Sin ttulo de diapositiva

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The Environmental Radioactivity Group presents
The Detective Work of Atoms in Nature
Technical design Francisco Hernández Graphic
design Linda Karlsson Text F. Hernandez Farid
El-Daoushy
Pac.man
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UPPSALA
UNIVERSITY
PHYSICS
DEPARTMENT
Produced by the environmental radioactivity group
Starring
Elb,
Pac,
Mar
and Paw
Matt,
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Radionuclides
Ra-226
Radionuclides are special nuclei which transform
themselves into other nuclei giving away
measurable amounts of energy
Ra-226
Radionuclide Colour
Radionuclides of the same element are presented
with the same colour
Name tag
All radionuclides will carry a name tag
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A seminar is being given at the Physics
Department at Uppsala University....
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Symbol - Element Pb - Lead Ra - Radium
Rn - Radon Cs - Cesium
Rn-222
Teacher Class...Today we are going to see an
example of
how we can use radionuclides as tracers
(detectives) of
different phenomena which occur in nature.
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Because of their physico-chemical properties,
radionuclides can be used as detectives of
different transport and deposition processes of
pollutants in the environment
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Symbol - Element Pb - Lead Ra - Radium
Rn - Radon Cs - Cesium
Zzzz
Teacher Our story begins in any soil where some
important radionuclides such as
Ra-226 exit naturally....
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Rn-222
Ra-226
Mar ... Then, you will soon decay into Rn-222
Mat Yes, my life-time determines so...
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Radionuclides decay at a constant rate. This rate
is determined by their mean life-time. Rn-222
is a daughter of the parent radionuclide Ra-226.
At normal conditions, Rn-222, is a gas.
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Zrrrrrr !!!
When radionuclides decay, most of the energy is
released in the form of radiation
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Rn-222 atoms acquire some initial velocity from
the remaining energy of the Ra-226 decay and move
within soils. In some cases the Rn-222 atoms can
escape into the atmosphere (emanation and
exhalation).
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Rn-222
Intense dude!
Matt yeeeeeee haaaaaaa !!!!!!
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Rn-222 atoms which exhalate from the soils rise
to higher layers in the atmosphere where they mix
with other stable and unstable atoms. Rn-222 can
be used to trace the exhalation from soils of
gases such as CH4 and CO2.
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Pb-206
Cs-137
Pb-210
Paw I come from the factory down the road. I am
an industrial product. They call me lead
pollution.
Elb My name is Pb-210, I am a natural
radionuclide. I am a decay product of Rn-222. I
have the same origin as you. In a few days you
too, Rn-222, will become Pb-210.
Mat Hello guys, how did you all get here ?
Pac I come from Chernobyl. I am a fission
product. They call me nuclear waste.
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Although Rn-222 constantly decays, there are
always fresh inputs from soils. The next
long-lived daugther of Rn-222 is Pb-210 with
a mean life-time of approximately 32 years.
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Zrrrrrr !!!
After a few short-lived daughters of Rn-222,
Pb-210 is formed
.
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Like many other atoms, Pb-210 attach itself to
nanoparticles and form aerosols in the
atmosphere. As both Pb-206 and Pb-210 are
chemically similar so they behave the same.
Pb-210 can then be used to follow stable
lead. Water droplets can form around the aerosols
in the atmosphere
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Oh! Oh!
Pb-210
Pb-210
Pb-206
Mat What is ... glup .... happening ?
Paw There is water .. glup... everywhere!
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Particulates and/or droplets deposit over the
soil surface either in the form of wet
deposition (rain or snow) or in the form of dry
deposition (dust).
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Pb-210
Ahh!!!
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Some of the particulates which are brought down
to the earths surface by dry and wet deposition
end up in natural reservoirs such as lakes.
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(No Transcript)
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Most of the matter which exists in the lake
water, either via direct input and/or internal
production, settles down to the bottom forming
sediment layers.Thus sediments can be used as
historical archives of environmental changes
including atmospheric deposition
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Pb-210
Mat Where are we going now?
Elb Dont know, I think we are settling down !!!
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Sedimentation is a natural cleaning mechanism of
a lake water. Matter is removed from the water
and binded into the sediments.
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Old Fish The water is not as clean as it used to
be !!!
Old Fish If you really want to find out, you can
check the sediment record at the bottom of the
lake !!! .
Young Fish How clean was it ?
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The history of the lake is recorded on its
sediments if its original order is not disturbed.
Pb-210 can be used as a time indicator of the
last 200 years of the lake history.
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Stop pushing this is my place !
Mat I think all the sits deeper in the sediment
are taken, I guess we will have to stay up here
on the top!!!.
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Radionuclides such as Pb-210 make the calculation
of deposition rates of other important elements
such as phosphorous, nutrients and heavy metals
possible. Among other things, this information
can be used to study pollution damages to our
delicate aquatic environments and help the making
of protective policies.
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Mat Ahhhhh!, what is happening now ?.
There we go again!
Sediments are being collected for scientific and
monitoring studies.
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Sediments can be collected, sliced and measured
in order to obtain information about the history
of a lake. A common tool used to measure key
radionuclides such as Pb-210, Cs-137 and Am-241
is gamma spectrometry.
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Let me out!
Aaaaa...
Sediments are being prepared for measurement in a
specialised lab
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The ultra-low background gamma spectrometry lab
at the new Ångström Laboratory is one of the only
European laboratories specialised in the
measurement of radionuclides in recent aquatic
deposits
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Ultra low level gamma spectrometry lab at
Ångström laboratory
Cool!
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bye
Teacher ... so this is only one example of how
we can use radionuclides as detectives in nature
...
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The End
Hasta la vista...baby!
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Radioactivity
in the
environment
and studies of
Group leader Farid El-Daoushy PhD Francisco
Hernández For more information visit our
homepage http//130.238.194.166/
environmental
systems