Monday, April 30, 2012

Polonium in Drinking Water

Wikipedia: [excerpted] "Polonium has 33 known isotopes, all of which are radioactive. They have atomic masses that range from 188 to 220 u. 210Po (half-life 138.4 days) is the most widely available. 209Po (half-life 103 years) and 208Po (half-life 2.9 years) can be made through the alpha, proton, or deuteron bombardment of lead or bismuth in a cyclotron.

210Po is an alpha emitter that has a half-life of 138.4 days; it decays directly to its stable daughter isotope, 206Pb. A milligram of 210Po emits about as many alpha particles per second as 4.5 grams of 226Ra. A few curies (1 curie equals 37 gigabecquerels, 1 Ci = 37 GBq) of 210Po emit a blue glow which is caused by excitation of surrounding air. A single gram of 210Po generates 140 watts of power.[4] Because it emits many alpha particles, which are stopped within a very short distance in dense media and release their energy..." [end excerpt]

Citation: Seiler RL, Wiemels JL 2012. Occurrence of 210Po and Biological Effects of Low-Level Exposure: The Need for Research. Environ Health Perspect.

Received: 10 October 2011; Accepted: 26 April 2012; Online: 26 April 2012


Background: 210Po concentrations exceeding 1 Bq/L in drinking-water supplies have been reported from four widely-separated States where exposure to it went unnoticed for decades. The radionuclide grandparents of 210Po are common in sediments and segments of the public may be chronically exposed to low levels of 210Po in drinking water or in food products from animals raised in contaminated areas.

Objectives: To summarize information on the environmental behavior, biokinetics and toxicology of 210Po and identify the need for future research.

Methods: Potential linkages between environmental exposure to 210Po and human-health effects were identified in a literature review.

Discussion: 210Po accumulates in the ovaries where it kills primary oocytes at low doses. The ovary may be the critical organ in determining the lowest injurious dose for 210Po because of its radiosensitivity and tendency to concentrate 210Po. 210Po also accumulates in the yolk sac of the embryo and in fetal/placental tissue. Low-level exposure to 210Po may have subtle, long-term biological effects because of its tropism towards reproductive and embryonic/fetal tissues where exposure to a single α particle may kill or damage critical cells. 210Po is present in cigarettes and maternal smoking has several effects that appear consistent with the toxicology of 210Po.

Conclusions: Much of the important biological and toxicological research on 210Po is more than 4 decades old. New research is needed to evaluate environmental exposure to 210Po and the biological effects of low-dose exposure to it so public-health officials can develop appropriate mitigation measures where necessary.

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