70
PLUTONIUM
3. HEALTH EFFECTS
plutonium. Chromosomal aberrations were observed in monkeys and hamsters following inhalation
exposure to plutonium. Increases in chromosomal aberrations in blood lymphocytes were seen in
immature Rhesus monkeys exposed to
239
PuO
2
at concentrations resulting in initial lung burdens of 1.9–
19 kBq
239
Pu/kg body weight (LaBauve et al. 1980) and Cynomolgus monkeys exposed to
239
Pu(NO
3
)
4
at
a concentration resulting in a projected initial lung burden of 40 kBq (Brooks et al. 1992),
but not at lower
levels. Dose-related increases in the frequency of chromosomal aberrations were observed in Chinese
hamster blood cells 30 days after exposure of the animals at aerosol concentrations resulting in deposition
of 370–9600 kBq
239
Pu/g of lung tissue (DOE 1976). Increases in chromosomal aberrations in bone
marrow cells were observed in mice following intravenous
injection of
239
Pu (as the citrate) at 13 kBq
239
Pu/kg body weight (Svoboda et al. 1987). The highest incidence of these mutations was observed in
the early days postinjection. Increased frequency of chromosomal aberrations was observed in liver
tissue of Chinese hamsters intravenously given
239
Pu or
238
Pu (as the citrate or the dioxide) to achieve
levels ranging from 0.026 to 0.74 kBq
239
Pu or
238
Pu/g of liver tissue (DOE 1976) or 74 kBq
239
Pu/kg
body weight (IAEA 1976b). The frequency of aberrations was much higher in
hamsters exposed by
intravenous injection to
239
Pu or
238
Pu (as the citrate) than in hamsters exposed to
239
PuO
2
or
238
PuO
2
(IAEA 1976a, 1976b). Stroud (1977) reported significantly increased frequency of chromosomal
aberrations in lung cells of Syrian hamsters following inhalation exposure to
238
PuO
2
-ZrO
2
particles at a
level
resulting in initial
238
Pu lung burden of approximately 5.2 kBq.
The induction of micronuclei in pulmonary alveolar macrophages (PAM) was noted in mice exposed to
238
PuO
2
or
239
Pu O
2
aerosols under exposure conditions that resulted in mean initial lung deposits of
approximately 550 and 580 Bq, respectively (approximately 22 and 24 Bq/kg body weight, respectively)
(Talbot et al. 1989). Micronuclei in
PAM of control mice averaged <0.1%, whereas peak incidences of
micronuclei in the
238
PuO
2
- and
239
PuO
2
-exposed mice reached 3 and 5%, respectively, at 21 days
postexposure.
Increased frequency of chromosomal aberrations have been observed in spermatogonia of rodents
following parenteral administration of plutonium compounds at activity levels much higher than those
known to cause marked life shortening and increased cancer incidence. Markedly increased frequencies
of chromosomal aberrations were observed in spermatogonia of mice receiving a single intraperitoneal
injection of
238
Pu(NO
3
)
4
at
238
Pu activity levels ≥231 kBq/kg body weight (Pomerantseva et al. 1989).
Increased frequency of reciprocal translocations in spermatogonia was observed in male mice 6–18 weeks
after intravenous injection of
239
Pu (as the citrate) at 370 kBq
239
Pu/kg body weight (Beechey et al. 1975).
An increase in the frequency of heritable translocations was also observed in spermatogonia
of male mice
71
PLUTONIUM
3. HEALTH EFFECTS
intravenously injected with
239
Pu (as the citrate) at 370 kBq
239
Pu/kg body weight (Generoso et al. 1985).
The frequency of translocations increased as a function of time and dose. However, induction of
reciprocal translocations was not significant in male mice intravenously injected with 150 kBq
239
Pu/kg
body weight (Searle et al. 1976). No statistically significant increases in the
incidence of chromosomal
aberrations per spermatogonia cell were observed in mice or hamsters following intravenous
administration of
239
Pu (as the citrate) at activity levels (ranging from 22 to 74 kBq
239
Pu/kg body weight)
high enough to induce marked life shortening and increased cancer incidence (Brooks et al. 1979).
Dominant lethality has been observed in plutonium-exposed mice. Fetal intrauterine death occurred in
female mice mated with male mice that had received
239
Pu (as the citrate) at levels ranging from 3.7 or
18.5 kBq 4 weeks prior to mating (IAEA 1976k; Lüning et al. 1976). The effects of the dominant
lethal
mutations were also observed when untreated females were mated with male
mice from the F
1
generation.
Exposure of male mice to higher doses of
239
Pu resulted in sterility 12 weeks postexposure (IAEA 1976k;
Lüning et al. 1976). Pomerantseva et al. (1989) reported the induction of dominant lethal mutations in
male mice that had been administered single intraperitoneal injection of
239
Pu(NO
3
)
4
at levels
≥0.925 kBq/g body weight 2–22 weeks prior to mating; males receiving 1.85 kBq/g body weight became
sterile 9 weeks postinjection. Exposure of female mice to plutonium also resulted in dominant lethal
mutations (Searle et al. 1982). Intravenous injection of female mice with
239
Pu (as the citrate) at 740 kBq
239
Pu/kg body weight resulted in marked oocyte killing and subsequently reduced number of mice which
became pregnant, compared with the controls. Both pre- and postimplantation dominant lethals were
induced when mating occurred at long periods (12 weeks) after intravenous exposure to plutonium.
Consistently positive genotoxicity results have been reported in various test systems exposed to the alpha
radiation from plutonium compounds
in vitro (see Table 3-5). Chromosomal aberrations were reported in
human peripheral blood lymphocytes and lymphoblasts (DOE 1980h; Purrott et al. 1980); bone marrow
and 10T1/2, 3T3 cells from mice (Kadhim et al. 1992; Nagasawa et al. 1990a); and M3-1, V79,
and ovary
K-1 cells from Chinese hamsters (Griffin et al. 1994; Nagasawa et al. 1990b; Welleweerd et al. 1984).
Sister chromatid exchanges were noted in plutonium-exposed human peripheral blood lymphocytes
(Aghamohammadi et al. 1988), mouse 10T1/2, 3T3 cells (Nagasawa et al. 1990a), and Chinese hamster
ovary cells (Nagasawa and Little 1992; Nagasawa et al. 1990b). Bilbao et al. (1989) reported plutonium-
induced micronuclei in human peripheral blood lymphocytes. Other positive genotoxicity results include
gene mutation in human and hamster cell lines (Barnhart and Cox 1979; Chen et al. 1984; DOE 1980h;
Thacker et al. 1982), DNA double-strand breaks in Chinese hamster V79-4 and V79-379A cells (Fox and
McNally 1990; Jenner et al. 1993), DNA damage in Chinese hamster V79379A cells (Prise et al. 1987),