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Onion soaks up heavy metal, researchers find



December 10, 2012 – Comments (6)

Very nice story. I also recall that the Swedish use some sort of grass / bush that fixes toxic metals in their roots without spreading through the rest of the plant. If I remember the story correctly, they were able to use this technique along with others to convert an old landfill into residential and park area.

Plus there is good ole cilantro :) -- This one is an oldie but a goodie.


Onion soaks up heavy metal, researchers find
December 10, 2012
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Onion and garlic waste from the food industry could be used to mop up hazardous heavy metals, including arsenic, cadmium, iron, lead, mercury and tin in contaminated materials, according to a research paper published in the International Journal of Environment and Pollution.

Biotechnologists Rahul Negi, Gouri Satpathy, Yogesh Tyagi and Rajinder Gupta of the GGS Indraprastha University in Delhi, India, explain how waste from the processing and canning of onion (Allium cepa L.) and garlic (Allium sativum L.) could be used as an alternative remediation material for removing toxic elements from contaminated materials including industrial effluent. The team has studies the influence of acidity or alkalinity, contact time, temperature and concentration of the different materials present to optimize conditions for making a biological heavy metal filter for industrial-scale decontamination.

They have found that at 50 Celsius (122 Fahrenheit), the efficiency of the clean-up process is largely dependent on pH (acidity or alkalinity) and equilibration time usually occurs within half an hour; a pH of 5 was optimal. They demonstrated the maximum extraction was achievable for lead, one of the most troublesome metallic environmental pollutants. They could extract more than 10 milligrams per gram of Allium material from a test solution containing 5 grams per liter of mixed metal ion solution, amounting to recovery efficiency of more than 70%. The absorbed metals can be released into a collecting vessel using nitric acid and the biomass reused.

The team experimented with Allium biomass to demonstrated effective removal of heavy metals from both simulated and actual industrial effluents. "The technique appears to be industrially applicable and viable," they suggest. "This may provide an affordable, environmental friendly and low maintenance technology for small and medium scale industries in developing countries," they conclude.

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6 Comments – Post Your Own

#1) On December 10, 2012 at 6:27 PM, constructive (99.97) wrote:

Interesting, but is canning onions and garlic common? They have long shelf lives and are plenty convenient in their normal form.

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#2) On December 10, 2012 at 9:54 PM, ChrisGraley (28.69) wrote:

It's been wide known for a long time that plants will absorb metals. I find it very hard to believe that the plant would be viable for food after the fact. 

Not that it's really important. A plant that can clean up an industrial mess is still valuable even if you have to dispose of it afterward.


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#3) On December 11, 2012 at 1:48 AM, ikkyu2 (98.04) wrote:

Quite common, Megashort.  You just outed yourself as a rich guy.  Lots of folks get their 'fresh' garlic from bottles at Wal-Mart.  Still, I suspect the majority of what's being talked about here are the by products of onion and garlic used as flavorants or ingredients in other canned food.

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#4) On December 11, 2012 at 8:32 AM, Bkeepr100 (< 20) wrote:

This is nothing new, alfalfa is used to extract miro gold for use in nanorobots. Some plants even are used as indicators of where to dig for gold and silver.  Plants all take up whatever elements are in the ground.

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#5) On December 11, 2012 at 12:03 PM, constructive (99.97) wrote:

Well, you learn something new every day.

Ikkyu, I haven't spent too much time in the canned vegetable aisle. But it's not because I'm in the foie gras aisle :)

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#6) On December 11, 2012 at 4:43 PM, lemoneater (57.08) wrote:

Thanks for the article. I eat enough onions :).

Lovely picture, MegaShort.

Yes, for convenience I use the canned pepper/ tomato/onions for Spanish rice and just add hot pepper flakes. But I prefer fresh or frozen peppers of several colors and heat levels :).

Once upon a time, I sliced 90 pounds of onions. To top it off that evening I went to a concert, but not with a date!

Dried onions work well for recipes you do not wish to be watery, but still want the onion flavor.

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