United States Environmental Protection Agency	Office of Research and Development

National Exposure Research Laboratory
Research Abstract

Government Performance Results Act (GPRA) Goal 2
Annual Performance Measure #202

Significant Research Findings:

Method Development for the Determination of
N-Nitrosodimethylamine (NDMA) in Drinking Water

NDMA is an emerging drinking water contaminant that is of interest to
EPA and the environmental community. Its presence in drinking water is a
potential health concern, because the EPA's IRIS data base lists the
concentration of NDMA required to result in a one in one million lifetime
cancer risk to be only 0.7 ng/L. NDMA is produced by industrial sources,
such as the manufacture of rocket fuel, but has also been identified as a
potential disinfection by-product. The focus of NERL's research was to
develop an improved analytical method for the analysis of NDMA in
drinking water that was sensitive, specific and cost-effective. Existing
methods for measuring NDMA in water are expensive and labor intensive,
and some require the use of very large amounts of toxic solvents such as
methylene chloride. In addition, the sensitivity of some existing methods is
insufficient for conducting low-level monitoring. The method was
developed for inclusion in EPA's Unregulated Contaminant Monitoring
Rule, scheduled for proposal in 2005, in order for the EPA Office of Water
to collect nationwide occurrence data on nitrosamines in drinking water and
make a regulatory determination. If NDMA or other nitrosamines become
regulated drinking water contaminants in the future, the method could also
be used for compliance monitoring.

The research goal was to develop a sensitive, selective and cost-effective
method for measuring NDMA (and other additional nitrosamines.) The
initial method sensitivity goal for NDMA was to demonstrate a Minimum
Reporting Level (MRL) near 1 ng/L, a value as close as practically possible
to the one in one million cancer risk concentration. Gas chromatography
with chemical ionization tandem mass spectrometry (GC/MS/MS) was
investigated for the chromatographic separation and detection steps,
because of its sensitivity and its specificity. To avoid the use of large
volumes of toxic organic solvents, solid phase extraction techniques were
investigated for the extraction of nitrosamines. A variety of commercially
available solid phase sorbents proved to be ineffective for NDMA, given its
high water solubility. However, the research demonstrated that coconut

Scientific
Problem and
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charcoal was both efficient as the solid phase sorbent and provided the
additional benefit of being inexpensive. The approach involved developing
procedures for (1) sample collection, preservation, shipping and handling,
(2) extraction and concentration of the target analytes from aqueous
solution, (3) separation of the analytes chromatographically, and (4)
detection and quantitation.

Results and	The analytical method developed by NERL has overcome many of the

Impact	difficulties related to the current methods (poor sensitivity, specificity and

cost-effectiveness, complexity and use toxic solvents), and provides a well
documented and standardized method for the measurement of NDMA and
other nitrosamines.. The analytical method developed from this research
can be used to measure NDMA and six additional nitrosamines in drinking
water samples. The MRL achieved for NDMA was 1.6 ng/L, and ranged
from 1.2 to 2.1 ng/L for the other method analytes. This method is an
improvement over other published methods for nitrosamines in the
following ways: (1) the sample preparation steps are simple, efficient, and
relatively inexpensive while using only small amounts of toxic solvents, (2)
use of the tandem mass spectrometer as the detector provides positive
identification of all method analytes without the use of additional
confirmatory techniques, and 3) the quality control steps in establishing and
verifying the MRL ensure both precision and accuracy in the measurement
of trace amounts of the method analytes. These improvements will meet
EPA's data quality objectives in the collection of nationwide occurrence
data to support regulatory decision making for nitrosamines, while reducing
the cost of analysis.

Publications resulting from this research:

Munch, J.W. and M. V. Bassett, "Methods for Emerging Contaminant
Groups: Explosives and Nitrosamines", Proceedings: American Water
Works Water Quality Technology Conference, Philadelphia, PA, Nov. 3,
2003.

Munch, J.W. and M.V. Bassett, "U.S. EPA Method 521: Determination of
Nitrosamines in Drinking Water by Solid Phase Extraction and Capillary
Column Gas Chromatography with Large Volume Injection and Chemical
Ionization Tandem Mass Spectrometry (MS/MS)", National Exposure
Research Laboratory, Microbiological and Chemical Exposure Assessment
Research Division, Chemical Exposure Research Branch, 26 W. Martin
Luther King Dr., Cincinnati, Ohio, 45268-1564.

Future Research Due to the success of the method development, no further research is

planned at this time. This method, EPA Method 521, is available for use as
the required analytical method in the Office of Ground Water and Drinking
Water's upcoming proposal for the Unregulated Contaminant Monitoring

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Rule. When finalized, this regulation will require a nationwide monitoring
survey of selected CCL contaminants and emerging drinking water
contaminants, including NDMA. Occurrence data from this survey will be
used in the decision making process for the possible regulation of NDMA.

Contacts for

Additional

Information

Questions and inquiries can be directed to:

Jean W. Munch
USEPA

National Exposure Research Laboratory
26 W. Martin Luther King Dr.

Cincinnati, OH 45268-1564
Phone: (513) 569-7465
e-mail: munch.iean@epa.gov

Funding for this project was through the U.S. EPA'S Office of Research
and Development, National Exposure Research Laboratory, and the work
was conducted by the Microbiological and Chemical Exposure Assessment
Research Division.


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