Water, Air, & Soil Pollution最新文献

Reactive transport models (RTMs) are widely adopted supporting tools for the design and management of aquifer in-situ bioremediation systems. However, their use has not been yet fully demonstrated for the design and management of operational-scale sequential bioremediation system (SBSs). In this work, a multispecies RTM was developed to reproduce an SBS coupled to a pump-and-treat (P&T) system in a chloroethene-polluted alluvial aquifer of Northern Italy. It is one of the first-ever documented applications of multispecies process-based RTM to simulate an operational-scale SBS. Two different model configurations were created to study the importance of adopting a more homogeneous or heterogeneous spatial distribution of transport parameters. The first configuration embedded three different reaction zones (RZs), each one described by spatially—invariant first-order reaction rates ((k)) simulating parent-daughter transformation of chloroethenes (PCE→TCE→DCE→VC). The second configuration embedded a spatially variant distribution of reaction rates within the three RZs, resulting in a more heterogeneous parametrization. Given the larger number of fitting parameters, the more heterogeneous model provided a better match of the field observations. Compared to it, calibrated (k) obtained from the more homogeneous model were largely underestimated for more-chlorinated compounds (PCE, TCE) and overestimated for less-chlorinated compounds (DCE, VC). The heterogeneous model showed that the capacity of the SBS to degrade the chemicals varied significantly across the different site areas, a feature not captured by the homogeneous model, and which could have important implications regarding the potential closure of selected P&T wells.

The composition and source analysis of dissolved organic matter (DOM) in sewage outfall into the sea is an effective means of pollutant traceability, which is of great significance to the ecological environment protection in coastal areas. This paper selects Dongguan, an important coastal industrial city in China’s Pearl River, for research. Water samples from 42 sewage outfalls into the sea were measured by three-dimensional fluorescence spectroscopy (3D-EEM). Combined with fluorescence characteristic parameters, similarity analysis and parallel factor analysis (PARAFAC), the spectral characteristics, DOM composition and source were analyzed. The average values of fluorescence parameters fluorescence index (FI), biological index (BIX) and humification index (HIX) were 1.80, 0.94 and 0.55, respectively. The overall PARAFAC analysis found that DOM in the sewage outfall of Dongguan was mainly composed of two fluorescent components, namely tyrosine-like (C1) and humus-like (C2), where tyrosine-like fluorescence was higher than humus-like. This indicates that DOM comes from both terrestrial and endogenous biological activities, but endogenous sources are the primary sources. The similarity analysis divided sewage outfalls into four categories, namely urban rainwater drainage characteristics, typical urban sewage, Jiulong paper-related wastewater and aquaculture water in fish ponds. At the same time, in the PARAFAC analysis, the fluorescence components of 14 urban rainwater outfalls were consistent with the overall analysis results. There are 3 effective parallel factor fluorescence components in 23 outfalls most likely to be contaminated by domestic sewage, namely tyrosine (C1) Humus-like (C2) and tryptophan (C3), C3 components in the characterization of the protein fluorescent tryptophan substance region appeared a strong response peak, belonging to the source pollution, consistent with similarity analysis results. This study suggests that the same source sewage outfalls should be classified management, strengthen the source tracing of sewage outfalls into the sea in neighboring cities, and build a collaborative pollution control system for river basins, estuaries and coastal.

Microplastics (MPs) pollution in soil have emerged as a significant environmental concern, infiltrating ecosystems and posing threats to ecological, plants, human, and animal health. We aim to provide a comprehensive understanding of microplastics, exploring their types, sources, pathways, and impacts across different environmental compartments. Begins with an introduction to microplastics, this review offers details on their classification and examines their omnipresence in aquatic and across other environments highlighting their persistent nature and complex pathways. It culminates the urban runoff, industrial discharges, anthropogenic activities, and agricultural inputs as major contributors, underscoring the need for targeted intervention strategies. The review underscores the detrimental effects of microplastics on aquatic life, soil fertility, and food safety, while also addressing the broader societal implications, including economic costs and public health concerns. Sampling and detection methods for microplastics are critically reviewed, covering advanced techniques and technologies that enable accurate identification and quantification of these pollutants. Overall, underscoring the dynamic nature of the microplastic pollution by synthesizing current knowledge and advancements, this review calls for the long-term monitoring and adaptive management strategies for future research, policy-making, and public initiatives towards a sustainable and microplastic-free environment.

