NANOPARTICLES VERSUS NATURE: A team of scientists at Duke University is investigating the effects of silver nanoparticles on soil microbes and plant growth.
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Silver nanoparticles, used for their potent antimicrobial properties in hospitals and consumer products, may negatively impact plant growth as they make their way into the environment, according to a new study. Whereas it may not spell the end of all flora as we know it, the findings suggest that the nanomaterial has environmental impacts worthy of further investigation.
The antimicrobial properties of silver in its ionized form have been recognized for centuries. When it is nanosize—between one and 100 nanometers, which is smaller than many viruses (a nanometer is one billionth of a meter)—silver is even more effective at killing microbes. This antimicrobial potency has prompted manufacturers to include silver nanoparticles in a wide variety of consumer products, such as odor-resistant clothing, hand sanitizers, water treatment systems and even microbe-proof teddy bears. (Currently, labels on products for sale in the U.S. are not required to disclose the presence of nanomaterials. Consumers can learn more about which products contain nanoparticles by visiting the Web site for The Project on Emerging Nanotechnologies.)
Although the microbicidal effects of silver nanoparticles are well documented, their impact on the environment is less understood.
"There have been a lot of lab studies looking at silver nanoparticles showing that they are highly toxic to bacteria, fungi, other microorganisms," explains Ben Colman, a postdoctoral researcher at Duke University who led the study. "Most of these studies have been conducted in very simple lab settings, [with] one species of bacteria—often the "lab rat" of the bacteria world, E [scherichia]. coli —[in] a test tube with very simple media and nanoparticles. So we wanted to move beyond this because it's really hard to extrapolate from these single-species studies in simple environments to what will inevitably happen when these particles enter the environment."
Nanoparticles likely enter the environment through wastewater, where they accumulate in biosolids (sewage sludge) at wastewater treatment plants. One of the ways in which the sludge is disposed of is through land application, because it is valuable as a fertilizer. Whereas fertilizers add nutrients to the soil that are essential for plant growth, plants also depend on soil bacteria and fungi to help mine nutrients from the air and soil. Therefore, the antimicrobial effects of silver nanoparticles could have impacts at the ecosystem level—for example, affecting plants whose growth is dependent on soil-dwelling microorganisms.
In order to examine silver nanoparticles' ecosystemic impact the researchers prepared series of outdoor "mesocosms"—intermediate-sized "fields" of plants growing in rubber tubs. They applied 0.2 kilograms of biosolid to each tub, amending the fertilizer with 11 milligrams of silver nanoparticles per tub. This concentration is within the range that the U.S. Environmental Protection Agency reported finding in a recent survey of biosolids from water treatment plants (pdf). The nanoparticles reduced the growth of one of the tested plant species by 22 percent as compared with silver-free biosolid treatment. Similarly, microbial biomass was reduced by 20 percent. Colman presented the findings August 4 at the 95th annual meeting of the Ecological Society of America.
Colman noted that in his previous in vitro studies of sediment he saw no effect on the amount of microbes present even though he used 1,250 milligrams of nano-silver per kilogram of sediment.
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16 Comments
Add Comment"They applied 0.2 kilograms of biosolid to each tub, amending the fertilizer with 11 milligrams of silver nanoparticles per tub."
Reply | Report Abuse | Link to thisIf a wastewater treatment plant was the source of the biosolids used in the experiment, and WWTPs are known to be concentrators of silver nanoparticles in digested sludge, was the biosolids' silver nanoparticle content determined before adding the known amount (11mg)?
" nano tobe radio could wipe out the human race. That is what the bible implies" - WTF? that is almost as wacked out as Xenu, and that the suposed "ARK" has Dino's on it . .
Reply | Report Abuse | Link to thisWow the things people come up with . .
When you believe an imaginary being has control of your life and the world, crazy is easy and ignorance the norm.
Reply | Report Abuse | Link to thisWhen you believe an imaginary being controls your life and the world, ignorance is the norm and crazy is easy.
