Environmental pollution
...
discusses the environmental contamination that has resulted from nuclear weapons
testing and accidents, and how discharges from current uses are being controlled.
We have seen in Chapter 7 that natural radionuclides pervade our environment.
This chapter deals with the artificial radionuclides that have
been widely dispersed
by events such as tests of nuclear weapons in the atmosphere and the Chernobyl
accident and by the deliberate discharge of radioactive wastes from nuclear and
other installations.
Such radionuclides find their way from air and water onto
the ground and into foodstuffs and so deliver radiation doses in various ways
to human beings.
Nuclear weapon tests
When nuclear weapons were tested above ground, they propelled a variety
of radionuclides from hydrogen-3 (tritium) to plutonium-241 into the
upper atmosphere. From there, the radionuclides transferred slowly to
the lower atmosphere and then to the Earth’s surface.
Around 500 atmospheric
explosions were conducted before the limited test ban treaty was enacted
in 1963, with a few more until 1980. The concentrations of radionuclides
in air, rain and human diet are now much lower than the peak values in the
early 1960s.
