Heavy Metals in Drinking Water: International Risks

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By J. E. Hinners, MD MPH

drinking waterYou’re in a foreign country, and you’re seeking solutions to be able to drink the water in that country.

Is boiling the water enough to minimize health risks of drinking that water?

 If the region you’re in has a high risk of containing heavy metals in the drinking water, then the answer is “NO.”

In fact, by boiling water that contains heavy metals, you may actually increasing the concentration of the heavy metals in your drinking water.

What is a heavy metal?

A heavy metal has traditionally been defined as an element with a specific density greater than 5 g cm-3; arsenic, lead, cadmium, and mercury are at the forefront of heavy metal human health concerns, even though arsenic is technically a “metalloid.” There are 19 additional elements in the “heavy metal” category, and a small handful of those metals are actually considered essential for good health in minimal doses (such as zinc, copper, manganese, iron, and cobalt).

What happens when your body experiences heavy metal toxicity?

When your body is exposed long-term to unhealthy high doses of heavy metals, some possible health effects include:

  • neurological, muscular, and physical degenerative diseases
  • allergies
  • cancer
  • gangrene
  • hypertension
  • ischemic heart disease

Excessive water ingestion of heavy metals have been linked with the following symptoms and diseases (this list only focuses on 4 heavy metals):

ARSENIC:  DNA damage, cerebrovascular diseases, diabetes mellitus, kidney diseases, melanosis, neuronal development problems, cancer, leucomelanosis, keratosis, skin and liver lesions, hormonal and mucosal immune response dysfunction, hyperkeratosis, hyperpigementation, heart lesions, hypertension, ischemic heart disease, gangrene, and lung function failure

LEAD: Brain and central nervous system dysfunction and degeneration, Parkinson disease, lung and blood accumulation, chronic renal failure, and lower energy levels.

CADMIUM: Kidney failure, fetal membrane and DNA damage, and fetal risk of stillbirth.

MERCURY: Accumulation in liver and muscle and damage to DNA.

For a more extensive list of heavy metals and health effects, read here.

How does drinking water get contaminated with heavy metals in the first place?

Drinking water can become contaminated with heavy metals from both the soil and rocks underground (sometimes from mining, construction or older fruit orchards’ pesticide residue) and also from water piping, drinking water fittings, household gutters, and roofing materials. Heavy metal leakage into the water supply is therefore not necessarily limited to “foreign countries,” as merely older buildings with older piping may also pose heavy metal risks in drinking water.

How are excessive heavy metal concentrations in drinking water measured?

There are several different drinking water quality guidelines around the world that list specific permissible thresholds for various heavy metals in drinking water. Some guidelines are more strict than others on levels of heavy metals considered to be “permissible.” World Health Organization, Health Canada, United States Environmental Protection Agency, European Commission Environment, and Australian Drinking Water Guidelines are several of the organizations or committees that have created drinking water standards that include heavy metal limits.


While this “white paper” country comparison by Carr and Rickwood (UNEP GEMS/Water Programme) does not focus specifically on heavy metal contamination in drinking water, it does reflect general drinking water quality (which includes heavy metals in the analysis):

National Ranking Overall Water Quality
To see larger, click on graph or else view original document HERE.

The top 10 ranked countries for overall drinking water quality in this graph were as follows (starting with the best):

  1. New Zealand
  2. Finland
  3. Serbia
  4. Lithuania
  5. Latvia
  6. Slovenia
  7. Sweden
  8. Albania
  9. Italy
  10. Bulgaria

The worst 10 ranked countries for overall drinking water quality in this graph were as follows (starting with the worst):

  1. Liechtenstein
  2. Papua New Guinea
  3. Algeria
  4. Cote d’Ivoire
  5. Czech Republic
  6. French Guiana
  7. Jordan
  8. Iraq
  9. Niger
  10. Malta


The United Nations report on global drinking water quality (2007) shows the distribution of which drinking water parameters exceeded the recommended limit. These figures represent global averages and include both heavy metals and other water contaminants:

A) Drinking water quality index, B) Health of drinking water quality index; FCB=fecal colliform bacteria
A) Drinking water quality index, B) Health components of drinking water quality index; FCB=fecal colliform bacteria



Arsenic exceeding the limit of 10 μg L-1 has been observed in U.S. groundwater, and high levels exceeding the guideline limit have been found in drinking water aquifers in New England, the Great Lakes region, the western U.S., and New Mexico near the Middle Rio Grande Basin.

