Landfill waste fire: oxidative stress and elements accumulation in bees

Landfill fires are relatively frequent incidents that can contribute significantly to air pollution and have environmental and health impacts (1). Various pollutants can be emitted during waste combustion, such as carbon monoxide and dioxide, nitrogen oxides, volatile organic compounds, persistent organic pollutants, aldehydes, and toxic or potentially toxic elements (1,2). Bees are important pollinating insects sensitive to environmental contaminants (3). Toxic elements, such as As, Cd, Hg, and Pb, can weaken their immune system and induce oxidative stress in these valuable insects (4,5). The present study aimed to evaluate the impact of air pollution from waste fires on bee health, in terms of oxidative stress and metal accumulation, as well as the possible beneficial effect of feeding probiotics and Quassia amara to bees. Six beehives were considered near the Malagrotta landfill, central Italy (41°51'49.9 N 12°19'46.5 E) before and after a landfill fire event on 15 June 2022. Bees, fed with different nutrients (placebo, probiotics, and Q. amara), were analyzed for elemental content by a quadrupole inductively coupled plasma mass spectrometry and cold vapor atomic fluorescence spectrometry (3,4), oxidative stress by hydrogen peroxide and protein carbonyl group contents (5), and metabolic profiles by 1H-NMR (4). Compared with control bees, lower concentrations of As, B, Ba, Cd, Co, Fe, Li, Mn, Ni, Pb, Sn, Ti, and U were found in probiotic-fed bees, and Ba, Be, Cd, Co, Fe, Li, Mn, Sn, Ti, and U in Q. amara-fed bees, indicating a possible protective action of probiotics and medicinal plants against the accumulation of toxic or potentially toxic elements (3,4). The administration of probiotics and Q. amara to bees has also shown a protective effect against the oxidative stress caused by the fire of landfill waste (4). The comparison of the metabolic profiles through pre- and postevent PCA analyses showed that bees treated with different feeds react differently to the environmental event. The greatest differences in metabolic profiles are observed between the placebo-fed bees compared to the others. This study can help to understand how some stress factors can affect the health of bees and to take measures to protect these precious insects. Acknowledgements The authors wish to thank Marco Papi, Marco Papi Azienda Agricola ed Apistica, Rome (Italy), for the study’s precious support and all the sampling stages. We acknowledge the Ph.D. programs on green topics, PON Research and Innovation 2014–2020 project, funded by FSE REACT-EU. 1. D. Dabrowska, W. Rykala, V. Nourani. Sustainability, 2023, 15(7), 5713, 10.3390/su15075713 2. EMEP/EEA air pollutant emission inventory guidebook 2023. EEA Report 06/2023. www.eea.europa.eu/ds_resolveuid/745f4e2e388147eba041d47727e3fa84 3. M. L. Astolfi, M. E. Conti, M. Messi, E. Marconi. Chemosphere, 2022, 308, 136261, 10.1016/j.chemosphere.2022.136261 4. O. Giampaoli, M. Messi, T. Merlet, F. Sciubba, S. Canepari, M. Spagnoli, M.L. Astolfi. Environmental Science and Pollution Research, 2023, 1-17. 10.1007/s11356-023-31561-x 5. M. Alburaki, K. D. Smith, J. Adamczyk, S. Karim. Journal of insect physiology, 2019, 117, 103891. 10.1016/j.jinsphys.2019.103891