Reply | Report Abuse | Link to thisvery confusing study(or maybe write up)...
Reply | Report Abuse | Link to thislatest experiment is using 200 grams of biosolid and 11mg of silver in a tub that appears to be roughly 40cm x 20cm by 10 cm or 8000 cc of soil or roughly 32kg of soil(just guessing 4gm per cc)
earlier experiment was using 1.25gm of silver per kilo of soil which equated to the latest would be 40gm in a 32kg tub or a difference in silver concentration of 4000 to 1(previous vs latest)
how can that be...just very confusing....
It seems the question should be, how do we neutralize or alternatively remove through processing the nanoparticles that will ultimately end up in WWTPs? Perhaps this question should be fully addressed before we start injecting these nanoparticles into the environment through manufacturing processes.
Reply | Report Abuse | Link to thisSilver nanoparticles are a health hazard contaimant, like mercury mines in chinese rice have poisoned the food, so too will nanoparticles make the environment hostile and increasingly deadly to human life too.
Reply | Report Abuse | Link to thisWhat is the difference between silver nanoparticles and colloidal silver?
Reply | Report Abuse | Link to thisThe article cites the US EPA's Targeted National Sewage Sludge Survey: Statistical Analysis Report (2009) to justify the dosage rate of 64 mg nano-silver /kg (was that dry weight?), the US EPA only measured total silver, not nano-silver. Their report does not contain the word 'nano'. Ben Colman's work is interesting and something that we need to understand but if Scientific American has reported him accurately, this does seem rather sloppy. The mean silver concentration in the survey was 20 mgAg/kgDS (Std Dev 20) the 95th percentile was 57 mg/kg [all after excluding one statistical outlier]. What really is the concentration of nano-silver in biosolids? Is the potency of nano-silver the same when it has come through the whole wastewater collection and treatment system as when it is just dosed prior to applying the spiked biosolids to the plots? What was the background concentration of nano-silver in the biosolids?
Reply | Report Abuse | Link to thisPresuming for the moment that the article is generally correct, that new materials entering the environment are capable of directly impacting the soil microorganisms, this should be a major concern. As I understand, the soil microorganisms are crucial for producing soils' ability to support the growth of trees and other fauna, crops, etc. If I recall, the world's largest organism is a subterranean fungus growing throughout much of Oregon and Washington. I suspect the soil micro fauna is more critical to the environment than is generally understood.
Reply | Report Abuse | Link to thisDDT was banned when it was found to be an environmental threat. Biosolids were still land applied following the DDT ban. Why are people looking to find something wrong with the biosolids instead of the nanoparticles? Ban the nanoparticles. Nanoparticles may be a threat so lets ban them until we know more. Biosolids have been proven to be a valuable resource, lets keep our resources.
Reply | Report Abuse | Link to this@Fred Bauder
Reply | Report Abuse | Link to thisConsidering that Colloidal Silver is a liquid suspension of silver particles, I suspect the significant difference is the size of the particle. Colloidal silver will likely be orders of magnitude larger than nano-silver particles, which would make nano-silver much more reactive per gram than colloidal, since there would be far more surface area per gram and greater dispersion per gram. Imagine the difference in size; for one colloidal silver particle, you would have thousands to millions of nan0-silver particles.
Micro werewolves beware!
Reply | Report Abuse | Link to thisComing soon: Bio-sludge fertilizer that's bad for your plants!
Next week: Air, how much do we really need?
Here we go again, with the old "silver is dangerous to the environment" scam.
Reply | Report Abuse | Link to thisThere are an estimated two million tons of trace silver in the oceans of the world. Yet those oceans are teeming with life, both plant and animal.
There are extremely high silver content-laden soils throughout the mining areas of California, Colorado, Nevada, etc., yet the soils are teeming with uncountable numbers of plant and animal life.
There are extremely high silver content-laden rivers and streams, yet they too are teeming with innumerable bio-systems.
