Baguio boy’s experiment shows banana peel absorbs metals

BAGUIO CITY—Robert Nelson Leung, 11, recently placed fresh banana peels in a container filled with water taken from the community of Balatoc in Itogon town in Benguet province, host to many of the country’s oldest mines.

After a full day, the Grade 6 pupil of Baguio Achievers Academy here discovered that the polluted water became much cleaner because the peels had absorbed the lead, copper and iron that had contaminated the liquid.

In November, Leung presented the results of his experiment at the Cordillera Regional Science Fair in Apayao province, where he was awarded the top prize for providing the latest evidence yet that plants can be harnessed to clean the environment.

“Phytotechnology” (using plants to solve engineering problems) and “bioremediation” (use of biological organisms to neutralize pollutants) are some of the buzzwords being thrown about to advocate the use of plants to clean waterways polluted by toxic elements.

The mining industry has, in fact, embraced phytotechnology.

During this year’s National Mine Safety and Environment Conference, held in Baguio City last month, experts said plants were providing the industry a cheap way of detecting soil toxicity to help companies rehabilitate mined-out areas.

Professor George Bañez of De La Salle University (DLSU) identified plant species that react strongly to metals in soil, part of the university’s study with the Philippine Council for Industry, Energy and Emerging Technology Research and Development (PCIEERD) of the Department of Science and Technology (DOST).

Heavy metals do not disintegrate, are not diluted by water and do not lose toxicity over the years, said Julius Ceasar Sicat, DOST Cordillera director.

“Heavy metals accumulate in our water. We need to remove or collect the heavy metals from our water systems to preserve the plants, animals and even people, who rely on these water sources,” he said.

Advanced industries use chemicals to separate heavy metals from water, but bioremediation is a far better option, Sicat said.

Leung said he had been reading about fruits being used to clean water and was inspired to undertake the science project in April after realizing bananas were abundant in the Philippines.

The boy took his water samples from Balatoc to the Philippine Institute of Pure and Applied Chemistry (Pipac).

Pipac tested the sample and determined it contained lead, copper, iron, mercury and arsenic, which were in concentrations much   higher than the maximum contaminant level for drinking water.

Leung then chopped separate sets of dried and fresh banana peels, which were soaked in vials containing the Balatoc water samples.

He said the dried peels appeared to work best on copper and iron, while fresh peels absorbed more lead.

Leung said he did not have enough money to test how the peels absorb other minerals, as well as the mercury and arsenic used by old mines.

Phytotechnology has been studying the potentials of more plant varieties on minerals.

During the mining conference, Bañez and professor Esperanza Maribel Agoo of DLSU’s department of biology identified more than 400 plants that neutralize metals, among them ferns like Blechnum orientales, grass like Saccharum spontaneum and tick trefoil flowers.

They have been testing the potency of these plants in Kalinga, Marinduque, Cebu, Negros Occidental, Albay (Rapu-Rapu Island) and Compostela Valley provinces, through PCIEERD’s Program for Rehabilitation and Restoration of Mining Areas through Phytotechnologies.

“Plants are cheaper alternatives. Plants are easily available, and anyone can propagate [these],” Bañez said.

He said mine companies could even be compelled to plant these species.

In their paper abstract, Bañez and Agoo said some species of fern curl up or produce yellow or red colors when these absorb metals.