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

The CMCs are viable materials for applications in industry and process innovation for removing heavy metal ions since they may be used in static and dynamic adsorption processes. It is necessary to develop simple, low-cost water treatment methods that use organic, biodegradable polymers such as nanomaterial-modified cellulose microcrystals. The column technique was used to investigate the effects of operational parameters such as pH, bed depth, concentration and flow rate. The input concentrations of 20, 40, 80 and 120 mg L^-1, feed flow rates of 5, 10, 15 and 20 mL min^-1, and bed heights of 5, 7.5, 10 and 12.5 cm. Experimental findings showed that the adsorption capacity decreased with increasing flow rate and increased with bed depth and input concentration, which were among the breakthrough parameters evaluated. The optimum adsorption capacity of 258.09 ± 0.96 mg g^-1 was found to be achieved with an ideal pH of 6, an initial concentration of 200 mg L^-1, a contact period of 300 min, and a dosage of 5 g/200 mL. The Langmuir model best fits the adsorption of indigo carmine, whereas the pseudo-second-order model, which governs the adsorption mechanism, may be described by physisorption combined with chemisorption. From a thermodynamic perspective, the adsorption was exothermic and spontaneous. In continuous adsorption, the Yoon-Nelson and Thomas models provided a good match for the hole curve, whereas the Bohart-Adams model fitted the breakthrough curve's initial portion ((C_t/C₀) <0.5) perfectly. A three-dimensional adsorbent that has been chemically modified. The chemically modified CMCs adsorbent was characterized using FTIR, SEM and TGA.

Water treatment plants (WTPs) produce thousands of tons of sludge annually, which is destined for landfill disposal, an environmentally and economically impractical alternative. Chemical, mineralogical, and morphological characterization besides environmental classification has been performed for WTP sludge and it was evaluated application potential in building materials, from a literature review. The characterization was carried out by X-ray fluorescence spectrometry, X-ray diffraction, scanning electron microscopy analysis, and leaching and solubilization tests. The results show that the presence of activated charcoal residues from water treatment in one type of sludge was of little relevance for changes in the properties of the waste. Both sludges have a wide range of particle sizes, consisting mainly of silica, aluminum and iron oxides, as well as kaolinite, quartz, and iron minerals. Special attention must be paid to the solubilization of metallic contaminants to avoid contamination risks and order to make the application safer and more effective, it is necessary to study deeply ways to inert the WTP sludge. The sludges studied have a high potential for application in ceramic products, mortars, geopolymers and concrete paving stones. Depending on the type of building material, different contents of sludge in natural or calcined state can be incorporated.

Artemia is a brine shrimp genus adapted to extreme habitats like ranges salinity from 5-25 g/L and in temperatures from 9 to 35 °C. It is widely distributed and used as an environmental quality biomarker. Artemia franciscana and Artemia salina species are commonly used in ecotoxicological studies and genotoxicity assays due to their short life cycle, high fecundity rate, easy culture, and availability. Thus, considering the importance of these tests in ecotoxicological studies, the present study aimed to present Artemia genus as a biological model in genotoxicity research. To this end, we reviewed the literature, analyzing data published until July 2023 in the Web of Science, SCOPUS, Embase, and PubMed databases. After screening, we selected 34 studies in which the genotoxicity of Artemia for various substances. This review presents the variability of the experimental planning of assays and biomarkers in genotoxicity using Artemia genus as a biological model for ecotoxicological studies and show the possibility of monitoring biochemical alterations and genetic damage effects. Also highlight innovative technologies such as transcriptomic and metabolomic analysis, as well as studies over successive generations to identify changes in DNA and consequently in gene expression.

In this study, humic acid was used as a model pollutant to investigate the removal effect of a macroporous weakly alkaline anion exchange resin D301 on natural organic matter (NOM) in water. 3D fluorescence spectroscopy, UV - visible spectrophotometry and Fourier transform infrared (FTIR) spectroscopy were employed to analyze changes in the physical and chemical properties of humic acid solution and natural water samples before and after resin adsorption. The results showed that using humic acid as a model pollutant to simulate NOM in water is feasible. Through kinetic and thermodynamic analysis, ion exchange was identified as the dominant mechanism for the adsorption of organic matter by D301 resin. According to the Langmuir adsorption isotherm, the maximum adsorption capacity of the resin was 37.78 mg/g. The adsorption of NOM by the exchange resin effectively conformed to the Thomas, Yoon - Nelson, and BDST models, offering a reliable basis for practical application prediction. Using sodium chloride solution as the regeneration solution for D301 resin column, after several regenerations, the adsorption efficiency of the resin did not change significantly, which indicated that the anion - exchange resin can be used as an efficient and reusable adsorbent for the removal of NOM from water.

