Reuters

Pollution mounts as cities grow and sewage infrastructure lags

One of the largest and most famous lakes in South America is facing a gradual threat from its shores. Urban growth and increasing populations in the areas around Lake Titicaca are contributing to growing amounts of pollution in the lake, which lies on the border of Bolivia and Peru and is the continent’s largest lake by volume.

As the Guardian reports, a rural-to-urban migration has brought thousands of people to cities and new urbanizing areas within the lake’s watershed. Nearby cities like El Alto, Bolivia, a suburb of La Paz, have seen steady growth rates in recent years. El Alto has grown at 4 percent for the past two decades, and despite only being incorporated in 1985 is now Bolivia’s second largest city, with more than 950,000 residents.

But water and sewage infrastructure have not kept pace with the city’s growth. This, coupled with its location on one of the many rivers that feed into Lake Titicaca, has resulted in raw sewage from the city flowing directly into the lake. Human waste and the waste of cows grazing in the watershed’s many pastures are contributing to growing problems with plant life in the shallow areas of the lake, where oxygen levels are falling. If the problem continues to mount, the pollution will cut even deeper into the lake’s fishing industry.

The polluted river is probably more of a problem than the polluted lake:

The Pallina River is one of several in the string that connects El Alto to Lake Titicaca. Aymara Indian Rigoberto Rios Miranda has lived on its banks for more than 60 years. "When I was a child the Pallina River was clean, the water was crystalline. About 15 or 20 years back they contaminated it. There were fish here – then one day waters came – I don't know from where, but all the fish were dead," he said.

Rios Miranda, like many farmers, is digging wells on his property after deciding livestock should no longer drink from the river. "Calves are born with birth defects, the cows don't gain weight. Pollution affects everything," he said. The cause of birth defects is hard to verify because there are so few studies on them, but according to a United Nations report released earlier this year, heavy metal contamination originating in the industries of El Alto has "alarming concentrations" of cadmium, arsenic and lead.

Reducing the impact of the pollution will require more careful handling of waste by the people and farmers in Lake Titicaca’s watershed. But without an increased effort by the governments of these growing cities to build the sewage infrastructure needed, the people may be left with no other options besides continuing to pollute the rivers and lake that may no longer be able to feed them.

Photo credit: Pilar Olivares / Reuters

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