Human Absorption and Retention of Polonium-210 from Caribou Meat

Abstract

The gastrointestinal (GI) absorption factors and the biological retention times for polonium were determined for a group of 14 volunteers--seven men and seven women--from Saskatoon, Saskatchewan, Canada. Each volunteer consumed 2.0 kg of caribou meat containing known amounts of naturally occurring 210Po. Urine and faecal samples were collected for up to 65 days after meat consumption and analysed for 210Po. The average GI absorption factor for the 14 volunteers was 56 +/- 4% (range = 31-71%), not significantly different from the ICRP value of 50%. About 3% of absorbed polonium underwent prompt excretion by the urinary pathway. The remainder was retained by the body with a half-time >100 days, compared to the ICRP value of 50 days. The effect of these findings increases the dose estimate for ingestion of 210Po in food by a factor of 1.5 to 3.5. Thus, background doses to people consuming caribou and reindeer may be higher than previously thought.

210Pb: A Predictive Biomarker of Retrospective Cigarette Smoke Exposure

“…The median urinary 210 Po activity concentration in smokers (19 mBq) was also close to being statistically greater than that in nonsmokers (15 mBq Po is absorbed (39), whereas only 15-20% of ingested 210 Pb is absorbed (40)] to a larger extent than it is influenced by inhalation intakes or internal body stores. Most recently, a group in central Italy published their study of the 210 Po activity concentration in the 24-hour urine samples of 132 residents and also failed to find a statistically significant difference in the urine of smokers versus nonsmokers (41).…”

Variation of 210Po daily urinary excretion for male subjects at environmental level

“…ICRP 30 (1980) also states that the total 210 Po content in the human body is typically 40 Bq, and 60 % of this activity is in the mineral bone. The other 40 %, or 16 Bq, is assumed to be in soft tissues and thus available for redistribution and also for excretion (Thomas et al 2001). The fact that the 24-h excretion of 210 Po through urine in the studied time period was rather constant for the investigated volunteers is very remarkable because of the extremely small mass associated with the measured activities (5 mBq 210 Po corresponds to about 10 -16 g), which must pass through many compartments (tissues) of the body, where there are different elements and molecules in incomparably greater amount present.…”

“…The time period was chosen in accordance with Hunt and Allington (1993) and Thomas et al (2001) who determined 210 Po in urine and faeces before and after consumption of crab resp. caribou meet (in an effort to determine the gastrointestinal absorption factor of polonium for humans).…”

Excretion rate of210Po in urine of general population (a review)

“…According to Thomas et al (2001) approximately 3% of the absorbed 210 Po is excreted by urine in course of several days after the intake.…”