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Industrial wastewater poses significant environmental and health risks due to its diverse pollutant composition. This study investigates the effectiveness of coagulation-flocculation treatment using aluminum sulfate (alum) for treating paper and pulp wastewater. The results highlight the significance of pre-biological treatment, pH optimization, alum dosages, and pre-filtration in enhancing removal efficiency for total solids (TS), total dissolved solids (TDS), total organic carbon (TOC), and ion concentrations. Pre-filtration significantly improved treatment performance, resulting in a 67% reduction in TS. Ion chromatography provided insights into post-treatment ion concentration changes. Under optimal conditions, including a treatment with 500 ppm alum dosage, alkaline pH of 11, and pre-filtration, the highest TS and TOC removal efficiencies were (52%) and (77%), while TDS reduction reached a maximum of 40% at lower alum dosages (100 mg/L). This study contributes crucial insights into optimizing alum coagulation-flocculation for paper and pulp wastewater treatment, offering potential solutions to mitigate industrial pollution and secure water resources.

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Sediment serves as a vital role in the contamination of rivers with potentially toxic metals(PTMs), particularly in regions with seasonal variations in river flow. The alternating wet and dry conditions during different seasons significantly affect the release of PTMs from sediments. Our study focused on the Xiaoqing River in northern China, a representative seasonal river. In a laboratory setting, we simulated and analyzed the physicochemical properties of sediments under varying wet and dry conditions, and focused on the release behavior of internal PTMs, namely Cu and Cr. The results indicate that under alternating wet and dry conditions, pH and oxidation–reduction potential (ORP) remained relatively stable, but there is a significant change in dissolved organic matter (DOM). Conversely, constant humidity conditions led to notable effects on pH and ORP, showing a strong correlation with the release of Cu and Cr. Fluorescence properties analysis revealed the interconversion of DOM components in sediments during the release process, especially under constant humidity conditions. Over time, humic substances in DOM increased, while protein-like substances decrease. In both scenarios, Cu and Cr concentrations in sediments decrease, but under alternating wet and dry conditions, the Cu contents of A1, A2 and A3 decreased by 19.08%, 11.99% and 15.75%, respectively, and the Cr contents decreased by 23.75%, 29.17% and 26.69%, respectively. the percentage decreases in Cu and Cr were significantly greater, PTMs release intensified, posing higher environmental risks. This condition notably affected Cu chemical forms, whereas constant humidity impacts both Cu and Cr. This study will be conducted under varying conditions of dry–wet alternation frequency and cycles, ultimately serving as a theoretical foundation and technical guide for future endeavors in water pollution control and environmental protection of the river.

In order to predict the fuel consumption and carbon emission of vehicle driving on mountain city road, this research constructs energy conversion, fuel consumption and carbon emission model for N2 class heavy-duty diesel vehicle. The model is constructed based on the first law of engineering thermodynamics and the driving dynamic theory. The constructed model fully considers the impact of road slope characteristics on fuel consumption of mountain city roads and requires fewer parameters. The accuracy of the model is verified by actual road driving test data. Then, the prediction model is improved by adopting actual acceleration characteristics. Next, this research discusses the effects of speed, acceleration and slope on fuel consumption and carbon emission characteristics. Result indicates that when assuming the vehicle travels at a constant speed, the errors are large between measurement value and prediction value, the average errors are approximately 13% for fuel consumption and 14% for carbon emission. After considering the acceleration factor, the accuracy of the prediction model is significantly improved. Result shows that the correlation coefficient R² between predicted value and tested value increased by 0.154 for fuel consumption and 0.183 for instantaneous work done, indicating an enhanced correlation between these values. This article constructs a vehicle fuel consumption and carbon emission model for mountain city roads. The predicted results of the model can reflect the actual fuel consumption and carbon emission levels during driving. Model developed in this paper has a typical physical meaning and can be applied to other roads and other vehicles.

