NJDEP New Jersey “TIC” Study
The characterization of Tentatively Identified Compounds (TICs) in water
samples collected from public water systems in New Jersey
Eileen Murphy, NJDEP, Brian Buckley, EOHSI, Ill Yang,
EOHSI, Lee Lippincott, NJDEP
Presently, certain conventional analytical methods for
analyzing drinking water samples from public water supplies for specific,
or targeted, organic chemical contamination are required by the NJ Safe
Drinking Water Act. For the most part, this routine testing is adequate
for the determination of commonly occurring volatile organic chemicals
(VOCs). It was always known that VOCs, which are the current regulatory
focus of analysis for organics in drinking water, may serve as markers
for the presence of mostly unregulated non- and semi-volatile contaminants
in addition to being significant in their own right. In situations where
impacted water is being used as a potable source, this issue is very important.
In the past, reliable analytical methods were not available to determine
the presence or the nature of many non-volatile (e.g., some pharmaceuticals,
dyes, inks) and semi-volatile (e.g., plasticizers, fragrances, some components
of fuel oils) contaminants, with the exception of certain types of semi-volatiles
(i.e., some pesticides and plasticizers).
A volatile compound is defined chemically as one with
a relatively low boiling point. That is, a volatile compound “evaporates”
readily into the air. Whereas, a non-volatile compound evaporates much
more slowly or not at all. A semi-volatile compound falls in between.
Thus, due to the historical focus on VOCs, the full picture of exposure
and health risk from contaminated drinking water may not have been adequately
determined. With the emergence of more sensitive analytical capabilities
for non- and semi-volatile organic contaminants, a more complete assessment
of this additional contamination, if and where it exists, can be made,
and appropriate steps can be taken to protect public health.
This study was able to address the potential detection
of hundreds of chemicals because the instrumentation was set up to screen
for tentatively identified compounds (TICs). A TIC is a compound that
can be seen by the analytical testing method, but its identity and concentration
cannot be confirmed without further analytical investigation. An analogy
is when a photograph is taken of a subject. The picture also captures
the information in the background, and often this information is fuzzy,
but the focus of the picture is the subject. The subject (i.e., target
item) is clear, but the background components (i.e., the tentatively identified
items), while captured in the picture, are fuzzy.
There were three related objectives to this multi-year project.
1. Tentatively identify and possibly quantify chemicals
present in raw and treated water samples collected from water supply systems
impacted by hazardous waste sites.
2. In instances where chemicals are present in the raw water, determine
if existing water treatment is effective at removing them.
3. Characterize the types of unregulated compounds present in water samples
due to sampling and laboratory contamination.