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Vanadium (V) is ubiquitously distributed in environmental media, imposing toxic hazards to organisms in biogeosphere. This review focuses on a comprehensive summary of the ecological and human health risks ascribed to V pollution, based on existing V toxicity relevant publications. Lower doses of V (< 2 mg/L) is beneficial to plant growth, however, V reduces plant biomass, induces toxic effects on plant morphology and adversely affects the absorption of essential plant elements at higher levels (≥ 2 mg/L). Oxidative stress induced by reactive oxygen species (ROS) produced under V stress may be the main reason for V toxicity to terrestrial and aquatic organisms. Although V contributes to high-efficient biological nitrogen fixation as a co-factor, V alters microbial community structures and drives its evolution. V can also accumulate in and harm human bodies. Knowledge gaps and further perspectives in aspects of V risks are thereby proposed, such as more toxic data reports for deriving V environmental quality criteria, elucidating the molecular mechanisms of detoxification and tolerance of organisms to V for bioremediation applications, and exploring the medical potential of V with the prevention of V toxicity to humans. This review advances our understanding of the toxic effects of V in the ecosystem and inspires future efforts on V management as well as application.

Recently, crAssphagehas been proposed as a human-specific marker for tracking fecal contamination. However, its performance has always been validated in a limited number of host samples, which may obscure our understanding of its utility. Furthermore, few studies have quantified confidence of fecal contamination when using crAssphage. Here, we evaluate the performance and confidence of crAssphageby analyzing a large panel of metagenomic data sets combined with Bayesian analyses. Results demonstrate that crAssphageexhibits superior performance with high host sensitivity and specificity, indicating its suitability for tracking human fecal sources. With the marker, a high confidence (>90%) can be obtained and particularly, multiple samples with positive results provide a near certainty of confidence. The application of crAssphagein the sediments of three Chinese urban rivers shows a high confidence of >97% of human fecal contamination, suggesting the serious challenge of sewage pollution in these environments. Additionally, significant correlation is observed between crAssphageand antibiotic resistance genes (ARGs), expanding the utilization of crAssphagefor pollution management of ARGs. This study highlights the benefit of using metagenomic-based analysis for evaluating the performance and confidence of microbial source tracking markers in the coming era of big data with increasing resources in available metagenomic data.

The attapulgite (ATP) is a good adsorbent of heavy metal ion due to its high surface area, low cost and environmental compatibility. But the natural ATP has limited adsorption capacity and selectivity. In this study, a cost-effective and ready-generated adsorbent, FeCl3-modified attapulgite (Fe-ATP), was evaluated to remove uranium ions from simulated wastewater. After preparation, Fe-ATP was characterized by fourier transform infrared spectroscopy (FTIR), scanning electron microscope(SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy(TEM) analysis. The impacts of pH, contact time, ionic strength, temperature and initial U(VI) concentration on the adsorption capacity of Fe-ATP beads were examined. The adsorption kinetics of U(VI) dominated by the pseudo-second order model,and the adsorption isotherms fitted the Freundlich isotherm. The adsorption mechanism involved chemisorption, surface complexation and ions exchange. These results indicate that Fe-ATP bead is a cheap and promising adsorbent for the U(VI) removal and holds potential to be used for radioactive wastewater treatment.

The catalytic performances of different commercial cobalt oxides(CoxOy, i.e., Co2O3, Co3O4, and CoO) for peroxymonosulfate(PMS) activation in dye degradation were compared in this study. The CoO/PMS system exhibited the highest catalytic oxidation performances with more than 96% methylene blue(MB) removal at 90 min. The concentration of dissolved cobalt ions from CoO was 1.474 mg/L at neutral pH and 5.231 mg/L at acidic pH at 90 min which accounted for the high MB removal and CoO activated PMS homogeneously compared to the associated CoSO4/PMS. Co3O4and Co2O3exhibited similar catalytic performances and characteristics. The MB removal in Co3O4/PMS and Co2O3/PMS system were more than 88% at neutral pH and over 64% at acidic pH, respectively, in 90 min. The concentration of dissolved cobalt ions from Co3O4and Co2O3was less than 0.018 mg/L at neutral pH and 0.036 mg/L at acidic pH at 90 min. The MB removal achieved by Co3O4/PMS and Co2O3/PMS were approximately three times higher than that achieved by their associated CoSO4/PMS systems and the heterogeneous catalysis played a principal role in the processes. According to scavenger experiments, the contributions of the hydroxyl radicals in the MB degradation were negligible compared to sulfate radicals in the CoO/PMS system. Hydroxyl radicals contributed one-third or more and sulfate radicals were the dominant oxidizing species in the Co3O4/PMS and Co2O3/PMS systems. CoxOycould also effectively activate PMS to generate free radicals for degradation of other dyes. The dyedegradation processes in Co3O4/PMS, Co2O3/PMS and CoSO4/PMS systems followed pseudo-first-order kinetic model and dye degradation rates in different systems were also compared.

Various colloids are present in the natural groundwater environment, and colloids act on the processes involved when radionuclides leak from a repository in a high-level waste disposal site. This paper investigates the effect of colloidal silicate in natural groundwater environments on the migration behaviour of Sr(II). Three different experimental cases have been designed: (1) effect in the presence of colloidal silicate, (2) effect in the presence of a porous medium, and (3) effect in the presence of both colloidal silicate and porous medium (referred to as CS, PM, and PC, respectively). Batch experiments were used to study the effect of influencing factors on Sr(II) migration behaviour, such as the amount of CS, solid-to-liquid ratio, pH, contact time, and initial concentration of Sr(II). The experiments showed that the effect of PC on the migration behaviour of Sr(II) was greatest, and the presence of CS enhanced the sorption. The colloid amount, pH, and solid-to-liquid ratio significantly affected the migration behaviour. The more the colloids were added, the better the adsorption effect. The optimal pH and solid-to-liquid ratio were 6 and 20 : 1, respectively. The alkaline environment is more conductive to colloid sorption. When the solid-to-liquid ratio was 20 : 1, the sorption percentage of PC is 0.5 times larger than PM. Although the PC has a longer adsorption equilibrium time, the percentage of adsorption can be larger than that in the other two cases. The kinetics and isotherms of Sr(II) were best described by the pseudo-second-order and Langmuir models. It was inferred that strong chemical interactions and/or surface complexation contributed primarily to Sr(II) sorption, and the process was on the monolayer adsorption of the outer surface. These findings provide valuable information for the migration behaviour of strontium in groundwater environments of geological disposal site. At the same time, it provides information for the implementation of permeable reactive barrier technology to control the transport of radioactive Sr(II) and its species in natural surface and groundwater.