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Nuclear Science Study Guide
THE MANY BENEFITS of nuclear technology are historically
misunderstood. The word ‘nuclear’ conjures up thoughts of cold
war, radioactive fall-out and threats to health and peace. But our
world is surrounded by radioactive materials, and measuring
these with sensitive instruments reveals much about Earth’s
building blocks, its biological systems and how they function. Life
on this planet has existed peacefully with low-level radioactivity
for nearly four billion years.
At the Australian Nuclear Science and Technology Organisation
(ANSTO), nuclear technology is used to explore a plethora of
environmental issues including climate change, water resource
sustainability and air pollution. The sensitivity of the tools used at
ANSTO provides insights into these areas, which are impossible
using other techniques.
Professor John Dodson, Head of ANSTO’s Institute for
Environmental Research, explained that ANSTO’s nuclear science
facilities offer Australian researchers state-of-the-art technology
for understanding past, present and future climates.
“Past climates leave their signatures in a variety of places including
tree rings, ice cores, corals and cave stalagmites,” said Dodson. “For
example, ANSTO has dated water from bores in the Great Artesian
basin, showing it contains rainfall that fell over 300,000 years ago.
We need to know this and the rate of artesian water replenishment
if we are to make use of it as a sustainable water resource.
“In these times of water scarcity Australian cities and towns
are turning more and more to groundwater as a source because
surface water resources have become over-exploited,” he said.
“However, we know precious little about groundwater reserves
and we need to get smart about them, along with developing
sensible recycling and economical water use for long-term water
“With Australia occupying about 5.4 per cent of the global land
mass but with only one per cent of its water, we have problems
unlike other nations,” Dodson said.
ANSTO is now embarking on a project to enhance understanding
of the water resources of south-western Australia, which has one
of Australia’s most rapid population growth rates. Most of the
surface water resources are already fully exploited and rainfall has
decreased in recent decades. Perth needs to identify sound ways
of ensuring water security.
Groundwater around Perth rises and falls with the winter rainfall
patterns (at appropriate lag intervals). However, the rate at which
this occurs, and the age of the groundwater, is only broadly known.
Nuclear tools are being used to measure the age of groundwater
and, with the help of Water WA, ANSTO scientists will establish
the age of water in various aquifers. This will help form a basis for
comparison with longer term rainfall records.
Dodson explained that the recent decline in rainfall is based on
knowledge from the measured meteorological records, which are
little more than 100 years old.
“We are part-way through a program to generate high resolution
records of rainfall variability over the last 1000 years for the region
using cave stalagmites which contain the records of past rainfall
embedded in their atomic structure,” he said.
“This will provide a better basis for understanding recent rainfall
changes and reveal if the rainfall in the last few decades is unusual,
or if it is the norm.”
The study will also reveal the recurrent rate of long drought
periods, as well as heavy rainfall decades, and tell scientists how
important tropical and southerly rainfall systems are in the mix
of rainfall received. These will empower decision makers to plan
water use from appropriate baselines.
Atmospheric dust also has a direct impact on climate systems
and human health.
“Australia is the largest source of atmospheric dust in the Southern
Hemisphere and the liberation of dust into the atmosphere has
impacts well beyond our shores, although much of this dust is
valuable topsoil,” Dodson said.
“ANSTO has established protocols for measuring bushfire smoke,
soil erosion, household fires and pollution from cars and industry.
We know the season cycles in the Sydney Basin and the origins
of atmospheric air masses which drive some of the change and
this information helps us to assist nations overseas to assess and
manage their own air pollution problems.
“Overall, the growth of nuclear science is very exciting and at
ANSTO our work and the work of other groups we support,
needs to be better understood by the community, especially
the benefits of managing the world of today and tomorrow,”
ARTICLE THREE NUCLEAR TOOLS FOR CLIMATE CHANGE
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