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

As a critical protection zone in the Yangtze River Basin, the water quality of the Ching River, located in the middle reaches of the Yangtze River, has long been a research focus in aquatic environmental science. To clarify the quantitative relationship between nitrogen concentrations in overlying water and sediments, and to elucidate the regulatory mechanism of sediments on water column nitrogen levels, sediment samples were collected, and a series of laboratory experiments, including nitrogen adsorption-desorption kinetic tests and adsorption thermodynamic analyses, were carried out. The results indicate that along the flow direction, the equilibrium adsorption capacity of sediments for ammonia nitrogen presents an increasing trend, while the equilibrium release capacity shows a decreasing tendency. Elevated temperature and pH values exert an inhibitory effect on the ammonia nitrogen adsorption capacity of sediments, whereas the increase in sediment organic matter content enhances the adsorption performance. The calculated equilibrium nitrogen concentration (ENC₀) of the sediments is higher than the ammonia nitrogen concentration in the overlying water, suggesting that the sediments in the Ching River pose a potential risk of endogenous nitrogen release.

Chromium (Cr), classified by the International Agency for Research on Cancer (IARC) as a carcinogen, poses significant risks to human health. This study evaluated the uptake of Cr in Arachis hypogaea, Vigna unguiculata, and Zea mays cultivated in Cr-contaminated soils and assessed the associated toxicological risks to human consumers. A greenhouse experiment was conducted using soils contaminated with Cr at 10 and 30 mg kg^-1. Chromium concentrations in soils and plant tissues were quantified using ICP-OES, and bioconcentration and translocation factors (TFs) were determined to assess Cr uptake and movement within the plants. The lifetime incremental cancer risk (ILCR) was determined to evaluate potential long-term health risks. Results showed that all three species accumulated significant amounts of Cr in roots and aerial tissues, with bioconcentration factors (BFs) greater than one in most treatments. However, TFs remained below or equal to one for most cases, indicating limited upward movement of Cr. Importantly, ILCR values were within permissible limits, suggesting no significant carcinogenic risk for consuming these crops. These findings indicate that A. hypogaea, V. unguiculata, and Z. mays are resistant to Cr contamination and can be safely cultivated and consumed in soils containing up to 30 mg kg^-1 of Cr. This study provides valuable insights for ecotoxicological risks and for the safe management of Cr-contaminated agricultural soils in Mozambican industrial areas.

Paints used as cosmetic and architectural surface coatings constitute essential structural components, however, they may also act as significant environmental pollutants due to abrasion and weathering processes. Following environmental disturbances such as earthquakes and landslides, these materials can contribute substantially to surface and groundwater contamination. Seven commercially available wall paints of different colors and formulation qualities were selected for analysis, including Sand White (P1), Beige (P2), Ceiling White (P3), Ivory (P4), Exterior White (P5), Anthracite (P6), and Red (P7), which were expected to contain distinct additive compositions. Structural characterization was performed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and elemental analysis via energy-dispersive X-ray spectroscopy (EDX). Particle size distributions were determined with a Malvern Zetasizer Nano-ZS. Although all paints demonstrated a measurable potential to generate microplastics (MPs), no acute toxicity was observed in Danio rerio or Escherichia coli under the tested conditions.

This study compares the effectiveness of sonication and flocculation in treating acid mine drainage (AMD) using calcined magnesite. Techniques such as X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), X-ray fluorescence (XRF), and Scanning Electron Microscopy (SEM) were used to characterize the calcined magnesite and residues. Sonication and flocculation parameters, including calcination temperature, contact time, and dosage, were evaluated in batch mode. Saturation indices of metal oxides were determined using PHREEQC geochemical modeling. The temperature of 800 °C was found to be optimal for calcining magnesite, based on MgO content (85.67%). This was also confirmed by XRD, which showed the formation of periclase, magnesium oxide mineral phase, on calcined magnesite. Sonication increased the pH from 2.25 to 10.1 within the first minutes of contact, whereas the maximum pH at the same time during flocculation was 9.2. This indicated that sonication performed better than flocculation. The product water was suitable for irrigation purposes. Sludge characterization revealed that sonication promoted more extensive mineral precipitation than flocculation. Geochemical modeling indicated that Al- and Fe-hydroxyoxides and hydroxysulphates were likely to precipitate, and that a greater diversity of minerals would form with sonication. Based on these results, sonication performs better than flocculation, and further studies are recommended to explore the potential to recover valuable minerals from AMD using sonication and calcined magnesite.

Near-road particulate matter poses significant risks to public health and the ecological environment, and its levels are affected by the meteorological and traffic factors significantly. However, the contributions of these factors to particulate matter concentrations and the interactions among these factors were not well studied. In this study, the causal relationships among traffic flow (TF), near-road PM_2.5 levels, and meteorological factors were elucidated based on the long-term real-time data on near-road PM_2.5 concentrations alongside concurrent meteorological and traffic data. A predictive modeling framework was developed to predict near-road PM_2.5 concentrations using traffic and meteorological data as input. The results indicate that the correlation between TF and near-road PM_2.5 concentrations is significant (P < 0.05). Furthermore, robust causal relationships were identified between TF and meteorological parameters such as temperature and atmospheric pressure. It is suggested that TF could indirectly influence the level of near-road PM_2.5 by altering meteorological factors. By comparing the prediction performance among Long Short-Term Memory (LSTM), Backpropagation (BP) and Extreme Learning Machine (ELM) models for near-road PM_2.5 concentrations, combined with Shapley Additive exPlanations (SHAP) for feature importance analysis, it revealed that the inclusion of TF data markedly improves model accuracy in near-road PM_2.5 concentrations prediction.

