Moss that can remove lead from water identified

Tokyo, Jan 23 (PTI) Scientists have identified a type ofmoss that can efficiently absorb a large amount of lead,providing a green alternative for d...
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Tokyo, Jan 23 (PTI) Scientists have identified a type ofmoss that can efficiently absorb a large amount of lead,providing a green alternative for decontaminating pollutedwater and soil.

Lead-contaminated water is a serious environmentalconcern that has recently proved to be disastrous when leftuntreated.

Compounding the problem, the typical way to remove leador other heavy metals from water requires fossil fuels and atremendous amount of energy.

As an alternative to these typical processes,phytoremediation is a method that uses photosynthesisingorganisms to clean up soil or water contamination.

Researchers from RIKEN Center for Sustainable ResourceScience (CSRS) in Japan began their search for aphytoremediation-based removal method by looking at Fhygrometrica, a moss that is known to grow well in sitescontaminated with metals like copper, zinc, and lead.

"We found that the moss can function as an excellent leadabsorbent when in the protonema stage of development," saidMisao Itouga, first author of the study published in thejournal PLOS One.

"This valuable ability means that moss protonema willlikely make exceptional wastewater cleaners in mining andchemical industries," Itouga said.

To characterise the metal-absorbing ability of the moss,the team first prepared solutions with varying concentrationsof 15 different metals and exposed them to F hygrometricaprotonema.

After 22 hours of exposure, mass-spectrometer analysisshowed that the moss cells had absorbed lead up to 74 per centof their dry weight, which is quite high and much higher thanany of the other metals.

Knowing where the lead accumulates is important forunderstanding how it occurs and for developing the mostefficient phytoremediation.

Analysis showed that within the moss protonema cells,more that 85 per cent of the lead had accumulated in the cellwalls, with smaller amounts being found in organelle membranesand inside the chloroplasts where photosynthesis occurs.

Focusing on the cell walls, the team found that theyabsorbed lead even after being removed from living moss.

This means that there is something special about the cellwalls of this species of moss that allows them to thrive inenvironments that are toxic to other plants.

Analysis with two-dimensional nuclear magnetic resonanceindicated that polygalacturonic acid in the cell walls wasresponsible for absorbing the lead.

"We compared F hygrometrica data with those from landplants and seaweeds and found that the presence ofpolygalacturonic acid in the cell wall is one of thecharacteristics that separated this type of moss from otherplants," said Itouga.

They next determined that the protonema cells absorbedlead well at pH values between 3 and 9, which is importantbecause the acidity of metal-polluted water can vary.

"Our findings show that F hygrometrica is a useful bio-material for recovering lead from aqueous solutions, and willcontribute to the Sustainable Development Goals set by theUnited Nations, specifically the Life on Land goal," saidHitoshi Sakakibara, from CSRS. PTI MHNMHN.

This is unedited, unformatted feed from the Press Trust of India wire.

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