Health Risks of Ionizing Radiation: - Clark University

80 Radiation Workers
Figure 6-10. A pool type reactor at the Livermore facility is
pictured here (http://www.llnl.gov/timeline50s.html).
Los Alamos National Laboratory. Los Alamos
National Laboratory (LANL) is located on 27,000
acres of land 35 miles west of Santa Fe, NM. LANL
was established in 1943 as a secret laboratory (then
known as Project Y) with a mission to design,
construct and test the first atomic bomb. Nuclear
research has continued at the laboratory since then.
Primary forms of radiation that workers at Los
Alamos are exposed to are x-rays, gamma rays and
neutrons (externally), and tritium and plutonium
(internally).
After observations at Lawrence Livermore
National Laboratory of increased malignant
melanoma among employees, researchers at Los
Alamos were prompted to investigate disease
incidence in their workforce. Acquavella et al.
(1982) reported 6 cases of malignant melanoma,
not significantly more than the 5.7 expected
cases. In 1983, Acquavella et al. published a casecontrol
analysis of LANL workers and again found
no association between radiation exposure and
malignant melanoma; this report suggested that
melanoma incidence increased with educational level
(potentially reflecting lifestyle risk factors). Wiggs
et al. (1994) conducted a more general analysis of
mortality rates at Los Alamos. This study reported
one case of osteogenic sarcoma, a notable finding
since it is a rare bone cancer that has been related
to plutonium exposure in animal studies. There was
also an elevated risk of lung cancer among workers
monitored for internal exposure to plutonium (RR
1.78, 0.79-3.99). This finding is notable because
lung cancer mortality was relatively low among
externally exposed workers indicating a strong
healthy worker effect. Significantly positive doseresponse
relationships were found between external
exposure and brain/CNS cancer, esophageal cancer,
and Hodgkin’s disease. Hodgkin’s disease is not
typically associated radiation exposure.
Portsmouth Uranium Enrichment Plant. The
Portsmouth Uranium Enrichment Plant site, located
in Pike County, Ohio, covers approximately 4,000
acres. Uranium enrichment activities began in 1954
and continued through 1981. During the years of
operation the plant employed approximately 3,000
people. Studies of this cohort have not been peerreviewed
and have been largely inconclusive.
Brown and Bloom (1987) investigated mortality
over a relatively short study period, with a maximum
observation period of only 28 years. 40% of the
cohort was hired after 1965 leaving only 17 years for
follow-up. These authors did find elevated SMRs for
stomach cancer (1.69, 0.81-2.10) and lymphopoietic
cancers (1.46, 0.92-2.18). Ahrenholz et al. (2001)
also examined risks at the Portsmouth plant and
again found non-significant increases in cancers of
Figure 6-11. Dr. John Gofman (second from left) at the time
that this photo was taken (1960s) was the first Associate
Director for the Biomedical Program at Lawrence Livermore
National Laboratory (http://www.llnl.gov/50th_anniv/
decades/1960s.htm).