Even Snow-Capped Mountains Polluted

by Danielle Knight

But a new scientific study shows that even pristine regions of the world are susceptible to the accumulation of toxic industrial pollutants and agricultural pesticides.

From the Swiss Alps to the Sierra Madre mountain ranges in Mexico, temperate-zone mountain regions -- which tend to receive high levels of rain or snow while being close to sources of pollution -- may be prone to greater concentrations of harmful chemical compounds known as Persistent Organochlorine Pollutants (POPs).

In surveying the temperate mountains of western Canada, scientists found that the higher they went, the higher the concentration of contaminants -- according to the study published October 8 in the magazine Nature.

Some of these chemicals are pesticides and industrial products; others are the chemical by-products of manufacturing processes. These include dioxins and furans which are created during incineration or through the production of chlorine.

What all POPs have in common is that they remain in the environment for years after being released -- often traveling great distances through air, wind and water. Because of their ability to mimic naturally occurring hormones, the substances have been blamed for cancers, birth defects, immune disorders, neurological defects, reproductive abnormalities, and low sperm counts.

"These chemicals are undermining the development of the brain and children's intelligence is being compromised," said Theo Colborn, a senior scientist with World Wildlife Foundation.

POPs also "bio-accumulate" -- when consumed, they are not excreted but accumulate in fatty tissue instead. Thus, animals high up in the food chain, which eat large quantities of other animals, retain higher doses of the chemicals. The contaminants have been found from monk seals of the Black Sea in Turkey to polar bears in the Arctic.

POPs crop up in surprisingly high concentrations in colder regions, like the Arctic because of the phenomenon called "cold condensation."

The chemicals vaporize in warm climates and then tend to condense out as soon as they get somewhere cooler. So because these substances travel well, a POP that originated in a warmer part of the world may eventually be found in a colder region thousands of kilometers away.

The Nature magazine study expanded this "cold condensation" theory by proving that, at least in the observations in Canada, higher altitudes which are also colder tend to have more POPs than lower elevations.

By taking samples of snow that fell in the mountains of western Canada in 1995 and 1996, David W. Schindler of the University of Alberta, Canada and other scientists found that the concentration of POPs show a 10- to 100-fold increase between 770 and 3,100 meters altitude.

Besides being found in higher concentrations at a higher altitude, the chemicals were also more abundant higher up because of the increase in precipitation at that elevation.

Researchers were prompted to take samples when several studies observed that fish from lakes located at high altitudes of the Canadian Rocky Mountains contain high concentrations of such contaminants.

Further investigations on mountain ranges that exceed the Canadian mountains elevation need to be done since there is reason to believe that the levels of the chemicals would continue to increase at higher altitudes, said the study.

"It is at present unclear how much of the contaminants deposited at high elevations may find their way into the surface waters at more populous low altitude sites," the study said.

"It's definitely worth taking a look because some cities, like Denver and Mexico City, derive their water supply from snowmelt on mountains more than 3,000 meters high," Schindler told IPS.

While researchers press for more studies, environmentalists have been urging governments to globally ban the harmful substances altogether since they travel such long distances.

In response to this push, in 1995 about 100 countries agreed to negotiate a global treaty to reduce and eliminate the "dirty dozen" -- aldrin, chlordane, DDT, dieldrin, dioxins, endrin, furans, heptachlor, hexachlorobenzene, mirex, PCBs and toxaphene.

Negotiations that began with the conference in Montreal are expected to be completed by the year 2000, yet many obstacles stand in the way of implementing such a treaty, the first attempt to control these kinds of synthetic chemicals on a global basis, say environmentalists and government officials.

They maintain that developing countries do not have the legal structures in place, nor economic resources, for dealing with chemical regulation. Also alternatives to the harmful chemicals, used in public health programs to eradicate disease-carrying mosquitoes in developing nations, are very expensive.

Governments, the chemical industry and environmentalists also disagree on whether the POPs should be banned outright or limited in use.