Relationship Between Bees Activity Level with Their Load of Lead, Cadmium and Selenium and Climatic Conditions of the Sites

The present study, conducted in 2022, had the aim to evaluate honeybees’ metals and a metalloid (Pb, Cd and Se) load in relation to microclimatic conditions (Temperature, Relative Humidity, Air Pressure Rain level and Solar Radiation) and according to their activity level. For this purpose, two apiaries, each composed of four top bar hives, located in the province of Lodi were considered. One apiary was located in San Fereolo, a biodiverse peri-urban site rich in plants and flowers, and the second one in Rossate di Comazzo, a rural zone with maize and soybean intensive cultivation, near the TEEM highway. Results showed a positive reduction of the load of metals on bees, in line with the literature. The San Fereolo site, more «biodiverse» than Rossate, was characterized by lower metal concentrations in general, but by a higher concentration of Selenium on bees, a metalloid responsible for hypoactivity and sub-lethality of the colonies. Results put in evidence the relationship between the level of activity recorded during the month before sampling and the pollutants load, except for Selenium, higher on San Fereolo bees, less active and reared in a biodiverse site. Linear regressions revealed a relationship between animal activity and the combination of temperature and solar radiation, according to the hive-site.