This study focuses on utilizing Oryza sativa husk (rice husk) to produce a nanosilica-doped smectitic clay (Os-Sm) for the adsorption of Basic Blue 9 from aqueous solutions. Response surface methodology was employed to investigate the impact of dye concentration (10—30 mg/L), initial pH (8—11), and contact time (0—100 min). The regression model exhibited a remarkable predictive capability, accounting for over 99% of the targeted response variation within the specified ranges of the factors (R² = 99.98%) with a 95% confidence level. The analysis of variance confirmed the significance and accuracy of the mathematical model, with F-values (1539.08 > > 1) and p-values (< 0.05) indicating the statistical significance of almost all factors within the studied ranges. These findings were supported by factorial, surfaces, and contours plots. Furthermore, the pseudo-second-order kinetic and Langmuir models demonstrated excellent fitting to the experimental data, with determination coefficients of 0.976 and 0.965, respectively. At optimal conditions (30 mg/L, pH 11, t > 50 min, and adsorbent dose of 0.5 g/L), approximately 96.33% of the dye was successfully removed. Os-Sm emerges as a promising and efficient alternative for Basic Blue 9 removal in aqueous solutions.

Nanostructured Fe/Zn codoped CeO₂ photocatalyst revealed high visible light mineralization efficiencies for removal of pharmaceutical ciprofloxacin and industrial reactive yellow 145 dye. Nanocrystalline pure and Fe/Zn codoped CeO₂ (Ce_0.93Fe_0.03Zn_0.04O₂) powders have been synthesized by a simple coprecipitation manner. The X-ray crystal structure analysis proved the formation of face-centered cubic CeO₂ phase with low nano-crystallite sizes (7–9 nm). The transmission electron microscope (TEM) images of the two samples illustrated that the powders are composed of very small nano-sized particles have approximately spherical view. All particles of both powders have nearly homogenous size and shape. The Kubelka–Munk plot demonstrated that the energy band gap of the synthesized CeO₂ nanopowder was 3.18 eV. The modification of CeO₂ nanopowder by Fe/Zn ions improved the visible light absorption and also reduced its band gap energy to 2.52 eV. Environmentally, 98% and 96% removal efficiencies for reactive yellow 145 dye and medical ciprofloxacin antibiotic were realized by Fe/Zn codoped CeO₂ nanocatalyst. The perfect mineralization, good reusability and high elimination of different concentrations (10–30 ppm) encourages the use of this nanocatalyst for wastewater treatment. The radical trapping tests verified that the superoxide and hydroxyl radicals are the energetic species during the photodegradation reaction of pharmaceutical ciprofloxacin and industrial reactive yellow 145 dye.

In this study, the pollution characteristics and risks of heavy metals in road dust from long-term polluted areas were investigated. Fifteen road dust samples were collected from five villages along the Dongdagou Stream in Baiyin, China. All samples were tested for heavy metals using an inductively coupled plasma optical emission spectrometer (ICP-OES). Results showed that the concentrations of Cr, Mn, Ni, Cu, Zn, Cd, Pb, As, and Hg in the samples were 67.59 ± 6.01, 414.10 ± 31.62, 171.75 ± 25.92, 91.36 ± 118.56, 369.92 ± 504.87, 2.94 ± 4.37, 71.27 ± 76.56, 6.37 ± 2.55 and 1.46 ± 2.61 mg/kg, respectively. The Nemerow integrated pollution index (NIPI) showed that Minle (ML), Liangzhuang (LZ), Shuanghe (SH), Minqin (MQ) and Shapogang (SPG) villages were heavily polluted, with Hg being the main pollutant. Risk index (RI) results indicated that all the five villages were at considerable or high ecological risk. Hg was the main contributor to the potential ecological risk, accounting for 75.82%. Health risk assessments indicated that exposure to road dust heavy metals in preschool children occurs mainly by ingestion. The hazard indexes (HI) values of the five villages were above or close to 1.0, indicating the risk potential of non-carcinogens to preschool children. For carcinogens, the total carcinogenic risk did not exceed the acceptable range for preschool children. Overall, strong pollution and considerable/high ecological risk were found in the road dust of the present study area and the pollution might pose a non-carcinogenic risk to preschool children.