I agree with Prof.Mahmood H.M too and hope soon the mechanism and also high permissible level of it would be announced by WHO for environment.

dear Ahmed Moosa ;

The mechanisms of action of AgNPs are still not well understood, and there is a lack of information on the potential effects of AgNP exposure on animal models of enhanced susceptibilities, such as hypertension, diabetes, and asthma. therefore, more investigations are required to understand the mechanisms of toxicity following various modes of exposure to AgNPs. More details in these references;

• file:///C:/Users/POWERLOGIC/Desktop/ijms-21-02375.pdf
• https://www.frontiersin.org/articles/10.3389/fenvs.2018.00152/full

moreover, Some studies showed that nanoparticles are able to pass through the blood-brain-barrier, It has been shown that silver nanoparticles can induce a toxic response of different mammalian cell lines; as reported in the following references;

• J. S. Kim, “Toxicity and tissue distribution of magnetic nanoparticles in mice,” Toxicological Sciences, vol. 89, no. 1, pp. 338–347, 2006.
• P. Chairuangkitti, S. Lawanprasert, S. Roytrakul, et al., “Silver nanoparticles induce toxicity in A549 cells via ROS-dependent and ROS-independent pathways,” Toxicology in Vitro, vol. 27, no. 1, pp. 330–338, 2013.
• M. Grodzik and E. Sawosz, “The influence of silver nanoparticles on chicken embryo development and bursa of Fabricius morphology,” Journal of Animal and Feed Sciences, vol. 15, pp. 111–114, 2006.

Dear Prof. Mahmood H.M.

Thank you very much for your answer.

I agree with you and in brief, there are limited well-controlled investigations on potential toxicities of nano-silver particles. An additional long term studies are needed to better characterize and understand the risk of using nano-silver particles

Silver nanoparticles can induce various toxicities folowing exposure modes.

Regards !

Dear Fatima

Thank you

Dear prof. Ahmed Moosa; you're welcomed with my regards and appreciation, attached interesting research regarding the same subject;

https://www.al-madina.com/article/301102/%D9%83%D8%AA%D8%A7%D8%A8/%D8%AA%D9%82%D9%86%D9%8A%D8%A7%D8%AA-%D8%A7%D9%84%D9%86%D8%A7%D9%86%D9%88-%D9%81%D9%8A-%D9%85%D8%AC%D8%A7%D8%A8%D9%87%D8%A9-%D9%81%D9%8A%D8%B1%D9%88%D8%B3-%D8%A7%D9%84%D9%83%D9%88%D8%B1%D9%88%D9%86%D8%A7

Interesting

I agree with Prof.Mahmood H.M.

I agree with Prof.Mahmood H.M too and hope soon the mechanism and also high permissible level of it would be announced by WHO for environment.

Wonderful question .. Follow-up to the wonderful answers from the professors

Interesting topic

There are many observations about the use of nanochemical compounds, including nano-silver and nano-zinc. Do they have negative effects on the skin, causing skin cancer, for example? There is a master's thesis at the Faculty of Agriculture, Saba Pasha, Alexandria University, Egypt, in which the researcher used Nan Silver on the Rhizoctonia solani mushrooms and the cotton crop may give positive results as the nanosilver negatively affected the growth of the fungus.

Dear Prof. Mahmoud Hamdy Abd El-Aziz

Greetings

Nano-silver exhibits higher toxicity to microorganism. The AgNPs toxicity may be cause by attachment of AgNPs to the cell membrane surface and disturbing permeability and respiration functions of the cell. Or it is also possible that AgNPs not only attach to the surface of cell membrane, but can also enter inside the bacteria .

Please see Sahayaraj, K., Rajesh, S.: Bionanoparticles: Synthesis and antimicrobial applications. In: Méndez-Vilas, A. (ed.) Science against microbial pathogens: communicating current research and technological advances. pp. 228–244. Formatex Research Center, Badajoz, Spain (2011).

Ahmed Moosa

There's a lot of confusion in the literature because silver in the zero oxidation state ('silver metal') is not present on the surface of any 'silver nanoparticles' in contact with air or water. It's the sparingly soluble Ag+ ion that is the active bactericide and silver is present as Ag2O that dissolves to form 'AgOH'. Certainly silver in high concentrations is toxic (but probably not fatal) and a blue-black skin is the outcome in a condition called argyria in humans. See, for example:

https://en.wikipedia.org/wiki/Argyria

The ultimate fate of silver nanoparticles will be an outcome of the dissolution and the irreversible aggregation that occurs when these particles encounter other particles or surfaces. See these webinars (registration required):

Silver colloids and invisible ink

https://www.malvernpanalytical.com/en/learn/events-and-training/webinars/W150902SilverColloidInvisibleInk.html

Dispersion and nanotechnology

https://www.malvernpanalytical.com/en/learn/events-and-training/webinars/W190528DispNanoMat

Finding such bound particles in the environment will not be easy. The effect on shellfish, mollusks, and amphibians may be totally different.

