For Israel, seawater desalination has become an indispensable technology in the fight against the region’s deteriorating water situation. Today, the country produces around 600 million cubic meters of desalinated seawater per year, which constitutes 60% of the water provided to Israeli households and 50% of the nation’s entire water supply (including for agriculture). Despite its paramount importance to water security in the drying Middle East, desalination turned out to cause adverse human health effects – which are the concern of scientists as well as government officials in Israel.
The Big Four – Calcium, Magnesium, Fluoride, and Iodine
In 2002, Israel ventured on an unprecedented path by drastically shifting the country’s source of water supply towards seawater desalination. For this purpose, large-scale desalination plants were built along the Mediterranean coast using reverse osmosis, a technique whereby pressurized water is forced through a membrane which filters out the salts. So far, the decision to switch to desalination enabled Israel to stay ahead of the increasing water scarcity in the region.
However, this technology comes at a price. According to Prof. Yona Amitai, a pediatrician, toxicologist, and expert for public health at the Bar Ilan University in Israel, desalinated seawater is lacking four essential minerals that are vital to human health – calcium, magnesium, fluoride, and iodine. The minerals are removed during the desalination process, along with the salts.
The potential risk for public health due to the consumption of low–mineral water hasn’t escaped the eyes of the authorities. Israel, like many other countries, has a long experience in reintroducing minerals to drinking water – especially fluoride, which has been added to the water since the 1980s. The fluoridation of drinking water has been a subject of debate among experts and policymakers in Israel for quite some time. After a brief suspension, following a decree by then Health Minister Yael German in 2014, it was continued in 2016.
Adding fluoride to the tap water is known to prevent dental caries, and is, therefore, a convenient method to increase public dental health. Moreover, the costs of adding fluoride are marginal at about $8 – $10 million per year. The Ministry of Health (MoH) assures that fluoride-enriched water at the levels added in Israel (0.7 mg/L) is safe to drink and that no studies exist linking water fluoridation to cancer or other any diseases, contrary to those who oppose the practice.
Consequently, a lack of fluoride likely does not entail severe health consequences and is being addressed. But this isn’t the case with other minerals. Low iodine intake potentially leads to iodine-deficiency disorders such as thyroid dysfunction, which particularly in young children might resultin poor intellectual and cognitive abilities. In pregnant women, low iodine intake can cause severe impairments of the fetus like mental retardation, goiter (enlargement of the thyroid gland), and physical deformation.
In 2016, Israeli researchers for the first time examined the possibility of desalinated water being the cause of iodine deficiency and thyroid diseases. The study, conducted at the Barzilai University Medical Center in Ashkelon – a city located on Israel’s Mediterranean coast, getting most of its municipal water from the nearby desalination facility – showed that 70% of the 74 participants had iodine intake below the Estimated Average Requirements (EAR). Twenty-nine participants were diagnosed with non-autoimmune thyroid disease (NATD). It was concluded that iodine intake of those patients living in areas depending on desalinated seawater is too low, which might be directly connected to iodine deficiency and thyroid health.
The Ministry of Health (MoH) acknowledges the problem of iodine deficiency in Israel but dismisses the notion of adding iodine to desalinated seawater due to the risks involved in such an application. “It should be noted that worldwide it is not acceptable to add iodine, even in countries with substantial shortages,” a spokesperson of the ministry says. The ministry thus recommends the public to switch from regular salt to iodized salt, and keep a balanced diet rich in iodine. Amitai, however, says that the World Health Organization recommends adding iodine to salt, which is done in more than 100 countries, but not in Israel.
Unlike iodine, calcium seems to be less of a problem in Israel, as it is already being added to desalinated seawater in order to avert pipe corrosion. Still, the MoH does not publish any figures regarding the cost of adding calcium to the water.
But by far, the most controversial issue at the moment is the lack of magnesium in desalinated seawater, which, according to estimates by the Ministry of Health, is responsible for the death of 250 Israelis every year. However, these are estimates made ten years ago when the supply of desalinated seawater was less than half the supply of 2019.
Israelis Have a Low Magnesium Intake
Close to ten years ago, a committee appointed by the Ministry of Health and headed by Prof. Avner Adin developed new regulations on drinking water quality in Israel, which included the assessment of desalination issues.
According to Prof Amitai, the Adin Committee decided, although aware of the importance of magnesium, against its addition to desalinated seawater, intending to closely watch the population for ten years and see what the actual consequences are going to be.
Only 20% of a person’s daily magnesium supply comes from water, while the other 80% are ingested with solid food. Amitai argues that magnesium derived from water may be considered as a “safety net” offsetting inadequate nutrition. Nevertheless, since the majority of the Israeli population has a dietary magnesium intake lower than the recommended WHO levels, consumption of magnesium deficient water may aggravate magnesium deficiency.
