# Particulate Matter Contamination of Bee Pollen in an Industrial Area of the Po Valley (Italy)
###### Abstract  
The global demand for bee pollen as a dietary supplement for human nutrition is increasing. Pollen, which comprises proteins and lipids from bees' diets, is rich in essential amino acids, omega fatty acids, and bioactive compounds that can have beneficial effects on human health. However, bee pollen may also contain contaminants due to environmental contamination. To date, data on bee pollen contamination by environmental pollutants refer almost exclusively to pesticides and heavy metals, and very little information is available on the potential contamination of bee pollen by airborne particulate matter (PM), a ubiquitous pollutant that originates from a wide range of anthropogenic sources (e.g., motor vehicles, industrial processes, agricultural operations). In the present study, pollen grains collected by forager bees living in an industrial area of the Po Valley (Northern Italy) were analyzed for contamination by inorganic PM. The morpho-chemical characterization of inorganic particles using SEM/EDX allowed us to identify different emission sources and demonstrate the potential risk of PM entering the food chain and exposing bees to its ingestion.  
bee pollen; particulate matter; pollen contamination; industrial pollution; vehicular traffic; SEM/EDX +
Footnote †: journal: Medical  
have demonstrated that, in heavily trafficked areas, bee pollen is contaminated by ultrafine PM originating from vehicle braking systems, thus endangering the safety of food produced at traffic-influenced sites and the health of bees [5]. Pollen contamination by PM may also threaten the overall health of bees. Previous studies on the oral exposure of bees to airborne particles indicate cytological and histological modifications of the gut epithelium or alterations in the gut microbial community [11; 12].  
The study area of the present work is in the peri-urban area of the city of Parma (Po Valley, Northern Italy). The Po Valley is one of the most important industrial and agricultural areas in Europe, characterized by high levels of PM\({}_{10}\) and PM\({}_{2.5}\) that mainly originate from traffic and agriculture [13; 14; 15]. A previous source apportionment study carried out in the area using honeybees has been used as an alternative sampling system for airborne PM. Agricultural operations and high-temperature combustion processes, probably linked to the Parma incineration plant, have been identified as a major sources of PM [16]. The honeybee (_Apis mellifera_ L.), which is an important control in the biomonitoring of environmental pollutants [17; 18; 19; 20], can act also as an efficient sampler of airborne dust [5; 16; 21; 22; 23]. The generation of static electricity on a bee's body during flight attracts airborne particles that can be analyzed by scanning electron microscopy (SEM) coupled with X-ray spectroscopy (EDX) to evaluate size, morphology, and chemical composition [21; 22]. Such information can facilitate the identification of PM emission source(s) and potential health hazards [5; 16; 22; 21].  
In the present work, airborne PM contamination of pollen grains collected by honeybees in the study area was investigated by SEM/EDX, with the aim of characterizing the nature, morphology, and mineralogical composition of particles and evaluating their possible origin. Such analysis also allowed us to demonstrate the potential risk of PM entering the food chain and exposing bees to its ingestion.