Banana peels, useful in polishing silverware and leather shoes, may have another surprising use -as a water purifier.
Gustavo Castro and colleagues said that minced banana peels performed better than a number of other purification materials in removing potentially toxic metal contamination from water.
Mining processes, runoff from farms and industrial wastes can all put health and environment harming heavy metals such as lead and copper into waterways.
Current methods of removing heavy metals from water are expensive, and some substances used in the process are toxic themselves.
Previous work has shown that some plant wastes, such as coconut fibers and peanut shells, can remove these potential toxins from water.
The researchers found minced banana peel could quickly remove lead and copper from river water as well as, or better than, many other materials.
They noted that a purification system made of banana peels can be used up to 11 times without losing its metal-binding properties.
Banana peels are attractive as water purifiers because of low cost and because they don't have to be chemically modified in order to work, they added.
The study appears in ACS's journal Industrial and Engineering Chemistry Research.