Water Testing for Iron and Copper

Water quality is a continuous concern across the world. Since water is a universal solvent, many compounds, molecules, metals and elements can exist within water. The majority of these are odorless, flavorless and colorless. Detection by the traditional methods of smell, taste and sight are rendered useless. Chemical testing of water is required.

A metal is a category of chemicals that is quite unique. They are typically heavy in weight and atomic mass. That distinction gives them the nickname of Heavy Metals.

Many can conduct currents or electricity, while others do well absorbing heat. Some of these are naturally occurring in nature, while others are only constructed in laboratories to make alloys with various mixtures of additional elements.

Consisting of a high density and durability, these metals are widely used in engineering, industry, utilities, building materials, and construction. During manufacturing, disposal and mining for these metals/ores, some do end up in the surrounding waterways as pollutants. Iron and Copper are two common elements that can be found in the water supply.

Fe (Iron)

Iron spans the entire globe; from the molten core to the city structures. Additionally, the chemical even exists in the living organisms.

Blood has a complex protein called Hemoglobin which contains iron. That iron binds to four oxygens and allows the blood to appear red when it is full oxygenated. It is a necessity for life as we know it.

The silvery metal reacts rapidly when oxygen and water are nearby. When air oxidizes the metal in moist environments, it turns bright red, and the chemical composition becomes iron oxide (Fe2O3). The rusting effect is called corrosion.

Sometimes, the rust can stain porcelain, sinks and faucets. The rust can break off into shards, residues and runoff which gets into the water supply. They will appear red in the water column. Those can be filtered out, but the existing faulty source of pipes, plumbing or water tank will need replacement.

Testing for iron inside water includes many options.

Some small batch testing can be ordered for home-use. These mini-chemistry experiments involve taking water samples, adding chemicals and reagents and then watching for a response. A reagent is typically a solid powder, but it can be a liquid. These pre-measured reagents for chemical analysis come in kits.

Such examples for iron testing include: Phenanthroline (C12H8N2), Sulfuric Acid (H2SO4), Sodium Sulfite (Na2SO3), 2,2`-Bipyridine (C10H8N2), Zinc, Sodium metabisulfite (Na2S2O5), Sodium dithionite (Na2S2O4), Ferrozine (C20H13N4NaO6S2), or Potassium Chloride (KCl) to name a few.1

These reagents can react with the iron in the sample almost instantaneously to make a color change of pink, orange or red. Or, they could begin bubbling and turn the test tube warm to the touch. Some even form a precipitate.

A precipitate is a solid that immediately forms directly from the liquid after a chemical reaction. When that occurs, or any of the color changes, iron presence in water can conclusively be stated.

Testing strips for iron are a viable alternative.These strips change color when iron is detected upon reaction with 2,2`-Bipyridine (C10H8N2). Then the test uses the color scheme on the side of the bottle for comparison. Large-scale facilities use spectroscopy or spectrometry to view a snapshot of water contents.

Cu (Copper)

Copper is a metal that is orange or red in color. It is used in plumbing because it does not react with normal water to corrode. Even though it is highly durable, it is a relatively soft metal that allows excellent electrical conductance. Outdoor copper can become discolored over time when acids or acid rains react with it. Copper exists naturally in the body and is critical to many cellular processes.

Excessive copper enters the water supply by mining, recycling, manufacturing and industrial processes.  If water is acidic (pH<7), then it starts to break down the copper pipe by corrosion. Parts of copper can then break off into the water flow and will appear as small orange flecks.  Those can be filtered out.

There are domestic testing and at-home kits for copper. They use tablets or solutions to act as reagents.  These reagents can include, [2,2`-Biquinoline]-4,4`-dicarboxylic acid (C20H12N2O4), Dipotassium phosphate (K2HPO4), Potassium salt (KCl), Carboxylic acid salt, Carbonate salt.  Color, and Ammonium Hydroxide (NH4OH). Upon reaction, the chemical changes or precipitates out of solution to indicate if copper is in the water sample. Many different kits exist and there is even one that tests for copper and iron.3 Finally, water strips are available to perform a color change when copper is present. The combination of 2,2′-biquinoline (cuproine) (C18H12N2) and copper form a color change to be compared to the color scale on the bottle.4

Iron and Copper Water Standards

Metal Recommended Daily Intake5,8 Lethal Dose9,10

 

Secondary

Maximum Chemical Level

(MCL) 6

Noticeable Effects above the Secondary MCL6 Maximum Contaminant Level Goal (MCLG)7 Health

Effects7

Iron 8-15mg/day 200-250mg/kg

Body Weight

0.3 mg/L Rusty color; sediment; metallic taste; reddish or orange staining 4.0mg/L Can have many interactions with common prescriptions.

Low Iron levels can lead to anemia,

 

Copper 1.5-3mg/day 4-400mg/kg Body Weight 1.0 mg/L
Metallic taste; blue-green staining
1.3mg/L Short term exposure: Gastrointestinal distress

Long term exposure: Liver or kidney damage

 

References:

  1. http://www.lamotte.com/en/drinking-water/individual-test-kits/3347-01.html
  2. http://www.sensafe.com/test-strips/sensafe-iron-check-fe2-30-pkts-of-1/
  3. http://www.lamotte.com/en/browse/2066.html
  4. http://www.lamotte.com/en/pool-spa/insta-test/2991-g.html
  5. http://www.mayoclinic.org/drugs-supplements/copper-supplement-oral-route-parenteral-route/proper-use/drg-20070120
  6. https://www.epa.gov/dwstandardsregulations/secondary-drinking-water-standards-guidance-nuisance-chemicals
  7. https://www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations#one
  8. http://www.mayoclinic.org/drugs-supplements/iron-supplement-oral-route-parenteral-route/proper-use/drg-20070148
  9. http://www.who.int/water_sanitation_health/dwq/chemicals/iron.pdf
  10. http://www.who.int/water_sanitation_health/dwq/chemicals/copper.pdf

Photo Credit: Angus on Flickr

2017-11-27T16:53:08+00:00

About the Author:

Natalie Abram

Natalie is new to freelancing, but has worked as an aquatic content editor for the past 7 years. She teaches biology online at multiple schools. Her background and Master’s education is in Biology, Aquatic Ecology and Education.

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