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Saturday, 2 June 2012

Nanopollution Revised


Since naturally occurring nanoparticles are not pollutants (according to my personal opinion and of some authors), nanopollution only began after the appearance of nanofabrication of nanoengineered nanoparticles that are hazardous to the environment. Therefore, nanopollution is a considerably recent phenomenon.



Preface

In my last article ("nanopollution") I wrote about this subject briefly. After publishing the article, I reviewed some concepts. My ideas were consolidated and I believe that my perspective changed for the better. Thus, for reasons of loyalty to my readers, here are my revised concepts of nanopollution.


Introdution

Following my article "The Roots of Nano-Fear Decoded", I start here an atte
mpt to point out ways and propose solutions in order to demystify the nano-fear.

From what I can understand, the roots of fear seem to be of the fasciculate 
type. In other words, there are not a "primary root" and "secondary roots". I choose to state that they all have approximately an identical importance.

Addressing nanopollution without addressing nanotoxicity is in theory and in practice an artificial effort, I'd say. Nanopollution exists in the environment and affects the biosphere (including Humans). The biosphere is exposed to nanotoxicity and, in turn contaminates the environment. We are therefore facing an indissociable 
circleHowever, due to space limitations, this article will try to address nanopollution revised. Later I will write about combating nanopollution. Only then I will address nanotoxicity. Naturally, what I write is in line with my way of understanding this issue, in the present.

Before I start writing about nanopollution, I propose a brief analysis of pollut
ion as a concept.


Pollution

Pollution is the introduction of contaminants in the natural environment. Pollution causes instability, several disorders, harm or discomfort to the ecosystem.

The ecosystem comprises:

  • Physical systems;
  • Systems of living organisms (including humans)
Pollution may involve:
  • Chemicals;
  • Energy in various forms (e.g. heat, noise, radiation).
The presence of pollutants in the environment is the cause pollution. Pollutants may be coming from either:
  • Naturally occurring substances (or energies);
  • Substances (or energy) which is strange to the environment (contaminants).


Nanopollution


I will continue to follow the same thinking regarding pollution.

Nanopollution is the introduction of nanosized contaminants in the natural environment. Nanopollution causes instability, several disorders, harm or discomfort to the ecosystem.

The ecosystem is the same, whether we are addressing pollution or nanopollution. 
The ecosystem comprises:
  • Physical systems;
  • Systems of living organisms (including humans)
The presence of nanopollutants in the environment is the cause nanopollution.


Nanoparticles


Some authors claim that the nanopollutants can be naturally occurring nanoparticles or nanoengineered nanoparticles.

In the case of naturally occurring particles, h
owever, some authors claim that these are non-polluting. Personally, I share this position. Nature produces and always produced nanoparticles. I believe that naturally occurring nanoparticles have always existed on our planet, even before there was life. Naturally occurring nanoparticles have never constituted an obstacle to that life came up our planet. These naturally occurring nanoparticles also have never been an obstacle to biological evolution of species until today.

Follow some examples of naturally occurring nanoparticles:
  • Nanoparticles expelled by volcanoes, along with ash and other natural materials;
  • Nanoparticles naturally occurring on the ocean spray; formed by the violent burst of waves;
  • Nanoparticles naturally occurring in mineral composites;
  • Nanoparticles naturally produced by living organisms.
Nature produces mechanisms for its own balance. If naturally occurring nanoparticles are produced by nature, then, not only are not pollutants as also play a necessary role in establishing the ecological equilibrium. This is my personal opinion about naturally occurring nanoparticles.

Regarding, nanoengineered nanoparticles, as I pointed out on "The Roots of Nano-Fear Decoded"nanoengineered nanoparticles are nanoparticles produced by Humans that have been specifically designed for a specific function (e.g. packaging coating, protection of radiation in sunscreens).

In the case of nanoengineered nanoparticles, I have to put this idea very clearly. Nanoegineered nanoparticles do not necessarily have to be nanopollutants: some may be nanopollutants to the environment; others may be harmless to the environment and some can even be beneficial to the environment. Only through intensive study and detailed nanocharacterization (among other scientific studies) it is possible to demonstrate - based on scientific evidence - the degree of hazard (or the degree of benefit) of each nanoengineered nanoparticle to the environment.

Still with respect to nanoengineered nanoparticles, 
I believe they only recently came into existence through the processes of nanofabrication.

Studies suggest that nanoparticles are, by nature, extremely reactive. This means that the nanoparticles are most commonly found clustered in groups or linked to other atoms, nanostructures, organic material or blends than in its native form. With respect to the nanoengineered particles that are pollutants to the environment, and the ones which are nanotoxic, these 
authors claim that, through high reactivity, the degree of hazard or toxicity is greatly reduced.


How Can The Environment Spread Nanoparticles to The Entire Biosphere?

Nanoparticles are present in the air, in the water and in the soils. All requirements for the entire biosphere is contaminated with the ubiquity of nanoparticles are gathered.


For example, nanoparticles present in the air:
  • Mix with humidity also present in the air. Consequently, precipitation (e.g. rain, sleet, snow) become contaminated with nanoparticles. Precipitation reaches the soils and the open water (oceans, seas, rivers, lakes); 
  • Are incorporated in plants through their by the aerial components, for the processes of photosynthesis and respiration; 
  • Are incorporated in animals through respiration; 
  • Contaminate food exposed to air; 
  • Contaminate drinking water exposed to air; 
  • Are mixed with open water (e.g. oceans, rivers, streams, creeks, lakes); 
  • Are infiltrated in soils.
For example, nanoparticles present in the water:
  • Pass into the atmosphere accompanying the water vapour during the evaporation of water;
  • Contaminate soils (trough groundwater);
  • Are absorbed by roots of aquatic plants;
  • Are absorbed by aquatic animals;
  • Contaminate food during the process of washing with water and when water is used to cook.
Nanoparticles present in soils:
  • Pass into the atmosphere accompanying the water vapour during the evaporation of water; 
  • Are absorbed by underground roots of terrestrial plants; 
  • Are absorbed by underground and terrestrial animals; 
  • Contaminate groundwater. 
On the other hand, nanoparticles present into plants and animals traverse the entire food chain until reach Humans.


Final Comments

There are some ideas that I want to present here:
  • Since naturally occurring nanoparticles are not pollutants (according to my personal opinion and of some authors), nanopollution only began after the appearance of nanofabrication of nanoengineered nanoparticles that are hazardous to the environment. Therefore, nanopollution is a considerably recent phenomenon; 
  • Regardless of the degree of risk of nanoengineered nanoparticles (pollutants, harmless or beneficial), they are present in the environment and human beings are exposed to them.

2 comments:

TAREK said...

Many thanks Luis to your big effort which I appreciate to put the light on all these meanings.
As Everybody know many people are hiding knowledge behind codes, not all of us can pay to reach this knowledge.
But still some great people are generous and always give what their information to light brains others even by a good advise.

Luís Bastos said...

Thank you, dear Tarek, by your words - I know they are sincere. If I put light on this subject, it was you who have placed a candle in my hand. Thank you for the candle in my hand - a gesture that can only be considered generous. Best Regards, Luís.

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