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Buried Trouble

How did you choose your present profession?
Rebolledo: “My father was a high school biology teacher, so I grew up surrounded by science. Usually my Christmas presents were either a chemistry set or a toy microscope.”

Read Mario Rebolledo Vieyra
full Q&A »

Beddows: “I can't remember having specific heroes or mentors when I was growing up although I loved reading science magazines like Discover and National Geographic.”

Read Patricia Beddows
full Q&A »

Meacham: “I did not so much chose it as it chose me. My lifelong passion has always been SCUBA diving.”

Read Sam Meacham's
full Q&A »

Most thirsty Americans need only turn on their tap to find drinkable water. However, for more than one billion people, one-sixth of the world’s population, clean water for drinking, bathing or agriculture is simply out of reach. Now scientists are finding that even formerly safe reserves are becoming tainted. How is this happening?

Water covers 70 percent of the planet, but only a mere 3 percent of it is freshwater. While much of this water flows from surface sources, seasonal glacial melt, lakes and rivers, 25 percent is held underground in vast limestone labyrinths known as karst systems. When precipitation seeps through karst limestone, it creates small pathways that can eventually connect to great underground rivers. Such systems are found all over the world. In the United States, they hold nearly 40 percent of our nation’s freshwater.

One of the world’s most impressive and extensive karst systems is located in Mexico’s Yucatán Peninsula. Here, nearly all the region’s freshwater flows through a vast subterranean maze with hundreds of miles of caves and rivers connected to the surface through pools called cenotes. The word cenote (pronounced seh-NO-tay) is derived from the Maya word dz’onot, which means well. The Maya viewed cenotes as sacred wells—windows to a mysterious, watery underworld. What many Mexicans don’t realize, however, is that their sacred wells are rapidly being poisoned by their own prosperity.

In the last three decades, Mexican tourism has exploded into a billion-dollar industry. The tourist corridor in the Yucatán now stretches across 75 miles (120 km) of coastline that was once sparsely inhabited.  As the population grows, so too does the generation of sewage and water-borne pollutants. Unfortunately, one of the most common means of wastewater disposal here involves simply pumping this sludge hundreds of feet belowground. Out of sight, out of mind? Not quite. Pollutants can, and do, find their way into the hidden limestone labyrinths and can resurface to pollute cenotes and drinking supplies.

Hydrogeologists Mario Rebolledo from the Center for Scientific Investigation in the Yucatán and Patricia Beddows from McMaster University in Canada are trying to find out how and what pollutants and bacteria are infiltrating these waters. By bouncing electromagnetic sound waves through the ground, Rebolledo exposes areas of water versus soil and rock. He also samples for pollutants.  Beddows uses nontoxic dye along with other techniques to track the course of water underground. Combined with the courageous efforts of cave diver and explorer Sam Meacham, the team is mapping this secret world and pinpointing regions at greatest risk of contamination. (For more on human impacts to the Yucatán’s coral reefs, visit www.coralconnections.org Off-site Link)

With innovative efforts such as these, karst systems and other freshwater resources can be safeguarded. And the sooner we act the better: as our planet warms, shifting rainfall patterns, melting glacial reservoirs and rising sea levels will only compound our freshwater problems. The actions we take today can change the direction of this tide, and all our positive changes can add up to large beneficial impacts. Here are some ways you can make a difference:

  • Conserve water through simple actions like switching to low-flow plumbing fixtures and fixing leaks.
  • Don’t use storm drains as garbage dumps. Take oil and other chemicals to proper disposal facilities.
  • Use cleaning and garden products that are made of natural ingredients and are biodegradable.
  • Support manufacturers that dispose of their waste properly, or better yet, recycle their waste into other products.
  • Reduce your carbon footprint. Check out the Strange Days Climate Friendly Checklist (English | Spanish) [PDF file]
  • Support local and global policies that encourage proper wastewater management, treatment and water conservation.

For more ways to help visit: What can we do?



The Global Water Crisis, USAID Environment, http://www.usaid.gov/our_work/environment/water/water_crisis.html Off-site Link
Accessed Feb 6 2008.


IPCC Fourth Assessment Report (ARA) Climate Change 2007 Synthesis Report, The AR4 Synthesis Report, (2007):http://www.ipcc.ch/ipccreports/ar4-syr.htm.Off-site LinkAccessed February 6th 2008.

» Beddows, P.A. (2003). An Introduction to the Yucatán Peninsula hydrogeology: A world class example of a coastal carbonate density stratified aquifer
www.karstscience.com/publications Off-site Link In Cavern Guide Training Program, Asociación de Prestadores de Servícios Acuáticos/ Riviera Maya Association of Dive & Watersports Operators—APSA, 45–54.

For more topic references see the Resources section »

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