This paper presents the design and application of a portable multi-electrode cold plasma corona discharge system for pollutant degradation in wastewater. The system generated stable plasma without a dielectric barrier, producing active species such as hydroxyl radicals, hydrogen peroxide, nitrite, and nitrate. The experimental results presented a pollutant degradation efficiency of 100%, reducing methylene blue as a model pollutant from 6 ppm to 0 ppm within 125 s at an optimized electrode distance of 0.20 cm. This optimization minimizes the risks associated with the arcing and self-collision of plasma streams while sustaining continuous plasma discharge, ensuring the maximum breakdown voltage and high ion density for efficient plasma production. The system further demonstrated its application in treating hand washing as a target pollutant to reduce the risk of infection during the COVID-19 pandemic. A comparative analysis highlighted the advantages of the system in terms of rapid treatment, energy efficiency, and low-cost operation. The processed water met the World Health Organization (WHO) wastewater discharge standards and WHO guidelines for virus elimination, with residual nitrogen compounds maintained below 50 ppm and hydrogen peroxide levels kept under 5,000 ppm, confirming the effectiveness of the system in pathogen reduction and wastewater purification.

Large volumes of wastewater are generated during petroleum refining processes. Petroleum refinery wastewater (PRW) can contain highly toxic compounds that can harm the environment. These toxic compounds can be a challenge in biological treatment technologies due to the effects of these compounds on microorganisms. These challenges can be overcome by using ozone (O₃) as a standalone or as a pretreatment to the biological treatment. Ozone was used in this study to degrade the organic pollutants in the heavily contaminated PRW from a refinery in Mpumalanga province of South Africa. The objective was achieved by treating the raw PRW using ozone at different ozone treatment times (15, 30, 45, and 60 min) at a fixed ozone concentration of 3.53 mg/dm³. The ozone treatment was carried out in a 2-liter custom-designed plexiglass cylindrical reactor. Ozone was generated from an Eco-Lab-24 corona discharge ozone generator using clean, dry air from the Afrox air cylinder as feed. The chemical oxygen demand, gas chromatograph characterization, and pH analysis were performed on the pretreated and post-treated PRW samples to ascertain the impact of the ozone treatment. The ozone treatment was effective in reducing the benzene, toluene, ethylbenzene, and xylenes (BTEX) compounds in the PRW. The 60-min ozone treatment of different BTEX pollutants in the PRW resulted in the following percentage reduction: benzene 95%, toluene 77%, m + p-xylene 70%, ethylbenzene 69%, and o-xylene 65%. This study has shown the success of using ozone in reducing the toxic BTEX compounds in a heavily contaminated PRW.

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.

Environmental pollution results in serious health hazards to animals, reflected in biogenic and risk element concentrations in animal tissues. The objective of this study was to examinate concentration of selected elements in testes, and epididymal spermatozoa motility of wild boars. Wild boars were hunted in region Žuhračka - Levice, Slovak Republic. Testes were removed postmortem, spermatozoa were collected from cauda epididymis and assessed by CASA system. Elements concentrations were measured by ICP and by CV-AAS. Spermatozoa motility was 44.29% and progressive motility 18.47%. Concentration of elements in testes was in following order: K > Na > Mg > Ca > Fe > Zn > Al > Cu > Se > Mn > As > Cr > Pb > Mo > Sr > Ni > Ba > Cd > Li > Hg. The most notable correlations indicate association between Se and total spermatozoa motility, as well as with progressive motility, furthermore between As and velocity curved line and beat cross frequency. A high positive significant correlation was found between mercury and beat cross frequency. The data may serve as a fine control indicator to detect potentially toxic elements accumulated from polluted environment that can affect reproduction of wild animals.

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.

Wastewater pollution caused by organic dyes is a growing concern due to its negative impact on human health and aquatic life. To tackle this issue, the use of advanced wastewater treatment with nano photocatalysts has emerged as a promising solution. However, experimental procedures for identifying the optimal conditions for dye degradation could be time-consuming and expensive. To overcome this, machine learning methods have been employed to predict the degradation of organic dyes in a more efficient manner by recognizing patterns in the process and addressing its feasibility. The objective of this study is to develop a machine learning model to predict the degradation of organic dyes and identify the main variables affecting the photocatalytic degradation capacity and removal of organic dyes from wastewater. Nine machine learning algorithms were tested including multiple linear regression, polynomial regression, decision trees, random forest, adaptive boosting, extreme gradient boosting, k-nearest neighbors, support vector machine, and artificial neural network. The study found that the XGBoosting algorithm outperformed the other models, making it ideal for predicting the photocatalytic degradation capacity of BiVO₄. The results suggest that XGBoost is a suitable model for predicting the photocatalytic degradation of wastewater using BiVO₄ with different dopants.