Pollen storage by stingless bees as an environmental marker for metal contamination: spatial and temporal distribution of metal elements

Abstract

Pollen storage by stingless bees as an environmental marker for metal contamination: spatial and temporal distribution of metal elements IntroductionSince the middle of the 20 th century, growing industrialization, urbanization, transportation and agriculture has led to overall ecosystem contamination and major modifications to landscape structure and composition. The presence of metals in the environment can be the result of external sources such as industrial smelter pollution, emissions from ferrous metallurgy, external mining activities and busy highway traffic (Bilandžić et al., 2011;Lambert et al., 2012).Mining activities represent a major source of environmental contamination by metal residues (Freedman & Hutchinson, 1981;Perugini et al., 2011). In the Brazilian state of Minas Gerais, mine exploitation in the Iron Quadrangle reached its peak towards the middle of last century and the activity is still intense (Meneses et al., 2011). One of the consequences of this industry is the daily release of huge amounts of dust into the atmosphere (Meneses et al., 2011). AbstractSince the middle of the 20 th century, human activities have led to overall ecosystem contamination and to major modifications in landscape structure and composition. Mining activities represent a major source of environmental contamination by metal residues. The objective of our study was to evaluate the presence of heavy metals and other elements on stingless bee pollen, and compare them to samples of Suspended Particulate Material (SPM) in five points a Mineral Province, in Brazil. More than 50 elements were identified by ICP-OES and ICP-MS, after microwave digestion. Overall, we found a strong relation among elements present on pollen and SPM. Samples from the four areas exhibited higher levels of minerals compared to the reference site. Mineral levels varied widely within the two seasonal periods. Some elements, like Pb, Cd, As, Cu, Zn, and Fe were found at levels considered potentially toxic to human health. Pollen stored by stingless bees was a successful bioindicator, and demonstrated the value of quantitative ecological information for detecting air pollution. The rocks (or soils) of Iron Quadrangle naturally have high levels of metals that can be considered toxic for human health (Rapini et al., 2008;Azevedo et al., 2012;Messias et al., 2013;Carvalho-Filho et al., 2010). On the other hand, these regions shelter a relatively high variety of very poorly studied metallophilic plants, living in a harsh environment with high concentrations of metals in the soil and subject to atmospheric deposition of those toxic elements, due to the mining activities. Studies carried by Valim (2012) and Baêta (2012) for example, found that relevant quantities of elements such as Al, Ba, Ca, Fe, K, Na, Mg, Mn, S, Sr, and Zn are deposited annually on the soil surface and vegetation via wet and dry deposition. According to these authors, this deposition depends on the geochemical nature of the environments that may be affected by weathering and anthropic ...

Potential Existence of Heavy Metal Pollution and Pesticide in Honey-Based Products

“…Authors [73][74][75], detected the presence of heavy metals, such as Cd, Pb, Fe, Mg, Zn and As in samples of propolis, beeswax and bee pollen. Nascimento et al [76] also detected some heavy metals present in the pollen stored by the stingless bees that live near mining activities.…”

Pollutants and Their Interaction with Diseases of Social Hymenoptera

“…However, these subtle individual-level effects may be amplified over time, resulting in long-term negative effects on colony fitness [19,29,30]. For example, pollutants incorporated into stored foods or nest materials, including beeswax, may accumulate over time [31][32][33][34][35][36][37][38][39][40], leading to a constant exposure to pollutants of larva and adults of new generations of workers, as well as sexuals [37,41,42]. In this way, even subtle effects on individuals can have quite extreme negative consequences for social insect colonies, threatening their existence [21,29,30,43].…”