Dear Dr.Alan F. Rawle

Thank you very much for the valuable answer. We all know that the use of silver can be traced back in history. Silver coin and silver container were

used in ancient time to preserve water. It was documented that silver was used

for medicinal purposes in 750AD.

However we are dealing with nano silver and I think it will better to regulate the use of AgNPs. See for example

Edwards-Jones V. (2009). The benefits of silver in hygiene, personal care

and healthcare. Lett Appl Microbiol, 49, 147–152.

Silver S, Phung LT, Silver G. (2006). Silver as biocides in burn and wound

dressings and bacterial resistance to silver compounds. J Ind

Microbiol Biotechnol, 33, 627–634.

Ahmed Moosa

The FDA published in 1999 its view of 'silver' treatments. In air silver blackens if sulfur is present. My point is that silver nanoparticles are not silver on the surface. They would have little or no bactericidal activity if this was true. XPS shows this as I indicated in the first webinar above.

Regulation would be difficult - what would you propose would be in this 'regulation'? Especially when there are people orally ingesting large quantities of 'silver colloids'...

Thanks for the valuable information

AgNP due to their bactericidal action, have found practical applications in medicine, cosmetics, textiles, electronics, and other fields. But their antibacterial properties may be disadvantageous for agriculture and waste management.

Source: Bartłomiejczyk T, Lankoff A, Kruszewski M, Szumiel I. Silver nanoparticles -- allies or adversaries? Ann Agric Environ Med. 2013;20(1):48-54. PMID: 23540211.

Every metals is harmful for enviornment in some extent ..

Silver nanoparticles may create hurdle in the growth of microorganisms and some bacteria; also essential for the effluent treatments. In some cases silver nanoparticles may be threat to aquatic life. It's also reported for skin and eyes irritation.

Silver nanoparticles may create hurdle in the growth of microorganisms and some bacteria; also essential for the effluent treatments. In some cases silver nanoparticles may be threat to aquatic life. It's also reported for skin and eyes irritation.

Dear Aijaz

Thank you for your comments. I agree with you

I agrre with Alan F Rawle !

Thank you Fatma

Very well explained by group members.

Learned something new today.

Thank you everybody

Dear Sj Malik

Thank you

It is an important issue about the synthesized nano particle. I would recommended that If you to utilize the specified amount and a suitable concentration of nano particle synthesized in your research, you should observed the environmental protocol according to the issued instructions international scientific and pharmaceutical forums and follow it carefully.

https://doi.org/ 10.3390/ijms21072375

https://doi.org/10.3389/fenvs.2018.00152

https://doi.org/10.1016/j.scitotenv.2011.03.020

There are literature deficiency about nano silver toxicity data. Additional research is needed to investigate whether silver nano particles present a threat to environmental health. Lack of cooperation between the manufactures of nano silver and nano silver containing products and Federal regulatory agencies in providing manufacturing information regarding shape, size, surface chemistry and synthesis methods. The important question to be raised is to validate the hypothesis that toxic effects of nano particles are proportional to the activity of the free silver ions released by the nano particles.

Interesting discussion !

Dear Fatma

Thank you very much for your comment

You are welcome

The dangerous of silver nano particles to the environment

The toxicity of manufactured nanoparticles varies greatly depending on the test species in consideration and estimates of toxicity may also be confounded by test media in which the organisms are cultured. 

Over the last 30 years, the number of products containing engineered nanomaterials increased across diverse fields mainly due to our growing capacity to synthesize and manipulate such materials.

Among the nanomaterials, silver nanoparticles (AgNPs) are considered as one of the most important due to its exceptional broad spectrum bactericidal properties, relatively low cost of manufacturing AgNPs, unique properties and ability to form diverse nanostructures. AgNPs are used in a growing number of applications across a diverse range of commercial consumer products such as food storage containers, coating materials, liquid fabric softeners and detergents, fabrics and clothing, sporting goods, cosmetics, wound dressings, toothbrushes, and antimicrobial coatings.

There are however concerns regarding the extensive application of NPs and rapid proliferation of NP-enabled products which may lead to a high release into the environment and cause deleterious effects on the organisms that are constantly exposed to these materials. Tons of nanosilver are added into the aquatic environment annually from wastewater plants, septic tanks and agricultural lands with concentrations expected to range from 0.03 to 0.32 micrograms per liter. Despite the fact that most AgNPs tend to accumulate in the sludge solids in waste water treatment plants (WWTPs), it is estimated that a significant proportion of AgNPs will be released in the effluent. 

Please read more in the following article:

DOI:10.3389/fenvs.2018.00152

Dear Ayman S. Al-Hussaini

Thank you for your comments

Nice question