Diffusion and Concentration of Particles
As we have already briefly described, the particulate pollutants we deal with can remain suspended in the atmosphere for a very long time. When they finally touch the ground, a little wind is enough to lift them up again and restart the journey. In addition, as repeatedly stressed, most of the solid and inorganic particles are not degradable, and therefore, the journeys they make due to physical diffusion phenomena, wind, changes in atmospheric pressure, Coriolis fictitious force, rain, etc., can last for a very long time, covering long distances, thus allowing a sort of homogenisation at a planetary level. It must be taken into account that polluting particles can have very different sizes, from a few nanometres of aerodynamic diameter up to tens of microns, with all that this entails in terms of mass and, therefore, in terms of the time during which they can remain for a more or less long time suspended and move.
Another necessary consideration is to remember that particles can either crumble, as is the case with the fragile, spherical and hollow ones, or aggregate with each other and, as is characteristic of secondary particulate matter, stick with non-particulate chemical substances such as dioxins and furans more or less occasionally present in the atmosphere. In addition to the consequence of becoming a carrier of organic pollutants which would not otherwise have a great chance of travelling, joining necessarily means increasing mass and volume with all which follows. On the other hand, as is obvious, crumbling means giving origin to more numerous and lower-mass particles.
Because of all this, the diffusion patterns of the polluting particles currently applied are often oversimplifications with significant margins of error.
If one considers a polluting source, it is evident that the concentration of the particles is especially high in its vicinity and decreases with distance. For this reason, the quality and quantity of particulate pollutants appear different from area to area and, in some way, characterise it. The images of cities suffocated by pollution are known to everybody, and it is equally well known that we always rely on atmospheric events to mitigate the situation.
Given the fact, it must be added that part of the fallen particles seriously affects the composition of the soil up to the aquifers by changing their characteristics; this too must be taken into account when assessing the impact of a polluting source on a certain territory. It is usual that when bureaucratic permission is required to install a plant which emits pollutants, documentation is presented which refers exclusively to that particular plant as if it were the only source of pollution in the area and on the basis of that documentation the permit to be built and to go into operation is released. Almost never the authorities in charge take into consideration how that particular pollution adds to what is already present and, perhaps, to pollution coming from areas which are not close. Again, the toxicological concept that one plus one equals a higher sum than two is valid.
In the course of our investigations on the environment, we dealt with relatively large polluting sources such as heavy-oil power plants, waste incinerators, foundries and cement factories. Each of them has profoundly affected more or less vast expanses of territory.
Each source of pollution has its own peculiarities, and micro-and nanoparticles are excellent markers which can be found both in samples taken from the environment and in patients’ tissues. And it is not rare that it is h orn the analyses on the particles contained in pathological tissues that it is possible to trace the source of pollution. In several cases, such scientifically irrefutable evidence has been used in criminal courts.
Figure 4.11 Cast iron industry pollution. The so-called 'Ferriera di Servola' is an industrial complex dating back to 1896 specialised in the production of cast iron, located in a district of the Italian city of Trieste, in an area now quite densely inhabited. From its smokestacks, fumes containing generally coarse iron-based particles come out and fall into the surrounding area. Significant quantities of dust can be collected daily anywhere in the vicinity.
The following images (Figs. 4.11-4.14) witness the dispersion of the industrial pollution in the surrounding environment of factories.
Figure 4.12 Steelwork pollution in a child's brain. The particles shown in the electron microscopy images were detected in the brain of a child who died of brain cancer at the age of 5. The boy lived in the Italian town of Taranto, where one of the largest foundries in Europe has stood for decades. The ferrous particles are typical of the pollution of that territory, while those based on calcium probably formed inside the cancerous tissue, as is quite characteristic of those pathological conditions.
Figure 4.13 Steelwork pollution in an insect. Some samples taken in the air, on leaves, on metal objects and on windowsills in an area around a large foundry located in the industrial area of Udine (Italy) showed the obvious presence of spherical particles typical of the castings. That type of pollution which had existed for many years had damaged the small orchards and the gardens around the houses. Among the exhibits, we also collected a dying insect sprinkled with particles, as can be seen in the two low-magnification photographs.
Figure 4.14 Heavy-oil power plant pollution on a T-shirt. Inside the Italian river Po Delta Regional Park, there is a power plant once operating with heavy oils, which has been inactive for a few years. The fallout from the fumes polluted a relatively vast, once uncontaminated area. The particles were so aggressive that they corroded the bodywork of cars. The particles shown in the photographs were contained in oily droplets fallen on a T-shirt hanging out to dry. The local criminal court instructed us to determine whether the fallout with (Continued)
which the inhabitants of the area complained actually came from the thermal power plant. The presence of vanadium, an element which is not often found in polluting particles, was constantly detected both in the fuel used by the plant and in the particles found in the numerous finds examined. This, together with other tests, analyses and evidence, allowed us to establish with certainty the origin of the fallout.
Figure 4.15 Pollution identified in a blood of a baby affected by leukaemia. The images refer to the case of a four-year-old girl with leukaemia and her mother with breast (Fig. 4.16) and thyroid cancer (Fig. 4.17). Mother and daughter live in an area which is heavily polluted by the emissions of numerous ceramic industries, and a great number of inorganic particles are present in the girl's plasma. Note also the presence of small calcium-based particles of very probable endogenous origin: a very frequent finding in cases of cancer. In both breast and thyroid biopsies of the mother, the presence of solid, inorganic particles is evident. Again, the cancerous tissues contained small calcium-based particles. It may be interesting to note the greater complexity from the point of view of the elemental chemical composition of the particles present in the thyroid compared to those of the breast.
One of the cases we came across is that of a four-year-old girl with leukaemia (Fig. 4.15). In the area where the family lives, there are many industries which produce ceramic material, almost exclusively tiles. The little patient’s mother had worked for some time in one of those industries and had suffered from breast cancer. She has recently been diagnosed with thyroid cancer (Figs. 4.16 and 4.17). It is interesting to note that particles of an origin ascribable to the ceramic industries are present in the girl's blood and in the mother’s biopsy samples. It should be added that what is emitted from the chimneys of those industries is quite varied, because, in addition to the basic materials, glazes, dyes and different chemical products are used, which can be different from company to company. To this pollution is added that of the very intense traffic of trucks used for the transport of raw materials and finished products.
It would have been interesting to have been able to analyse the cerebrospinal fluid which was taken every week from the child, but unfortunately, the doctor in charge refused to give us a sample.
Figure 4.16 Contamination identified in the breast cancer of the mother.