The Minnesota Water Experiment

by
Philip Bell
KIE Developer

Why aren't the deformed frogs everywhere?

Why are people in Minnesota finding deformed frogs in some lakes but not in others? Scientists thought that perhaps something was in the water of some lakes and not others. Perhaps a chemical or an organism in the water was causing the frogs to develop strangely. Whatever it turns out to be, they thought it might be present in some lakes -- where deformities are being found -- and not in other lakes where the frogs are still healthy.

The Minnesota Water Experiment

Scientists ran an experiment to see if lake water had an effect on deformities. Lake water was the "variable" they wanted to test. To find out if it made a difference, they had to "control" (or keep constant) the other variables in frog development.

Scientists took samples of two different kinds of water: water from lakes where deformed frogs had been found AND water from other lakes where deformed frogs had NOT been found. In a lab, they put frog eggs in each kind of water and watched them develop. By comparing how frogs develop in these two sources of water, they might be able to figure out if water from certain lakes was causing the deformites.

The Results of the Experiment

Scientists compared the frogs that had grown up in the two types of water. In the water from lakes where deformities had been found, scientists saw that more frogs had deformities. They concluded that something was wrong with the Minnesota water.

They tried the same experiment using the drinking water of people that lived near the lakes where deformities were found. Again, numbers of deformed frogs were high. As a result, some people have started drinking bottled water until the mystery is solved.

OPTIONAL READING: If you want more details, a scientific article from NIH is available that describes this study.

A Press Conference Was Held and Other Scientists Reacted

After doing their experiment, the scientists decided to report their findings to the public. They held a press conference to warn people that some lake water was producing deformed frogs.

But, other scientists disagreed with how the Minnesota Water Experiment was conducted and how quickly the results were reported to the public. What questions do you have about these results? Can you see any problems with the experiment?

OPTIONAL READING: You can take a look at the press release from the Minnesota Pollution Control Agency (MPCA) and the National Institutes of Health’s National Institute of Environmental Health Sciences (NIEHS). These agencies were the ones that tested the water.