Eroded Radioactive Phosphogypsum
Radioactivity: the
property possessed by some elements (as uranium) or isotopes
(as carbon 14) of spontaneously emitting energetic particles
(as electrons or alpha particles) by the disintegration
of their atomic nuclei; also : the rays emitted
Glossary
of Terms
Bequerel
(Bq) and Bq/m3
Bequerel is the international standard unit for radioactivity;
that is the rate that radioactive materials decay. One Bq
is one decay per second. The US unit of radioactivity is
the Curie(Ci). One Ci is 3.7x 1010 decays per second. Bq/m3
is the international unit for volumetric activity concentration.
The relationship between activity concentrations is that
1 pCi/L = 37 Bq/m3
Dose
units: RAD, REM, Gray(Gy), Sievert (Sv) ...
Dose is a measure of energy absorbed in matter. The basic
units are RAD (US) and Gray (international). 1 Gy=100 RAD.
Dose Equivalent includes the energy deposited and the effectiveness
of that dose at producing damage in biological cells. The
basic units are REM (US) and Sv (international). 1 Sv=100
REM. Effective Dose Equivalent includes the sensitivity
of the human organ to the Dose Equivalent. It is a new concept
and is only given in units of Sv.
PicoCurie
and pCi/L
The US unit of radioactivity is the Curie(Ci). One Ci is
3.7x 1010 decays per second. One picoCurie is 3.7x 10-2decays
per second or 3.7x 10-2Bq. pCi/L is the US unit for volumetric
activity concentration. The relationship between activity
concentrations is that 1 pCi/L = 37 Bq/m3
Radon
A nickname for the isotope 222Rn of the element Radon. 222Rn
has a 3.8 day half-life, the longest of any Radon isotope.
It is a noble gas generated by the decay of radium found
in rocks and derived materials. It decays via alpha and
beta emission through a series of short-lived progeny, 218Po,
214Pb, 214Bi, 214Po to a moderately long-lived (21 years)
isotope of lead; 210Pb. 210Po is radon's last mortal daughter.
She decays into 206Pb
Radon
progeny/decay products/daughters
The series of nuclei that are produced when radon decays:
|
Nucleus:
|
222Rn
|
218Po
|
214Pb
|
214Bi
|
214Po
|
210Pb
|
210Bi
|
210Po
|
206Pb
|
|
Emits:
|
a
|
a
|
b
|
b
|
a
|
b
|
b
|
a
|
—
|
|
Life:
|
4
d
|
3
min
|
27
min
|
20
min
|
<1
ms
|
21
y
|
5
d
|
138
d
|
stable
|
Thoron
A nickname for the isotope 220Rn of the element Radon. 220Rn
has a 55 second half-life, much shorter than 222Rn. It is
a noble gas generated by the decay of radium found in rocks
and derived materials. It decays via alpha and beta emission
through a series of short-lived progeny. It is not as common
as radon in the environment. Indoors it is thought to contribute
about 10% of the total airborne radiation dose.
Resource
Information About Cancer and the Environment
|
|
|
Phosphogypsum, a waste by-product derived from
the wet process production of phosphoric acid, represents one of
the most serious problems facing the phosphate industry today. This
by-product gypsum precipitates during the reaction of sulfuric acid
with phosphate rock and is stored at a rate of about 30 million
tons per year on several stacks in central and northern Florida.
The main problem associated with this material
concerns the relatively high levels of natural uranium-series radionuclides
and other impurities which impact the environment.
[to be continued]
Radioactive
Cancer Risk Calculators from Exposure to Radiation Information and resources for Americans exposed to I-131 (a form of radioactive iodine) through fallout from above-ground nuclear testing in the 1950s and early 60s.
Common
Questions About Phosphogypsum
Phosphogypsum contains
radioactive material (radionuclides), which could potentially
result in harmful exposure to radiation. Prior
to processing, phosphate rock contains radium, uranium, thorium,
polonium, and lead. Once the rock has been crushed and processed,
the resulting waste has concentrated levels of these radioactive
materials. Depending on the quality of the phosphate rock, the
phosphogypsum could contain as much as 60 times the levels normally
found prior to processing.
From a radiation protection perspective, EPA is concerned primarily
with the radium, which tends to stay with the waste during processing.
Radium-226 gives off radon-222, an odorless, colorless, and tasteless
cancer-causing radioactive gas. There is also a small amount of
radiation being emitted from phosphogypsum in the form of gamma
rays.
Did you know?
Facts about Uranium 238
- It is pyrophoric: When it hits an object it bursts into flames,
producing tiny aerosolized particles less than 5 microns in diameter
that are easily inhalable into the terminal air passages of the
lung.
- It is a potent radioactive carcinogen, emitting a relatively
heavy alpha particle composed of 2 protons and 2 neutrons. Once
inside the body -- either in the lung if it has been inhaled,
or in a wound if it penetrates flesh, or ingested since it concentrates
in the food chain and contaminates water -- it can produce cancer
in the lungs, bones, blood, or kidneys.
- It has a half-life of 4.5 billion years, meaning it will remain
effectively radioactive for the rest of time.
- Children are 10 to 20 times more sensitive to the effects of
radiation than adults (In the Iraqi town of Basra, for example,
they are reporting an increase of 6 to 12 times in the incidence
of childhood leukemia and cancer). The incidence of congenital
malformations has doubled in the exposed populations in Iraq where
these weapons were used. Among them are babies born with only
one eye or missing all or part of their brain.
- That one-third of the American tanks used in Desert Storm were
made of uranium 238? Their crews were exposed to whole-body gamma
radiation.
Toxicological Profile for : Uranium
The ATSDR toxicological profile
succintly characterizes the toxicologic and adverse health effects
information for the hazardous substance
described here. Each peer-reviewed profile identifies and reviews
the key literature that describes a hazardous substance's toxicologic
properties. Other pertinent literature is also presented, but is
described in less detail than the key studies. The complete list
of topics covered (chapter titles) is shown at the left and in
more detail further down this page.
Uranium levels in various soils
Uranium
levels in various soils from Toxicological Profile for
Uranium (Draft) US Agency for Toxic Substances and Disease Registry
(ATSDR) September 1997, p. 255.
The
Depleted Uranium Cover-up and Associated Risks to Soldiers
in the Afghanistan and Iraq
Thousands of veterans returning from the Gulf War reported a variety
of disease symptoms, including chronic fatigue syndrome, immune
dysfunction, urinary disorders, joint pains, and amyotrophic
lateral sclerosis, but the Veterans Administration fobbed them
off with the same all-purpose diagnosis they had first imposed
on the Vietnam vets—battle stress. [John MacArthur,
author of Second Front: Censorship and Propaganda in the Gulf
War, reminds
us that both Bush administrations shared many of the same top
officials. "These are all the same people who were running
it more than ten years ago," he says. "They’ll
make up just about anything to get their way."]
|
Radioactivity
