Removing Metals from Drinking Water

There may be no single best water filter when it comes to removing harmful heavy metal contaminates from you drinking water. Instead, it is often recommended to use a multistage water filter system.


We do not want to filter out all of the metals from our drinking water because certain metals, such as manganese, iron, copper and zinc, are important micronutrients. They are crucial to life in the correct amounts, and chronically low exposures to these metals may have some severe long-term health effects.

However, in larger amounts in excess of our bodies requirements, they can be harmful and even deadly.
Some of these hazardous metal pollutants in our drinking water (and even toys) have even been linked to autism in children. Cadmium remains in our bodies for a half-life between 10 – 35 years, and primarily attacks the kidneys which can cause kidney failure. Children’s bodies can absorb 4 – 5 times as much lead as adults which can lead to anemia and or neural diseases in kids that are exposed to unsafe levels.

Metals are introduced into our water systems through natural occurrences like rock and soil sediments or volcanic activity, but also due to a number of human activities that involve mining, refining, and the manufacturing of materials and products containing metal contaminants.


There are different sources for pollutants:

Point Sources (local pollution), where contaminates come via specific, distinctive sources.
Non-Point Sources, where contaminants derive by scattered and difficult to identify sources.

The most prevalent heavy metals contaminants are arsenic, cadmium, chromium, copper, nickel, lead and mercury.
Some sources of localized metal contamination include the natural weathering of ore and small metal particles coming from coal-fired power plants, the soil and water along the facility, and even from its smokestacks. However, the most common man-made cause of metal pollution in our drinking water comes from mining operations.

Due to metal’s solubility in acidic solutions they will often use acid mine drainage methods to release the metals from the ore. It’s in the drainage process when the acid solvent is easily distributed into groundwater, carrying with it high levels of metal contaminates.

Total allowable concentrations of metals in natural waters, as recommended by the Environmental Protection Agency:

Metal

Chemical Symbol

mg m-3

Barium

Ba

1000

Cadmium

Cd

10

Chromium

Cr

50

Iron

Fe

300

Lead

Pb

5

Manganese

Mn

50

Mercury

Hg

0.144

Nickel

Ni

13.4

Selenium

Se

10

Silver

Ag

50

Thallium

Tl

13

To bring drinking water down to healthy and acceptable levels, one may use a combination of different filter types / water filter technologies.

When you decide to buy a water filter system for home use, be it a more pricey multistage whole house filter system or if you’re researching the best inexpensive under sink filters, you should read the data sheets and reviews to ensure that filter system is right for you.

Reverse Osmosis (RO) works best with soft water because water that is rich in aluminum and lead contaminants can quickly foul the filter’s membranes. So, using a home filtration system that utilizes prefilters is recommended.
Activated Carbon filters by themselves may have limited ability to remove toxic metals from our drinking water.
Ion Exchange systems are very effective and will remove heavy metals, however in some cases they may leave a fishy odor in drinking water making it unpleasant, and the water filter system can be expensive.