Magnesium deficiency can cause a variety of adverse health effects and increase the risks of cardiovascular diseases, such as myocardial infarction, hypertension, cardiac arrhythmia, and atherosclerosis, but also diabetes and even colon cancer.
Mortality Rate Higher in Regions with Desalinated Water
In 2018, scientist established a link between the consumption of desalinated water in Israel and a 6% higher risk of suffering from heart-related diseases and death by heart attack. For this purpose, 178,000 members of Clalit, Israel’s largest health care provider, were examined between 2004 and 2013.
Two years prior to that, a high-profile research study conducted at Bar Ilan University by Prof. Amitai, PhD Student Meital Shlezinger and in collaboration with Prof. Michael Shechter and Prof. Ilan Goldenberg both from the Sheba Medical Center, found mortality from myocardial infarction was significantly higher in subjects living in those regions that are supplied with desalinated seawater.
The findings had a significant impact on the public and caused countrywide outrage as the scientists could establish that mortality rates before the introduction of desalination were similar in all regions.
In the wake of the bombshell report, Israel’s Prime Minister Benjamin Netanyahu prompted the Ministry of Health to carry out a feasibility study of adding magnesium to desalinated seawater. Although the Ministry of Health took a stance by recommending to add magnesium to the water, no measures have been taken so far.
According to Amitai, appropriate steps have been deferredbecause the Water Authority opposes the idea of adding magnesium to the municipal water system, claiming the costs were too high and outweighed the benefits. “Adding magnesium should have happened many years ago when the Ministry of Health first gave their recommendation. However, the Water Authority dismisses the proposal saying that adding magnesium will increase the cost of drinking water.”
The MoH, on the other hand, reports a pilot project iscurrently underway, examining different methods of adding magnesium, their costs and the implementation in the field. Subsequently, one or more facilities will be built to test the proposed plans. “The cost we will know after implementing the pilot in the field,” the spokesperson adds.
“Even if you have a balanced diet you might not take up enough magnesium.”
According to the Water Authority, only 1% of the desalinated seawater is ultimately used for drinking, the rest goes into utilities, agriculture, etc. “This is a misleading argument,” Amitai says. “First of all, it is much more than 1%, and second, 80% of our daily magnesium uptake comes from dietary sources other than water, mainly from vegetables and fruits. Now, if those crops are irrigated with desalinated seawater, they would, by implication, have low magnesium levels. Therefore, even if you have a balanced diet, you might not take in enough magnesium.”
Recently scientists from Gilat Research Center in the Negev examined the effects of desalinated seawater on agriculture. The study found a gradual decrease of magnesium and sodium concentrations in produce grown in Israel since the inception of nationwide seawater desalination in 2008. The researchers tested over 500 samples of 29 different fruits and vegetables for magnesium levels and compared them to the same products from the USA. It turned out that levels in all 29 products were considerably lower than in those taken from the USDA database.
The results of the study have caused Prof. Amitai to believe that mortality in Israel due to magnesium deficiency in desalinated seawater is even higher than the estimate made by the MoH ten years ago, and might claim the lives of up to 600 Israeli’s every year.
No other western country depends on desalination as Israel does.
Israeli citizens have become increasingly concerned with the water quality from their tap, especially the magnesium levels, and demanded accurate information about the percentage of desalinated water they receive. But as it turns out, such data is not available to the public.
According to the MoH’s official statement, the percentage of desalinated seawater in the supply systems varies greatly, depending on the locality, the season, time of the year, and even time of day. Thus, they cannot give accurate information on the matter. Furthermore, periodic reviews of the water quality are only performed at the source and not in the system, assuming minerals are neither added nor subtracted but change only due to the mixing of different water sources.
Although variability is a factor in the distribution of desalinated water in Israel, Amitai questions the integrity of the Ministry’s response. “Variability might play a role in the water distribution, but not to an extent where a large scale testing would be rendered inconclusive. The Ministry could easily do a one-time analysis of water samples from hundreds of different places and substantiate our findings“, Amitai stresses. And indeed, scientists found out that tap water in the center of Israel has an average magnesium content of 5-10 mg per liter, while in the northern regions of the country (which still receive most of their water from natural sources)concentrations are around 30 mg per liter.
Israel is a pioneer of desalination, which is why Amitaiemphasizes the importance of thorough research and policy. “The WHO has recommended to all countries to consider adding magnesium to desalinated seawater, but also doing it according to local requirements and research. Since Israel is leading the field of desalination technology, the burden lies with us first. Our research in this sector will be paving the way for other nations which will face the same issues in the future,” Amitai concludes.
The Water Authority hasn’t submitted a response to the arguments posted in this article.
By Dominik Doehler, ZAVIT