Apis mellifera: un esempio di campionamento di particolato atmosferico inquinante nei pressi di un cementificio

[Autom. eng. transl.] Recent studies have shown that the honey bee (Apis mellifera L.) is an excellent tool for monitoring airborne atmospheric particulates. These particles, known as PM (particulate matter), can have different sizes - from the coarsest (PM 10) to the ultrafine (PM 0.1) - and two sources of origin: natural - resulting from the erosion of the lithosphere, volcanic eruptions etc. - or anthropogenic, produced for example by industries and vehicular traffic. The latter mainly include fine and ultrafine particles which are particularly harmful to human health. During foraging activities, the foraging bee, in addition to taking nectar, pollen and water for the family, accidentally captures the PM that settles on the body and on the bristles of the insect, and remains attached to it. The present study, started in the spring of 2018, was conducted near a cement factory in Val d'Arda (PC): bee wings taken from a beehive near the cement factory were analyzed to detect the presence of environmental markers related to the cement production and suggest strategies to reduce PM dispersion. Qualitative analyzes of PM contaminating bees were carried out through the use of a scanning electron microscope (SEM) equipped with an X-ray energy dispersion microprobe (EDX) which allowed to study the morphology, the dimensions and the chemical composition of the powders. A sample of "raw flour" and one of cement were also analyzed in order to make a comparison with the particulate matter observed on the wings of the bees. The samples found essential ingredients for the production of cement such as calcium carbonate minerals (calcite and dolomite) of different grain sizes, quartz and phyllosilicates rich in both silica and aluminum with traces of iron, all potentially attributable to transport and the handling of raw materials and the final product. In addition, minerals such as iron oxides / hydroxides potentially attributable both to the processing of cement, as they were added to the clinker before the final grinding, and to vehicular traffic due to wear and tear of the vehicle brake system were found. In some samples, nanometric particles (<0.1 µm) of barium sulphate were observed, resulting in particular from the erosion of the brake pads. In conclusion, using the bee as a PM sampler and characterizing the powders that contaminate it through SEM / EDX allows the identification of specific emission sources, thus allowing the promotion of adequate control strategies and prevention of emissions.