Water, Air, & Soil Pollution最新文献

Wastewater from wheat starch industries is the one with high chemical oxygen demand (COD) level that has adverse effects on the environment and thus special attention to its treatment for the discharge limits satisfaction is crucial. Biological treatment methods have challenges such as requiring extensive space and process time, high sludge production, and efficient management and operation demands. To overcome these challenges, electrochemical methods such as electrocoagulation (EC) and electro-Fenton (EF) can be efficient approaches due to their higher process speeds, minimal facility requirements, and easy operation which make them economically viable. In this study, electrochemical processes, including EC and EF methods were applied for wastewater treatment of a wheat starch industry. After preliminary experiments to identify the effective factors and ranges, the response surface method (RSM) was applied to design the experiments. In RSM seven factors were considered including initial COD, pH, electrode distances, process time, temperature, current intensity, and hydrogen peroxide concentration along with the COD removal efficiency as the response. Statistical analysis showed that hydrogen peroxide concentration and initial COD had the most significant impact, while pH had the least effect on COD removal in the electrochemical process. The optimum results showed that for synthetic wastewater with an initial COD range of 2000–4000 mg/L a COD removal of 75–85% for EC and 89–93% removal for EF were obtained. The results were validated for raw natural wastewater with 88% removal for EC and 92% for EF. In conclusion, while the removal efficiency of the EF process was superior to EC, the former incurs higher costs due to the use of hydrogen peroxide.

Biochar nanoparticles can act as carriers of pollutants in the groundwater, posing a threat to the environment. This study explored the transport and retention behavior of wood-based (NWBCs) and corn-residues-based (NCBCs) acid-modified biochar nanoparticles produced at different pyrolysis temperatures (at 400 °C and 700 °C). The effects of feedstock type, pyrolysis temperature, and input concentration on the mobility of nanoparticles in a saturated sand column were evaluated. Additionally, sequential transport and co-transport experiments were conducted to assess the nanoparticles' ability to remobilize pre-adsorbed Pb²⁺ and the transport of the nanoparticle-Pb²⁺ complex. HYDRUS-1D simulations using depth-dependent and Langmuirian models were applied to evaluate nanoparticles' retention. Nanoparticles produced at the pyrolysis temperature of 400 °C were more mobile than those produced at 700 °C. The highest nanoparticle mobility was observed when acid-modified wood-based biochar nanoparticles produced at 400 °C (NWBC400) were applied at an input concentration of 100 mg L⁻¹, while the lowest mobility was observed at an input concentration of 300 mg L⁻¹. The sequential transport and co-transport experiments revealed that NWBC400 quickly removed the pre-adsorbed Pb²⁺ from the sand. Also, Pb²⁺ in the metal-nanoparticle complex was highly mobile. Moreover, depth-dependent retention was detected as the dominant process describing nanoparticles' retention. As biochar nanoparticles increased the Pb²⁺ mobility in the porous media, adopting policies eliminating such conditions is essential for the environment. Also, understanding and managing biochar nanoparticle mobility can help protect water resources and public health from pollution risks.

Face masks serve as protective measures against pathogens and environmental pollutants. However, microplastic and phthalate pollutants present in the structure of masks may enter the nasal passages, potentially leading to health issues. In this study, we quantified microplastics and phthalate acid esters in masks used by hospital employees in various departments and in the nasal lavage fluid of these personnel before and after mask use. There were 200 participants, and the number of used masks was 160. The results indicated that the highest levels of microplastics (861.21 MP/mask) and Σ phthalate acid esters (3578.99ng/mL) were found in used masks from the laboratory. The amount of microplastics and phthalate acid esters in both masks and nasal lavage samples in the hospital departments were ranked as Laboratory > Physiotherapy > Emergency > Endoscopy. In nasal lavage samples, the amounts of these two pollutants decreased after mask use compared to the no-mask condition. Among the target phthalate acid esters, DEHP was the most prevalent in all mask and nasal lavage samples. These findings can be used for health risk assessment purposes.

