64
PLUTONIUM
3. HEALTH EFFECTS
1977). Hamsters were also resistant to radiation-induced lung cancer following exposure to other alpha-
emitting radionuclides, such as radon and radon daughters (Agency for Toxic
Substances and Disease
Registry/EPA 1990).
All cancer effect levels (CELs) for dogs and nonhuman primates exposed to aerosols of plutonium
compounds are recorded in Table 3-3 and plotted in Figure 3-1.
3.2.2
Oral Exposure
3.2.2.1 Death
No studies were located regarding death or lifespan shortening in humans
after oral exposure to
plutonium.
In neonatal rats, given a single 1.2x10
4
kBq
238
Pu /kg dose (as plutonium citrate) by gavage,
45% mortality was observed by 2 weeks postexposure; no deaths were reported following dosing at
3.7 kBq/kg (Fritsch et al. 1987).
3.2.2.2 Systemic Effects
No studies were located regarding respiratory, cardiovascular, hematological, musculoskeletal, hepatic,
renal, or dermal/ocular effects in humans or animals after oral exposure to plutonium.
Gastrointestinal Effects.
No studies were located regarding gastrointestinal effects in humans after
oral exposure to plutonium.
Gastrointestinal effects were observed in neonatal rats following oral administration of
238
Pu/kg (as
plutonium citrate) by gavage (Fritsch et al. 1987). Mild hypertrophy of the crypts of the small intestine,
which form the secretions of the small intestine, was observed in the rats receiving a 5,300 kBq
238
Pu/kg
dose. Total disappearance of epithelial cells and crypts, combined with intestinal hemorrhaging, was
observed in rats that received 17,400 kBq
238
Pu /kg (Fritsch et al. 1987). Increased neutrophils were
noted on the surface epithelium and superficial cellular layers of the large intestine in adult rats given
155 μCi
238
PuO
2
/kg (5,740 kBq/kg) (Sullivan et al. 1960). This effect was noted at 3 (but not 6) days
postexposure.
65
PLUTONIUM
3. HEALTH EFFECTS
No studies were located regarding the following health effects in humans or animals after oral exposure to
plutonium:
3.2.2.3 Immunological and Lymphoreticular Effects
3.2.2.4 Neurological Effects
3.2.2.5 Reproductive Effects
3.2.2.6 Developmental Effects
3.2.2.7 Cancer
3.2.3
Dermal Exposure
3.2.3.1 Death
No studies were located regarding death or the shortening of lifespan in humans or animals after dermal
exposure to plutonium.
3.2.3.2 Systemic Effects
No studies were located regarding respiratory, cardiovascular, gastrointestinal, hematological,
musculoskeletal, hepatic, renal, or dermal/ocular effects in humans or animals after dermal exposure to
plutonium.
No studies were located regarding the following health effects in humans or animals following dermal
exposure to plutonium:
3.2.3.3 Immunological and Lymphoreticular Effects
3.2.3.4 Neurological Effects
3.2.3.5 Reproductive Effects
3.2.3.6 Developmental Effects
3.2.3.7 Cancer
3.2.4
Other Routes of Exposure
Numerous health effects studies are available for plutonium-injected animals. Results of the injection
studies support the findings from the inhalation studies. For example,
bone and liver tumors were
observed in dogs exposed to aerosols of
238
PuO
2
or
239
Pu(NO
3
)
4
that resulted in toxicologically significant
66
PLUTONIUM
3. HEALTH EFFECTS
systemic distribution of plutonium (see Section 3.2.1). Similarly, bone and liver tumors were associated
with intravenous injection of
239
Pu (as plutonium citrate) in dogs (Lloyd et al. 1993, 1995a, 1999a, 1999b;
Taylor et al. 1991). Detected plutonium levels in testes and ovaries of mice intravenously injected with
239
Pu (as the citrate) provide suggestive evidence that internalized plutonium could result in the irradiation
of germ cells (Green et al. 1976, 1977). However, Brooks et al. (1979) noted
the lack of significantly
increased frequency of chromosomal aberrations in spermatogonia of rodents following intravenous
injection of
239
Pu (as the citrate) at levels high enough to induce marked life shortening and increased
cancer incidence. Collectively, these results indicate that irradiation from internalized plutonium is not of
particular reproductive toxicity concern.
Because adequate information is available regarding health effects in animals following inhalation
exposure to aerosols of plutonium compounds that resulted in toxicologically significant levels of
internalized plutonium, the results of the injection studies are not presented in detail in this toxicological
profile for plutonium.
3.3 GENOTOXICITY
Abundant information is available regarding the genotoxicity of ionizing radiation (refer to the
Toxicological Profile for Ionizing Radiation for a detailed discussion of the genotoxic effects of various
forms of ionizing radiation). The genotoxicity of alpha radiation from plutonium sources has been
investigated in various
groups of plutonium workers, as well as
in vivo animal studies and a variety of
in vitro
test systems. Tables 3-4 and 3-5 present the results of
in vivo and
in vitro genotoxicity studies,
respectively.
Although epidemiological studies do not provide conclusive evidence that plutonium produces genetic
damage in humans, results of some studies provide suggestive evidence of dose-related increases in
chromosomal aberrations in plutonium workers with measurable internalized plutonium. For example,
Livingston et al. (2006) examined relationships between
external radiation dose, internal radiation dose,
and frequencies of chromosomal aberrations and micronuclei in peripheral blood lymphocytes of a group
of 30 retired plutonium workers with dosimetrically-estimated internal and external radiation doses
>0.5 Sv, another 17 workers with predominantly external radiation doses <0.1 Sv, and 21 control subjects
with no history of occupational radiation exposure. Frequency of chromosomal aberrations was
positively correlated with the bone marrow dose (alpha radiation from internalized plutonium; 168 mSv