You could just as easily make the case that silver -- rather than being detrimental to ecology and life -- is instead ESSENTIAL to it.
It seems the only places silver turns out to be harmful is in the "controlled studies" conducted by environmentalist researchers.
Go figure.
And please don't lecture me on the difference between trace silver found in the environment and "nanosilver."
Once released into the environment, nanosilver particles quickly agglomerate with other minerals -- such as sulfur for just one example -- and in the process lose their nanoscale properties (i.e., small size) as well as their nanoscale attributes (i.e., potency). This is the very reason the silver was found in the sludge, rather than the liquid discharge.
I know dozens of people who use nanoscale colloidal silver to keep their plants healthier, and make their fruits and vegetables grow faster and stronger. A non-published experiment during the last growing season demonstrated that tomato seeds planted in soil treated with small amounts of nanosilver produced 30% more sprouts than the same amount of seeds planted in non-silver-treated soil. And they grew nearly twice as fast over the first 15 days of the experiment before leveling out and growing normally after that.
I've used nanoscale colloidal silver to kill mid-season tomato fungus by spraying it onto the leaves and stems of the affected plant, and spraying small amounts onto the soil at the base of the plant. The tomato fungus is effectively obliterated and the plants grow healthier and stronger and produce beautiful fruit afterwards.
My wife sprayed her garden with colloidal silver all season long last year, and won blue ribbon awards for her veggies at the local fair.
The environmentalists are always crying "The sky is falling." They just can't help it. The spirit of the Luddite is alive and well in them.
God help us all due to the breakthroughs we could enjoy, were it not for the environmentalist spoilers mucking up progress.
200,000 mg of Biosolids to 11mg of (what kind of?) silver = 55PPM. What exactly is this silver and how was it made? Chemical reduction of silver nitrate? Electrolysis of silver in pure water?
Reply | Report Abuse | Link to thisIf the former, sodium borohydride is used as a reducing agent with silver nitrate to produce colloidal particles in the 10-20nm range if done correctly.
If the latter, electrostatic ionic binding would occur up to the saturation limit of about 13PPM in pure water and metallic colloids would be produced afterwards and so a solution would contain 13PPM Ionic with rest being small to sub nanometer colloidal particles. Few people are capable for this method as equipment is custom.
I have personally observed Ionic and Colloidal silver being used in the agricultural sector with amazing results and am aware of a trial being implemented by a Provincial Body in Canada to utilize Colloidal Silver for soil remediation and fungal and microbial control with soft fruits.
It's amazing how Big Pharma gets everywhere! They will lie through their teeth, "publish" ANYTHING they can to get what they want. Silver nanoparticles ARE NOT HARMFUL IN ANYWAY!!! According to studies done before 1940 American soil contained 5% silver "nano" particles. That silver was found inside the food that was grown in that soil. But because man decides to use pesticides, herbicides, etc. Those particles and more then half of the nutrients that used to be in the soil have been depleted. As a result, infectious disease is now rampant in the world, not just America.
Reply | Report Abuse | Link to thisThere was a recent article written by a very famous MD who is an expert on infectious disease and antibiotics. He stated in less then 10 years ALL ANTIBIOTICS USED TODAY WILL BECOME USELESS!!!
Anyone who does any studies has learned the Big Pharma knows this. They have been working on a whole string of "new" antibiotics they want to be able to patent and charge large sums of money for them. They are ALL SILVER BASED ANTIBIOTICS!!!
So, if they can "appear" to show that they are dangerous, yeah right (do you hear the sarcasm?) then they can get them banned, then convince the government that they can be used safely by Big Pharma so they can "legally" patent them and distribute them and charge huge sums of money for them! Just like they do with everything they do.
I GUARANTEE that if you did some study to find the source of this "study" you'd find Big Pharma on the other end funding this "study". And what gets me is some well respected publication like Scientific America would actually publish this crap as though it were real, unless.....hmmm...I wonder how much money they were paid under the table for touting this crap in the first place. I have now lost all faith in this publication!