Impacts of a tailing dam break on the contamination of pollen and honey from the stingless bee Tetragonisca angustula (Apidae: Trigonini).

Abstract

Metal and metalloid pollution are one of the main negative impacts of mining activities. Furthermore, the mining wastes are often stored in tailing dams, which are prone to failures and even total collapse. The Fund~ao tailing dam collapse in Brazil in 2015 flooded large areas of river floodplains below the dam. We analyzed the effect of the tailing deposition from the dam disaster on metal/metalloid levels in honey and pollen samples from the stingless bee Tetragonisca angustula. Pollen and honey samples were taken from the initial stretch of the impacted areas, as well as adjacent control areas and an additional external control area. In total, we analyzed 55 pollen samples and 53 honey samples, which were collected directly from the honey and pollen combs stored within the hives. The samples were wet acid digested in a microwave oven and the concentrations of the elements were determined by ICP-OES and ICP-MS. The metal/metalloid contents in honey and pollen samples were compared between the impacted and the non-impacted points. We found significantly higher concentrations of As, Ba, Cr, Mn, Ni and Zn, in honey and pollen samples, from some impacted points compared to the reference non-impacted ones. However, most concentrations we found were similar to those found in other works, including areas with mining activity in the Iron Quadrangle (Minas Gerais, Brazil). These results suggest that the tailing dram break, followed by deposition of the dam waste, contributed to a high concentration of some elements found in the pollen and honey samples at our study site.