In an April 26 letter, the EPA said the Energy Department had failed to provide enough information on the extent of the contamination to justify setting the exposure limit of 15 millirems
of radiation per year.
A 15 millirem
standard is being used at Santa Susana, allowing an estimated potential cancer risk of one in 3,333 - not as strict as the one in 1 million potential cancer risk activists want and the EPA strives for.
56) Lowering of standards might also raise questions with the timing for the change in the allowable standard for radiation dose per screening from 10 millirems
in 2002 to 25 millirems
in 2009, the standard allowing more radiation per dose by two and a half times from the 2002 (57) standard to the 2009 (58) standard.
Exposure to radiation can be measured in minute particles called millirems
As the agency works its way through the process of evaluating its standards--which the spokes-woman says now cover only the ingestion pathway, not inhalation or dermal routes--one starting point will be its current thresholds: 30 [micro]g/L for uranium, 5 picocuries per liter (pCi/L) for combined radium-226 and -228, 15 pCi/L for gross alpha radioactivity, and 4 millirems
per year for beta/gamma radioactivity.
are measured in either sieverts or millirems
, but scientists aren't sure how much radiation is transferred through consumption of contaminated tuna.
The million-year standard requires that any person outside the boundaries of the repository receive no more than 15 millirems
per year for 10,000 years and 100 millirems
per year for the next 990,000 years.
An MIT website says 300 millirems
a year is the normal exposure to radiation for a resident of Boston and 400 is the normal exposure in mile-high Denver, while 5,000 millirems
is the yearly limit for adults in the United States who work with radioactive material.
A typical medical diagnostic X-ray will expose a person to between five and 100 millirems
On average, Miley said, Americans receive 360 millirems
of naturally occurring radiation per year, just from the sun, rocks and soil.
leaves the EPA standard intact for the first 10,000 years, at a mean all-pathways individual dose of 15 millirems
per year, with a separate groundwater protection standard that conforms with the EPA Safe Drinking Water Act standard of 4 millirems
EPA has since proposed another health standard, which appears to ignore the court ruling by allowing radiation exposure to residents of the nearby Amargossa Valley to jump from a mean of 15 millirems
per year for the first 10,000 years to a median value of 350 millirems
per year subsequently.