People need water to survive, and the water has to be clean—or
they get very sick. Clean water, however, can be hard to come
by. Now, scientists are exploring a clever way to make dirty
water clean for small communities in Mexico. The secret is the
goo from an edible cactus found all over that country. The nopal
cactus, or prickly pear, could help Mexican communities purify
drinking water. Long ago, people in Latin America used prickly
pear cactuses to filter their water, says Norma Alcantar. She’s
a chemical engineer at the University of South Florida in Tampa.
First, they would boil the plant, which they could eat. They
then dumped the boiled water into their drinking water. Gritty
particles settled to the bottom, and the water on top was good
to drink. To see if they could revive this practice, Alcantar
and her coworkers studied a material called mucilage, which they
extracted from cactus plants. Mucilage is a thick, gooey
substance that allows the plant to store water. The researchers
already knew that ad