More than 80 contaminants have been set as standasrds according to EPA (US Environmental Protection Agency), that may occur in drinking water. The contaminants fall into 2 groups according to the health effects they cause:

Acute Effects

Those occur within hours or days of the time that a person consumes a contaminant. People can suffer acute health effects from almost any contaminant if they are exposed to extraordinarily high levels (as in the case of a spill). In drinking water examples include microbes, such as bacteria and viruses, which are the contaminants with the greatest chance of reaching levels high enough to cause acute health effects.

Chronic Effects

These occur after people consume a contaminant at levels over EPA’s safety standards over the course of many years.
The drinking water contaminants that can have chronic effects include chemicals (such as disinfection byproducts, solvents and pesticides), radionuclides (such as radium), and minerals (such as arsenic). Examples of these chronic effects include cancer, liver or kidney problems, or reproductive difficulties.

Drinking Water Contaminants Categories 

There are 4 general categories of drinking water contaminants:

1. Physical Contaminants:
   primarily impact the physical appearance or other physical properties of water.
   Examples of physical contaminants are sediment or organic material suspended in the water of lakes, rivers and streams from soil erosion.
2. Chemical Contaminants:
   are elements or compounds. These contaminants may be naturally occurring or man-made.
   Examples of chemical contaminants include nitrogen, bleach, salts, pesticides, metals, toxins produced by bacteria, and human or animal drugs.
3. Biological Contaminants:
   are organisms in water. They are also referred to as microbes or microbiological contaminants.
   Examples of biological or microbial contaminants include bacteria, viruses, protozoan, and parasites.
4. Radiological Contaminants:
   are chemical elements with an unbalanced number of protons and neutrons resulting in unstable atoms that can emit ionizing radiation.
   Examples of radiological contaminants include cesium, plutonium and uranium.

Common Contaminants

A few common drinking water contaminants include:

• Aluminum
• Ammonia
• Arsenic
• Barium
• Cadmium
• Chloramine
• Copper
• Fluoride
• Bacteria & Viruses
• Lead
• Nitrates/Nitrites
• Mercury
• Radium
• Selenium
• Silver
• Uranium

Water and Health In Europe

This great joint report-publication from the European Environment Agency and the WHO Regional European office takes forward some of the issues raised in Environment and Health. Microbial contamination, organic matter content, a number of serious diseases that can be spread via contaminated drinking water, health-problems associated with waterborne chemicals and radioactivity are just a few of the many critical aspects presented in this truly valuable joint > report-publication.