access groundwater and
aquifers.
When hazardous waste sites are under remediation,
samples of soil are continuously collected and analyzed.
4- SIBS determines the elemental composition of soil by emission spectroscopy using electrically generated
pulsed plasma as an excitation source.
4- Using the technology, detection limits for Pb, Cr, Cd, Hg, and Ba have been determined to be near 25 mg
metal/kg soil, and determination times of a few minutes are possible.
4- SIBS offers greater potential sensitivity and more representative sampling than other technologies,
such as laser-induced breakdown spectroscopy.
4- By operating in situ, the technology avoids the high capital and operating costs of inductively coupled
plasma atomic emission spectroscopy and microwave methods.
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PSI's SIBS monitor determines the elemental
composition of soil, including dangerous heavy
metal pollutants.
These samples determine the type and extent of the con-
tamination, and ongoing sampling is necessary as the
remediation proceeds. These samples are usually ana-
lyzed offsite in a laboratory setting. This approach is
reliable, but the time required for the continuing sample/
analysis iteration is lengthy and adds substantially to the
labor budget of site clean up. A portable or onsite multi-
metals field-screening instrument will be a valuable
addition to the onsite arsenal of the hazardous waste
remediation team.
SIBS offers greater potential sensitivity and more repre-
sentative sampling than other technologies, such as
laser-induced breakdown spectroscopy and uses an inex-
pensive spark power supply in place of a laser. By operating
in situ, the technology avoids the high capital and oper-
ating costs of inductively coupled plasma atomic emission
spectroscopy and microwave methods and uses simple
and inexpensive radiometric optical detection.
SIBS was evaluated at a joint EPA/U.S. Department of
Energy test at the Rotary Kiln Incinerator Facility at Re-
search Triangle Park, NC. The instrument was configured
for real-time, in situ measurement of Pb and Cr in gas-
borne particulate at target levels of 15 and 75 /ig/dscm in
simulated combustion flue gas. Both Pb and Cr were de-
tected at the low- and high-level concentrations. The
hardware performed without failure for more than 100
hours of operation and acquired data for all of the refer-
ence tests (data were acquired using EPA Reference
Method 29).
COMMERCIALIZATION SUCCESS
Although not yet fully commercialized, this monitor has
attracted a good deal of attention from potential com-
mercial partners. Using internal funding, PSI has
designed a manufacturable model of the monitor that
will be the size of a briefcase and be saleable on the
open market for less than $10,000.
COMPANY HISTORY
PSI was founded in 1973 by employees of Avco-Everett,
a large and well-known defense contractor. Since then,
PSI has focused on providing contract research and
development services in a variety of technical areas to
both government and commercial customers. PSI has a
staff of more than 120, approximately one-half of whom
are at the doctoral level. The company's core technolo-
gies have been developed with more than $250 million
of federal and industrial funding over 3 decades of op-
erations, a period in which PSI has acquired an
international reputation for technical excellence and in-
novation. The SBIR Program has played a pivotal role in
PSI's technical and commercial success, and has been
responsible for a family of intelligent instrumentation
products based on proprietary electro-optical and elec-
tromechanical technologies.
EPA's Small Business Innovation Research (SBIR) Program was created to assist small businesses in
transforming innovative ideas into commercial products. The SBIR Program has two phases—Phase I is
the feasibility study to determine the validity of the proposed concept and Phase II is the development of
the technology or product proven feasible in Phase I. EPA also offers Phase II Options to accelerate the
commercialization of SBIR technologies and to complete EPA's Environmental Technology Verification
(ETV) Program. For more information about EPA's SBIR Program and the National Center for Environmental
Research, visit http://www.epa.gov/ncer/sbir.
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