[en] Highlights: • High-throughput sequencing was used to compare sludge bacteria with and without TC. • Bacterial diversity increased with TC addition despite of various oxygen conditions. • Total TRGs proliferated with TC addition in three kinds of sludge. • The concentration of efflux pump genes was the highest in the three groups of TRGs. - Abstract: Two lab-scale anaerobic-anoxic-oxic (AAO) systems were used to investigate the changes in tetracycline (TC) resistance and bacterial diversity upon exposure to TC pressure. High-throughput sequencing was used to detect diversity changes in microorganisms at the level of class in sludge from different bioreactors with and without TC. Real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) was used to detect the abundances of eight tetracycline resistance genes (TRGs), tetA, tetB, tetC, tetE, tetM, tetO, tetS and tetX. The results showed that the diversities of the microbial communities of anoxic, anaerobic and aerobic sludge all increased with the addition of TC. TC substantially changed the structure of the microbial community regardless of oxygen conditions. Bacteroidetes and Proteobacteria were the dominant species in the three kinds of sludge and were substantially enriched with TC pressure. In sludge with TC added, almost all target TRGs proliferated more than those in sludge without TC except tetX, which decreased in anaerobic sludge with TC addition. The concentration of efflux pump genes, tet(A–C, E), was the highest among the three groups of TRGs in the different kinds of sludge

[en] Background: The development of the nuclear industry caused uranium contamination to the environment. As an economical and environmental friendly technique to repair uranium contaminated soils, phytoremediation has attracted much attention in recent years, and the key to this technology is uranium bioavailability in soils. Purpose: The present work investigates the impact of several inorganic anions in soils on uranium desorption from the uranium contaminated soils. Methods: Leaching test and inductively coupled plasma-mass spectrometry (ICP-MS) was used in this study. Results: It was found that uranium desorption rate increased with CO_3"2"- concentration, and the equilibrium was obtained with resolution rate of 85%-90%. Uranium desorption rate could increase from 41%-53% when SO_4"2"- content was in the range of 5-40 g·L"-"1. While Cl”- had no effect on uranium desorption. Uranium desorption obtained equilibrium at a volume of 20 mL for strippant with 5-g uranium contaminated soil. In the former 3 days, uranium desorption rate increased rapidly, and finally obtained equilibrium at 105-h with a desorption rate of 90%. Conclusions: First, CO_3"2"- and SO_4"2"- have better effect on uranium desorption compared to other anions. Effect of CO_3"2"- was greater than SO_4"2"- due to a greater binding ability of CO_3"2"- to U(VI), while Cl”- had little effect. Second, the solvent volume and leaching time also impact uranium leaching yield. This study would be helpful to increase the knowledge of improving uranium bioavailability in the soil, which also laid a theoretical foundation to improve the efficiency of phytoremediation. (authors)