POTASSIUM, RADIOACTIVE: Nuclear Power Plant Emissions
Plant Concentrations :
Potassium-40 concentrations in plants collected from Livingston Island
(Antarctic Regions) were 34.7, 64, 374, and 131 Bq/kg wet weight, in mosses
(genus Bryum), lichens (Usnea antarica), algae (Gigartina papillosa), and algae
(genus Desmarestia), respectively(1). Potassium-40 levels in wild and edible
plants in the vicinity of the Kozloduy nuclear power plant in Bulgaria were 950,
2130, and 1400 Bq/kg in Taraxacum officinale, Plantago lanceolata, and Populus
nigras Italica, respectively, detection limit of 360 mBk/kg(2).
Sediment/Soil Concentrations :
SOIL: Potassium-40 concentrations in rocks range from 70-1,500 Bq/kg(1). Average
concentrations of potassium-40 in continental crust and soil are 850 and 400 Bq/kg,
respectively(1). Average concentration of potassium-40 in igneous rocks,
sandstones, shales, and limestones are 810, 330, 810, and 81 Bq/kg,
respectively(1). A study to determine radionulcides in soil within a 0-15km
radius from coal-fired power plants in Melnik and Hodonin and a nuclear plant in
Dukovany, Czechoslovakia found no relevant increase in soil concentration of
potassium-40 even though the radionuclide is present in fly ash(2). Average
activity in soil samples collected and analyzed from 1976 through 1978 were
2.0%, 1.5%, and 2.0% in the vicinity of the plants at Melnik, Hodonin, and
Dukovany, respectively(2).
Food Survey Values :
Potassium-40 is the predominant radioactive component in most foods(1,2).
Seafood collected from the Ligurian Sea (Northern Italy) after the Chernobyl
accident contained mean potassium-40 concentrations ranging from 122.6 to 164.0
Bq/kg wet weight in Smallspotted catshark (Scyliorhinus canicula) and Hake (Merluccius
merluccius), respectively(3). The mean concentration of potassium-40 in
composite samples of wild edible mushrooms collected from 1985-1997 from
coniferous forests around the Nuclear Centre of Mexico was 1,021 Bq/kg dry
weight(4). A mean potassium-40 concentration of 83.1 Bq/kg (range 39.1 to 132.9
Bq/kg) was reported for 39 honey samples collected 12 years after the Chernobyl
accident(5). Average potassium-40 concentrations of 22.0 and 23.6 Bq/kg were
reported in honey from areas around Warsaw, Poland in 1989 and in the
Piedmontese (Italy) in 1987(5). Foods purchased during the US FDA's Total Diet
Study, conducted from 1991 to 1997 were analyzed for radionulcides, including
potassium-40; results indicated trace amounts present consistent with the near
disappearance of contamination from nuclear weapons testing conducted during the
early 1960s(6).
Food Survey Values :
Potassium-40 levels in edible plants from South Bulgaria(1).
| Plant | Mean Concentrations (Bq/kg) | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Onion | 148-329 | ||||||||
| Cabbage | 59-60 | ||||||||
| Potatoes | 98-160 | ||||||||
| Tomatoes | 57-163 | ||||||||
| Peppers | 63-100 | ||||||||
| Grapes | 30 | ||||||||
| Corn | 100 |
MORE ABOUT HEALTH EFFECTS
Human
Toxicity Excerpts:
/OTHER TOXICITY INFORMATION/ Potassium-40, which is the inseparable radioactive
component of natural, biologically important potassium, will probably cause the
largest portion of the internal dose ... in the fetus because it doesn't
breathe.
/OTHER TOXICITY INFORMATION/ The diffusion coefficients for the exchange of
potassium across the membrane of erythrocytes of humans ... have been determined
by the use of artificially radioactive potassium, both into and out of the
erythrocytes both in vitro and in vivo. The diffusion coefficients found in
minutes were 0.2 to 0.25x10-3 ...
Probable Routes of Human Exposure:
As there are no specific commercial or medical uses for potassium-40(1),
occupational exposure is not expected(SRC). The general population will be
exposed via ingestion(2) to potassium-40(SRC), since potassium-40 is present in
small amounts (0.012%) in potassium, which is found widely in the
environment(1). Occupational exposure to potassium-42 and -43 may occur via
dermal contact; general population exposure may be limited to those being
administered these radioisotopes as a result of medical applications(SRC).
Body Burden:
The body content of potassium is under strict homeostatic control and is
maintained at a relatively constant level of about 140 g/70 kg. This amount of
potassium contains approximately 0.1 uCi (4,000 Bq) of potassium-40. Because the
body controls the potassium balance, environmental variations have little effect
on the potassium-40 content in the body. This natural potassium-40 delivers a
dose of 20 mrem/year (0.2 mSv/year) to the gonads and other soft tissues and 15
mrem/year (0.15 mSv/year) to bone.
Potassium-40 is the predominant radioactive component in human tissues(1). The
potassium-40 content in the human body is on the order of 0.1 uCi(1). However,
because the body controls the potassium balance, variations in environmental
levels have little effect on the potassium-40 content in the body(2).
Probable Routes of Human Exposure:
As there are no specific commercial or medical uses for potassium-40(1),
occupational exposure is not expected(SRC). The general population will be
exposed via ingestion(2) to potassium-40(SRC), since potassium-40 is present in
small amounts (0.012%) in potassium, which is found widely in the
environment(1). Occupational exposure to potassium-42 and -43 may occur via
dermal contact; general population exposure may be limited to those being
administered these radioisotopes as a result of medical applications(SRC).
Body Burden:
The body content of potassium is under strict homeostatic control and is
maintained at a relatively constant level of about 140 g/70 kg. This amount of
potassium contains approximately 0.1 uCi (4,000 Bq) of potassium-40. Because the
body controls the potassium balance, environmental variations have little effect
on the potassium-40 content in the body. This natural potassium-40 delivers a
dose of 20 mrem/year (0.2 mSv/year) to the gonads and other soft tissues and 15
mrem/year (0.15 mSv/year) to bone.
Potassium-40 is the predominant radioactive component in human tissues(1). The
potassium-40 content in the human body is on the order of 0.1 uCi(1). However,
because the body controls the potassium balance, variations in environmental
levels have little effect on the potassium-40 content in the body(2).
All of the above is directly from http://toxnet.nlm.nih.gov/