There was a time when if you were thirsty all you had to do was walk over to your kitchen sink and pour yourself a glass of water; it was always clear, healthy and ready to quench your thirst. But nowadays you have to be concerned about the quality of the water coming out of your tap, whether you’re in the city or in the country because what you don’t see can hurt you or at least make you very sick. But where do you start to make sure that your glass of water is just water? .
- Water contaminants : There are five principal groups of water contaminants:
1) particulate, which includes particles of rust, dirt and sediment;
2) dissolved inorganics, including heavy metals (mercury, lead, chromium, silver, etc.), and asbestos;
3) organics, which include calcium and magnesium carbonates, the components that make water “hard,” and nitrates, chemical solvents, pesticide residues, and industrial pollutants;
4) radiological contaminants, both natural and industrial, such as radon and radium; and
5) biological pathogens, including bacteria, viruses and protozoa.
Problems associated with the particulate category involve mainly appearance, smell and taste. Particulates can be removed with simple filters. Filters are effective only against larger particles. They are ineffective against dissolved toxic chemicals.
• Dissolved inorganics
Dissolved inorganics are a very serious problem, especially lead. However, another major inorganic pollutant is nitrate. Nitrate contamination occurs mainly in groundwater, especially in agricultural areas.
Chemical fertilizers and manure from animals are particularly concentrated sources. The danger is particularly great for children. Nitrates are converted to nitrites in the digestive tract, and nitrites interfere with the ability of blood to carry oxygen, which can result in brain damage and death.
Dissolved organics include some serious problems. Many public water supplies contain low levels of organic compounds created as byproducts of water chlorination. Pesticides, industrial effluent, and hazardous waste sites are other sources of organic pollutants. These chemicals are associated with liver, kidney, and nervous system damage, and possibly cancer.
Dissolved organics include some harmless, although annoying, chemicals such as calcium and magnesium carbonates.
• Radiological contaminants
Radiological contaminants, such as uranium, radium and radon, occur naturally in various parts of the country. The most serious effects of radiation exposure include birth defects and cancer.
• Biological pathogens
Biological pathogens, such as viruses, bacteria and protozoa, are uncommon in public water supplies due to chlorination. But some organisms are becoming resistant to chlorine, and this may become more of a problem in the future.
• Water purity checks
If you have municipal water, ask the local utility for a copy of its latest water analysis. Federal law requires periodic testing and making the results available for inspection. You can have lead levels checked by a private testing laboratory.
If your water is from a well, you can call the local public health department to inquire about groundwater problems in your area. In general, if your water is from a private well, you should also test for organic chemicals. In agricultural areas, nitrates and pesticides should be among the requested tests. If your house is more than 30 years old or contains copper pipe, you should test for lead.
• Home water treatment : The three primary home water treatment methods are:
1) activated carbon filters,
2) reverse osmosis systems, and
3) water distillers.
1) Activated carbon filters : Activated carbon filters work by a process known as adsorption whereby the carbon attracts and holds various pollutants in a honeycomb of tiny channels and pores. They are best suited for removing bad tastes, odors, chlorine, organic chemicals, and pesticides. They are not effective against microorganisms, lead or heavy metals, sodium, fluoride, or minerals that produce hardness.
• Drawbacks – Carbon filters can become breeding grounds for microorganisms. Sediment in water can clog the filter. Effectiveness declines over the period of use-it is necessary to be diligent about replacing cartridges.
• Advantages – Activated carbon filters are the least expensive of the three main water treatment methods. The solid carbon filters are considered the best, while powdered carbon filters are the least recommended.
2) Reverse osmosis : Reverse osmosis is effective at removing inorganic contaminants, such as dissolved salts, fluoride, nitrate, lead and some organic contaminants. It is not effective against high levels of hardness minerals.
• Drawbacks – Reverse osmosis systems waste a lot of water. Only 10-25% of the water passing through the unit is forced through the membrane. The rest goes down the drain. Reverse osmosis is slow, 3-6 gallons per hour.These systems can be expensive to install and maintain.
• Advantages – Reverse osmosis systems do not use electricity, and the cost per gallon of treated water is less than distillation.
3) Water distillation : Water distillers work by boiling water and then condensing the steam into purified water. Distillation is most effective at removing sediment, dissolved inorganics (including heavy metals), radiological contaminants, and biological pathogens. It is less effective against some volatile organic compounds unless combined with a carbon filter.
• Drawbacks – Water distillation is slow and uses considerable electricity, making it the most expensive method of water treatment. .
• Advantages – Distillation, especially when combined with a carbon filter, is the most effective means of home water treatment.