This study aimed to assess the pollution levels, sources, and human health risks of heavy metals in street dust from a typical industrial district in Wuhan City, Central China. In total, 47 street dust samples were collected from the major traffic arteries and streets around Wuhan Iron and Steel (Group) Company (WISC) in Qingshan District, Wuhan. The concentrations of heavy metals (Cr, Mn, Ni, Zn, Fe, Cu, and Cd) in street dust were determined by atomic absorption spectroscopy. Results indicated that the mean concentrations of Zn (249.71 mg/kg), Cu (51.15 mg/kg), and Cd (0.86 mg/kg) in street dust were higher than their corresponding soil background values in Hubei Province. Heavy metal enrichment is closely related to urban transportation and industrial production. The pollution level of heavy metals in street dust was assessed using the geo-accumulation method (I_geo) and potential ecological risk assessment (PERI). Based on the I_geo value, Cr, Mn, Fe, and Ni showed no pollution, Zn and Cu showed light to moderate contamination, and Cd showed moderate contamination. The PERI values of heavy metals in street dust ranged between 76.70 and 7027.28, which represents a medium to high potential ecological risk. Principal component analysis showed that the sources of heavy metals in street dust were mainly influenced by anthropogenic activities. Among the studied metals, Cu, Cr, Zn, Fe, and Mn mainly come from industrial processes, while Ni and Cd come from traffic exhaust. The non-carcinogenic risk indexes of heavy metals for children and adults are ranked as Cr > Cu > Ni > Cd > Zn. The health risks to children through the different exposure pathways are higher than those for adults. Hand-to-mouth intake is the riskiest exposure pathway for non-carcinogenic risk. In addition, Cr, Ni, and Cd do not pose a carcinogenic risk for the residents.

In order to study the pollution characteristics, sources, and health risks of heavy metals in urban atmospheric PM_2.5, samples were collected in Huangshi City from June 2021 to May 2022. The contents of 16 kinds of metal elements were analyzed by XRF, and the pollution degree and sources of elements were analyzed by the enrichment factor method, correlation analysis, and cluster analysis. The health risk of heavy metal elements was evaluated by the USEPA health risk assessment model. The results of enrichment factor analysis show that the metal elements carried by PM_2.5 were affected by human emissions except for Ti. Heavy metals mainly come from industrial sources, motor vehicle sources, mixed combustion sources, and dust sources, according to correlation analysis and cluster analysis. Mn had a non-carcinogenic risk to children, and the non-carcinogenic risk of other elements to the human body was generally acceptable. The carcinogenic risks of Cr, As, Cd, and Co exceeded the acceptable carcinogenic risk threshold (10⁻⁶ ~10⁻⁴), and there were potential carcinogenic risks.

In this study, the zero-valent iron Fenton reagent (ZVI Fenton-like) system was combined with the chemical precipitation method for the deep treatment of desulfurization wastewater from coal-fired power plants, and the chemical oxygen demand (COD) was used as the evaluation criterion for organic matter in the desulfurization wastewater. The effects of reaction time, H₂O₂ dosage, zero-valent iron dosage, pH, and reaction temperature were also investigated. The results showed that the COD concentration of the effluent was the lowest when the running time of the ZVI Fenton-like reagent system was 1 h, the dosage of H₂O₂ was 33.3 mg·L⁻¹, the dosage of iron was 0.075 g·L⁻¹, the pH was 4.5~6.5, the reaction temperature was 35 °C, the COD concentration of the wastewater was the lowest and its operating conditions were the best, and the internal reaction mechanism was finally deduced. In summary, the zero-valent iron Fenton reagent system provides a new idea for the treatment of desulfurization wastewater from coal-fired power plants.

An innovative composite adsorbent from bamboo biochar was successfully synthesized by dual-modification of Fenton oxidation and surface generation of α-FeOOH and exhibited highly efficient Cu( ii ) adsorption.