Quite a number of Canadian regions (British Columbia, Manitoba, Alberta, New Brunswick, Newfoundland and Labrador, Nova Scotia, Quebec, and Saskatchewan) have been noted as having similar high arsenic levels; some Canadian bottled drinking water has also been found to contain high levels of copper and nickel.

Northern Mexico has been shown to have arsenic, mercury, and lead contamination in drinking water, and other areas of Mexico (Coahuila and Chihuahua) show high arsenic concentrations mostly due to volcanic and mining processes.


Certain regions in Chile (such as Antofagasta) have been found to have high arsenic levels in drinking water–particularly near rivers containing high inorganic arsenic levels. Surface water in Venezuela’s Coyuni river basin has been reported as having high levels of mercury due to nearby gold mining.

Tin has been found in some Brazilian water samples, and Bolivia’s drinking water has been found to have excessive iron, aluminum, manganese, and arsenic. Overall, an estimated 4.5 million people appear to be exposed to high arsenic levels in Latin America, in general.


Drinking water in eastern Thessaly in Greece has been found to be contaminated with high levels of arsenic and antimony; northeastern Greece was found to contain high levels of manganese and iron. Excessive arsenic levels have also been observed in Serbia, Croatia, and South Tuscany, Italy (most likely due to water pipes). Spain and Austria’s drinking water contains high levels of lead.

Belgrade (in Serbia) showed radioactive uranium and strontium in drinking water; elevated uranium has also been recorded from water sample from private wells in various communities throughout the world (Germany, Greece, Australia, and the U.S.). Nickel has been observed in Denmark’s water.

Bottled water samples were also taken from Europe, and 4.63% were shown to exceed acceptable limits of either arsenic, nickel, barium, or manganese; ten samples revealed excessive radioactive uranium concentrations. There have also been some reports of excessive tellurium in some bottled water and in some of Germany’s surface water.


Copper, lead, and zinc have been observed in aquatic systems in northern Queensland, Australia. Australian rainwater is one significant source of drinking water for both Australia and New Zealand, and untreated rainwater, in general, has been linked to heavy metal health risks as well.


Drinking water in Ghana has been found to be contaminated with arsenic, mercury, manganese, iron, and lead. Water samples from Koekemoerspruit, South Africa has been demonstrated as having elevated arsenic and cadmium.


Thailand, Nepal, China, Bangladesh, Taiwan, Vietnam, Cambodia, and India all have high levels of arsenic in the groundwater and drinking water–with special mention to India, which has been noted as having a high degree of associated health effects (including skin lesions and reduced lung function). Drinking water from Assam, India was found to additionally contain excessive levels of lead, and villages near Kali river in India are exposed to excessive iron levels, according to water samples taken from the region.

Some wells in Bangladesh were found to contain excessive uranium, manganese, arsenic, lead, nickel, and chromium. Pakistan drinking water (in Muzaffargarh) has been shown to contain excessive arsenic in 58% of samples taken; other regions of Pakistan (Skardu) suggest excessive levels of zinc, iron, nickel, lead, cobalt, copper, and chromium.

Chronic arsenic ingestion is the leading drinking water contaminant in Vietnam, however the country also reveals high levels of barium, cadmium, nickel, tin, lead, and uranium in the drinking water. Sri Lanka populations are at risk for excessive water ingestion of cadmium.

Mercury has been found in high levels in drinking water in Indonesia and in the Philippines. Copper, zinc, and arsenic are risks in Shanghai, China’s drinking water, while high uranium concentrations (and associated kidney dysfunction) have been observed in Central Asian countries, including Kazakhstan.

I am skipping the report of Antarctica in this article, but more information about Antarctica may be found here.

So. That’s rather depressing. It appears that heavy metals in drinking water are somewhat prevalent no matter where you live.

Now what?


We’ve discussed already that the heavy metal problem can’t be avoided by boiling water (and in fact, it may be worsened by doing so).

We’ve also seen from the regional data above that bottled water is no guarantee of drinking water that is free of heavy metals.

What, then, is the solution?

Ah. Well, that would be the discussion of next week’s article. Stay tuned..!

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