This study aimed to characterize the water quality of 4 sites in Lake Idku, the third largest wetland region in Egypt regarding the physicochemical indicators, the spatial distributions of certain trace elements and organochlorine compounds (OCs). Most of the tested water quality indicators were above the permissible limits of River Nile water except nitrate was lower than the permissible limits. The distribution and concentrations of Fe, Cu, Zn, Mn, Pb, and Cd significantly differed (p > 0.05) among the sampling sites, where mean concentrations of these trace elements in all the tested sites ranged from 0.0226–0.0392, 0.010–0.098, 0.3570–1.0160, 0.084–0.942, 0.015–0.024, and 0.011–0.023 mg/L, respectively. The west site of the lake contained the highest contents of the trace elements, followed by the east, north, and then south sites. Water collected from the south site had the highest concentrations of Fe and Cu, while those collected from the west site had the highest concentrations of Zn, Pb, and Cd, and samples from the east site had the highest concentrations of Mn. The concentrations of Cu, Zn, Pb, Cd, and Mn in all samples which exceeded the Egyptian regulations, except those collected from the south site which contained levels of Mn that met the regulations. Regarding the residues of OCs, the ∑OCs can be grouped in descending order as follows: north site > east site > west site > south site, with values of 5.632, 5.230, 4.731, and 4.650 µg/L, respectively. All the detected OCs were above the maximum acceptable levels as compared to WHO standards of 0.1 μg/L, except for p,p'-DDT, p,p'-DDD, and p,p'-DDE which were at lower levels. In conclusion, the water quality of Lake Idku may at risk to biota and humans, monitoring, management, and mitigation strategies are urgently required to prevent further pollution by restricting the discharge of industrial and agricultural wastewater into Lake Idku.

This study applies green chemistry principles to promote sustainable and environmentally friendly chemical processes by utilizing plant extracts, which are rich in bioactive compounds, as a sustainable resource for synthesizing nanoparticles. Iron nanoparticles (FeNPs) were synthesized using ferric chloride (FeCl₃) and kermes oak (Quercus coccifera L.) leaf extract. The synthesized FeNPs were characterized using UV–Vis spectroscopy, Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR), Dynamic Light Scattering (DLS), and Zeta potential measurements. The antioxidant and dye degradation capabilities of the FeNPs were evaluated. The results revealed that the extract is rich in phenolic and flavonoid compounds. According to SEM analysis, FeNPs appeared aggregated and granular. The FeNPs exhibited ABTS and DPPH radical scavenging activities with values of 4.95 ± 0.52 µg/mL and 1.54 ± 0.014 μg/mL, respectively. The FeNPs demonstrated exceptional photocatalytic activity in degrading Methylene Blue, Crystal Violet, Congo Red, and Methylene Orange dyes. Experiments conducted over 180 min showed that FeNPs degraded Methylene Blue, Crystal Violet, Congo Red, and Methylene Orange dyes by 89.8%, 73.1%, 50.7%, and 37.9%, respectively. This study highlights the potential of FeNPs for the photocatalytic degradation of organic dyes, emphasizing their importance in wastewater treatment applications.

The long-term heavy dependence of human beings on petroleum products has led to a large amount of oily sludge discharge, and improper treatment of oily sludge will seriously pollute the environment and ultimately affect human health. However, the composition of oily sludge is too complex and difficult to treat. In this study, a new method for the joint treatment of oily sludge with surfactants and microorganisms was utilized, in which the organic matter in the oily sludge was eluted by the surfactants, and the residual organic matter, which was difficult to be eluted, was further degraded by microorganisms. This combined chemical-biological treatment method significantly improved the degradation efficiency of the oily sludge, and reduced the Total petroleum hydrocarbon (TPH) content of the oily sludge from 52,400 mg/kg to 4,190 mg/kg, with a TPH removal rate of 92%, and the residual oily sludge had a TPH content of 1.43%, which was already in compliance with the emission standards. The mechanistic analysis in this study also showed that the addition of appropriate amount of inorganic salt can promote the formation of surfactant micelles and significantly improve the elution effect of surfactant. This study will provide a useful reference for the efficient green treatment of oily sludge.

