Regional variation in radiation dose to caribou in the Canadian north: 1992--94

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:367523

Macdonald, C R; Ewing, L L; Wiewel, T M ^[1]

---

1. AECL, Pinawa, Manitoba (Canada). Whiteshell Labs.

Research to support Canada`s concept of the disposal of nuclear fuel waste has shown that caribou are chronically exposed to high radiation doses from natural {sup 210}Pb and {sup 210}Po accumulation. Initial results showed that weighted absorbed dose to caribou could reach 500 mGy{center_dot}a{sup {minus}} in some animals. The research continued in 1993/94 to determine the regional variability of these nuclides and to compare observed doses in caribou with criteria recommended to protect the environment. Muscle, liver, kidney and bone from several herds were analyzed for {sup 137}Cs, {sup 40}K, {sup 210}Pb and {sup 210}Po. The results confirmed the high levels of naturally-occurring nuclides in some herds, while non-detectable levels were observed in other herds. Maximum muscle {sup 137}Cs activity (238 Bq/kg) was observed in the central Canadian Arctic. In all herds, {sup 137}Cs activity was lower than in 1988 and substantially lower than comparable tissues in reindeer from northern Europe. Mean bone {sup 210}Pb activity ranged from non-detectable to 1,285 Bq/kg in a herd from the northeastern Canadian Arctic, including a maximum of 3,600 Bq/kg. Both {sup 210}Pb and {sup 210}Po activities in eastern Canadian herds were higher than in European and Russian herds reported in the literature. Regional differences in bone {sup 210}Pb activity correspond with natural {sup 210}Pb deposition and lichen community composition. It is not known if the long-range transport of {sup 210}Pb derived from fossil fuel and gasoline combustion adds significantly to the Canadian Arctic relative to natural sources. Mean weighted absorbed doses to the caribou ranged from < 1 mGy{center_dot}a{sup {minus}1} in herds in the western Arctic to 300 mGy{center_dot}a{sup {minus}1} in the east. Studies on {sup 210}Po distribution show that doses to specific tissues may be substantially higher than these estimates, which assume uniform distribution in tissues.

• OSTI ID: 367523
• Report Number(s): CONF-9511137--; ISBN 1-880611-03-1
• Country of Publication: United States
• Language: English

Related Subjects

56 BIOLOGY AND MEDICINE
APPLIED STUDIES
ARCTIC REGIONS
CANADA
CESIUM 137
CHRONIC EXPOSURE
CONTAMINATION
DEER
LEAD 210
POLONIUM 210
POTASSIUM 40
RADIATION DOSES
TISSUE DISTRIBUTION