What happens to film as it ages?

----- Original Message -----
From: "Donald Qualls"
Newsgroups: rec.photo.equipment.large-format
Sent: Saturday, October 16, 2004 10:25 AM
Subject: What happens to film as it ages?

Some text omitted

? FWIW, coal- and oil-burning power plants release more radioactivity (in
the form of carbon-14 and a trace of tritium) into the atmosphere in
day-to-day operation every year, year in and year out, than all the
nuclear accidents in history combined, including Chernobyl. Nuclear
accidents are more of a concern because the fission products released
tend to concentrate in food and in the body, where carbon-14 released by
fossil fuel burning doesn't significantly change the background level of
this material, which regenerates via solar radiation.


This is very OT but in 1985 while doing a project involving C14 and H3
tagged materials, we used a very sensitive and sophisticated instrument
called a Scintillation Spectrometer. Just for kicks, we took urine samples
from a group of college kids working summer jobs just prior and after their
4thofJuly week-end sojourn to the beach. Comparative tests showed a 3-fold
increase in H3 that dissipated within a day or two. We always speculated
about, but never determined the source. Maybe it was those power plant
discharges from "the North" blowing out to sea.

Truly, dr bob.

----- Original Message -----
From: "Donald Qualls"
Newsgroups: rec.photo.equipment.large-format
Sent: Saturday, October 16, 2004 10:25 AM
Subject: What happens to film as it ages?

Some text omitted

? FWIW, coal- and oil-burning power plants release more radioactivity (in
the form of carbon-14 and a trace of tritium) into the atmosphere in
day-to-day operation every year, year in and year out, than all the
nuclear accidents in history combined, including Chernobyl. Nuclear
accidents are more of a concern because the fission products released
tend to concentrate in food and in the body, where carbon-14 released by
fossil fuel burning doesn't significantly change the background level of
this material, which regenerates via solar radiation.


This is very OT but in 1985 while doing a project involving C14 and H3
tagged materials, we used a very sensitive and sophisticated instrument
called a Scintillation Spectrometer. Just for kicks, we took urine samples
from a group of college kids working summer jobs just prior and after their
4thofJuly week-end sojourn to the beach. Comparative tests showed a 3-fold
increase in H3 that dissipated within a day or two. We always speculated
about, but never determined the source. Maybe it was those power plant
discharges from "the North" blowing out to sea.

Truly, dr bob.

----- Original Message -----
From: "Donald Qualls"
Newsgroups: rec.photo.equipment.large-format
Sent: Saturday, October 16, 2004 10:25 AM
Subject: What happens to film as it ages?

Some text omitted

? FWIW, coal- and oil-burning power plants release more radioactivity (in
the form of carbon-14 and a trace of tritium) into the atmosphere in
day-to-day operation every year, year in and year out, than all the
nuclear accidents in history combined, including Chernobyl. Nuclear
accidents are more of a concern because the fission products released
tend to concentrate in food and in the body, where carbon-14 released by
fossil fuel burning doesn't significantly change the background level of
this material, which regenerates via solar radiation.


This is very OT but in 1985 while doing a project involving C14 and H3
tagged materials, we used a very sensitive and sophisticated instrument
called a Scintillation Spectrometer. Just for kicks, we took urine samples
from a group of college kids working summer jobs just prior and after their
4thofJuly week-end sojourn to the beach. Comparative tests showed a 3-fold
increase in H3 that dissipated within a day or two. We always speculated
about, but never determined the source. Maybe it was those power plant
discharges from "the North" blowing out to sea.

Truly, dr bob.

From: "Donald Qualls"
Newsgroups: rec.photo.equipment.large-format
Sent: Saturday, October 16, 2004 10:25 AM
Subject: What happens to film as it ages?

Some text omitted

? FWIW, coal- and oil-burning power plants release more radioactivity (in
the form of carbon-14 and a trace of tritium) into the atmosphere in
day-to-day operation every year, year in and year out, than all the
nuclear accidents in history combined, including Chernobyl. Nuclear
accidents are more of a concern because the fission products released
tend to concentrate in food and in the body, where carbon-14 released by
fossil fuel burning doesn't significantly change the background level of
this material, which regenerates via solar radiation.


I'm pretty sure that this is wrong. If you assume that the proportion of 14C
in the atmosphere is constant, at roughly 0.00000000013% of the total
carbon, then each tonne of fossil fuel would have 6.5 x 10^16 atoms of 14C
when it was laid down. The half-life of 14C is about 5,730 years so it would
take about 55 half-lives, or 315,150 years, to get down to just one 14C atom
per tonne. However, the Carboniferous era, when the coal was laid down, is
300 million years ago.....another 952 half-lives further on. There is,
therefore, no possibility of there being any 14C in fossil fuels, at least
by my reckoning.

Andy

From: "Donald Qualls"
Newsgroups: rec.photo.equipment.large-format
Sent: Saturday, October 16, 2004 10:25 AM
Subject: What happens to film as it ages?

Some text omitted

? FWIW, coal- and oil-burning power plants release more radioactivity (in
the form of carbon-14 and a trace of tritium) into the atmosphere in
day-to-day operation every year, year in and year out, than all the
nuclear accidents in history combined, including Chernobyl. Nuclear
accidents are more of a concern because the fission products released
tend to concentrate in food and in the body, where carbon-14 released by
fossil fuel burning doesn't significantly change the background level of
this material, which regenerates via solar radiation.


I'm pretty sure that this is wrong. If you assume that the proportion of 14C
in the atmosphere is constant, at roughly 0.00000000013% of the total
carbon, then each tonne of fossil fuel would have 6.5 x 10^16 atoms of 14C
when it was laid down. The half-life of 14C is about 5,730 years so it would
take about 55 half-lives, or 315,150 years, to get down to just one 14C atom
per tonne. However, the Carboniferous era, when the coal was laid down, is
300 million years ago.....another 952 half-lives further on. There is,
therefore, no possibility of there being any 14C in fossil fuels, at least
by my reckoning.

Andy