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Current human health risk assessments of soil arsenic (As) contamination rarely consider bioaccessibility (IVBA), which may overestimate the health risks of soil As. The IVBA of As (As-IVBA) may differ among various soil types. This investigation of As-IVBA focused As from geological origin in a typical subtropical soil, lateritic red soil, and its risk control values. The study used the SBRC gastric phase in vitro digestion method and As speciation sequential extraction based upon phosphorus speciation extraction method. Two construction land sites (CH and HD sites) in the Pearl River Delta region were surveyed. The results revealed a high content of residual As (including scorodite, mansfieldite, orpiment, realgar, and aluminum arsenite) in the lateritic red soils at both sites (CH: 84.9%, HD: 91.7%). The content of adsorbed aluminum arsenate (CH: 3.24%, HD: 0.228%), adsorbed ferrum arsenate (CH: 8.55%, HD: 5.01%), and calcium arsenate (CH: 7.33%, HD: 3.01%) were found to be low. The bioaccessible As content was significantly positively correlated with the As content in adsorbed aluminum arsenate, adsorbed ferrum arsenate, and calcium arsenate. A small portion of these sequential extractable As speciation could be absorbed by the human body (CH: 14.9%, HD: 3.16%), posing a certain health risk. Adsorbed aluminum arsenate had the highest IVBA, followed by calcium arsenate, and adsorbed ferrum arsenate had the lowest IVBA. The aforementioned speciation characteristics of As from geological origin in lateritic red soil contributed to its lower IVBA compared to other soils. The oxidation state of As did not significantly affect As-IVBA. Based on As-IVBA, the carcinogenic and non-carcinogenic risks of soil As in the CH and HD sites decreased greatly in human health risk assessment. The results suggest that As-IVBA in lateritic red soil should be considered when assessing human health risks on construction land. [Display omitted] • In lateritic red soil, As from geological origin has low bioaccessibility. • SBET can mainly extract the adsorbed arsenate on Al, Fe and Ca arsenate. • The bioaccessibility of soil As is not related to its oxidation state. • The occurrence of As in Lateritic red soil is dominated by low solubility minerals. • Soil remediation target values can be significantly promoted based on As-IVBA. [ABSTRACT FROM AUTHOR]

Di-(2-ethylhexyl) phthalate (DEHP) is one of the most extensively utilized plasticizers in the plastic manufacturing process. It is widely used in various fields due to its low cost and excellent effect. Although there is evidence that DEHP is harmful to animal and human health, DEHP-induced gill toxicity in aquatic organisms is inconclusive, and its mechanism has not been fully elucidated. Here, we investigated the effects of DEHP acute exposure on crucian carp gills at environmentally relevant concentrations of 20, 100, and 500 μg/L. Multi-omics profiling and biochemical assays were employed to characterize the potential toxicological mechanisms. The results showed that acute exposure to 100 and 500 μg/L of DEHP leads to oxidative stress in gills, as evidenced by overproduction of reactive oxygen species (ROS), increased antioxidant enzyme activity, and the transformation of glutathione from reduced to oxidized form, resulting in lipid peroxidation. Integrative analysis of transcriptomics and metabolomics indicated that increased purine metabolism was the potential source of increased ROS. Moreover, lipid metabolism disorder, including arachidonic acid metabolism, induces inflammation. Further, DEHP causes the imbalance of the CYP enzyme system in the gill, and DEHP-induced gill toxicity in crucian carp was associated with interference with CYP450 homeostasis. Taken together, this study broadens the molecular understanding of the DEHP-induced gill toxicity in aquatic organisms and provides novel perspectives for assessing the effects of DEHP on target and non-target aquatic organisms in the environment. [Display omitted] • DEHP activates protective responses in the antioxidant system of the gill. • ROS overproduction is related to the increase of purine metabolism. • Dysregulation of lipid metabolism contributes to increased pro-inflammatory effects. • DEHP-induced gill toxicity is associated with disrupting the CYP450 homeostasis. [ABSTRACT FROM AUTHOR]

Hydrothermal carbonization (HTC) can improve biomass quality in both physical and chemical aspects for energy application. This study aims to investigate the characteristics and reactivities of rape straw (RS) hydrochars. Hydrochars were prepared at 160–240 °C with residence time of 15–120 min. Mass yield, energy yield, microstructure, functional group and migration of alkali and alkaline earth metals (AAEMs) were studied to evaluate the influence of different conditions on properties of hydrochar. The results showed that O/C and H/C ratio decreased, while the higher heating value (HHV) increased with increasing temperature and residence time. The effect of increasing temperature on hydrochar properties was more significant than residence time. The structure was changed, and hydrochar possessed a more stable form after the aromatization reaction. For the gasification reactivity of hydrochar, decomposition rate curves showed that the peak of pyrolysis and gasification moved to a higher temperature region with the increasing of HTC temperature because of the developed aromatic structures in hydrochar. The pyrolysis activation energy decreased from raw RS 71.68 to 41.03 kJ/mol in 240 °C, while gasification activation energy increased from 80.42 to 251.30 kJ/mol. Moreover, it was found that HTC can reduce the content of AAEMs efficiently and the best removal condition is 200 °C. Ca content dropped to a minimum value at 200 °C and then increased at higher temperature which may be caused by well-developed pore structure in hydrochars. This study provides basic data for comprehensive utilization of rape straw and migration mechanism of AAEMs in HTC process. [Display omitted] • The effects of HTC on RS structure and reactivity were quantitatively studied. • Temperature effect was more obvious than residence time during HTC. • Effects of HTC on kinetics of pyrolysis and gasification were studied separately. • Energy yield reached max at 180 °C, while AAEMs reached minimum at 200 °C. • The migration behavior of total and active AAEMs is studied. [ABSTRACT FROM AUTHOR]