|
Real-Time Portable Sensor for Measuring Arsenic
Concentration in Water
Badawi Dweik,
Ph.D., Giner Inc., Newton, MA
Collection and Analysis of Arsine Gas from Contaminated
Marsh Sediments
Kent McCord, RMT,
Inc., Madison, WI
Robert
Stanforth, RMT, Inc., Madison, WI
Real-Time Portable Sensor for Measuring Arsenic
Concentration in Water
Badawi Dweik, Ph.D., Project Manager, Giner Inc., 89
Rumford Avenue, Newton, MA 02466-1311, Tel:
781-529-0520, Fax: 781-893-6470, Email:
bdweik@ginerinc.com
Arsenic in drinking water is a severe health risk to
populations throughout the world. In recognition of this
risk, the Environmental Protection Agency (EPA) lowered
its water standard for arsenic from 50 ppb to 10 ppb.
The EPA has estimated that some 13 million people
in the
United States
are exposed to high concentration of arsenic in drinking
water. Enforcement of the 10 ppb standard for arsenic in
potable water requires innovative solutions that are
efficient, cost effective, and robust.
There is a compelling need for an inexpensive,
real-time, ppb-level sensor capable of measuring the
concentration of Arsenic in water with a detection limit
of 1
mg/L
(ppb). The
preferred design would use no reagents and require
little or no maintenance. Such a real-time ppb-level
arsenic sensor will have immediate utility to the EPA,
World Health Organization (WHO), research programs, and
treatment facilities.
To
comply with the new standard, Giner Inc. is working to
develop and demonstrate an easy-to-use reliable, field
deployable, and practical real-time sensor device that
can be used to perform rapid on-site screening and
quantitative determination (at ppb levels)
of dissolved arsenic in drinking water.
Microchip sensors were fabricated utilizing two
select electrode materials in a microarray configuration
design and tested over a range of arsenic concentrations
to demonstrate the concept feasibility.
The effect of
several variables such as arsenic concentration, and
electrochemical operating parameters were investigated.
Our results demonstrated the feasibility that arsenic
concentrations could be determined with a resolution in
the sub-ppb range using specially fabricated microchip
sensor. The
prototype sensor instrument includes an electronics
package for electrode potential control, data
collection, data transfer, and data display.
The sensor will have the feature to be connected
to a laptop computer, which will operate the electronic
control circuit, collect and analyze the data.
Collection and Analysis of Arsine Gas from Contaminated
Marsh Sediments
Kent
McCord,
RMT, Inc. 744 Heartland Trail, Madison, WI 53717, Tel:
608 662-5382, Fax: 608 831-3334, Email:
kent.mccord@rmtinc.com
Robert Stanforth, RMT, Inc. 744 Heartland Trail,
Madison, WI 53717, Tel: 608 662-5310, Fax: 608 831-3334,
Email: robert.stanforth@rmtinc.com
Bioreduction is being evaluated as a method of
remediating arsenic-contaminated sediments.
During the bioreduction, arsenic in the sediments is
converted to arsine gas and volatilized. Since arsine is
a toxic gas, it is important that the amounts and
concentrations of arsine being generated during the
remediation be evaluated. The gas generated from the
marsh was trapped and collected in a Tedlar bag. The gas
was then passed through an absorbent tube, and analyzed
for arsine. The paper presents the design of the
collector and the results from the field trials.
Top
|
