The disadvantages of water softeners using salt include:
The
process of regenerating the ion exchange bed dumps salt water into the environment. The elevated sodium concentration of most
softened water can affect the taste and may not be good for people on low sodium diets, although sodium concentrations are
typically quite low relative to sodium levels in most food. Cation exchange does not reduce the level of anions (like nitrates),
or biological contaminants (bacteria, viruses, cysts) ; nor does the process reduce the levels of most organic compounds.
Typically, approximately 50 gallons of rinse water per cubic foot of resin is required to totally remove hardness and excess
salt from the resin after each regeneration.
Sodium and Health
About 42 million adults, 20 percent of the population, have persistent high blood pressure (hypertension).
About half of those with high blood pressure are sensitive to sodium and can reduce blood pressure by reducing sodium. Although
some people can consume excessive levels of sodium without increased blood pressure, many cannot. Other risk factors for high
blood pressure include excess weight, alcohol consumption, and a family history of high blood pressure. Many scientists believe
sodium sensitivity is inherited. If this is true, susceptible people may be able to avoid hypertension by minimizing high
sodium intake (limiting dietary sodium to less than 1,800 mg per day).
High
levels of sodium may aggravate existing high blood pressure. Factors to help reduce high blood pressure include a low sodium
diet, increased fruit and vegetable consumption, exercise, weight control, and medication if necessary.
Studies
of more than 20 cultures worldwide, from Greenland Eskimos to natives of the Solomon Islands, show that hypertension is rare
in populations using little salt. Kung bushmen of Africa and Yanomamo Indians of Brazil have virtually no hypertension. Their
diets are extremely low in salt. Their blood pressure does not rise with age as it does in people who live in industrialized
societies. By contrast, in countries where people consume large amounts of salt, hypertension is a serious concern. People
in northern Japan, where salt is used as a food preservative, areamong those with the highest incidence of high blood pressure.
They may consume 30,000 mg (1/8 cup) of salt each day, about 60 times as much as 500 mg for the African and Brazilian tribes.
Excess salt in the diet causes increased sodium in the blood. In some people the volume of blood increases,
thus causing blood pressure to increase and the heart to work harder. The danger of high blood pressure is possible damage
to the heart and arteries, which may result in heart attack,
Water Deionizers use
both Cation and Anion Exchange to exchange both positive and negative ions with H+ or OH- ions respectively, leading to completely
demineralized water. Deionizers do not remove uncharged compounds from water, and are often used in the final purification
stages of producing completely pure water for medical, research, and industrial needs.
A potential
problem with deionizers is that colonies of microorganisms can become established and proliferate on the nutrient-rich surfaces
of the resin. When not regularly sanitized or regenerated, ion-exchange resins can contaminate drinking water with bacteria.
