Waste: The Production of Incidental Nanoparticles
We have already pointed it out: man has characteristics which are unique among all creatures living on earth. Among them, we produce waste and we need energy. Ofcourse, in spite of what most of us firmly believe, those are not primary needs nor are they a right, as man is an animal just like any primate and for at least 15,000 centuries has lived the way any ape does. And apes neither produce waste (at least not materials nature can't reuse) nor need energy (at least, not of the type employed by humans). But, though with enormous time differences among different places, more or less half a million years ago, man started to know how to light fire and, later, how to use it to make artifacts. It was then that man began to differentiate himself significantly, not in anatomy or physiology but in ethology, from any other animal, producing naturally unusable waste and using energy which was not naturally given.
Until relatively recently, waste was not a particular problem: the number and habits of the world’s human population were easily compatible with the planet's ‘physiology’ or, better, they were tolerable, and for both technical and economic reasons, man did not produce large quantities of objects, nor did his technical procedures leave too much waste.
Nowadays, particularly in the course of the last century, each individual started to use and ‘need’ more and more objects, each of which required the use of materials and of energy to be manufactured, each of which had a shorter and shorter usable life (nowadays many products have a planned obsolescence), becoming inevitably true waste, that is, something which nature is at a loss with and does not know how to deal with. Nor, it must be admitted, is nature interested in doing, as the world always finds a balance, even if it is not certain that the new one will be something compatible with the prospering of human life.
Some decades ago, when plastics began to be widely used to make more and more numerous products, making them less expensive and, therefore, more within the reach of a growing number of people, the illusion was that we would spare natural resources, though plastics are made of oil, which is obviously a natural resource. The situation now, just after a very short time as compared with our presence in this planet, is that we have huge quantities of plastic waste we don't know how to cope with.
And, facing an ever-growing demand, energy and its supply too are becoming a problem. As a matter of fact and with few exceptions, however with little significance, the energy coming, be it directly or indirectly, from the sun is the only one living beings, humans, animals and vegetables alike, have available and have ever used. Though it is delivered in a quantity far exceeding our ‘necessities', without getting into an argument which can't be part of this book, we are not technically able to use it, nor are we willing, except to a very small degree. So, we are forced to resort to sources coming not from without but from within the closed system which is the earth, by this condemning humanity to run out of supplies by a time which is still difficult to predict but which sooner or later will inevitably come. In short, if we use the fuel contained in a tank without the possibility of the tank being refilled, there is no escape: sooner or later the tank will be empty.
Regardless of how we get rid of waste in an uncontrolled manner, much of what we discard ends up in landfills: by no means a satisfactory solution. The technological way adopted in most cases to solve the more and more embarrassing problem, then, is that of burning waste with the advantageous side effect of obtaining precious energy.
But, as to energy, if calculations are done correctly and all data are duly taken into consideration without forgetting, underestimating
or neglecting any of them, burning involves a loss-making budget, since the manufacture of what is burned requires quantities of energy which far exceed what is obtained by combustion. But, apart from this aspect whose discussion cannot belong in this book, one of the many demonstrations of how much man prefers to consider what is convenient for him at the moment by pretending that facts do not exist, account must be taken of the principle of conservation of mass according to which matter can't be destroyed but only transformed. So, scientifically speaking, waste is not eliminated but only transformed into something else.
Burning implies the oxidation, in fact the addition of atmospheric oxygen, of the substances which can be oxidised, and, for technical reasons, considering all the technology needed, combustion in an incinerator requires not only oxygen but also water, methane, activated carbon, carbonates, ammonia, etc. All this means adding to waste more or less as much mass, a mass which is then inevitably discharged as such or transformed into different pollutants into the environment But, as already mentioned and leaving aside the thousands of organic pollutants (among which dioxins, furans, polychlorobiphenyls, a huge variety of polycyclic organic compounds, etc.), combustion means producing primary and secondary particles which, also as ash (approximately 1/3 of the initial waste mass is transformed into ash), enter the environment and accumulate. When treated legally, ash is disposed of in landfills and, being particularly toxic, makes this means of miscellaneous waste storage definitely dangerous. In some circumstances, we worked in landfills obtained from disused quarries, with the ashes which, together with a set of other toxic substances, carried by rainwater ended up in the aquifers. Mixed with asphalt, as it happens in some circumstances, that toxic ash constitutes a further risk to health, as asphalt gets rapidly worn, thus liberating those particles into the atmosphere. All in all, a similar risk is that of ashes mixed with cement, with the aggravating circumstance of obtaining a poor-quality product. More will be said in a few pages.
We have already described the formation of primary and secondary particles. Now, neglecting other details which are not part of this discussion, it should be remembered that air is a mixture composed of roughly one-fifth of oxygen and four-fifths of nitrogen. When this mixture is heated above a certain temperature, a temperature which is easily reached by waste incinerators and internal combustion engines, the two gases react together and give origin to nitrogen oxides (NOx): substances which are harmful both to the environment and to health.
No matter what technology is used, because of what (for us, modern humans) is an unfavourable natural law, not theleast fraction of waste is eliminated, being it just transformed into something by far more toxic than the original. The ‘advantage’ is that combustion makes waste invisible to the eye, but unfortunately - and this is the con - very visible to the rest of our organism.
It is certainly a truism: the only acceptable waste with regard to the environment and health is that which is not produced.
When these obviousnesses are noticed, the most frequent reaction is to be told that whoever mentions them is an enemy of progress and would like to go back to the Stone Age. None of this: it is only a matter of realising how things are according to science.
We had a few chances to analyse ash from incinerators (Figs. 3.1-3.4) and fallen particles (Fig. 3.2) and other pollutants around some industries.
Figure 3.1 Spherical particles emitted by an incineration plant.
