[ RadSafe ] " Jordan's fossil water source has high radiation levels "

[Jaro]

Another Ramsar, Kerala, or Guarapari ?

 Jaro
^^^^^^^^^^^^^^^^^^^^^


http://www.physorg.com/news154714642.html
Jordan's fossil water source has high radiation levels
February 24th, 2009 in Space & Earth science / Environment

Ancient groundwater being tapped by Jordan, one of the 10 most
water-deprived nations in the world, has been found to contain twenty times
the radiation considered safe for drinking water in a new study by an
international team of researchers.

"The combined activities of 228 radium and 226 radium - the two long-lived
isotopes of radium - in the groundwater we tested are up to 2000 percent
higher than international drinking standards," said Avner Vengosh, associate
professor of earth and ocean sciences in the Nicholas School of the
Environment at Duke University.

Making the water safe for long-term human consumption is possible, he said,
but it will require extra steps to reduce its radioactivity. {{....so it was
unsafe until now ? ....is there anyone left alive in Jordan ? }}

Vengosh and his research team, made up of scientists from Jordan, Palestine,
Israel and the United States, published their findings Feb. 19 in a paper in
the peer-reviewed journal Environmental Science & Technology.

Jordan's annual water use exceeds the natural replenishment of its major
river, the Yarmouk, and its local aquifers that are becoming salinized as a
result of over-pumping.

In 2007, the Jordanian government announced plans for a $600-million project
to pump low-saline fossil groundwater from the Disi aquifer, located along
the nation's remote southern border with Saudi Arabia, and pipe it 250
kilometers north to the capital, Amman, a city of 3.1 million people, and
other population centers.

Fossil groundwater is a nonrenewable supply of water trapped underground in
aquifers. In recent years, policymakers in countries facing chronic water
shortages have increasingly viewed low-saline supplies of fossil groundwater
as an important potential source of water for human and agricultural use.
Libya and Saudi Arabia, for example, have relied extensively on fossil
groundwater from Nubian sandstone aquifers similar to the Disi to meet their
water needs in recent decades.

Most fossil groundwater resources in North Africa and the Middle East are
characterized by high-quality water with low salinity. "The assumption has
been that unsafe radioactive levels occur primarily in high-saline
groundwater, so low-saline sources, such as water from a Nubian sandstone
aquifer, are relatively safe resources just waiting to be tapped," Vengosh
said.

To test that hypothesis, Vengosh and his colleagues investigated water from
37 pumping wells in the Disi aquifer's Rum Group, where low-saline
groundwater is extracted from Cambro-Ordovician sandstone, and from wells in
the Khreim Group, where saltier water is extracted from an aquifer
containing larger amounts of clay minerals and oxides. All samples were
analyzed for major and trace elements and for four radium isotopes. For
comparative purposes, sandstone rocks from the Disi aquifer, along with
Nubian sandstone rocks from the nearby Negev Desert in Israel, were also
measured for radium.

"We found a lack of correlation between salinity and radioactivity," Vengosh
said. "Instead, our findings suggest that an aquifer's geological properties
may be a much more significant factor."

Vengosh and his group hypothesize that an aquifer with a higher content of
clay minerals and oxides provides more adsorption sites for radium, and this
results in lower radionuclide levels in the water itself. Sandstone
aquifers, on the other hand, offer fewer adsorption sites, and, as a result,
generate radium-rich groundwater.

"Given that most of the aquifers in the region that contain fossil water are
composed of Nubian sandstone and are characterized by low-saline
groundwater, similar to that in the Disi aquifer, we suggest that
high-radioactive groundwater may also exist in these basins. This could pose
health risks for a large population," Vengosh said. Groundwater from the
Disi aquifer is already used for drinking water in parts of Jordan and, more
extensively, in Saudi Arabia, where it is known as the Saq aquifer.

"Making groundwater from the Disi aquifer and similar sandstone basins in
the region safe for long-term human use will require a significant reduction
of radionuclide levels," Vengosh said.

Health officials could reduce radioactivity to safe levels by diluting
radium-rich water with low-radium water from other sources, he said, or by
treating it with ion exchange, reverse osmosis desalination or lime
softening. Each of these three treatment technologies does a good job of
removing radium, Vengosh noted, but each produces solid and liquid residues
that would have to be handled and disposed of as low-level radioactive
waste.

The U.S. Environmental Protection Agency (EPA) classifies radium as a
Group-A carcinogenic material, which means exposure to it could cause
cancer.

More information: The paper is online at
http://pubs.acs.org/doi/abs/10.1021/es802969r.

Source: Duke University