Journal of Environmental Science and Health Part A-toxic\/hazardous Substances & Environmental Engineering最新文献

The present work deals with the optimization of basic fuchsin dye removal from an aqueous solution using the ultraviolet UV/H₂O₂ process. Response Surface Modeling (RSM) based on Box-Behnken experimental design (BBD) was applied as a tool for the optimization of operating conditions such as initial dye concentration (10-50 ppm), hydrogen peroxide dosage (H₂O₂) (10-20 mM/L) and irradiation time (60-180 min), at pH = 7.4 under ultra-violet irradiation (254 nm and 25 W intensity). Chemical oxygen demand (COD abatement) was used as a response variable. The Box-Behnken Design can be employed to develop a mathematical model for predicting UV/H₂O₂ performance for COD abatement. COD abatement is sensitive to the concentration of hydrogen peroxide and irradiation time. Statistical analyses indicate a high correlation between observed and predicted values (R² > 0.98). In the BBD predictions, the optimal conditions in the UV/H₂O₂ process for removing 99.3% of COD were found to be low levels of pollutant concentration (10 ppm), a high concentration of hydrogen peroxide dosage (20 mM/L), and an irradiation time of 80 min.

In recent years, there has been a growing focus on the issue of exposure to hazardous chemical compounds and the potential health risks associated with them. Fuel stations play a critical role in society, supporting the transportation industry and serving the general public. However, the routine activities at these stations expose workers and customers to dangerous chemical compounds, posing potential health risks. As part of a pilot study, the exposure of workers and customers to hazardous chemical compounds at fuel stations in Kuwait, characterized by its hot and arid environment, was investigated. The study specifically looked at volatile organic compounds (VOC) concentration and their effects on human health. Three hundred-eight air samples were collected in a hot, arid environment, focusing on fuel stations. Two sampling methods were used in this pilot study: personal inhalation exposure using active sampling and workplace air sampling using passive sampling. Samples were collected in fuel filling areas, indoor control rooms, and through personal exposures, adhering to ISO procedures (EPA TO-17). The study also assessed the non-carcinogenic and carcinogenic risks to human health to potential exposure to hazardous hazardous chemicals. The findings revealed that hazardous chemicals levels in the pump area were lower than those in the indoor control rooms. Workers' inhalation exposure to hazardous chemicals remained below the international occupational exposure limit (OEL). However, the study identified unsafe inhalation exposure levels to Benzene, which could have adverse carcinogenic effects. In contrast, exposure to ethylbenzene was found to be within safe limits, with no associated carcinogenic effects. This study underscores the importance of identifying the risks associated with exposure to hazardous chemical compounds to minimize human health risks and promote a safe working environment.

The effect of temperature on the solubility of lead-bearing solid phases in water distribution systems for different water chemistry conditions remains unclear although lead concentrations are known to vary seasonally. The study objective is to explore the effect of temperature on the solubility of the lead(II) carbonate hydrocerussite under varying pH and DIC conditions. This is achieved through batch dissolution experiments conducted at multiple pHs (6-10) and DIC concentrations (20-200 mg CL^-1) at temperatures ranging from 5 to 40 °C. A thermodynamic model was also applied to evaluate the model's ability to predict temperature effects on lead(II) carbonate solubility including solid phase transformations. In general, increasing temperature increased total dissolved lead at high pHs and the effect of temperature was greater for high DIC conditions, particularly for pH > 8. Temperature also influenced the pH at which the dominant lead(II) solid phase switched from hydrocerussite to cerussite (occurred between pH 7.25 to 10). Finally, the model was able to capture the overall trends observed despite thermodynamic data limitations. While this study focuses on a simple lead solid-aqueous system, findings provide important insights regarding the way in which temperature and water chemistry interact to affect lead concentrations.

PM_2.5 is an important risk factor for the development and progression of cognitive impairment-related diseases. Ferroptosis, a new form of cell death driven by iron overload and lipid peroxidation, is proposed to have significant implications. To verify the possible role of ferroptosis in PM_2.5-induced neurotoxicity, we investigated the cytotoxicity, intracellular iron content, iron metabolism-related genes, oxidative stress indices and indicators involving in Nrf2 and ferroptosis signaling pathways. Neurotoxicity biomarkers as well as the ferroptotic cell morphological changes were determined by Western Blot and TEM analysis. Our results revealed that PM_2.5 induced cytotoxicity, lipid peroxidation, as indicated by MDA content, and neurotoxicity via Aβ deposition in a dose-related manner. Decreased cell viability and excessive iron accumulation in HT-22 cells can be partially blocked by ferroptosis inhibitors. Interestingly, GPX activity, Nrf2, and its regulated ferroptotic-related proteins (i.e. GPX4 and HO-1) were significantly up-regulated by PM_2.5. Moreover, gene expression of DMT1, TfR1, IRP2 and FPN1 involved in iron homeostasis and NCOA4-dependent ferritinophagy were activated after PM_2.5 exposure. The results demonstrated that PM_2.5 triggered ferritinophagy-dependent ferroptotic cell death due to iron overload and redox imbalance. Activation of Nrf2 signaling pathways may confer a protective mechanism for PM_2.5-induced oxidative stress and ferroptosis.

