Drinking Water - International Recommendations on Metals

International recommendations on metals in Drinking Water have been drawn up by the World Health Organization (WHO). These recommendations are contained in the third edition of “Guidelines for Drinking-water Quality”.

Everyone needs Drinking Water, and most of us believe everyone is entitled to Drinking Water quality that is as safe as practicable. The “Guidelines” defines safe drinking-water as water that does not represent any significant health risks if you drink it throughout your entire life. This does not mean the Drinking Water poses no health risks at all - simply that it does not represent “significant” health risk to the drinker.

The “Guidelines” are not international law. They are recommendations that individual nations can follow in drawing up Drinking Water regulations.

International recommendations on metals in Drinking Water are contained in the eighth chapter of this publication, “Chemical Aspects”.

International Recommendations on Metals in Drinking Water

The following Drinking Water information is derived from the WHO “Guidelines”. It is presented in simple terms. For more complete, technical information, please order a copy of the “Guidelines” from WHO.

The abbreviation “ug/L” refers to micrograms per liter. One microgram per liter equals one part per billion.

The abbreviation “mg/L refers to milligrams per liter. One milligram per liter equals one part per million.

3.1 ug/L divided by 1000 = 0.0031 mg/L

* Antimony - 20 ug/L
* Arsenic - 0.01 mg/L
* Barium - 0.7 mg/L
* Boron - 0.5 mg/L
* Cadmium - 0.003 mg/L
* Chromium - 0.05 mg/L
* Copper - 2000 ug/L
* Lead - 10 ug/L
* Manganese - 0.4 mg/L
* Mercury - 0.001 mg/L
* Molybdenum - 0.07 mg/L
* Nickel - 20 ug/L
* Selenium - 0.01 mg/L
* Uranium - 0.015 mg/L

No International Recommendations on Metals in Drinking Water

Metals not mentioned above, such as aluminum, iron, silver, and zinc, appear to have no recommendations. The most common reason given for this is that the available data was inadequate.

In some cases, available data seemed to indicate that levels should be set. Drinking Water treatment facilities, however, seem to have fought back. Aluminum, for example, although thought to cause or contribute to Alzheimer’s disease, is used in water treatment. To set limits on it would require changes in water treatment methods. No limits were set.