The slippery yellow skins are better known as a comedic prop, but now research has demonstrated they have a capacity to absorb lead and copper from river water. Previously, other plant materials such as peanut shells and coconut fibers had been tried, but minced banana peels did the trick better.
Researchers also found minced banana peels could be used repeatedly to purify water contaminated by industrial plants and farms – up to eleven times – and still be effective. In their study paper titled “Banana Peel Applied to the Solid Phase Extraction of Copper and Lead from River Water: Preconcentration of Metal Ions with a Fruit Waste” they also noted the very low cost of banana peels and the fact there is no need to prepare them chemically for the water purification procedure.
They theorized the acid content of the peels make them a good material for absorbing the heavy metals. Heavy metal pollution in rivers and streams can be absorbed by species such as mollusks and algae, and eventually enter the food chain where it contaminates fish and frogs. They can make aquatic species sick and die, so an effective and affordable means of removing them is very beneficial.
A river in the Philippines suffered enough industrial pollution, including heavy metal poisoning, that it was recognized as biologically inactive. Restoring a river to its original natural health is obviously far more costly than preventing the pollution from damaging it in the first place, if it is even possible to restore it.
Using materials produced naturally is also helpful because they are less likely to result in extra contaminants being introduced into the polluted area. Some remediation projects use manmade chemicals to address the pollution and risk additional contamination. A very obvious example is the use of chemical dispersants in the Gulf of Mexico after the recent huge oil spill. Some say their use only added to the marine contamination, and there isn’t enough long-term data for gauging the overall impact of mixing that much oil and dispersant on the ecosystem health and for humans.
Gustavo Castro, Ph.D., Universidade Estadual Paulista in São Paulo was one of the lead researchers. Funding for the research was granted by the Sao Paulo Foundation.
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