The effect of coagulant dosage in a chemically enhanced primary treatment (CEPT) on the performance of a conventional wastewater treatment plant (WWTP) has been investigated. Lab-scale experiments simulations were carried out in order to evaluate the effect of coagulant addition on the primary settling performance. In these experiments, FeCl₃ was used as coagulant. Later, the WWTP was theoretically simulated using a commercial software (WEST®) to evaluate the effect of coagulation/flocculation on the global system, based on the results obtained at lab-scale. According to these results, the CEPT modifies the organic matter balance in the WWTP, decreasing the contribution of readily (S_S) and slowly (X_S) biodegradable fractions of COD to the aerobic biological process up to 27.3% and 80.8%, respectively, for a dosage of FeCl₃ of 24 mg L^-1. Consequently, total suspended solids in the aerobic reactor and the secondary purged sludge decreased up to 33% and 13%, respectively. However, the influence on effluent quality was negligible. On the contrary, suspended solids concentration in the sludge to be treated by anaerobic digestion increased, mainly regarding the S_s and X_s fractions, which caused an 8.1% increase in biogas production potential, with approximately 60% of CH₄ concentration.

This study aimed to evaluate heavy metals concentrations in soils and vegetables (cabbage, lettuce, and cassava) cultivated at Matola and Beluluane Industrial Parks, and to assess health risks linked to their consumption through estimated daily intake, hazard index (HI), and incremental lifetime cancer risk. Concentrations of Al, As, Co, Cd, Cr, Ni, Pb, and Zn were determined in the two sites. Soil concentrations of As at Beluluane site and As, Cd, and Cr at Matola site exceeded reference limits of the Food and Agriculture Organization/World Health Organization, showing heavy metal contamination. At Beluluane site, all studied vegetables presented As and Pb levels higher than reference limits, Cd concentrations were higher than the reference limit in cabbage, lettuce, and cassava leaves. At Matola site crops concentrations of As, Cd, Cr, and Pb exceeded the reference limits. Zinc exceeded the reference limit in all crops except in cabbage. HIs for vegetables from Beluluane exceeded 1.0 in cabbage (2.66), lettuce (2.27), and cassava leaves (2.37). Likewise, at Matola, HIs exceeded 1.0 in lettuce (1.67), cassava leaves (1.65), and root tubers (13). We found that vegetables cultivated in industrial parks present high carcinogenic risk due to heavy metal contamination, rendering them unsuitable for human consumption.

In this study, the average values of vertical velocity of particles emitted from an aluminum smelter in the surface layer of the atmosphere were estimated using a semi-empirical method. The method is based on regression analysis of the horizontal profile of pollutants measured along the selected direction using moss bioindicators. The selection of epiphytic mosses Sanionia uncinata was carried out in 2013 in the zone of influence of a metallurgical industry enterprise in the city of Kandalaksha, Murmansk region. The concentrations of As, Si, Ni, Zn, Ti, Cd, Na, Pb, Co, K, Ba, Ca, Mg, Mn, Sr, Fe, Al, V, Cr, Cu were determined using atomic emission spectrometry. The conducted assessments showed that the average particle velocity toward the Earth's surface, when considering large spatial and temporal scales, is tens of times higher than gravitational settling velocities.

Fine particulate matters-PM_2.5 in the air can have considerable negative effects on human health and the environment. Various human cell-based studies examined the effect of PM_2.5 on human health in different cities of the world using various chemical parameters. Unfortunately, limited information is available regarding the relationship between toxicity and chemical characteristics of PM_2.5 collected in Istanbul, Türkiye, located in one of the most populated cities in the world. To investigate the chemical characteristics and cytotoxicity of PM_2.5 in Istanbul, samples were collected for 12 months, then potentially toxic metals, oxidative potential, and particle indicators (e.g., functional groups and elements) were determined, and the cytotoxicity of PM_2.5 on human A549 lung alveolar epithelial cells was examined. The mean PM_2.5 mass concentration was 24.0 ± 17.4 µg m^-3 and higher in cold months compared to other seasons. Moreover, the results of the metals, elemental, and functional groups indicated that seasonal and monthly characteristics were influenced by the regional anthropogenic sources and photochemistry input. The cytotoxicity results also showed that the viability of A549 cells was reduced with the exposure of PM_2.5 (30-53%) and higher cytotoxicity was obtained in summer compared to the other seasons due to the impact of the metals, elements, and oxidative characteristics of PM_2.5.

Perceptron models have become integral tools for pattern recognition and classification problems in engineering fields. This study envisioned implementing artificial neural networks to forecast the performance of a mini-spray dryer for desulfurization activities. This work adopted k-fold cross-validation, a rigorous technique that evaluates model performance across multiple data segments. Several ANN models (21) were trained on data obtained from sulfation conditions, including sulfation temperature (120 °C-200 °C), slurry pH (4-12), stoichiometric ratio (0.5-2.5), slurry solid concentration (6%-14%) as the feed input and sulfur capture as the response. Three hundred synthetic datasets generated using the Gaussian noise data augmentation underwent a 10-fold cross-validation process before simulation on neural networks triggered by the logsig and tansig activation functions. The computation accuracy was further evaluated by altering the number of hidden cells from 2 to 10. The ANN architectures were assessed using statistical metrics such as mean square error (MSE), root mean square error (RMSE), mean absolute percentage error (MAPE), and the coefficient of determination (R²) techniques. Overall, error estimation suggests cross-validation and data augmentation are critical in efficient neural network generalization. The logsig function trained with 10 hidden cells presented closer data articulation when mapped onto actual values.