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6. POTENTIAL FOR HUMAN
EXPOSURE
Litaor 1999; Mulsow et al. 1999; Struminska and Skwarzec 2004). In particular, information is very
limited on levels in media associated with areas surrounding waste sites. Such information is needed in
order to quantify the potential exposure via these sources. Limited data are available on estimates of
human intake via specific media (e.g., food) (Cooper et al. 1992; Pietrzak-Flis and Orzechowska 1993;
Sanchez et al. 1999). This information would be important in determining the impact of exposure through
each of these media.
In general, plutonium levels found in environmental media that resulted from fallout
are low and exposure would also be expected to be low. Plutonium exposure would likely only be
relevant to individuals living near areas with known plutonium contamination (e.g., nuclear accident sites
or waste sites).
Exposure Levels in Humans.
Plutonium concentrations have been reported in various tissues and
biological fluids, including urine,
and in lung, liver, and bone tissues obtained from autopsy (Filipy et al.
2003; Ibrahim et al. 1999; Ivanova et al. 1995; Popplewell et al. 1988; Takizawa 1982; Voelz et al. 1997;
Wrenn and Cohen 1977). Occupationally exposed populations are likely routinely biomonitored through
urinalysis. However, such data are not made available and are needed to quantify exposure to these
individuals.
In addition, no information is available on biomonitoring of individuals around NPL sites
where plutonium has been found or of the general public.
This information is necessary for assessing the need to conduct health studies on these populations.
Exposures of Children.
Children would be exposed to plutonium from fallout by similar routes are
adults, such as ingestion of food and water and breathing ambient air. However, levels would generally
be low for children not living near areas with known plutonium contamination (e.g.,
areas where nuclear
accidents or former plutonium processing plants). Limited data on exposures of children to plutonium
were located. O’Donnell et al. (1997) reported
239,240
Pu levels in permanent teeth collected from children
in the United Kingdom and Republic of Ireland. Priest et al. (1999) reported
239
Pu content in urine in
North London school children.
There do not appear to be any childhood-specific means to decrease exposure to plutonium. However, as
levels of plutonium in food and ambient air are generally low, exposure to plutonium would also be
expected to be low.
No data were located on plutonium concentrations in breast milk or infant formulas.
Additional studies
on daily intake of plutonium in children and infants would be useful to estimate the exposure of this
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6. POTENTIAL FOR HUMAN EXPOSURE
population to plutonium, particularly in areas contaminated with plutonium where exposure may be of
greater concern.
Child health data needs relating to susceptibility are discussed in Section 3.12.2, Identification of Data
Needs: Children’s Susceptibility.
Exposure Registries.
No exposure registries for plutonium were located. This substance is not
currently one of the compounds for which a sub-registry has been established in the National Exposure
Registry. The substance will be considered in the future when chemical selection is made for sub-
registries to be established. The information that is amassed in the National Exposure
Registry facilitates
the epidemiological research needed to assess adverse health outcomes that may be related to exposure to
this substance.
USTUR established a database to document levels and distribution of uranium and transuranium isotopes
in human tissues for occupationally exposed workers who donate their bodies to science (USTUR 2003).
The Department of Energy (DOE) has developed the Comprehensive Epidemiologic Data Resource
(CEDR) Program to provide public access to health and exposure data concerning DOE installations. In
addition, studies relating to populations residing near DOE installations, as well as other studies of
radiation exposures and health effects, such as atomic bomb survivors, are included in CEDR (CEDR
2007).
6.8.2
Ongoing Studies
No ongoing studies pertaining to the environmental fate of plutonium or plutonium compounds were
identified in a search of the Federal Research in Progress database (FEDRIP 2007).
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7. ANALYTICAL METHODS
The purpose of this chapter is to describe the analytical methods that are available for detecting,
measuring, and/or monitoring plutonium,
its metabolites, and other biomarkers of exposure and effect to
plutonium. The intent is not to provide an exhaustive list of analytical methods. Rather, the intention is
to identify well-established methods that are used as the standard methods of analysis. Many of the
analytical methods used for environmental samples are the methods approved by federal agencies and
organizations such as EPA and the National Institute for Occupational Safety and Health (NIOSH). Other
methods presented in this chapter are those that are approved by groups such as the Association of
Official Analytical Chemists (AOAC) and the American Public Health Association (APHA).
Additionally, analytical methods are included that modify previously used
methods to obtain lower
detection limits and/or to improve accuracy and precision.
The accurate and reliable determination of plutonium in biological and environmental samples is
important because of the potential impact of this element on public health. Analytical methods used to
measure plutonium in biological and environmental media are highly refined compared to other
transuranics. Alpha spectrometry is the most widely used method for the determination of plutonium.
However, this method typically cannot resolve the
239
Pu and
240
Pu peaks due to their similar energies
(5.15 and 5.16 MeV). An independent mass spectrometric analysis is required in order to determine the
individual concentrations of
239
Pu and
240
Pu (Muramatsu et al. 2001a; Wolf 2006). Mitchell et al. (1997)
have described a deconvolution technique based on commercial software to resolve the
239,240
Pu peaks in
alpha spectroscopy. Other methods such as thermal ionization mass spectrometry (TIMS) and accelerator
mass spectrometry (AMS) have been used for the determination of plutonium. Inductively coupled
plasma-mass spectrometry (ICP-MS) has advantages of ease of operation and rapid analysis. In addition,
ICP-MS can provide information about the
239
Pu/
240
Pu ratio in a sample, which can, in turn, provide
important information about the source of plutonium contamination (Muramatsu et al. 2001a; Varga et al.
2007; Wolf 2006). Interferences that may be observed with ICP-MS are caused by polyatomic ions in the
plasma, such as
238
UH
+
and
238
UH
2
+
,
which can interfere with
239
Pu and
240
Pu, respectively, in samples
with high concentrations of uranium (Epov et al. 2005; Figg et al. 2000).
General environmental survey instruments (e.g., alpha particle meters) are available, but they are not
specific for plutonium. The predominant analytical method for measuring plutonium present at or near
background concentrations in both biological and environmental media requires radiochemical separation