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The maximum level of sulfate suggested by the World Health Organization (WHO) in the Guidelines for Drinking-water Quality, set up in Geneva, 1993, is 500 mg/l. EU standards are more recent, 1998, complete and strict than the WHO standards, suggesting a maximum of 250 mg/l of sulfate in water intended for human consumption.
Click here for more information
about drinking water standards.
Some soils and rocks contain sulfate minerals. As groundwater moves through
these, some of the sulfate is dissolved into the water.
Some minerals that contain sulfate are sodium sulfate (Glauber's salt), magnesium
sulfate (Epsom salt), and calcium sulfate (gypsum).
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Magnesium sulfate
Sodium sulfate
Calcium sulfate
(Epsom's salt)
(Glauber's salt)
(gypsum)
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Health risks for humans who drink water containing high sulfate levelsPeople not used to drinking water with high levels of sulfate can experience dehydration and diarrhea. Kids are often more sensitive to sulfate than adults. As a safety measure, water with a sulfate level exceeding 400 mg/l should not be used in the preparation of baby food. Older children and adults become used to high sulfate levels after a few days |
Is sulfate dangerous for animals?Animals are also sensitive to high levels of sulfate. In young animals, high levels may cause severe, chronic diarrhea, and in some cases, death. As with humans, animals tend to become used to sulfate over time. Diluting water high in sulfate with water low in sulfate can help avoid problems of diarrhea and dehydration in young animals and animals not used to drinking high sulfate water. The proportion of water high in sulfate to water low in sulfate can be progressively increased until the animals can admit the high sulfate water. Contact your local veterinary for more information. |
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Other problems caused by sulfateSulfate gives a bitter or medicinal taste to water if it exceeds a concentration of 250 mg/l. This may make it unpleasant to drink the water.High sulfate levels may also be corrosive for plumbing, particularly copper piping. In areas with high sulfate levels, it is common to use corrosion resistant plumbing materials, such as plastic pipe. |
There are three types of treatment systems that will remove sulfate from your
drinking water: reverse osmosis, distillation, or ion exchange. Carbon filters,
water softeners and sediment filters will not remove sulfate. Water softeners
exclusively change magnesium or calcium sulfate into sodium sulfate, which is
more laxative.
| Reverse osmosis (RO)
is a water treatment system that eliminates most dissolved elements and
chemicals, such as sulfate, from water by pushing the water through a
plastic surface similar to cellophane known as a "semipermeable membrane."
Generally, it can eliminate between 93 and 99 % of the sulfate in drinking
water. This depends on the type of unit. |
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Distillation
is a water treatment system in which water is boiled, and then the steam
is cooled until it condenses into a separate container. The dissolved
substances, such as sulfate, remain in the boiling pot. |
| Ion Exchange
is the most known method of eliminating big quantities of sulfate from
water for public, livestock, and commercial supplies, but is not generally
used for individual household water treatment. It is a process where one
element or chemical is replaced for another. |
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Any water treatment system needs adequate operation and maintenance
to ensure that it functions properly over time. It is important to follow the
recommendations of the manufacturer for the maintenance of the water treatment
system.
Click here for more information on ionic exchange systems.
Click here for more information on
the element Sulfur (S).
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