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Potentially toxic elements (PTEs) in manganese ore areas are prevalent in rainwater runoff and pose a major threat to human health. In this study, field investigation and geostatistical analysis methods of positive matrix factorization (PMF) and geographic information systems (GIS) were used to systematically study the pollution in rainwater runoff from a manganese mining area in Xiangtan, China, to evaluate source contributions for the health risk assessment of PTEs. The average concentrations (mg/L) of six PTEs were: 0.3357 (Mn), 0.0450 (Ni), 0.0106 (Cu), 0.0148 (Zn), 0.0068 (Cd) and 0.0390 (Pb). The coefficients of variation (CV) for Mn and Zn were >180% and >130%, with the other analytes having values below 70%. The GIS and PMF analysis produced more refined spatial source apportionments, including mining, smelting, transportation, agricultural production and natural sources. The results of the health risk assessment showed that the non-carcinogenic risk was negligible, and the carcinogenic risk was potentially dangerous but acceptable for both adults and children. In addition, the children's total carcinogenic risk value was greater than that of adults, highlighting their vulnerability. This study demonstrates the potential of PMF to provide a framework to spatially prioritize treatment objectives within the mining region to improve environmental conditions. HIGHLIGHTS Mn is the most serious contaminating element in rainwater runoff.; PMF was used to analyze five sources of PTEs in rainwater runoff.; These present no health risks in the region.;

Antimony (Sb) and its compounds are considered as global priority pollutants. Elevated concentrations of antimony in natural and industrial process wastewater are of global concern, particularly given interest in the potential toxicity and harm to the environment from aquatic exposure. Iron-based materials for treatment by adsorption are widely regarded to have potential merit for the removal of trace contaminants from water and especially in the search for efficient and low-cost techniques. In this paper, we review the application of iron-based materials in the sorption treatment of antimony contaminated water. The interaction of Sb is discussed in relation to adsorption performance, influencing factors, mechanism, modelling of adsorption (isotherm, kinetic and thermodynamic models), advantages, drawbacks and the recent achievements in the field. Although iron-based adsorbents show promise, the following three aspects are in need of further study. Firstly, a select number of iron based binary metal oxide adsorbents should be further explored as they show superior performance compared to other systems. Secondly, the possibility of redox reactions and conversion between Sb(III) and Sb(V) during the adsorption process is unclear and requires further investigation. Thirdly, in order to achieve optimized control of preferential adsorption sites and functional groups, the mechanism of antimony removal has to be qualitatively and quantitatively resolved by combining the advantages of advanced characterization techniques such as Fourier transform infrared spectroscopy(FTIR), X-ray photoelectron spectroscopy (XPS), Atomic force microscope(AFM), X-ray absorption near edge structure(XANES), and other spectroscopic methods. We provide details on the achievements and limitations of each of these stages and point to the need for further research.

In this study, adsorption behaviors and mechanisms of Sb(III) ions onto Fe(III)-treated humus sludge adsorbent (FTHSA) from aqueous solutions was investigated using batch adsorption techniques, Fourier transform infrared (FT-IR) spectra and scanning electron microscopy were coupled to an energy-dispersive spectrometer (EDS). FTHSA was prepared via immersion with 1 mol/L FeCl3. The effects of dosage, contact time, Sb(III) initial concentration, and pH on the adsorption of Sb(III) onto FTHSA were investigated. Sb(III) adsorption was favored at pH with 2.0 and decreased dramatically with increasing pH. The description of equilibrium data of Sb(III) adsorption by Langmuir, Freundlich, and Dubbin-Radushkevich isotherm models showed that Langmuir model provided the best fit for Sb(III) adsorption with maximum adsorption amount of 9.433 mg/g. Pseudo first-order, pseudo second-order, Elovich, and intraparticle diffusion model were applied to describe the adsorption process of Sb(III) ions onto FTHSA. The results showed that the pseudo second-order model described well how Sb(III) adsorption and chemical adsorption played a dominant role in the adsorption process. The FT-IR spectra also indicated that the chemical interactions as ion exchange among the metal ions and N-H, O-H, C=O, COO, and C-O were mainly involved in the adsorption process. Therefore, FTHSA has a suitable potential removal for Sb(III) ions in the practical process. [ABSTRACT FROM AUTHOR]