kid drinking water 298.8.
(photo credit: Ariel Jerozolimski)
A survey of the nation's drinking water released Sunday has found that the vast majority of samples met the severe standards set in 2000, but there are a number of sources - especially in the center of the country - that reflect "a tangible threat to water quality."
The study was prepared by the Health Ministry's environmental health department. It covered 2001-2005 and was based on 1,033 water sources - 977 of them subterranean, 34 from streams and 22 lakes and other standing surface water.
Nearly 300 of the sources underwent full chemical examination. Of 237 samples with "irregular" results, 152 were satisfactory when tested a second time. Eleven were prohibited for drinking; six were satisfactory after treatment; 21 were approved after being mixed with other water sources; and five were improved with treatment.
Excessive nitrates was the most common reason for prohibiting them as water sources. The levels of chlorides and nitrates in drinking water are increasing; last year, the ministry reduced permissible levels of these compounds from 90 to 70.
The main reasons for irregularity were turbidity, nitrates, oils, chlorides, ethylene dibromides and floating solids. Most of the sources forbidden to serve as drinking water were in the Central, Tel Aviv and Ashkelon regions (77%), with a minority in the Jerusalem, Northern and Southern regions (23%). Sixty-eight of the forbidden sources were supplied by local authorities and 22 by Mekorot.
To solve pollution problems relating to those water samples found to be a signal of danger, the ministry's water experts said anti-pollution laws must be better enforced and contamination of surface water must be prevented.
Twenty-five drills into groundwater sources showed excessive levels of pathogens in 20 percent of samples over the five years. "It seems that these groundwater sources are directly under the influence of surface water that cause their contamination," according to the report.
As for metals and cyanide, these were at "permissible levels," except for a handful of cases in which there was too much selenium. Organic materials did not rise above permitted levels in most cases, but there were cases in which results of a full chemical examination were higher than permitted, even though none of the parameters alone were excessive.
Such results are not addressed by official standards, the authors wrote, even though "some of these water sources are tangibly threatened by contamination." As a result, water suppliers "must give these sites their attention and even consider water treatment to reduce the level of contaminants," according to the report.
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