Water desalination has been extensively developed in Israel, particularly in the last decade. The desalination process provides fresh water that typically lacks minerals, and among these are ions that are essential to human health and/or to agricultural production, such as Mg. We analyzed 28 tap water samples originating from different cities across Israel to document their concentrations of Mg and other elements. The data from this survey (summer 2016) were compared with the results of similar observations conducted in 2008. Regarding toxic elements, tap water across Israel does not pose any health risk for consumers and may be used as drinking water without any household pretreatment. This condition has not changed since 2008. However, the problem of Mg deficiency due to the use of desalinated water was observed in about half of the sampling locations in 2016, whereas no Mg deficiency had been detected in 2008. Moreover, household filtration of tap water prior to consumption as drinking water may worsen the situation due to the Mg status resulting from rejection of this ion; this could be harmful to the consumer, particularly under prolonged exposure.

1. Mineral Composition of Tap Water in
Israel
The possible deficiency of
magnesium as a result of
desalinated water use
Vasiliy V. Rosen1
Yona Chen2
Orit Gal Garber1
1ZBM Analytical Laboratory
2The Department of Soil and Water Sciences
The Hebrew University of Jerusalem
The Robert H Smith Faculty of Agriculture, Food and Environment
1

2. Introduction
➢ The problem of drinking water deficiency.
➢ Sea water desalination as a solution.
The State of Israel: 4 desalination plants working.
2

3. Introduction
Water Authority
2015
3

4. Introduction
After Rejwan A., 2011. The State of Israel: National Water Efficiency Report
(www.water.gov.il)
Desalinated water
➢ Desalinated water as a drinking water:
possible health problem. 4

5. Introduction
Patients were not supplied
by desalinated water (total 3078)
Patients were supplied
by desalinated water (total 1600)
5
SURVIVAL
%

6. Mg in the tap water : Israel Ministry of Health data
July-September 2016
North, South and Center regions
Minimal Mg concentration in drinking water,
recommended by WHO (10 mg L-1)
After http://www.health.gov.il,
Periodical Reports of Water Quality (in Hebrew)
Introduction
6

7. Mg in the tap water : Israel Ministry of Health data
July-September 2016 After http://www.health.gov.il,
Periodical Reports of Water Quality (in Hebrew)
27
samples
Introduction
7

8. ❑ How much Mg does the tap water contain?
❑ Does the tap water contain some harmful
elements?
❑ Do we need to perform the home filtration
of the tap water?
❑ What are the main mineral components of our
tap water?
8

9. Sampling points on the map (28 points)
9

10. The area with highest population density was investigat
10

11. Sampling points
11

12. ❑ How much Mg does the
tap water contain?
12

13. 27
samples
13

14. 14
Water is ranked from
moderately hard to very
hard

15. How much Mg do we need?
USA recommendations
15

16. How much Mg do we need?
UK recommendations
16

17. Assumptions
❑ Drinking water demand is 2 L per day
❑ Tap water is the only source of drinking water
❑ RNI is 300 mg Mg per day
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18. Assumptions
❑ Drinking water demand is 2 L per day
❑ Bottled water is the only source of drinking water
❑ RNI is 300 mg Mg per day
Bottled water
18

19. 19
Mineral composition of tap water in several Israel cities in 2008

20. Cation/Anion Ramat A Sharon
Rehovot (Campus of the
Faculty of Agriculture)
Rehovot (city center) Aloney Aba Nes Ziona Tel Aviv Carmiel
ICP-OES data
Ca 79.3 92.1 127.9 48.99 120.57 83.87 94.8
Mg 37.7 23.8 32.32 32.78 15.5 34.11 37.7
Na 74.24 60.9 74.12 74.36 72.49 74.52 29.3
K 7.02 1.82 2.29 11.12 1.92 7.94 2.0
B 0.06 0.07 0.048 0.069 0.082 0.067 0.018
Ba 0.09 0.13 0.10 0.055 0.087 0.10 0.04
Cu <0.002 0.08 0.04 0.012 0.02 <0.002 0.09
Fe <0.001 0.61 <0.001 <0.001 <0.001 0.01 <0.001
Li 0.01 0.07 0.003 0.022 0.0028 0.01 0.0013
Si 6.48 9.04 10.98 3.737 8.18 6.74 6.04
Sr 0.82 0.50 0.84 0.698 0.39 0.75 0.21
Zn 0.08 2.73 0.13 0.015 0.83 0.22 0.25
IC data
F-
0.58 0.32 0.12 0.79 0.1 0.58 0.4
Cl
-
165 108 181 255 116 179 38
NO2
-
0.31 0.82 0.18 <0.01 0.13 0.16 0.08
Br-
0.58 0.87 0.32 1.41 0.25 0.73 0.04
NO3
-
4.31 54 58 0.04 62 17.1 3.28
SO4
2-
41 41 45 64 64 41 1.8
PO4
3-
0.02 1.04 0.05 0.04 0.04 0.02 0.11
Total (Ca+Mg) hardness
as mg/L CaCO3
349 323 446 255 359 346 387
Ca/Mg Ratio 2.1 3.9 4.0 1.5 7.8 2.5 2.5
Hardness very hard very hard very hard very hard very hard very hard very hard
mg L
-1
2016
Mineral composition of tap water in several Israel cities in 2008
20

21. ❑ What are the main mineral components of our
tap water?
❑ Does the tap water contain some harmful
elements?
21

22. ICP-OES data (mg L-1)
Ion Chromatograph data (mg L-1)
The main
components are:
Chlorides and
Sulfates (and
Bicarbonates) of
Ca, Na, Mg and K.
Toxic elements are
<LOQ
22

23. The daily changes of the tap water mineral content
Mg 7.16±4.8
CV=67.3%
Mg
9.53±4.4
CV=46.3%
Mg
4.96±0.03
CV=0.67%
3.3 % of
RNI
6.4 % of
RNI
4.8 % of
RNI
23

24. ❑ Do we need to perform the home filtration
of the tap water?
24

25. ❑From 23.7 to 45.6% (depending on city) of the interviewed
Israel citizens use home water filter of any kind.
25

26. Brita filter experiment
Rehovot tap water
26

27. Brita filter experiment
Jerusalem tap water
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28. ❑ How much Mg does the tap water contain?
❑ Does the tap water contain some harmful
elements?
❑ Do we need to perform the home filtration
of the tap water?
❑ What are the main mineral components of our
tap water?
Not pretty
much
Chlorides and sulphates
of Ca, Mg, Na and K
NO
NO!
28

29. ACKNOWLEGEMENTS
❑To Adi Maoz (M.Sc.): water survey in 2008
❑To Sarah Steiner (M.Sc.): IC water analyses
❑To all our sampling volunteers, especially to all “Dr.Golik”
company staff and specially to Darina Rosen (B.Sc., MBA)
29