Assessment of dermal absorption of beryllium and copper contained in temple tips of eyeglasses

Theoretical study of the adsorption capacity of potentially toxic Cd2+, Pb2+, and Hg2+ ions in hemicellulose matrices

Hemicellulose is widely available in nature, is a sustainable resource and has a wide range of applications. Among them, adsorption stands out for the removal of potentially toxic ions. Thus, in the study, the adsorption of Cd2+, Pb2+ and Hg2+ ions in two hemicellulose matrices were elucidated through computational simulations using density functional theory. Molecular electrostatic potential and frontier molecular orbitals demonstrated whether the interactions could happen. Four interaction complexes were highlighted due to the interaction energy criteria, ΔEBind, ΔH and ΔG < 0.00 kcal mol-1, that is: Hm1… Pb (1); Hm2… Pb (3); Hm2…Cd (4) and Hm2…Hg (4) and the results show that they occur through physisorption. In structural parameter studies, interaction distances smaller than 3000 Å were identified, which ranged from 2.253 Å to 2.972 Å. From the analysis of the topological parameters of QTAIM, it was possible to characterize the intensities of the interactions, as well as their nature, which were partially covalent or electrostatic in nature. Finally, based on the theoretical results, it can be affirmed that the hemicellulose can interact with Cd2+, Pb2+ and Hg2+ ions, evidencing that this study can support further experimental essays to remove contaminants from effluents.

Heavy metals in influent and effluent from 146 drinking water treatment plants across China: Occurrence, explanatory factors, probabilistic health risk, and removal efficiency

Heavy metals (HMs) in drinking water have drawn worldwide attention due to their risks to public health; however, a systematic assessment of the occurrence of HMs in drinking water treatment plants (DWTPs) at a large geographical scale across China and the removal efficiency, human health risks, and the correlation with environmental factors have yet to be established. Therefore, this study characterised the occurrence patterns of nine conventional dissolved HMs in the influent and effluent water samples from 146 typical DWTPs in seven major river basins across China (which consist of the Yangtze River, the Yellow River, the Songhua River, the Pearl River, the Huaihe River, the Liaohe River and the Haihe River) for the first time and removal efficiency, probabilistic health risks, and the correlation with water quality. According to the findings, a total of eight HMs (beryllium (Be), antimony (Sb), barium (Ba), molybdenum (Mo), nickel (Ni), vanadium (V), cobalt (Co) and titanium (Ti)) were detected, with detection frequencies in influent and effluent water ranging from 2.90 (Mo) to 99.30% (Ba) and 1.40 (Ti) to 97.90% (Ba), respectively. The average concentration range was 0.41 (Be)- 77.36 (Sb) μg/L. Among them, Sb (exceeding standard rate 8%), Ba (2.89%), Ni (21.43%), and V (1.33%) were exceeded the national standard (GB5749-2022). By combining Spearman's results and redundancy analysis, our results revealed a close correlation among pH, turbidity (TURB), potassium permanganate index (COD_Mn), and total nitrogen (TN) along with the concentration and composition of HMs. In addition, the concentration of HMs in finished water was strongly affected by the concentration of HMs in raw water, as evidenced by the fact that HMs in surface water poses a risk to the quality of finished water. Metal concentration was the primary factor in assessing the health risk of a single metal, and the carcinogenic risk of Ba, Mo, Ni, and Sb should be paid attention to. In DWTPs, the removal efficiencies of various HMs also vary greatly, with an average removal rate ranging from 16.30% to 95.64%. In summary, our findings provide insights into the water quality and health risks caused by HMs in drinking water.