Water, Air, & Soil Pollution最新文献

An analytical model is presented for assessing the coupled processes that govern water flow and volatile organic compound (VOC) transport from the saturated zone through the vadose region and into the atmosphere. The model is verified by a finite element solution. The sensitivity analyses are performed to evaluate the influence of key parameters, such as bubble upward velocity, water flow, atmospheric conditions on VOC transport and emissions from subsoil environments. VOC transport is sensitive to soil texture, which significantly impacts the capillary fringe in the vadose zone. Higher VOC concentrations are observed in sandy soils compared to silt loam, as the larger volumetric water content observed in the silt loam reduces effective VOC diffusivity. Traditional diffusion-limited models show a sharp concentration decrease in the saturated zone due to low diffusion coefficients of VOC in water, while bubble-facilitated transport maintains higher VOC concentrations in the saturated zone. The relative VOC concentration for diffusion-limited models can be around four orders magnitude lower than the calculated value for bubble-facilitated VOC transport model. Increased bubble transport velocity or reduced saturated zone thickness enhances the VOC concentration gradient, resulting in significantly higher emission fluxes. The atmospheric boundary layer also significantly impacts VOC concentrations and emissions. Ignoring the effects of the atmospheric boundary layer can lead to underestimations of VOC emission flux by a factor of 1.2. These findings highlight the significance of coupled bubble and water flow for the transport of VOCs in the saturated–unsaturated-atmospheric system.

This study investigates the treatment efficiency of biofilm immobilized MBBR (moving bed biofilm reactor) system for tannery effluent compared to suspended cells system. A mixed culture of biofilm-forming strains Bacillus vallismortis, Bacillus haynesii, Alcaligenes aquatilis, and Enterococcus faecium showed increased biofilm formation and Cr(VI) reduction compared to individual strains. The MBBR carriers were shown to have a greater biofilm formation (cell viability = 8.255 log units) and EPS yield (58 mg/g total solids) compared to the PUF (polyurethane foam) carriers (cell viability = 6.806 log units, and EPS yield = 36.4 mg/g total solids). The COD removal efficiency of the biofilm immobilized MBBR was higher (82.5%) compared to suspended cells treatment (61.3%) in the fed-batch treatment method. GC–MS analysis showed that 2,6-Bis(tert-butyl) phenol and 1-monopalmitin compounds were either diminished or transformed during treatment with biofilm immobilized MBBR. Furthermore, phytotoxicity and genotoxicity tests confirmed the lower toxicity of biofilm stabilized MBBR treated effluent compared to treated suspended cells on fenugreek plant and Allium cepa L. roots, respectively. The study indicates that treating tannery effluent with a mixed culture of B. vallismortis, B. haynesii, A. aquatilis, and E. faecium immobilized on MBBR effectively removes both organic and inorganic contaminants along with genotoxic effects.

This work investigated the fluoride removal efficiency by calcium oxide-based polyaniline nanocomposite (CaO-PAn NC) and optimization study using Response Surface Methodology (RSM) and Artificial Neural Network (ANN). The kinetic and isotherm studies were well explained by pseudo-second-order and Langmuir isotherm model. The maximum fluoride adsorption capacity was 186.58 mg/g. The thermodynamics studies indicate the adsorption process was spontaneous and endothermic in nature. The optimal value for fluoride removal by CaO-PAn NC and the interactive effect of input variables pH, dosage, temperature and reaction time was investigated using RSM and ANN. The performances were determined using statistical tool regression coefficient (R²), Root mean square error (RMSE), Standard error of prediction (SEP) and Absolute average deviation (AAD). RSM with R² (0.9984), AAD (0.0401), RMSE (0.0902), SEP (0.2089) was at higher side of accuracy than ANN with R² (0.9877), AAD (0.1223), RMSE (0.5897), SEP (0.6409). The maximum fluoride removal was predicted to be 91.05% and 92.01% by RSM and ANN at (pH ̴ 7, time 65 min, temperature 35 °C, dose 0.55 g/L) respectively. The PAn nanocomposite can be reused up to 6th cycles for defluoridation mechanism.

Incineration contributes about 10% of metals emission in Europe and leaching of metals from reuse or landfilling of incineration products remains a global concern. Thus, evaluating metal distribution in incineration residues is critical. The present study highlights the distribution of selected metals, Zn, Mn, Ni, Co, Fe, Cr, Al, Cu, and Pb, in incineration ashes in relation to incinerator capacities/sizes. Al was most distributed and Cd the least. Statistical evaluation with 2-factor ANOVA revealed significant variations (F > F_crit, α = 0.05) were observed except in fluidised bed (FB) residues for Zn and Co. Also, except Co for samples of similar features from one location, and Pb in FB residues with no significant difference (p > 0.05), other metals varied statistically (p < 0.05). The degree of contamination (mCd), geoaccumulation index (I_geo), enrichment factor (EF), pollution load index (PLI) and potential ecological risk index (PERI) revealed all matrices had PLI > 1. I_geo revealed moderate to strong accumulation of Zn and Cu in all matrices except in 3 matrices for Cu while IMSW-BA showed strong Pb accumulation. Al, Mn and Fe showed low enrichment in all matrices except in 2 matrices for Cu. Zn and Pb were extremely enriched in IMSWA-BA. PERI placed FB-Gd and FB-Lz as ecologically low-risk, IMSW-BA and IMSW-APC as considerable ecological risk and other matrices were ecologically moderate risk. The study found that the content of metals in the incineration residues requires more sustainable ways of management and disposal of incineration products in Poland and elsewhere.

