How safe is desalinated water?

Just been reading this, very interesting

[b]Desalinated water is potentially more corrosive than many other drinking-water sources [/b]and it is
important that the water is stabilised to minimise corrosion of metallic pipes
and fittings used in distribution and in buildings. Where distribution is through tankers then the
potential for corrosion of the tankers must also be considered. The requirement is that corrosion
should not give rise to levels of metals that exceed the guidelines or add unacceptable
appearance or taste, or physically damage water contact surfaces. (McGuire/Malcolm Pirnie,
2006) These can include metals from primary distribution and storage, particularly iron and
possibly nickel, and from plumbing and fittings in buildings, including lead and copper.[b] Iron has,
in the past given rise to problems with discoloured water that significantly reduces the
acceptability of the water for both drinking and for household uses. [/b]In many cases a range of
coatings and materials will be used to coat pipes or storage reservoirs, or for storage tanks in
buildings in order to protect against corrosion. It is important that these materials are of a
suitable quality for use with potable water and as indicated above approval schemes have an
important part to play in ensuring their safety and reducing the potential impact on consumer
acceptability. There is a particular consideration in the approval of materials since in many of
these circumstances they will be used at elevated temperatures, which can exacerbate leaching of
component metals.
3.7 Additional
[b]There have been suggestions that drinking very low mineral water can lead to a number of
adverse effects on humans, particularly on the gastrointestinal tract, even with a diet that
provides an adequate level of essential minerals [/b](Kozisek, 2004). This is unresolved and there is
a need to investigate this subject in order to determine if there is a significant issue that needs to
be taken into account.
Desalination has been used in some parts of the world for many decades and this
experience potentially provides a basis for epidemiological studies of various health outcomes.
Such studies if properly controlled and with proper consideration of potentially confounding
factors, would be of considerable value in assuring the safety of desalinated water.
3.8 Chemicals-Related Health Recommendations
• [b]The WHO and Desalination Guidelines encourage governments to adopt existing
systems or establish systems for specifying the appropriateness and quality of
additives encountered in desalination, or to adopt existing credible recognized
standards for those products that would be tailored to desalination conditions.[/b]• WHO GDWQ are encouraged to reassess the toxicity of boron and to provide
revised WHO recommended guideline values.
• [b]WHO GDWQ are encouraged to develop a GDWQ for bromide for reference
purposes due to its widespread presence in fresh waters and desalinated waters[/b].
[b]There is need to consider sodium and other minerals in water in relation to bottlefed
infants. WHO is encouraged to provide guidance as to the impact of higher
sodium for infant formula.[/b]• [b]There should be a re-examination of the llow dose carcinogenic risks of bromate in
the GDWQ in light of new information and followed by possible modification of
the guideline.[/b]• [b]Countries should carry out dietary and dental care studies, if necessary, to
determine the possible and appropriate role of their water supplies including
desalinated water as a contributor to total dietary intake requirements of fluoride
and minerals.[/b]• [b]There is need to consider the importance of mineral balance in drinking water,
particularly calcium and magnesium, with regard to risks of osteoporosis, and
ischemic heart disease, respectively, as well as fluoride in relation to loss of
fluoride from the skeleton.[/b]• [b]There is the need to examine in more detail the possibility of adverse effects
arising from drinking ultra-low mineral water[/b]

http://www.who.int/water_sanitation_health/gdwqrevision/desalination.pdf
<em>edited by tally-ho on 18/03/2011</em>