Search

The combined exposure to environmental pollutants can result in unanticipated adverse effects on human health, and how to compare and assess these effects has always been a matter of great concern for the international community. Currently, several prevalent methods for assessing combined exposure risks in the field of human health risk assessment primarily encompass the hazard index (HI) method, the point of departure index (PODI) method, the margin of exposure (MOE) method, and the relative potency factor (RPF) method. The review summarizes the application of these methods to the cumulative risk assessment of combined exposure to the same class of chemicals with the same toxic mechanism, primarily focusing on pesticides such as organophosphorus pesticides, pyrethroids, carbamates, and neonicotinoids, as well as typical compounds intimately related to human production and life, including organophosphorus flame retardants, per- and poly-fluoroalkyl substances, and bisphenols. Furthermore, progress in the application of physiologically based pharmacokinetics models to human health risk assessment has been introduced, which might provide more options for risk assessment of combined exposure to multiple chemicals, and help to provide insights for further exploration and establishment of more systematic and scientific approaches to human health risk assessment.

BACKGROUND Selenium (Se) is one of the essential trace elements for humans, and an important way for humans to obtain and supplement selenium is by eating natural selenium-enriched agricultural products. The geochemical characteristics of selenium in the survey area are an important basis for the effective utilization of selenium-enriched land resources and the development of selenium-enriched agricultural and sideline products. OBJECTIVES To investigate the geochemical characteristics of selenium content, distribution and influence factors in the study area. METHODS Soil and crop samples were collected from a central village of Zhaojue County, Sichuan Province. AFS, XRF and ICP-MS were used to determine the contents of elements including Se, Al2O3, TFe2O3, SiO2, OrgC, and pH values. Geochemical characteristics of selenium content, distribution and influencing factors in the study area were investigated using statistical and correlation analysis. RESULTS (1) The soil selenium content in the study area ranged from 0.04 to 1.50mg/kg, with an average value of 0.33mg/kg. The delineated selenium-enriched soil area was 7.23km2, accounting for 30.31% of the total soil area. The selenium content of the soil developed in basalt was the highest, with an average of 0.4mg/kg, indicating that the geological background in the area was closely related to the soil selenium content. The Se-enriched soil in the area was mainly controlled by the Emeishan basalt Formation, which contained basalt intercalating with picrite and tuffaceous sand and mudstone. (2) The enrichment capacity of selenium varied in different land utilization and soil types. The absorption capacity of selenium in soil decreased due to human agricultural activities. Clayey particles or iron oxides in the yellow-brown loam layer were easy to combine and enrich selenium. The selenium content in acidic soil was inversely correlated to pH value. There was a significant positive correlation between soil organic matter and selenium content. Soil texture had a certain effect on selenium content. (3) Corn and potatoes from selenium-enriched soils had very low selenium content. CONCLUSIONS During the exploitation and utilization of selenium-enriched soil, organic fertilizer should be added in time and soil pH should be adjusted in agricultural areas such as dry land and paddy field, and other agricultural products should be developed by using selenium-enriched resources.

Wastewater containing phenolic organic compounds, such as phenol, produced during industrial manufacturing processes, poses a significant threat to aquatic ecosystems and crops. Photocatalytic technology is considered the most promising approach to water treatment due to its efficiency and eco-friendly advantages. Compared to other photocatalysts, Bi-based oxides are more efficient due to their unique layered structure, which allows for photocatalytic reactions to occur between layers. This review introduces the synthesis methods of various bismuth-based multi-element oxides and their efficiency in the photocatalytic decomposition of phenol. The effects of elemental doping, defect introduction, and heterojunction construction on the catalytic performance and structure of Bi-based oxides are discussed. The mechanisms for the photocatalytic degradation of phenol over different materials are also summarized and discussed. [ABSTRACT FROM AUTHOR]

We report the magnetic and optical properties of Fe2(HPO3)3 ⋅ 4H2O. By combined magnetic susceptibility and specific heat measurements, we find two antiferromagnetic (AFM) transitions (TN1=9 K, TN2=5 K) which originate from the AFM exchange interactions mediated by the (HPO3)2− anions. Compared with the non‐hydrated compound Fe2(HPO3)3, the magnetic interaction strength and ordering temperature of Fe2(HPO3)3 ⋅ 4H2O are both reduced by a factor of ~2. Through density functional theory (DFT) analysis we find almost degenerate AFM states in Fe2(HPO3)3 ⋅ 4H2O which are close in energy. The competition of these AFM states might lead to the two successive AFM phase transitions at low temperature. The low ordering temperature as well as competing AFM states both imply frustrated magnetism in Fe2(HPO3)3 ⋅ 4H2O, probably originating from the complex competing AFM interactions. The optical properties of Fe2(HPO3)3 ⋅ 4H2O are also investigated by photoluminescence and infrared spectroscopies. [ABSTRACT FROM AUTHOR]

The hydrogenation of CO2 to free formic acid is not only one of the most effective measures to make waste profitable, but also a significant and promising method for the hydrogen storage. Herein, we firstly achieved the hydrogenation of CO2 to free formic acid at room temperature over Pd/MgAl‐LDH and the TON of free HCOOH could reach 116. The Ni dopant could further improve the performance of the catalyst and the TON could increase to 134 over PdNi/MgAl‐LDH, which results from more electronic‐rich Pd centre. It was also found that the chemical composition of LDH could affect the catalytic performance due to different alkalinity. [ABSTRACT FROM AUTHOR]