Environmental pollution caused by industrial activities, vehicle emissions, and improper waste disposal poses serious risks to human health and the ecosystem. This study investigates the adsorption of m-toluidine (m-T) using activated carbon derived from Balanites aegyptiaca seeds (BASC) via H₃PO₄ chemical activation. The BASC was characterized using scanning electron microscopy and Fourier transform infrared spectroscopy and analyzed for its moisture, ash, volatile matter, and carbon content. The material exhibited a high surface area of 675.0 m² g^-1, an iodine number of 581 mg g^-1, and a point of zero charge (pH_pzc) of 4.42. Batch adsorption experiments were performed to assess the effects of pH, contact time, and temperature. Results showed that adsorption efficiency increased with temperature. The adsorption behavior is favorable and followed the Temkin isotherm, pseudo-second-order kinetic model, and a three-step intraparticle diffusion mechanism. Thermodynamic analysis revealed that the adsorption process was endothermic, spontaneous, and associated with increased system entropy. These results underscore the potential of adsorption as an efficient wastewater treatment approach for eliminating organic contaminants such as m-T from actual aqueous environments.

Potentially Toxic Elements (PTEs) are hazardous for human and ecosystem health due to their non-biodegradable nature. In this study we investigated the concentrations of PTEs, including As, Co, Cr, Cu, Mn, Mo, Ni, Pb and V in sediments of Lake Tuz around the salt pans for possible contamination. Lake Tuz is a shallow saline lake where halite (table salt) production is carried out in the salt pans and has significant geo and eco-tourism potential due to its unique ecosystem and natural beauty. The extent of pollution level and ecological risk were evaluated by geochemical indices and guideline values. According to the Geoaccumulation Index (I_geo), Enrichment Factor (EF) and Contamination Factor (Cf) indices Cr, Mo, As and occasionally Ni accumulated in moderate to strong levels. Intensity maps of Pollution Load Index (PLI) and Modified Degree of Contamination (mCdeg) indicated pollution hotspots in the neck region and in the eastern shore of the lake respectively. The Potential Ecological Risk Index (PERI) values indicated low and moderate levels of ecological risk. Statistical analyses including Pearson Correlation Coefficient (PCC), Hierarchical Cluster Analysis (HCA) and Principal Component Analysis (PCA) suggested that Co, Cr, Cu, Mn, Mo, Ni and V are of geogenic origin and As and Pb are of anthropogenic origin. Provenance analysis suggested that host rocks for geogenic PTEs were granodiorites and ophiolites situated in the catchment area of the lake. Anthropogenic PTEs were most likely related to agrochemicals used in surrounding farmlands.

Core-shell Fe₃O₄@poly(acrylic acid)/chitosan (Fe₃O₄@PAA/CS) submicrospheres were synthesized through the polymerization of acrylic acid in CS solution, using uniformly sized magnetite colloid nanocrystal clusters (MCNCs) as the core materials. The obtained submicrospheres were characterized using scanning electron microscopy, transmission electron microscopy, dynamic light scattering, Fourier-transform infrared, thermo-gravimetric, vibrating sample magnetometer, and X-ray diffraction analyses. The results confirmed that the submicrospheres with the Fe₃O₄ nano-core located in the central region and encapsulated by a CS shell exhibited superparamagnetic behavior. The removal efficiency of Congo red (CR) dye by magnetic submicrospheres was determined by investigating several factors, including pH, adsorbent dose, contact time, and dye concentrations. Over 97.4% of CR (90 mg L^-1) was removed at a dosage above 1.2 g L^-1. The maximum adsorption capacity obtained from the Langmuir isotherm model for CR was 143 mg g^-1 at 290 K. Adsorption kinetics and isotherm data were well described by the pseudo‑second‑order and Langmuir models, respectively. Furthermore, the submicrospheres were successfully regenerated and, subsequently, reused for four adsorption-desorption cycles without any noticeable loss of stability. The exceptional removal performance of magnetic submicrospheres on CR renders it a highly appealing adsorbent for the treatment of dye-containing wastewaters.

Monitoring nitrate and fluoride levels in drinking water is essential due to their potential adverse health effects. While studies have assessed these contaminants across Iran, comprehensive analyses of their spatial-temporal distribution and probabilistic health risks remain scarce for Maragheh County. This study addresses this gap by applying Monte Carlo simulation (MCS) and principal component analysis (PCA) to 132 drinking water samples collected from 2018 to 2023. This novel framework identifies contamination sources and quantifies risks across demographic groups. Results revealed that 97% of nitrate and 96% of fluoride concentrations met World Health Organization (WHO) guideline limits. PCA explained 76.5% of total variance, with EC, TH, TDS, and Ca²⁺ as dominant factors. The water quality index (WQI) rated over 88% of samples as excellent and less than 1.5% as poor. Fluoride posed negligible health risks (HQ < 1), but nitrate exposure yielded elevated hazard indices (HI > 1) for children, signaling potential non-carcinogenic effects. Overall, findings underscore the need for ongoing monitoring, better wastewater and fertilizer management, and targeted protections for vulnerable groups in agricultural regions.

Diclofenac (DCF) is one of the emerging compounds in the environment. There are many sources of diclofenac, such as effluent of pharmaceutical industries, wastewater treatment plant effluent, and domestic wastewater. It requires advanced treatment because it cannot be removed from water and sludges using the conventional wastewater treatment process. Catalytic and free radical methods also known as advanced oxidation process (AOP) can degrade large and complex organic compounds into smaller ones. In this review, each AOP method is critically assessed for the removal of DCF in water.