TY - JOUR
T1 - Toxicity of uranium to microbial communities in anaerobic biofilms
AU - Tapia-Rodríguez, Aida
AU - Luna-Velasco, Antonia
AU - Field, James A.
AU - Sierra-Alvarez, Reyes
N1 - Funding Information:
Acknowledgments This work was supported by the University of Arizona, Technology and Research Initiative Fund, Water Sustainability Program. Support was also obtained from the Mexican National Council of Science and Technology (CON-ACyT) for a fellowship to A. Tapia-Rodriguez (ref. no. 206827/ 230752).
PY - 2012/9
Y1 - 2012/9
N2 - Microbial processes have shown promise for the remediation of uranium and nitrate in groundwater impacted by uranium mine tailings. This study investigated the inhibitory impact of uranium(VI) towards different microbial populations in anaerobic biofilms, including methanogenic, denitrifying, and uranium-reducing microorganisms, which are commonly found at uranium bioremediation sites. Results of batch activity bioassays indicated a very distinct level of toxicity depending on the targeted microbial community. U(VI) caused severe inhibition of acetoclastic methanogenesis as indicated by a 50 % inhibiting concentration (IC 50) of only 0.16 mM. Denitrifying populations were also impacted by uranium, but their sensitivity depended on the electron donor utilized. Sulfur-oxidizing denitrifiers were the least affected (IC 50 for denitrification activity∈=∈0.32 mM), followed by H 2- and acetate-utilizing denitrifiers (IC 50 of 0.20 and 0.15 mM, respectively). In contrast, exposure to U(VI) concentrations up to 1.0 mM did not inhibit the rate of U(VI) bioreduction with H 2 as electron donor in the presence or absence of nitrate. On the contrary, a considerable increase in the uranium-reducing activity of the denitrifying and methanogenic mixed cultures was observed with increasing uranium concentrations. The results suggest that microorganisms responsible for U(V) reduction could tolerate much higher uranium concentrations compared to the other microbial populations assayed.
AB - Microbial processes have shown promise for the remediation of uranium and nitrate in groundwater impacted by uranium mine tailings. This study investigated the inhibitory impact of uranium(VI) towards different microbial populations in anaerobic biofilms, including methanogenic, denitrifying, and uranium-reducing microorganisms, which are commonly found at uranium bioremediation sites. Results of batch activity bioassays indicated a very distinct level of toxicity depending on the targeted microbial community. U(VI) caused severe inhibition of acetoclastic methanogenesis as indicated by a 50 % inhibiting concentration (IC 50) of only 0.16 mM. Denitrifying populations were also impacted by uranium, but their sensitivity depended on the electron donor utilized. Sulfur-oxidizing denitrifiers were the least affected (IC 50 for denitrification activity∈=∈0.32 mM), followed by H 2- and acetate-utilizing denitrifiers (IC 50 of 0.20 and 0.15 mM, respectively). In contrast, exposure to U(VI) concentrations up to 1.0 mM did not inhibit the rate of U(VI) bioreduction with H 2 as electron donor in the presence or absence of nitrate. On the contrary, a considerable increase in the uranium-reducing activity of the denitrifying and methanogenic mixed cultures was observed with increasing uranium concentrations. The results suggest that microorganisms responsible for U(V) reduction could tolerate much higher uranium concentrations compared to the other microbial populations assayed.
KW - Denitrification
KW - Methanogenesis
KW - Microbial inhibition
KW - Uranium reduction
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U2 - 10.1007/s11270-012-1154-0
DO - 10.1007/s11270-012-1154-0
M3 - Article
AN - SCOPUS:84865525856
SN - 0049-6979
VL - 223
SP - 3859
EP - 3868
JO - Water, Air, and Soil Pollution
JF - Water, Air, and Soil Pollution
IS - 7
ER -