The increasing presence of microplastics (MPs) in aquatic ecosystems has raised concerns, mainly due to their adverse effects on aquatic organisms such as amphibians. This study evaluated the effects of exposure to naturally-aged polyethylene terephthalate (PET) microplastics on Physalaemus cuvieri tadpoles to investigate particle retention and toxicological impacts after cessation of exposure. The MPs were characterized through scanning electron microscopy and Raman spectroscopy analysis, and the weathering action was confirmed. Furthermore, our results indicated a significant increase in the mortality of tadpoles exposed to PET-MPs and partial retention of MPs after depuration. A higher Redox Balance Index (involving ROS levels and SOD and CAT activity) observed in the PET-MPs group at the end of the depuration period reveals a greater redox imbalance in these tadpoles. On the other hand, exposure to MPs induced neurochemical dysfunctions, such as reduced dopamine levels and increased AChE/BChE ratio, which were evident even after the end of exposure. Furthermore, the increase in total protein levels was observed throughout the experiment only in the control group. Finally, multivariate analyses (PCA and discriminant analysis) confirmed the occurrence of a phenomenon called the “legacy effect,” showing a clear separation between groups in the distinct phases of the experiment. In addition, multivariate linear regression analysis revealed a significant influence of MPs on the response of the animals only at the end of the exposure period, suggesting that the response observed at the end of depuration was cumulative, reflecting the damage induced during exposure. Thus, it is concluded that exposure to naturally-aged PET-MPs generates cumulative toxic effects in P. cuvieri, even after removing the pollutant, reinforcing the need for mitigation strategies to minimize the prolonged impacts of MPs on aquatic ecosystems.

The present research seeks to comprehend and evaluate the impact of varying concentrations of HCl acid solution on the compressibility and shear strength of silty clay. The compression test and the unconfined compressive strength test were conducted, and the SEM test was performed to analyze the microstructure of the soil with and without contamination. The results indicate that the contamination of silty clay soil with HCl acid caused a reduction in strength and an increase in the compression index and coefficient of consolidation; the more significant change in compressibility and strength was seen when the acid solution became more acidic. Concerning the SEM test, the images demonstrate the formation of macro pores between soil particles due to soil contamination. As the HCl acid solution concentration increased, more pores were formed and irregularly distributed across the whole soil surface. HCl acid solution contamination of soil causes the soil characteristics to degrade generally. Construction on this soil would consequently need to take into account the environment. Preparing the soil before building on it is suggested by adding materials that can increase the acid resistance of the soil.

Compared with a single pollutant, the comprehensive pollution index can reflect the degree of urban pollution more comprehensively. This article introduces the tax weighting method to calculate the comprehensive pollution index in the Yangtze River Delta (YRD). Based on the panel data of cities in the YRD from 2005 to 2017, the Spatial Durbin Model is utilized to empirically analyze the influencing factors and spatial spillover effects of the comprehensive pollution index. The results show: (1) The pollution of the cities in the YRD is unevenly distributed, and the eastern coastal areas are facing more serious pollution emissions than the western areas. (2) Changes in the urban industrial structure show an N-shaped curve impact on local industrial pollution emissions. The spatial spillover effect of the changes in industrial structure on the pollution emissions of surrounding cities presents an inverted N-shaped curve characteristic. (3) Economic openness and GDP per capita have a positive impact on pollution emissions. Government control can reduce pollution emissions. The impact of human capital and foreign direct investment on pollution emissions shows uncertainty over time and space. (4) The research results under the tax weighting method which can be proved to be applicable are consistent with the existing conclusions.