Figure 3.2 Ashes from an incinerator plant (Raibano, Italy). The ash shown in the images was collected in close vicinity of a waste incinerator plant placed in North Italy. As always when it comes to an origin from mixed waste, its composition is extremely varied and variable overtime, even in a matter of few minutes, and contains elements which are not often found (e.g. tantalum) in particles of other origins. In this particular case, but the case is far from unique, the incinerator is located on a hill a few kilometres away from beaches which are very popular during the summer. Inevitably, the ash, light as it is, is carried by the wind and falls on the sand and into the sea.
Figure 3.3 Ashes from an incinerator plant (Terni, Italy). The particles shown in the images belong to emissions from an incinerator plant located in a small Italian town and were collected in the air. The spherical shape with a surface made up of small juxtaposed crystals is typical of a high-temperature source. Very often other particles stick to larger ones when they are still hot and soft. Once cooled, the spherical particles, hollow inside, are very fragile and easily crumble, giving rise to particles which are obviously smaller and more numerous than the original ones. Steel, lead and titanium are the most common elements found in the environment.
The following images represent a selection of the dirtiness we inhale every day (Figs. 3.1-3.7).
Figure 3.4 Dust from a waste incinerator plant. The particles shown in the images come from the storage placed below the combustion griddle of the municipal waste incinerator plant of a small town where two more waste incinerators are located. Similar particles are found everywhere in the area, on the ground, on any object or plant and suspended in the air.
Figure 3.5 (a) A leaf damaged by waste incinerator emissions. Also the plants grown around incinerators are subjected to its pollution and can be severely damaged as this leaf demonstrates. The pollution identified on its surface is clearly related to the incinerator's emission, (b) The particles shown here were collected on leaves of plants grown in the outskirts of an industrial city, not far from a waste incinerator. The small particles are especially aggressive as they occlude the stomata of the leaves. The micro- and nanospherules are the result of high-temperature combustion. Elements like bismuth, iron and chromium were identified.
Figure 3.6 Leaf collected close to a waste incinerator plant, (a, b) The electron microscopy images refer to a leaf collected in the vicinity of a waste incinerator, (c) Elemental composition of the leaf, (d) Elemental composition (Fe-Cr-Ni, that is, steel) of some of the particles.
Figure 3.7 Leaf of a tree close to a ceramic factory. The particles shown were collected on leaves of plants grown in a glen at over 700 m altitude above sea level, far from inhabited centers. Wild vegetables grown in that place had fed for decades a person who then fell ill with peritoneal mesothelioma and eventually died of it. Note the composition of the particles containing thorium and uranium, two elements used as components of glazes by the small ceramic industries placed in a higher position, as the crow flies a couple of kilometres away from the glen, and with nothing standing in the way. We found also silver particles.
Figure 3.8 (a) Analysis of nose tissue affected by cancer in a patient living close to an incinerator plant. (b) Analysis of the nose cancer tissue, (c) Nose cancer. Basal cell carcinoma is the most common form of skin cancer. It is a papula or a slow-growing superficial nodule derived from some epidermal cells. They derive from keratinocytes close to the basal layer, which can be defined as basaloid keratinocytes. Metastases are not common, but untreated and let locally grow, they can destroy skin and bone. Barium-sulphur particles have been detected in this case. Barium sulphate is a very common salt used as a radiological contrast medium in the radiology of the digestive system. It can be used because it cannot be hydrolysed and, therefore, does not release barium ions, which are toxic. It is also often found in urban air pollution, resulting, among other origins, from the aging of buildings. Iron, cerium, lanthanum, neodymium and praseodymium are elements which can be very often found in smoking tobacco. Their particles are inhaled and breathed by smokers. In this case, it can be seen how, most likely, those particles crossed the alveolar barrier, were carried by the blood and ended up concentrating in the skin. One possible hypothesis is that the movement of the particles is an attempt by the organism to get rid of them without succeeding in going beyond the skin barrier.
If one considers them just from a chemical standpoint, nothing can be said about the biocompatibility of those pollutants, since they are substances which are not mentioned in specialised books and papers, and nobody tested their toxicity.
The following images (Fig. 3.8) show what was identified in the nose cancer of a person living in a house placed close to an urban waste incinerator plant
The ash of the incinerators must be stored in landfills, but our politicians created laws in order to reuse them as fillers of cement or of asphalt.
Figure 3.9 Insects, like all living things, are also attacked by particulate pollutants. The photographs show micro- and nanoparticles which have reached the eye of an ant. In this case, given the elemental chemical composition of the particles, it could be normal environmental dust generated by the soil.
Cement is not a material which is particularly capable of resisting time and bad weather. As for durability, its buildings can’t be compared to those built centuries ago, which are still perfectly usable and accessible. Just as an example, there are still bridges and aqueducts built by the Romans about 20 centuries ago or more which are still used today. Consular roads such as, for example, the Via Emilia in Italy have not needed major maintenance for 2000 years. As a matter of fact, cement cannot last longer than a few decades. Yet, we keep using huge quantities of cement and we produce it in different varieties according to the particular intended use.
To make matters worse, now and for some time, most of the cements have been mixed with the ash left by the combustion of incinerators, thereby affecting their mechanical properties. This is undoubtedly one of the reasons why it is not unusual to see buildings and viaducts collapse in a time relatively close to their construction.
In addition, many cement plants operate as real waste incinerators and their mitigation systems concerning the dispersion of pollutants are much less effective than the already far-from-satisfactory ones used by waste incinerators.
We had a chance to carry out an investigation in a territory where grape-growing is the prevalent activity.
The analyses of the grape leaves (with which a famous sparkling wine is made) carried out in June showed the presence of copper sulphate currently used in agriculture and of calcium sulphate (cement) particles (Fig. 3.10).