Assessing the chronic effect of the bioavailable fractions of radionuclides and heavy metals on stream microbial communities: A case study at the Rophin mining site

• DOI: 10.1016/j.scitotenv.2024.170692
• Publication Date: 2024-02-05T07:09:02Z
• Authors: Clarisse Mallet; Florent Rossi; Yahaya Hassan-Loni; Guillaume Holub; Le Thi-Hong-Hanh; Olivier Diez; Hervé Michel; Claire Sergeant; Sofia Kolovi; Patrick Chardon; Gilles Montavon
• Keywords: 570; 550; Bioavailability; Heavy metals; Bacteria; Microbial community; Fungi; [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph]; Radionuclides

This study aimed to assess the potential impact of long-term chronic exposure (69 years) naturally-occurring radionuclides (RNs) and heavy metals on microbial communities in sediment from a stream flowing through watershed impacted by an ancient mining site (Rophin, France). Four samples were collected along radioactivity gradient (for 238U368 1710 Bq.Kg−1) characterized for presence bioavailable fractions (226Ra, 210Po), trace metal elements (Th, U, As, Pb, Cu, Zn, Fe). Results revealed that available fraction contaminants was significant although it varied considerably one element another (0 % As Th, 5–59 U). Nonetheless, appeared significantly affected such (radio)toxicities. Several functions carried bacteria related with carbon nitrogen cycling have been impaired. The high values fungal diversity richness observed increasing downstream contamination (H′ = 4.4 Chao1 863) suggest community had likely shifted toward more adapted/tolerant as evidenced, example, species Thelephora sp. Tomentella bacterial composition also enrichment Myxococcales, Acidovorax or Nostocales at most contaminated points. Changes functional structure directly radionuclide contaminations, but organic matter which affected, indirectly, compositions. Although not possible distinguish specific effects RNs communities, is essential continue studies considering elements, only able interact microorganisms.