49
PLUTONIUM
3. HEALTH EFFECTS
The highest NOAEL values and all reliable LOAEL values for hematological effects in
dogs and
nonhuman primates exposed to aerosols of plutonium are recorded in Table 3-3 and plotted in Figure 3-1.
Musculoskeletal Effects.
Epidemiological Studies in Humans.
Possible associations between exposure to plutonium and mortality
from bone disease (e.g., bone cancer) and other musculoskeletal diseases have been examined in studies
of workers at U.S. plutonium production and/or processing facilities (Hanford, Los Alamos, Rocky Flats),
as well as facilities in Russia (Mayak) and the United Kingdom (e.g., Sellafield). The
most recent
findings from these studies are summarized in Table 3-2. Study outcomes for mortality (e.g., bone
cancer) are described in Section 3.2.1.1 (Carpenter et al. 1998; Koshurnikova et al. 2000; McGeoghegan
et al. 2003; Omar et al. 1999; Wiggs et al. 1994; Wing et al. 2004). Collectively, these studies have not
found statistically significant associations between mortality rates for noncancer bone or musculoskeletal
disease and exposure to plutonium among workers at these facilities (McGeoghegan et al. 2003; Omar et
al. 1999; Wiggs et al. 1994).
Studies in Animals.
Radiation osteodystrophy, characterized
by peritrabecular fibrosis, osteosclerosis,
and osteoporosis, was observed on necropsy in ITRI and PNL dogs exposed to
238
PuO
2
aerosols (Hahn et
al. 1991a; Muggenburg et al. 1996; Park et al. 1997). Although osteodystrophy in the
238
PuO
2
-exposed
ITRI dogs was often
associated with bone tumors, it also occurred in the absence of bone tumors (Hahn et
al. 1991a; Muggenburg et al. 1996). In the
238
PuO
2
-exposed PNL dogs, radiation osteodystrophy was
observed at initial lung burdens ≥1.17 kBq/kg (Park et al. 1997). The incidence and severity of
osteodystrophy was dose-related and necrotic osteoblasts and empty lacunae
near endosteal surfaces were
observed at high (not otherwise specified) initial lung burdens (Park et al. 1997). Radiation
osteodystrophy has also been reported in dogs exposed to
239
Pu(NO
3
)
4
aerosols (DOE 1986b, 1989).
Information on plutonium-induced bone tumors is reviewed in Section 3.2.1.7, Cancer.
The highest NOAEL values and all reliable LOAEL values for musculoskeletal effects in each species
and duration category are recorded in Table 3-3.
The highest NOAEL values and all reliable LOAEL values for musculoskeletal effects in dogs and
nonhuman primates exposed to aerosols of plutonium are recorded in Table 3-3 and plotted in Figure 3-1.
50
PLUTONIUM
3. HEALTH EFFECTS
Hepatic Effects.
Epidemiological Studies in Humans.
Possible associations between exposure to plutonium and mortality
from liver disease (e.g., liver cancer) have been examined in studies of workers at U.S. plutonium
production and/or processing facilities (Hanford, Los Alamos, Rocky Flats), as
well as facilities in Russia
(Mayak) and the United Kingdom (e.g., Sellafield). The most recent findings from these studies are
summarized in Table 3-2. Study outcomes for mortality (e.g., liver cancer) are described in
Section 3.2.1.1 (Carpenter et al. 1998; Gilbert et al. 1989b, 2000; McGeoghegan et al. 2003; Omar et al.
1999; Wiggs et al. 1994; Wing et al. 2004). Collectively, these studies have not found
statistically
significant associations between mortality rates for noncancer liver disease and exposure to plutonium
among workers at these facilities (McGeoghegan et al. 2003; Omar et al. 1999; Wiggs et al. 1994).
Studies of liver cancer morbidity among Sellafield and Mayak workers are described in Table 3-2 and in
greater detail in Section 3.2.1.7 (McGeoghegan et al. 2003; Omar et al. 1999; Tokarskaya et al. 2006).
Studies in Animals.
Adverse effects on the liver have been observed in dogs exposed to aerosols of
plutonium. Elevated serum liver enzymes and non-neoplastic liver lesions were noted in
dogs exposed to
238
PuO
2
and
239
Pu(NO
3
)
4
, and non-neoplastic liver lesions have been observed in dogs exposed to
239
PuO
2
.
In addition, bile duct hyperplasia was observed in dogs treated with
238
PuO
2
and
239
Pu(NO
3
)
4
. Although
elevated liver enzymes and non-neoplastic liver lesions indicate are indicative of plutonium-induced
hepatotoxicity, clinical signs of liver dysfunction (i.e., ascites, icterus, clotting disorders) have not been
observed (Park et al. 1997; Weller et al. 1995b). Information on plutonium-induced
liver tumors is
reviewed in Section 3.2.1.2, Cancer.
Exposure of Dogs to
238
PuO
2
.
Elevated serum alkaline phosphatase (ALP) and alanine aminotransferase
(ALT) was
observed in
238
PuO
2
-exposed ITRI and PNL dogs over the entire range of initial lung burdens
(≥0.36 kBq/kg) (Muggenburg et al. 1996; Park et al. 1997; Weller et al. 1995b). The increased enzyme
activity exhibited a biphasic (early and late effects) response that was dependent on time and exposure
level (Park et al. 1997; Weller et al. 1995a). The time to occurrence was inversely related to initial lung
burden, with elevations observed by 6–8 years postexposure in dogs with initial lung burden of 1 kBq/kg
and in 4–6 years postexposure in dogs with higher initial lung burdens ( ≥5 kBq/kg) (Muggenburg et al.
1996). The most common non-neoplastic liver lesion was nodular hyperplasia (or adenomatous
hyperplasia), followed by vacuolar degeneration (Muggenburg et al. 1996). Periportal fibrosis and biliary
fibrosis were also observed in
238
PuO
2
-exposed dogs (Gillett et al. 1988).