Heavy metal(loid)s accumulation in soil-crop systems is associated with lithologies weathering (black shales) a high geological background. To explore the heavy metal(loid)s pollution in areas with high geological background of black shale, pollution of As, Cd, Cr, Se, Hg and Pb in the soil-crop system in areas of typical black shale was investigated. The results showed that the soil-crop system was heavily contaminated with Se and Cd, with Se concentrations exceeding the environmental standard limit by a factor of 5.2. The bioaccumulation coefficients (BCFs) indicated that the crops had a high uptake capacity for Se and Cd. The BCF of cabbage for Se reached 14.7, followed by elemental Cd at 2.57, and that of maize for Cd was 2.95.The results of health risk showed that cabbage and rice were the main crops constituting the health risk in the study area, and the HI values of rice for elements other than Pb were greater than 10, which meets the criteria for toxicity, and elemental As was the high contributor to the HI value of rice, which reached 36.6. This study is crucial for understanding heavy metals (loids) in soil crop systems in black shale areas under high geological backgrounds.

Microplastic contamination and potential risk assessment in coral reef fish species have been under-studied, particularly in the Bay of Bengal. Quantification and characterization of microplastics and their potential health risks were assessed for six tropical fishes from Saint Martin's Island, Bay of Bengal. A total of 60 gastrointestinal tracts (GIT) from six fish species (10 individuals/species) were collected and digested with 20 mL of 65% concentrated HNO₃ + 80 mL of distilled water at 70 °C for 3 h, and microplastics were extracted by density separation using 4.4 M, 1.5 g/mL of sodium iodide solution. Microplastics were visually observed by a light binocular microscope, and then polymer types were detected with FTIR. Mean microplastic abundance ranged from 4.38 to 10 microplastics/GIT with an average occurrence rate of 100%. Red, transparent, black, and blue fibres (37.50 to 81.82%) were the most dominant MP colour. Most (88.35%) extracted microplastics were 100 to 1500 µm. Polypropylene and polyethylene were the most abundant polymers, accounting for 36.45 to 53.51% and 32.56 to 47.18%, respectively. A risk assessment of microplastics using the polymer hazard index revealed that microplastic contamination in these fishes (PHI = 565.40 to 659.26) from Saint Martin's Island were classified in the “Danger” risk category.

Nansi Lake, China, has an economically valuable aquaculture industry but fish kills caused by heavy metal pollution have been problematic in recent years. Freshwater supply is critical for centers of industrial activity, commerce, and residences, but growing urban populations pollute the water they rely on. In the case of Nansi Lake, China, there are concerns that continuing urban growth is contributing to heavy metal pollution of the lake water, with potential economic and health impacts, but the extent of this pollution is unclear. To thoroughly understand the spatiotemporal characteristics of heavy metal pollution in Nansi Lake, China, we measured the concentrations of six heavy metals in upper water from 18 sites distributed across four sub-lakes of Nansi Lake and performed a health risk assessment over four seasons. The average concentrations of Pb, Cd, and Hg exceeded those of tertiary water quality standards and were 3.18-, 4.16-, and 14-fold higher than the values listed in the national surface water quality standard of China (GB3838-2002), respectively. Meanwhile, Cu, Mn, and Zn concentrations did not exceed the values in these standards. The heavy metals generally had consistent seasonal distribution patterns in different lake areas, but these patterns differed among the heavy metals, indicating that the metals may have different sources or transformation patterns. The full-year risk value of non-carcinogens in Nansi Lake was 2.32 × 10^–6 a⁻¹, which was lower than the maximum acceptable risk level (5 × 10^–5 a⁻¹) specified by the International Commission on Radiological Protection, implying that these was no harm to human health from these carcinogens. However, the full-year risk value of the carcinogen Cd was 22.54 × 10^–5 a⁻¹, which was much higher than the maximum acceptable level; this risk value contributed to 98.98% of the total risk and requires further attention.

Heavy metal (HM) pollution in urban air, a global dilemma, has increased drastically in the last century. Aluminum (Al) is one of the HMs and a neurotoxic element that can be absorbed into human tissues through digestion, breathing, and skin. Al accumulation in humans can cause diseases and even cause death. Due to the risks it poses to human and environmental health, it is vital to track the Al contamination shifts in the airborne and decrease them. In this study, 40-year Al concentration differences in Pseudotsuga menziesii, Cedrus atlantica, Picea orientalis, Cupressus arizonica, and Pinus pinaster grown in Düzce, Türkiye, the fifth most polluted European town, in terms of direction, tree species, and tissue type were assessed. As a result, Al accumulation in the tissues generally varies as outer bark > inner bark > wood. Whole species can accumulate Al significantly, and Al transfer between adjacent cells in the wood part is limited. In conclusion, all species can be used as biomonitors to track temporal Al pollution changes. However, the highest concentrations, especially in the wood part, were observed in Cedrus atlantica, Picea orientalis, and Cupressus arizonica, and these species were chosen to be the most suitable species to be used in phytoremediation studies.

Biological invasions occur when species are moved by human activities from their native range to new areas where they have no evolutionary history and are a major global economic and ecological concern. This paper includes biological treatment of a new activated sludge system that can remove abundant organic matter (OM) in wastewater. The study presents also modelling of organic matter biodegradation process. Factors affecting the biodegradation rate were carried out Viz. the concentration of the organic matter, the mass of activated sludge, the dye content, and the optical density. The results showed that the biodegradation kinetics with time displays an exponential decay. However, the kinetics reaction is well fit by a pseudo second-order equation. After 1 h of treatment, the yields of 93.63 and 92.86% for concentration of 60 and 30 ppm were respectively recorded. UV–Visible spectra and fluorescence spectroscopy were also investigated. Fluorescence spectroscopy was used to characterize municipal waste water at various stages of treatment. A Principal Component Analysis (PCA) has displayed, in agreement with experiments, that the correlation between variables are significant.