How To Chose A Water Filter

Though U.S. drinking water has been  protected under the Safe Drinking Water Act since 1974, experts warn  that tap water increasingly does not meet health-safety guidelines.

A  recent investigation by The New York Times found that, since  2004, some 62 million people in the U.S. have been exposed to drinking  water contaminated with thousands of chemicals—albeit in low  concentrations—that are not regulated under federal law.

Of  course, the best way to ensure clean and safe drinking water is to  protect the source. Watersheds act as natural filters that remove  chemicals, pollutants, and sediment. Citizens can also urge Congress and  the federal government to update the Safe Drinking Water Act to include  and regulate potentially hazardous new chemicals.

In the meantime, many consumers are  turning to home water filters for added peace of mind.

The  first step in determining whether a water filter might make your tap  water cleaner is to find out what’s in your water, and if it contains  any dangerous, unregulated chemicals.

If possible, check out  your annual water-quality report—also called a consumer-confidence  report—from your water supplier. Some reports are available on the U.S.  Environmental Protection Agency (EPA)’s Web site. These  reports can be difficult to interpret, so download a guide to reading  them at the Campaign for Safe and  Affordable Drinking Water’s Web site.

The  Environmental Working Group’s “What’s in your  water?” tool is another useful mine of information on local  water supplies. The nonprofit recommends that most people in the U.S.  filter their tap water.

If you decide to purchase a water filter,  experts recommend selecting filters certified by the National Sanitation  Foundation, which tests products to ensure that they remove what is  required by water-filter manufacturers.

The foundation  maintains an extensive  database searchable by type of water treatment product.

No  filter will remove every contaminant, in part because the list of risky  chemicals keeps growing.  But here are the most common types of filters  and the major contaminants they are designed to trap:

1. Carbon  filters include countertop pitchers, faucet-mounted models, undersink  models (which usually require a permanent connection to an existing  pipe), and whole-house or point-of-entry systems (usually installed in  the basement or outside). Carbon, a porous material, absorbs impurities  as the water passes through.  What they remove: Lead, PCBs,  chlorine byproducts (chloramines and trihalomethanes), certain  parasites, radon, pesticides and herbicides, the gasoline additive MTBE,  the dry-cleaning solvent trichloroethylene, some volatile organic  compounds, some levels of bacteria (such as Cryptosporidium and Giardia) and a  small number of pharmaceuticals.
2. Reverse-osmosis systems push  water through a semipermeable membrane, which acts as an extremely fine  filter. They’re often used in conjunction with carbon filters. However,  these systems waste 4 to 9 gallons (15 to 34 liters) of water for every  gallon (3.8 liters) filtered.  What they remove: Chemicals carbon  filters may miss, including perchlorate, sulfates, fluoride, industrial  chemicals, heavy metals (including lead), chlorine byproducts, chlorides  (which make water taste salty), and pharmaceuticals.
3. Ultraviolet  light units disinfect water, killing bacteria. Countertop units can be  found for under U.S. $100, but most whole-house units cost $700 and  upward. What they remove: Bacteria. Experts recommend using them with  carbon filters to remove other contaminants.
4. Distillers, probably  the least practical home method, boil and condense water. While  countertop units are available, distillers use lots of electricity,  generate excess heat, and require regular cleaning. Explore filters or  other alternatives to remove your contaminants, or, in a pinch, buy  distilled water.  What they remove: Heavy metals (including lead),  particles, total dissolved solids, microbes, fluoride, lead, and  mercury.

Environmental Impact

Most U.S. citizens count on their local  governments to ensure that their water is clean and safe. And with  daily, mandatory testing, municipal water is actually more regulated  than bottled water, which is usually only tested annually.

Nevertheless, problems with municipal  supplies, convenience, and simply good marketing has led many consumers  to choose bottled water over tap water. But bottled water is associated  with an array of environmental concerns, including the generation of  billions of wasteful plastic bottles, the burning fossil fuels to  refrigerate and transport those bottles, and the draining of aquifers  and watersheds to fill the bottles.

At the same time, used water  filters—often housed in plastic casings—aren’t recycled either. So test  your water before investing in plastic filters that will ultimately get  tossed in a landfill.

Human Health Issues

Water filters remove  common contaminants in city water supplies, ranging from the minor  (taste and odor problems) to the serious (cancer-causing pesticides and  pharmaceuticals that can contribute to bacterial resistance). Here are  some of the most common chemicals found in city water:

13 Common  Water Contaminants

1. Alachlor is a potentially cancer-causing  herbicide applied to corn, soy, and sorghum crops in the U.S. Midwest  that can run off from fields into drinking water sources.
2. Arsenic, a naturally occurring poison that can also cause cancer, is  found in all 50 U.S. states, often in wells.  Higher levels are found in  the Southwest.
3. Atrazine, a widely used pesticide, may cause  hormone disruption, cancer, weight loss, muscular degeneration, and  cardiovascular damage. Found in all 50 states, it’s most common in the  Mississippi River Basin during spring runoff periods. [could link to:   http://news.nationalgeographic.com/news/2010/02/100301-atrazine-frogs-female-chemical/]
4. Benzene is a known carcinogenic chemical emitted by the petroleum and  chemical industries. It can taint drinking water via air pollution,  leaking underground gas storage tanks, industrial discharges, and poor  waste disposal.
5. Chromium is a heavy metal typically pollutes  drinking water via discharge from steel and pulp mills and erosion of  natural deposits. In various forms it can affect the respiratory system,  digestive tract, and circulatory system, among others.
6. Lead, a  heavy metal, can cause brain damage and developmental problems in  children and adversely affect blood pressure, kidneys, and red blood  cells.
7. Mercury, another heavy metal is produced in some industrial  facilities; during coal burning, landfill, and agricultural runoff; and  erosion of mineral deposits. Methylmercury, an organic compound of  mercury, is a known human neurotoxin linked to harmful health effects in  people, especially children.
8. Methyl Tertiary-Butyl Ether (MTBE), a  gasoline additive, occasionally leaks into groundwater from underground  fuel storage, spills, and stormwater runoff, and may cause cancer.
9. Nitrate, which comes from animal waste in dairies, on cattle farms, and  on feedlots, can cause “blue bay syndrome,“ which prevents blood from  holding oxygen. It’s more common in rural areas.
10. Pathogens such  as Cryptosporidium, E. coli, and Giardia, carried by animal and human waste, are  linked to gastrointestinal illnesses. Cryptosporidium infection can be life-threatening for people with weakened immune  systems.
11. Perchlorate, a contaminant from rocket fuel production,  has leaked into U.S. drinking water due in part to improper disposal.  The chemical harms the thyroid and may cause cancer. Currently, there is  no EPA standard for perchlorate, but its risks are being assessed.
12. Radium-266 is a radioactive element usually found around uranium  deposits.
13. Trihalomethanes (THMs), a byproduct of chlorine  treatment, are linked to cancer, miscarriages, and birth defects.

For  more information, see the Natural Resources Defense Council’s report,  which lists more than 30  drinking-water contaminants and their effects on health.  Also  visit EWG’s  water-filter buying guide.

Source: http://environment.nationalgeographic.com/