According to an old Mexican custom, boiling dirty river water with prickly pear cactus transforms the water from unpalatable to clear and drinkable. Upon further investigation, researchers have found that the squishy cactus interior absorbs sediments, bacteria, and a variety of unpleasant chemicals such as arsenic. Researchers are now looking into how cactus insides can be used in emergencies to treat water as well as in other contexts such as aquaculture tanks and even cleaning efforts after the Deep Horizon oil spill. The researchers presented these results at the 251st National Meeting & Exposition of the American Chemical Society.
Image by Mark Byzewski (Flickr: _MG_3985a) [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons