Water Air and Soil Pollution

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Numerical oil spill models, which predict the transport and behavior of oil spills, are an essential tool for risk assessment and clean-up during an actual accident. The existing numerical oil spill models are mainly applied to large-scale oil spills, while few models on small-scale oil spills exist. Therefore, this study focuses on the prediction model of small-scale oil spills. Oil diffusion experiments in seawater using different oil types, including heavy oil, light oil, and gasoline, at different addition amounts under various kinds of wind were carried out, and these diffusion processes were recorded by a camera. The experimental images were processed to obtain the spread oil film area. The oil film edge processing based on genetic algorithm (GA) and back propagation artificial neural network optimized by a particle swarm optimization (PSO-BP) is proposed. Numerical prediction models were then constructed using the BP artificial neural network, the genetic algorithm-optimized back propagation neural network (GA-BP), and the PSO-BP. Among the three methods, the PSO-BP has the fastest convergence speed and the highest stability, which can usually achieve the goal. The PSO-BP reduces the possibility of the BP-ANN and the GA-BP falling into a local optimum instead of reaching global optimization. The prediction performance evaluation data are R² = 1 and MSE = 3.58e⁻⁹ – 8.87e⁻⁸. Results show that the GA and the PSO-BP provide a new approach to small-scale oil spill prediction.
In this study, an innovative material (nitrogen, phosphorus, and oxygen controlling agent, NOC) was synthesized by calcium peroxide (CaO2), magnesium chloride (MgCl2), bentonite, zeolite, cement, stearic acid (SA), citric acid (CA), and silver sand. The treatment performance of NOC in mimic black-odor river water was investigated in lab-scale, and the results showed that over 73.7% phosphorus and 77% ammonia nitrogen were removed from river water with the addition of 470 g NOC at 30 mL h⁻¹ flow rate, demonstrating that the presence of NOC could remove phosphorus and ammonia nitrogen simultaneously. Moreover, the addition of NOC could release oxygen with tender influence on pH in water. Calcium phosphate (Ca-P), aluminum phosphate (Al-P), and ferric phosphate (Fe–P) in the river sediment increased from 1.6, 0.136, and 0.12 mg g⁻¹ to 2.16, 0.242, and 0.196 mg g⁻¹ for 28 days, respectively. The results manifested that the mobile phosphorus could be adsorbed by NOC and further transformed to inert phosphorus form, thereby restraining the release of endogenous phosphorus from sediment to the overlying water. Besides, the relative abundance of microorganisms could be enhanced with the existence of NOC, further promoting the removal of phosphorus. Hence, NOC could be applied to the efficient remediation of the black-odor river. Graphical abstract
This paper summarizes findings from a study in which the biochemical methane potential (BMP) of cheese whey was investigated. The cheese whey and mixtures of it with various co-substrates were used in anaerobic serum bottles for a period of about 90 days. The effects of inoculum were also investigated using granular anaerobic sludge from gum industry and anaerobic sludge from a municipal wastewater treatment plant. A total of 14 groups were set with two different inoculums and various substrate mixtures. The highest cumulative biogas and methane production were observed as 1229 mL and 790 mL, respectively, for a mixture of 50% whey, 33% slaughterhouse wastewater, and 17% cattle manure inoculated with granular anaerobic sludge. The highest BMP was obtained for whey (diluted to 13%) inoculated with anaerobic sludge as 360 mLCH4/gCODadded. Methane percentages in headspace for all serum bottles were above 50%. Several kinetic models to predict biogas production were calibrated. Results showed that the first-order model and the transference function showed the best prediction performance for most of the serum bottles.
In our previous work, efficient PO4³⁻ and NO3⁻ adsorption by calcined Meretrix lusoria powder was reported. This study addressed pilot-scale application of M. lusoria F800 for PO4³⁻ and NO3⁻ removal from the real site. The study investigated the performance of multicomponent (PO4³⁻ and NO3⁻) adsorption from domestic wastewater (DWW) in fixed bed adsorption column packed with Meretrix lusoria F800 beads. Prior the packing, M. lusoria F800 beads were successfully tested for 20 mg/L PO4³⁻ and NO3⁻ removal from synthetic wastewater (SWW) and DWW, respectively. In this research study, the effect of the column operational parameter including DWW influent flow rate (Q: 10, 30, and 40 mL/min) and adsorbate concentration (C: ≈ 60 mg/L) on breakthrough curves was well-evaluated. Thomas model was used to confirm the correlations of the experimental data with the maximum adsorption capacity of 23.6 mg/g PO4³⁻ and 9.31 NO3⁻ mg/g, at 10 mL/min flow rates, respectively. Results demonstrated that Thomas model well interpreted the experimental data. Moreover, PO4³⁻ and NO3⁻ removal capacity by regenerated M. lusoria F800 beads was observed additional adsorption cycle. Furthermore, scale-up column was successfully tested, where experimental values were in parallel with theoretical values. In conclusion, this study indicates that M. lusoria F800 beads can be economically and easily utilized in a fixed bed adsorption column for the removal of PO4³⁻ and NO3⁻ from DWW containing excessive PO4³⁻ and NO3⁻.
Map showing Porto-Novo Lagoon and sampling stations
Distribution of PAHs in water across sampling stations. Beaurivage (BORI), Djassin (DJAS), Douane-Tokpa (DOUA), Benin Industry Body Fat (IBCG)
Concentrations of PAHs in fish
Concentrations of PAHs (mg/L) according to the ring group in the investigated sampling sites. Beaurivage (BORI), Djassin (DJAS), Douane-Tokpa (DOUA), Benin Industry Body Fat (IBCG), Acenaphthylene, acenaphthene, fluorene, phenanthrene and anthracene (3-ring PAHs); fluoranthene, pyrene, benzo[a]anthracene, chrysene (4-ring PAHs); benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenzo[a,h] anthracene(5-ring PAHs) and BghiP, IncdP Indeno[1,2,3-c,d] pyrene, benzo[g,h,i]perylene (6-ring PAHs)
Relative concentration of PAHs with 2–6 rings in the Porto-Novo Lagoon
The Porto-Novo and Cotonou Lagoon complex serve as a trade route for goods and petroleum in both Nigeria and Benin Republic. The complex geographic location also makes it a sink for a large portion of pollutants coming from the city and surrounding areas, as well as from the Ouémé River, which receives pollutants from the north to the south of the country. In order to assess the level of polycyclic aromatic hydrocarbons (PAHs) contamination and the associated health risks, sixteen PAHs in Sarotherodon melanotheron and water from Porto-Novo Lagoon were evaluated. PAHs were extracted from fish and water from four locations and quantified by gas chromatography analysis. PAH concentrations in the water ranged from not detected (ND) to 64.65 mg/l and from ND to 46.24 mg/kg in fish. The PAH of the highest concentration was Benzo(b)fluoranthene while Naphthalene and Acenaphthene were the lowest. The total PAH concentrations ranged between 43.07 and 128.12 mg/L with a mean value of 89.30 ± 20.34 mg/L in water and 67.83 to 97.43 mg/kg with a mean value of 78.35 mg/kg in fish. Spatial distribution showed the highest total concentration in Djassin. Five rings PAHs predominated in water and fish. The hazard quotients (HQs) and hazard index (HI) were < 1.0 indicating that non-carcinogenic risk through water dermal absorption or fish consumption was low. The carcinogenic risk determined was high for Porto-Novo Lagoon water contact by the skin. Porto-Novo Lagoon fish consumption could result in a carcinogenic effect based on carcinogenic toxic equivalent (TEQ) values recorded (TEQ > screen value). The predominance of high-weight molecules (HMW) indicate that PAHs are mainly from pyrolytic sources.
Saline-alkali is one of the important environmental factors affecting oil-contaminated soil. In order to clarify the influence mechanism of salt content on microbial community of oil-contaminated soil, using 16S rDNA amplicon high-throughput sequencing technology, the composition of microbial community in oil-contaminated soil treated with different salinity (1%, 2%, 3%) were analyzed combined with soil environmental factors, and the variation trend of the abundance of functional genes under salt stress was analyzed. The results showed that salinity (1–3%) was positively correlated with soil microbial diversity and evenness. There were significant differences of dominant genera under different salinity stresses. The dominant bacteria were Halomonas and Dietzia at 1% salinity, Alcanivorax at 2% salinity, and Nocardioides, KCM-B-112, Staphylococcus, Bacillus, and Virgibacillus at 3% salinity. Redundancy analysis (RDA) showed that total petroleum hydrocarbon (TPH) and equivalent carbon were the decisive factors for the differential distribution of microbial communities in oil-contaminated soil. Salinity was significantly negatively correlated with Proteobacteria and Bacteroidota, and positively correlated with Firmicutes, Actinobacteriota, and Chloroflexi. TPH was significantly positively correlated with Chloroflexi, Actinobacteriota, Firmicutes, and Acidobacteriota. The results of KEGG functional annotation showed that salt stress decreased the abundance of genes related to metabolism, genetic information processing, and environmental information processing. In particular, the abundance of menbrance transport, xenobiotics biodegradation and metabolism, energy metabolism, and other genes closely related to membrane transport and degradation of oil hydrocarbon were negatively correlated with salinity. This study provides a basis for elucidating the stress mechanism of salt on microbial remediation of petroleum hydrocarbon–contaminated soil.
respectively. The photo-electrochemistry was under-taken to determine the conduction type of the spinel; a flat band of 0.06 V SCE with p-type behavior has been determined and an energy diagram of the hetero-system CFO/AgCl/Na 2 SO 4 electrolyte has been illustrated. As an application, the Solophenyl Red 3BL (SR 3BL), a recalcitrant dye, has been successfully oxidized. The effects of operational factors like the mass ratio (CFO/AgCl), pH, catalyst dose, and initial dye SR 3BL concentration (C o) were optimized. The results revealed a high photoactivity (100%) at pH ~ 3, a catalyst dose of 1 g/L, and an initial concentration (C o) of 10 mg/L within 150 min under visible light. The photo-oxidation data were fitted with the first-order kinetic, and half photocatalytic life of 19 min was extracted. In addition, photodegradation has also been experimented under solar light and a quasi-complete degradation was obtained with a faster kinetic. A pho-todegradation mechanism was proposed and the radical O 2 •− was found to be the main active species in the photocatalytic process. Moreover, this hetero-system demonstrated effective oxidation under solar light by facilitating photo-electron transport with the deference potential. Abstract To increase the photocatalytic activity of AgCl for environmental applications, a simple precipitation -deposition technique was established for the synthesis of the CoFe 2 O 4 /AgCl complex. For that, the phase of the nanoparticles was identified by X-ray diffraction (XRD), and combined scanning electron microscopy/energy-dispersive X-ray analysis. The point of zero charges (pHpzc) of CoFe 2 O 4 /AgCl was equal to 6.92. The gap energies of CoFe 2 O 4 (CFO) and AgCl, evaluated from the UV-VIS diffusion reflectance, were found to be 1.46 eV and 3.20 eV, Supplementary Information The online version contains supplementary material available at https:// doi.
Diffusion is one of the predominant transport mechanisms for the migration of contaminants in unsaturated soils. In most laboratory measurements of the diffusion coefficient, tedious chemical analyses of the soil are needed and the real-time concentration profiles cannot be obtained. In this study, the electrical resistance/resistivity (ER) method was combined with the half-cell method to measure the apparent diffusion coefficient in unsaturated soils. By using sodium chloride (NaCl) as a tracer, the influence of current frequency, energization history, and the insertion depth of the electrode on ER measurement was studied, as well as the effects of water content and NaCl concentration on soil ER. Diffusion tests with water contents ranging from 3 to 13% were performed. The concentration profiles were obtained by the ER and slice methods and the apparent diffusion coefficients at 72 and 144 h were determined by fitting the concentration profiles with Fick’s second law. The results showed that the measured soil ER values were stable under a current frequency higher than 1000 Hz and an electrode insertion depth ranging from 3 to 7 mm, and that the influence of energization history was negligible. Soil ER exhibited power function relationships with both water content and NaCl concentration. Furthermore, there was an obvious nonlinear relationship between diffusion coefficient and water content in the tested water content range. The results of the ER and slice methods agreed well, indicating that the ER method was a reliable and efficient way to establish diffusion characteristics in unsaturated soils.
Schematic representation of the vertical flow constructed wetlands
Average pollutant removal variation in different months in experiments 1 and 2 for TSS, COD, and BOD5 (experiment 1: with sand, experiment 2: with fine gravel)
Average pollutant removal variation in different months in experiments 1 and 2 for NH4-N and TKN (experiment 1: with sand, experiment 2: with fine gravel)
Average pollutant removal variation in different months in experiments 1 and 2 for PO4.³-P and TP (experiment 1: with sand, experiment 2: with fine gravel)
Performance comparison between experiments 1 (a) and 2 (b)
The objective of present study was to assess the water quality parameters in two experiments, comprising six configurations of pilot-scale vertical subsurface flow constructed wetlands (VSFCWs) by the comparison of the removal efficiency of organic matter and nutrient pollutants from water in arid region. Effluent treatments were studied in 5-month experiment under different operational conditions including (1) substrate type: sand (S) (experiment 1) or fine gravel (G) (experiment 2) and (2) agronomic species: Phragmites australis (Ph) or Typha latifolia (Ty). This experiment demonstrated that the vegetated wetlands were more efficient than non-planted (Np) ones in terms of removal of TSS, COD, NO3-N, and TKN from wastewater in the first experiment and more efficient for all water quality parameters except for TSS and BOD5 in the second experiment. For a given species, the efficiency of both experiments was generally higher with Ph–S than Ph-G and with Ty-S than Ty-G. Regarding unplanted CWs, Np-S performed better than Np-G for all of the tested water quality parameters except TSS. The wetland efficiency indicated that CWs planted with P. australis contributed greatly to the removal of COD, NO3-N, and TKN in the first experiment, and NO3-N, NH4-N, PO4³-P, and TP in the second experiment, whereas CWs planted with T. latifolia provided the highest removal only with TSS for the first experiment, and COD and TKN for the second experiment. The highest efficiency of unplanted setups (Np-S) was for BOD5, NH4-N, PO4³-P, and TP, while with Np-G was only for TSS and BOD5. In general, the first experiment is better than the second in removal efficiency for most of the tested parameters. Therefore, the use of sand substrate was more suitable than gravel for wastewater treatment in VSSFCW. As well as, P. australis performed better than T. latifolia for most of the studied parameters.
Soil polluted from Pb-acid batteries effluents (SPB) reduces the therapeutic potentials of Moringa oleifera, contaminates groundwater and surrounding soils via Pb transference. Amending SPB with P-loaded jujube twigs biochar (P-TB) can overcome these problems. Moreover, chitosan spray (CHs) on moringa, growing on SPB, can further biostimulate the production of essential phytochemicals and improve its anti-proliferative effects on human liver cancer cells (HePG2). In this pot experiment, moringa was grown on SPB (Pb = 639 mg kg–1) having control, CHs, TB, P-TB, TB+CHs, and P-TB+CHs treatments. Treatments effects on plant growth, Pb distribution in moringa leaf extract (MLE), shoots and roots, the status of plant phytochemicals and antioxidants, and concentrations of Pb and P in leachates were evaluated. Lastly, MLE was initially tested for its feasibility for human consumption through HEK 293 assay and later its antiproliferative efficacy on HePG2. Among all treatments, the P-TB+CHs exhibited the most significant results in compare to control. The P-TB+CHs resulted in the highest reduction of Pb concentrations in shoots, roots, and MLE by 79%, 70%, and 52%, whereas improved plant growth, phytochemicals, and antioxidants status. Interestingly, MLE at P-TB+CHs had Pb concentrations (3.27 mg L⁻¹) below the critical limit [5 mg kg⁻¹, WHO/FAO, 2007], was safer for consumption (HEK 293 cells viability = 133.6%), and depicted the least proliferation of HepG2 cells (35.8%). In leachates of P-TB+CHs, the concentrations of Pb (5.26 μg L⁻¹) and P (0.021 mg L⁻¹) were below the permissible limits for drinking water and preventing eutrophication, respectively. The lowest concentrations of Pb in MLE, plant parts, and leachates in P-TB+CHs were due to the formation of insoluble Pb-P compounds after Pb reacted with P present in P-TB and released P from P-TB. Hence, P-TB+CHs can remediate SPB, prevent groundwater contamination, avoid eutrophication, and boost the anti-cancer potential of moringa.
Hexavalent chromium (Cr(VI)) is the most hazardous and toxic oxidation state of chromium and for this reason, its effective removal from water below the drinking water limits is a major issue. Adsorption is a very promising technology, among several techniques, and activated carbon is a common adsorbent material, used for water treatment, due to its extensive surface area and porosity. In the last years, emerging composite adsorbents containing two or more metal oxides have gained significant attention. However, there are few publications related to the application of modified activated carbon with a combination of iron and manganese or copper oxides, to remove Cr(VI) from water, which is why these materials are the focus of this research. The effect of pH value, contact time, and initial Cr(VI) concentration was examined with respect to Cr(VI) removal. The results indicated that the maximum Cr(VI) removal was observed at pH 3 with 3 h contact time. The most effective adsorbent was the NFM material (Fe–Mn modified carbon) where a substantial quantitative removal of Cr(VI) (99.7%) was observed. Langmuir isotherm and pseudo-second order kinetic models fitted the experimental data sufficiently. The maximum adsorption capacity for NFM found was 44.42 mg/g by using the Langmuir model. Finally, the structure of the formed modified adsorbents materials was studied by the application of BET and SEM characterization techniques.
Since the modernisation of the agricultural sector in Morocco, the Triffa plain has been experiencing the development of techniques and increased production. However, agricultural intensification, the uncontrolled use of fertilisers and pesticides, and the succession of years of drought have contributed to the overexploitation of water resources and the degradation of the groundwater quality in the plain. To study the impact of the poor quality of groundwater (nitric pollution and salinisation) on the health of vegetation, we examined the spatiotemporal evolution of nitrates and salinisation in the plain, as well as the chlorophyll activity of crops (NDVI) using the Google Earth Engine (GEE) associated with MOD13Q1 version 6 images, for the years 2007-2009-2016-2022. The main results show an increase of 174% of the chlorophyll activity (NDVI ≥ 0.6) between 2007 and 2022, which make evidence of the significant intensification of the agricultural sector in the plain accompanied by a fast spread of nitric pollution regarding the groundwater. Hence, the area covered by the poor to very poor groundwater quality has almost doubled in a time interval of years (S2007Nmgl\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${S}_{2007}^{N\left(\frac{mg}{l}\right)}$$\end{document} = 235.5 km², S2022Nmgl\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${S}_{2022}^{N\left(\frac{mg}{l}\right)}$$\end{document} = 408.65 km²). According to the analysis of the normalised difference vegetation index maps calculated for the study periods: 2007-2009-2016-2022 and the Pearson correlation matrix between the different variables, we conclude that the degradation of groundwater quality negatively affects the chlorophyll activity, which will consequently have an impact on the crop yield. The results prove the excessive use of fertilisers and pesticides, which led to increased chlorophyll activity associated with fast degradation of the water’s quality concerning nitrate concentrations.
Characterization of the CNF beads, CNF-TG 60:40 beads, and Tara gum. a XRD spectra of both beads and Tara gum; b FTIR-ATR spectra of both beads and the Tara gum powder; c elemental percentage content data from the EA of the samples; and d thermogravimetric analysis with data extracts on the insert table
SEM images of a CNF beads and b CNF-TG 60:40 beads
Results of the adsorption kinetic experiments of 5 beads of CNF and CNF-TG 60:40 beads in a 15 ppm methylene blue (MB) solution corresponding to a removal efficiency, b adsorption capacity in mg of dye per gram of material, as well as the pseudo kinetic model fittings for c pseudo-first order and d pseudo-second order
a Adsorption capacity and b removal percent of the CNF and CNF-TG 60:40 beads obtained from the constant mass (200 wet mg) isotherm in solutions with 2, 5, 8, 10, and 15 ppm of methylene blue; c shows the Langmuir model fitting of the data, while d corresponds to the Freundlich model fitting
a Adsorption capacity and b removal percent of the data obtained from isotherms varying the amount of sorbent—CNF and CNF-TG 60:40 beads—from 0.1 to 0.8 g on solutions with 15-ppm of methylene blue
There is a growing interest in using naturally derived materials to generate adsorbent materials that can improve water quality by removing industrially derived pollutants such as dyes. In this work, composite beads were prepared from wood-based cellulose nanofibrils (CNF) and Tara gum (TG) by their co-dissolution in urea/sodium hydroxide alkaline media followed by co-regeneration in acidic media. The obtained beads were characterized by Fourier transformed infrared with attenuated total reflectance (FTIR-ATR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), elemental analysis (EA), and scanning electron microscopy (SEM), while the dye adsorption capacity was followed by UV–Vis spectroscopy. The results showed that a 40% substitution of the CNF with TG resulted in lightweight beads with 54% less solid content that maintained similar dimensions. These beads were tested for methylene blue (MB) adsorption at varying sorbent and pollutant concentrations. Methylene blue was selected as it is a common dye used as a redox indicator for tissue staining, dairy testing, microbiology, and in the textile and leather industries. Overall, the TG-CNF composite beads showed improved performance on dye adsorption, with 39.6% more capture when compared to the neat cellulose beads. The maximum adsorption capacity was calculated as 13.7 mg/g, utilizing an adsorption isotherm (2–15 ppm) fitted into the Langmuir model.
Microbially induced carbonate precipitation (MICP), a type of urease-based biomineralization, has been a well-researched technique in recent years for heavy metal immobilization; however, the efficiency of the process remains in question. Poly(amino acids) are known to enhance enzymatic activity. Thus, in the present study on carbonate precipitation induced by ureolytic Staphylococcus epidermidis HJ2, poly-Lysine (poly-Lys) was added to obtain higher enzyme activity, and response surface methodology-central composite design was used to identify the optimum conditions for this process. The effect of poly-Lys was investigated in lead (Pb) immobilization in aqueous solution by MICP. The results concluded that the addition of poly-Lys improved the capability of Pb remediation with 92% of the soluble Pb ions immobilized compared to 79% Pb ions in the absence of poly-Lys. The analysis of samples through X-ray diffraction and Fourier transform infrared spectroscopy further indicated that both a greater number and larger calcite crystals were formed during Pb immobilization in the presence of poly-Lys. This study confirms that the addition of poly-Lys is an effective and stable way to enhance MICP efficiency.
Natural radionuclides, radon exposure, soil particles, moisture, and dwellings from quarry towns in Greater Accra Region have been studied with hyper pure germanium detector (HPGe), passive radon detectors (CR-39), and sieving techniques. Soil formation and radioactivity levels have been estimated by determining correlation coefficient, clustering, principal, and factoring plot box. The average values for the ²²⁶Ra, ²³²Th, ⁴⁰ K, radon exhalation (²²²Rner), and indoor radon (²²²Rnin) are 27 ± 13 Bq/kg, 31 ± 14 Bq/kg 132 ± 103 Bq/kg, 87 ± 40 µBq/m²h, and 77 ± 37 Bq/m³. Eighteen (18%) and fifteen (15%) percent of the studied radon exhalation from the soil and radon indoor concentrations in dwellings from quarry towns were found to be more than the level of 125 µBq/m²h and 100 Bq/m³ from UNSCEAR and WHO reference level respectively. The average values for moisture and gravel, sand, and fine particles were 10.6 ± 6%, 33 ± 18%, 33.2 ± 13%, and 33.0 ± 6%. Radon exhalation with gravel particles and moisture recorded the highest positive and negative correlations of 0.81 and 0.85. The radon exhalation relates with moisture and soil particles far better than the indoor radon. Single-cluster and close bond was found to exist between the radon exhalation and ²²⁶Ra concentration. Three dimensional clusters contributed to 86.6% cumulative measured data variance. The study indicated that soil particles and moisture content have direct influence on natural radioactivity and radon levels in both indoor and outdoor environments. Statistical analysis performed also indicated that the natural radionuclides and radon concentrations have both positive and negative relation with the moisture and soil particles.
The integrated management of water resources is a requirement for environmental preservation and economic development, with the removal of nutrients being one of the main drawbacks. In this work, the efficiency of a bacterial consortium (Ecobacter WP) made up of eight bacterial strains of the genus Bacillus subtilis, Bacillus licheniformis, Bacillus megaterium, Bacillus cereus, Arthrobacter sp., Acinetobacter paraffineus, Corynebacterium sp., and Streptomyces globisporus was evaluated in the removal of nitrogen compounds in domestic wastewater in a plug flow system, in the extended aeration and bioaugmentation (FLAEBI). To promote the nitrification and denitrification processes, three doses were tested to establish the optimal concentration of the bacterial consortium on a laboratory scale and its subsequent application in an outdoor wastewater treatment plant (WWTP). The evaluation period was 15 days for each treatment in the laboratory and WWTP. The parameters monitored both at laboratory and outdoor were pH, temperature, dissolved oxygen, chemical oxygen demand (COD), biochemical oxygen demand (BOD5), ammonium, nitrites, and nitrates. The results indicated that the optimal concentration of the consortium was 30 mg L⁻¹, with a removal of 92% of nitrate at the laboratory and 62% outdoor. Such a difference is attributed to the different operation residence times and the volume that caused different concentration gradients. The consortium studied can be used to promote nitrification and denitrification processes that intervene in the removal of nitrogenous compounds in plants with similar operating conditions, without investment in restructuring or design modification of the WWTP. Graphical abstract
Column set up for the adsorption experiments: (a) standard solution of synthetic stormwater (0.2 mg L⁻¹ Zn²⁺ and 0.05 mg L⁻¹ Cu²⁺), (b) Masterflex peristaltic pump, (c) neoprene tube, (d) column, (e) Teflon disc, (f) packed shell particles, (g) glass wool, (h) beaker for eluent collection
Mean (± S. E.) copper (black) and zinc (white) concentrations detected in eluent after passing increasing volumes of synthetic stormwater through a column of scallop (squares), mussel (circles) or oyster (triangles) shell particles with a 63–150-μm size range. The initial concentrations of copper and zinc in the synthetic stormwater were 0.05 mg L⁻¹ and 0.2 mg L⁻¹, respectively
Mean (± S. E.) copper (black) and zinc (white) concentrations detected in eluent after passing increasing volumes of synthetic stormwater through a column of scallop (squares), mussel (circles) or oyster (triangles) shell particles with a 710–1180-μm size range. The initial concentrations of copper and zinc in the synthetic stormwater were 0.05 mg L⁻¹ and 0.2 mg L⁻¹, respectively
Mean (± S. E.) copper (black) and zinc (white) concentrations detected in eluent after passing increasing volumes of synthetic stormwater through a column of zeolite particles with a 1–2-mm size range. The initial concentrations of copper and zinc in the synthetic stormwater were 0.05 mg L⁻¹ and 0.2 mg L⁻¹, respectively
SEM micrographs of shell particles in the size range of 63–150 μm for mussel, oyster and scallop, before and after adsorption of heavy metal ions. Mussel shell before (a) and after adsorption (b) (1000×); c, d oyster shell before and after adsorption (1000×); e, f scallop shell before and after adsorption (1000×), respectively
Crushed shells from three bivalve mollusc species (mussel, oyster and scallop) in two particle size ranges (63–150 μm and 710–1180 μm) were tested for their ability to remove dissolved copper and zinc ions from synthetic stormwater in a column. For comparison, zeolite (1–2 mm), which is commonly used for heavy metal ion capture, was also assessed. All shell types of both particle sizes were effective in removing zinc from solution with 97–100% removal efficiency which was similar to the removal efficiency by zeolite (97.6%). The removal of copper was most efficiently achieved with oyster shell with a particle size range of 710–1180 μm (83.6%), which was similar to the removal efficiency by zeolite (83.4%). Brunauear-Emmett-Teller (BET) surface area measurements showed significant decreases in the surface area of the shells after exposure to synthetic stormwater due to adsorption of heavy metals, visually confirmed by observation of a fine layer of metal precipitate adsorbed to the shell particle surfaces using Scanning Electron Microscopy (SEM). Overall, the results indicate that crushed bivalve shells have excellent potential for the removal of dissolved zinc and copper from stormwater and should be tested in more complex stormwater studies. This work has significant implications for stormwater infrastructure design using a local, cheap and readily accessible waste material.
Despite the excellent potential of halloysite nanotubes (HNT) as an adsorbent for water-soluble molecules, their high aqueous dispersity makes it difficult to separate them from the aqueous media after adsorption. This study explores the potential of developing HNT-based magnetic field-responsive adsorbent to facilitate the separation of the HNT from aqueous media after adsorption. Fe3O4 was successfully synthesized from iron salt precursors using maize leaves extracts as reducing and capping agents after which different weight percentages were used to develop Fe3O4–HNT composites. The developed composite materials were characterized using x-ray diffraction, ultra violet–visible light spectrophotometry, scanning electron microscopy-energy dispersive x-ray spectroscopy, Fourier-transform infrared spectroscopy, and thermal gravimetric analysis. The adsorption capacity of the Fe3O4–HNT composite was examined using methylene blue dye and found to be dependent on the percentage of HNT in the Fe3O4–HNT composite. The adsorption kinetics of methylene blue by Fe3O4–HNT was best fitted with the pseudo-second-order adsorption kinetic model. The equilibrium adsorption of methylene blue was best described by the Freundlich isotherm model and the inter particle diffusion model describes the rate-controlling steps. The thermodynamic analysis of the adsorption process revealed that ΔG°, ΔH°, and ΔS° values were dependent on temperature and the amount of HNT in the Fe3O4–HNT composite. The results from the study revealed the potential application of HNT-based magnetic f ield responsive adsorbent in water treatment technologies.
Globally, universities, institutions, and companies are aiming to reduce the use of single-use plastics as plastic litter, and plastic degradation generates secondary microplastics, all of which cause negative impacts on the environment. In this study the authors conducted a questionnaire-based survey to assess the willingness and motivation of stakeholders within academic settings to change daily habits to minimize plastic and microplastic pollution. The questionnaire, which was answered by 276 individuals with affiliation to the American Farm School or collaborating academic institutions, but primarily the American Farm School, was used to draw conclusions. Results showed that most stakeholders are ready to adapt to eliminate the use of single-use plastic within their institution and showed a high level of willingness to participate in cleaning campaigns. It is crucial to combine any new measures or policies with the proper education around why these measures are being enforced, so as to raise awareness and receptivity to those that are not familiar with microplastics and microplastic pollution.
Metal(oid)s contamination in agricultural soils can create adverse environmental conditions and pose human health risks. The present study was conducted to assess metal(oid)s contents, source identification, and ecological and health risks due to metal(oid)s contamination in BISIC industrial region soils of Tangail district Bangladesh. The mean ± SD of chromium (Cr), nickel (Ni), copper (Cu), arsenic (As), cadmium (Cd), and lead (Pb) were 8.67 ± 8.27 mg/kg, 13.76 ± 18.13 mg/kg, 23.46 ± 23.62 mg/kg, 4.93 ± 2.87 mg/kg, 1.56 ± 1.70 mg/kg, and 16.63 ± 9.32 mg/kg, respectively. The positive matrix factorization model identified lead-acid battery sources (49.53%), industrial sources (33.66%), and agricultural practices (16.63%) as potential sources of studied metal(oid)s. Contamination factor value of Cd (1.65) in the study area soils showed moderate contamination, whereas Nemerow-integrated pollution index (1.95) indicated slightly soil pollution and potential ecological risk (179.67) showed considerable risks. The HI value for adult male, female, and children due to ingestion, inhalation, and dermal contact was higher than 1, assuming severe non-cancer health risks. Total cancer risk value of Cr (1.14E-02) Ni (7.24E-04), As (2.33E-03), and Cd (3.09E-04) for adult male; Cr (1.23E-02), Ni (7.81E-04), As (2.51E-03), and Cd (3.32E-04) for adult female, whereas Cr (5.32E-02), Ni (3.38E-03), As (1.09E-02), Cd (1.44E-03), and Pb (1.00E-04) for children were exceeded the highest acceptable limit (1.0E-04) indicating possible cancer risks. The present study will help environmental engineers and policymakers to control metal pollution in agricultural soils based on applicable and reasonable evaluation methods.
Remote sensing technology using synthetic aperture radar (SAR) images is the most effective technique for ocean oil spill surveillance in the hot spot regions like surroundings of oil platforms, oil rigs and major ship traffic routes to help protect the ocean ecosystem. A framework for the detection and quantification of daily oil pollution in the ocean is presented and explained in detail. This paper describes a new approach to SAR oil spill detection using bag of visual words (BOVW) method of feature extraction and classification. A labelled dataset of verified oil spills and look-alikes with the aid of Marios Krestenitis is used for demonstrating the use of BOVW method for feature extraction and classification of oil spills and look-alikes. The overall accuracy of 93% is obtained for the classification of oil spills and look-alikes from SAR images. An analysis of the BOVW method of feature extraction and classification in this paper has highlighted the importance of speeded-up robust features (SURF) features used by the algorithm for accurately classifying the oil spills and look-alikes. Fixed oil platforms and major ship traffic routes in the Eastern Arabian Sea are selected for oil spill surveillance. Initially, detection and quantification of some reported oil spills in the year 2017 is performed for validation. Subsequently, the technique is implemented for unreported oil spills from January to November 2020 to investigate the occurrence of oil spill incidents from oil fields and ships in the selected study region.
It is unreasonable to exclude all or part of the cold starting stage data in the current PEMS test data processing methods of heavy-duty diesel vehicles domestic and international. Therefore, this paper studies the PEMS data evaluation method including cold start stage data. In this study, PEMS tests were carried out on three different types of heavy-duty diesel vehicles. After that, the common data processing methods of the PEMS experiment were summarized and analyzed. In order to study the validity of different methods in processing the different stages’ experimental data of PEMS, the moving average window method (MAW) and cumulative averaging method (CA) were used to process the PEMS experiment data of cold stage and non-cold stage, respectively. Finally, a novel weighted evaluation method has been established creatively. The rationality of weight distribution was discussed, and 5 experiments were designed to verify the validity of the method. The results show that the MAW method only evaluates the effective window accounting for about 40%. The CA method can effectively evaluate the emission characteristics of cold and non-cold stages. The weighting method established based on the WHTC test can well reflect the contribution rate of pollutant emission in the cold start-up stage of the PEMS test of heavy diesel vehicles. Furthermore, for CO, NOx, and PN, the variation correlation coefficients between the emission in the cold stage and the weighted results are all above 0.8. The novel evaluation method can reasonably reflect the emission characteristics of the PEMS test of heavy-duty diesel vehicles during the cold stage and non-cold stage.
Traffic-related air pollutants are the main responsible for outdoor air pollution in cities. Transport has an essential role in the lives of individuals and societies, closely depending on outdoor workers, which are continuously exposed to ambient air pollution. Therefore, the aim of the present study was to determine both the levels and the health risk of NO2 and O3 exposure in professional drivers and the health effects of this exposure. Professional motorcyclists (n = 38) and office workers (n = 50) from Porto Alegre, Brazil, were enrolled in our study from November 2018 to March 2020. Individual exposure to air pollutants was assessed by passive monitoring. Glucose and lipid profile, blood pressure, and heart rate were performed in all subjects. Toxicological risk was estimated based on the potential intake dose. Individual exposure to NO2 and O3, fasting glucose (p = 0.0013), triglycerides (p = 0.0022), lipid accumulation product (p < 0.0001), diastolic blood pressure (p < 0.0001), heart rate (p = 0.0008), and risk quotient (p < 0.0001) were increased in the professional motorcyclists group. HDL levels showed an augmentation in the office workers group (p = 0.0166). Moreover, NO2 exposure showed a strong positive correlation with increased fasting glucose serum levels (p < 0.0001 and r = 0.8673), O3 exposure showed very strong association with triglycerides levels (p < 0.0001 and r = 0.9134), and associations between NO2 and O3 exposure and diastolic blood pressure were also found (p < .0001 and r = 0.6397 and p < 0.001 and r = 0.5946, respectively). Our results suggest that professional motorcyclists are at high risk to develop and/or worsening diseases due to long-term air pollution exposure.
Due to its porous texture and heterogeneous surface chemistry, activated carbon (AC) gained interest in the removal of pollutants. The present work aims at investigating granular activated carbon selectivity for nitrogen oxides (NOx) removal from diesel engine flue gases. Two samples of AC are investigated, namely, (1) raw-AC, named AC0, and (2) urea-supported-AC, named AC1. A regeneration of AC0 is conducted using a heat treatment at 800 °C. This study follows two pathways. First, a deep analysis of physical–chemical characters of activated carbon samples is carried out. The characteristic of activated carbon includes Brunauer-Emett-Teller (BET), Scanning Electron Microscope (SEM), and Boehm titration analysis. Second, experiments are conducted using the exhaust system post treatment to investigate the NOx-adsorption capability of AC0 and AC1. The NOx amount, which is chemically converted using AC1, equals 80%. Activated carbon could be a promoted precursor whether as NOx Storage Reduction (NSR) or as a Selective Catalytic Reduction (SCR) using urea.
The location of the sample collection site
Averaged deposition fluxes of nitrogen species (upper panel) and contributions of each nitrogen species to the TN (bottom panel) in the deposition by rainfall and throughfall
Averages of the measurements of the WD and TD, and the estimations of the DD and CE for the WION
The observations of rainfall, throughfall, stemflow, and aerosols were conducted at a forested site on the northern foot of Mt. Fuji in Japan. The aims of this study were to understand the deposition fluxes and processes of the water-insoluble organic nitrogen (WION) from the atmosphere to the forest canopy and floor. The deposition flux of the total nitrogen (TN) that includes all nitrogen species to the forest floor was 1.944 mgN m⁻² day⁻¹ on average. The contribution of the WION to the TN deposition flux was about 29%, which suggests the importance of the WION for discussing the nitrogen deposition from the atmosphere to forests and the nitrogen cycle in the forest ecosystem. The estimation by a canopy budget model indicated that the dry deposition of aerosols on the canopy was the most important process for the WION deposition.
Nutrient content in wastewater expressed in mg L.⁻¹ (source: Tak et al., 2013)
Concentration of different metals in different crops after wastewater irrigation application (source: Cheshmazar et al., 2018)
In many developing countries of the world, freshwater scarcity has made wastewater application a common practice in the agricultural sector. In water-deficit countries, wastewater is widely used for irrigation purposes. It is deemed as the most conventional and low-cost practice that has been receiving immense attention in the agricultural sector due to the global decline in freshwater resources. In many arid and semiarid areas of the world, where water reservoirs are limited and decreasing day by day, farmers are considering other alternative sources of water such as wastewater, seawater, rainwater, stormwater, and captured condensate. Hence, wastewater is the richest source of macro- and micronutrients, resulting in improving plant growth and performance. However, some negative impacts are also associated with the use of wastewater in agriculture including health risks and environmental degradation. Therefore, to minimize the potential health hazards, wastewater should be treated before its application. This review highlights the beneficial and harmful impacts of wastewater application on soils and plants which include the transfer of potentially toxic elements into plants and humans. Integrated sustainable solutions and future perspectives are also proposed.
Particulate matter (PM2.5) is one of the major threats to public health, particularly Dhaka City in Bangladesh, frequently cited as one of the worst cities in the World in terms of air quality. This study examines the effects of six environmental (land surface temperature (LST), digital elevation model (DEM), water vapor concentration, wind speed, rainfall, and normalized difference vegetation index (NDVI)) and six economic factors (population density, road density, gross domestic product (GDP), poverty rate level, and percentage of low-income groups in rural and urban setting) on PM2.5 concentration in five industrial cities of Bangladesh using geographically weighted regression modelling (GWR) and machine learning (ML) tools. The mean annual rate of PM2.5 concentration increased by > 42% during 2002–2020 in all cities. Dhaka and Narayanganj districts were affected the most. Goodness-of-fit (R2) was 93% (environmental factors) and 73% (economic factors). Environmental factors: LST (100%) and water vapor concentration (100%) were correlated positively with PM2.5, while DEM (100%), rainfall (83%), NDVI (81%), and wind speed (84%) had a negative relationship at 95% confidence level. β-coefficients of DEM (p < 0.02), LST (p < 0.01), water vapor concentration (p < 0.01), NDVI (p < 0.02), and poverty rate (p < 0.01) were correlated negatively. Moreover, machine learning has extracted a good prediction of PM2.5, ranging the R2 between 0.79 and 0.86%. This study can be replicated in other cities by incorporating socio-economical, local geo-environmental, and meteorological with other air pollutants.
Impact of solution pH on aqueous persistence of oxidants. a KMnO4 and b PS
Impact of matrix anions on the persistence of oxidants. Control represents the scenario with no matrix anion presence. a KMnO4 oxidant at 8 pH and 15 °C. b PS at 4 pH and 15 °C
Influence of the presence of soils on KMnO4 aqueous persistence. Control represents the scenario with no soil presence. a Decomposition of KMnO4 with different soils. b Change of the calculated NOD values of different soils consumed by KMnO4 in 30 days
Decomposition of PS with different soils. Control represents the scenario with no soil presence
Influence of the presence of subsurface minerals on oxidant persistence. Control represents the scenario with no soil presence. a KMnO4. b PS
To combat groundwater pollution, in situ chemical oxidation (ISCO) has been extensively adopted to degrade groundwater pollutants. A critical factor associated with the success of ISCO is the stability (or persistence) of the chemical oxidant. A higher oxidant stability can result in a higher integrity and a sustained oxidation capacity for the oxidants. Both potassium permanganate (KMnO4) and persulfate (PS) are two most commonly employed chemical oxidants for ISCO operations. Although a number of experimental studies have been conducted to evaluate the persistence of these two oxidants, systematic investigations of the persistence of KMnO4 and PS and especially the impact of different subsurface materials on oxidant stability are still limited. To fill these knowledge gaps, the stability of both KMnO4 and PS oxidants has been systemically evaluated in this study. For each type of oxidant, the impact of solution pH and the presence of matrix anions on oxidant stability were evaluated. Furthermore, the persistence of these oxidants was examined in the presence of a number of soils and subsurface minerals with the natural oxidant demand value of each subsurface material being determined. It is found that KMnO4 can directly react with the reducing constituents in the soils via chemical oxidation where PS requires to be activated first in order to produce sulfate radical to react with reducing species. This study provides the essential information of the stability of KMnO4 and PS under different physiochemical conditions and in the presence of different subsurface materials for groundwater ISCO treatment. The conclusions from this study can substantially facilitate the ISCO operations by use of KMnO4 and PS in a more efficient and cost-effective manner.
The present work calculates the steelworks increments of particulate matter (PM) mass and chemical composition of Partisol, Filter Dynamic Measurement System (FDMS), and Streaker data using wind sector analysis. Particulate matter sampling took place at the perimeter of a steelworks complex in Port Talbot, Wales, UK, between April 17 and May 16, 2012. Two sampling sites were selected representing the upwind and downwind sectors. Daily Partisol, hourly FDMS, and Streaker PM samples were analysed for mass and chemical composition using standard procedures. Wind-determined analysis was carried out on the daily and hourly PM results by finding the differences between the downwind and upwind PM data that were associated with the steelworks production units. Little Warren (LW) monitoring site located at the coastal site of Port Talbot represents the upwind site when the prevailing wind blows from westerly and south-westerly across the steelworks complex to the fire station (FS), the upwind site. When the prevailing wind blows from the southeast and south, LW represents the downwind sector. Results indicated common episodic days where both the FDMS and Partisol PM10 data exceeded the World Health Organization (WHO) limit of 50 µg m⁻³ (24-h mean). The Partisol PM2.5/PM10 ratios revealed elevated coarse particle concentrations, whilst the FDMS PM2.5/PM10 ratios showed domination by PM2.5 particles. Wind-determined profiles of PM during the 1-month campaign provided useful information about the tracer elements specific to a particular processing unit of the steelworks industry. The annual PM steelworks increments at Port Talbot by Partisol and FDMS are approximately 2.0 µg m⁻³.
The major focus of the research work is on the evaluation of the hydrogeochemical characteristics, water quality index (WQI), and health risk assessment in a coal mining region of eastern India. Fifty-six water samples were collected from tube wells, dug wells, streams, and rivers for the present study. The major hydrogeochemical facies are Ca-Mg-HCO3 and Ca-Mg-Cl-SO4, which indicates the dissolution of carbonate phase minerals. Relatively higher levels of Ca²⁺ and Mg²⁺ and lower SO4²⁻ concentration with alkaline pH conditions could have controlled the dissolution of ions in the coal-bearing aquifer. Rock-water interaction, ion exchange processes, and carbonate phase dissolutions are the major hydrogeochemical processes governing the ionic concentrations in the groundwater. Geochemical modeling shows groundwater samples are in near saturation to equilibrium condition with the carbonate phase minerals such as calcite and dolomite, while undersaturated with sulfate phase minerals such as anhydrite and gypsum. The results of the multivariate analyses reveal the contribution from natural and anthropogenic sources that determines the groundwater composition in the coal mining area. Based on (WQI) model, about 82% of the water samples were excellent to good category. The cumulative health risk assessment based on ingestion of (F⁻ and NO3⁻ concentrations) in groundwater indicates a non-carcinogenic risk of 90% for children and 92% for adults. Therefore, health risk reduction measures and necessary action plans should be adopted to improve the drinking water quality standard and for the protection of water resources in the coal mining regions.
Flowchart of the treatment system
Aerial view, schematic longitudinal, and 3D section of the constructed wetlands. (A) Conventional, (B) With horizontal baffles. (C) With vertical baffles
Total of microcontaminants divided by classes in the anaerobic reactors (A) and in the CWs (B) in the three phases
Contribution of each CW for the total discharge of microcontaminants in the three monitoring phases
The present study aimed to evaluate the potential of horizontal subsurface flow constructed wetlands (HSSF-CWs) with different arrangements of baffles inside and cultivated with fountain grass (Pennisetum setaceum) in the removal of microcontaminants from wastewater from a university campus. The HSSF-CWs were made of fiberglass with three different configurations: CW-A without baffles; CW-B with baffles fixed to the sides; and the CW-C with baffles fixed above and below the reactor. It was analyzed the contaminants ibuprofen (IBU), acetaminophen (PAR), 4-octylphenol (4OC), caffeine (CAF), 4-nonylphenol (4NP), naproxen (NPX), bisphenol-A (BPA), diclofenac (DCF), estrone (E1), estradiol (E2), ethinylestradiol (EE2), and estriol (E3) by pre-concentration using Strata SAX cartridge and determined by gas chromatography coupled with mass spectrometry. Microcontaminants were monitored monthly between November/2018 and April/2019. Among the twelve microcontaminants evaluated, the endocrine disrupters 4NP and EE2 were not identified in any of the samples. In the affluent, the average concentrations ranged from 87.3 to 2559.2 ng L⁻¹ for pharmaceuticals, 584.6 to 1658.3 ng L⁻¹ for caffeine, and 49.1 to 584 ng L⁻¹ for endocrine disruptors. The CWs with different baffle arrangements were efficient in removing the organic pollutants evaluated. Caffeine stimulant was the contaminant that presented the highest removal, followed by pharmaceuticals, and endocrine disruptors. Considering the risks related to the presence of these contaminants in wastewater, the results from this work represent an important contribution for studies related with the microcontaminants removal in HSSF-CW.
Groundwater pollution is a significant threat to the public health and environment. Existing groundwater remedial approaches include ex situ treatment and conventional in situ chemical oxidation methods. Although these two methods are widely adopted for groundwater cleanup, continual treatment effectiveness is not satisfactory due to several physicochemical challenges, such as tailing, back diffusion, and concentration rebound. Moreover, these two methods require significant energy and chemical inputs. As an alternative to conventional approaches, controlled release materials are able to discharge chemical oxidants in a continual manner with a substantially prolonged release longevity and treatment time. Thus, these materials are characterized as cost-effective and low-maintenance. In this study, controlled release bead (CRB) materials composed of potassium permanganate (KMnO4)-paraffin were synthesized and evaluated for their performance in degrading alkylbenzene organics. Both batch and dynamic degradation studies indicate that the fabricated CRBs can gradually release KMnO4 into the aqueous phase to degrade alkylbenzenes and the eventual effectiveness in pollutant degradation is on par with the aqueous KMnO4 solution. Furthermore, KMnO4-cement CRBs were fabricated and tested for KMnO4 release kinetics from the CRB surface. It shows that system temperature can considerably influence KMnO4 release longevity and hence treatment lifetime. This study provides the essential information of the novel CRB materials for groundwater pollution remediation with a reduced energy and chemical consumption and a lower environmental footprint. This study expands our capacity in designing, laboratory testing, and modeling these novel materials to facilitate their potential field remedial application.
Modified algae with nano copper oxide (CuO) were used as adsorption media to remove tetracycline (TEC) from aqueous solutions. Functional groups, morphology, structure, and percentages of surfactants before and after adsorption were characterised through Fourier-transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). Several variables, including pH, connection time, dosage, initial concentrations, and temperature, were controlled to obtain the optimum condition. Thermodynamic studies, adsorption isotherm, and kinetics models were examined to describe and recognise the type of interactions involved. Resultantly, the best operation conditions were at pH 7, contact time of 240 min, 5 g/L of dosage, initial concentration of 25 mg/L, and a temperature of 45 °C. The removal percentage of TEC under the optimum condition was 96%. Thermodynamic analysis indicated that the removal efficiency was slightly increased with temperature depending on the positive value of Δ𝐻°, thus indicating that the adsorption phenomenon was endothermic. The Langmuir model fitted the study (R² = 0.998), demonstrating that the adsorption sites were homogenous. The experimental results were best matched with the second-order kinetic model, implying that chemisorption was the primary process during the adsorption process. Compared to previous research and based on the value of qmax (15.60 mg/g), the biomass was suitable for TEC removal.
Location of sampling site
Concentration of nitrate species (HNO3, P-NO3⁻ and total nitrate (T-NO3⁻ = HNO3 + P-NO3⁻) determined in four-stage (type A) and five-stage (type B) filter pack systems. Here, P-NO3⁻ in type A is determined by PTFE filter and P-NO3⁻ in type B is expressed as the sum of PTFE (fine particle) and torus-shape quartz filter paper (coarse particle)
∆ and H⁺ concentration in the PTFE filter (F0) determined in type A and type B in summer (a), autumn (b), winter (c), and spring (d)
72-h backward trajectories calculated at 1500-m height in each season, in which trajectories in red color indicate the days with positive ∆
Particulate sulfate (SO4²⁻) usually exists in the atmosphere in the chemical form of (NH4)2SO4 and/or NH4HSO4. In contrast, we could successfully detect particulate sulfuric acid (H2SO4) without neutralization by ammonia in the monitoring campaign by filter pack methods. The presence of ambient H2SO4 was revealed from the concentration difference in a nitric acid gas (HNO3) determined by a four-stage filter pack and a five-stage filter pack. Ambient H2SO4 could exist more frequently in summer (August) than in winter (January). Trajectory analysis identified the attribution of ambient H2SO4 as follows: in summer, SO2 released from a domestic volcano in Japan was responsible for the ambient H2SO4, while in other seasons, SO2 was carried to the survey site by northwestern air masses from the Asian continent.
classes of VI in the study area, namely low (31.5-60), moderate (60-75), and high (75-13). The validation of the vulnerability model revealed a good correlation with NO 3 − and provided a high discretization of the groundwater vulnerability from anthropogenic pollution. This approach implies that more efforts should be taken to preserve the groundwater of the Regueb basin from contamination. And it could be used as a tool for water resource management in the future in similar regions. Abstract In recent years, Regueb basin has been facing groundwater quality degradation due to the excessive use of fertilizers and pesticides, which is the result of strong agricultural activities. Physicochemi-cal elements (TDS, NO 3 −) and several factor types (geologic, hydrogeologic, and geomorphologic) were used in this study. The weighted model (TDLFSGC) was used to determine the groundwater vulnerability index (VI) to the pollution which is subsequently validated by Pearson correlation with nitrate concentrations. The results show that the TDS in groundwater ranged between 1.19 and 16.92 g/L and the NO 3 − concentrations varied from 150 to 920 mg/L. The vulnerability map generated using GIS shows three
Solanum nigrum (S. nigrum), a newly discovered Cd-hyperaccumulator, has attracted the attention of many scholars. The present experiment was aimed to explore the difference of Cd accumulation ability among different S. nigrum genotypes and reveal the underlying mechanism. Three different genotypes of S. nigrum were grown in a hydroponic system with different Cd levels (0, 10,25, 50, 100 mg L⁻¹, respectively); the Cd content, subcellular distribution of Cd, net Cd fluxes of in S. nigrum roots, and organic acid content in S. nigrum leaves were investigated. The results showed that Cd was more abundant in cell sap and cell wall fraction than that in organelle fraction. The content of organic acids in three species of S. nigrum was citric acid > tartaric acid > acetic acid > malic acid > oxalic acid. Non-destructive micrometry (NMT) revealed that the net Cd fluxes of the same species of S. nigrum first increased and then decreased with increasing of Cd concentration. And among all tested genotypes, the net Cd fluxes were stronger in the genotype of S. nigrum (HZ).
AWCD, Shannon Index, richness, and evenness of each treatment (control, AsV, and AsIII) over 5 readings (24, 48, 72, 96, and 120 h) for all exposures (3, 30, 180, and 360 days)
2-way ANOVA test of the area under the curve of the parameters AWCD, Shannon Index, NUSE, and PUSE at four exposure times. *p = 0.03. **p = 0.01
Arsenic (As) is a soil contaminant with important interactions with the soil microbial community. Upon contamination, soil microbes can display metabolic changes, which can be measured through the profiling of their potential for the oxidation of organic substrates. The present study aimed to evaluate the microbial metabolic profile in soil samples containing different forms of inorganic As (AsIII and AsV) in a 360-day experiment. Soil samples were contaminated with AsIII or AsV (15 mg/kg soil) and the microbial metabolic profile was evaluated after 3, 30, 180, and 360 days of experiment. After these periods, the assay was performed using Biolog Ecoplate™ microplates followed by incubation with readings every 24 h for 5 days. The main parameters evaluated were metabolic activity (AWCD), diversity (Shannon index), and use of substrates containing N or P (NUSE and PUSE). It was observed that the microbial community reacted differently according to the exposure time and for the two contaminants. While metabolic activity decreased in the AsV group (p = 0.03) in 30 days when compared to the control group, the use of sources containing nitrogen decreased in the AsIII group (p = 0.01) only after 360 days when compared to the control group. These findings indicate that the soil microbial community suffers a decrease in metabolic activity when exposed to arsenate in short exposures, whereas, in soil with long-term exposure to arsenite, the microbial community suffers a decrease in the consumption of nitrogen-rich substrates.
In this study, the use of copper(II) oxide (CuO) powders as catalyst and continuous wave (CW) multimode semiconductor diode laser (450 nm) was investigated for decolorization of Basic Red 18 (BR18) and Reactive Red 180 (RR180) aqueous dye solutions. The effects of laser power (0.5–2.5 W), pH of solution (2–10), CuO catalyst loading (0.25–1.50 g/L), H2O2 concentration (0.28–2.22 mg/L), initial dye concentration (20–60 mg/L) were studied systematically. Maximum removal efficiency was observed as 100% for RR180 and 94.34% for BR18 under the optimum conditions. Kinetic analysis of BR18 and RR180 dye decolorization reaction indicated that the overall rate order of the reaction was the pseudo first order. CuO demonstrated satisfactory reuse capability as the catalyst for five consecutive cycles without any decrease in its activity for RR180 dye.
Study area and sampling sites. The red star represents the city, county, and district in the Jiulong River Basin (JRB), while the green dot represents the sampling sites in the Jiulong River Estuary (JRE)
Spatial distribution of THg and isotopic compositions in JRE (surface sediment is measured in ng/g, and surface water in ng/L). Each data was calculated as a mean ± 1 SD of all samples collected during the wet and dry season
Mass-independent fraction of mercury isotopes in the JRE. The analytical uncertainty of mercury isotope measurements (2σ) is presented in Table S1. a Surface water in the dry season; b surface water in the wet season; c surface sediment in the dry season; and d surface sediment in the wet season
Plot of Δ¹⁹⁹Hg versus δ.²⁰²Hg of surface water and surface sediments in the JRE. The analytical uncertainty of mercury isotope values (2σ) can be seen in Table S1. Error bars are calculated as mean ± 1 SD for seawater, soil, litter, and sediment, as well as deposition, and are presented in Table S4. Error bars were mean ± 2 SD for wastewater as reported in previous studies (Table S5). The gray rectangle with a black dashed line represents the potential urban source of mercury. References for plotted data are seawater (Huang et al., 2021), local wet deposition (Huang et al., 2018), remote dry deposition (Demers et al., 2013, 2015; Gratz et al., 2010), wastewater (excluding desulfurized seawater) and submarine groundwater (Zhang et al., 2020), rock (Zhang et al., 2020), industrial soil (Li et al., 2021), agriculture soil (Zhao et al., 2021), and forest soil/litter (Zheng et al., 2016b)
Plot of Δ²⁰⁰Hg versus δ.²⁰²Hg of surface water and surface sediment in the JRE. The analytical uncertainty of mercury isotope measurements (2σ) is presented in Table S1. Error bars were calculated as mean ± 1 SD for wet and dry atmospheric deposition and forest soil and litter (Table S3). Error bars were mean ± 2 SD for domestic sewage as reported in previous studies (Table S5). References for plotted data are forest soil/litter (Zheng et al., 2016b), local wet deposition (Huang et al., 2018), remote dry deposition (Demers et al., 2013, 2015; Gratz et al., 2010), and domestic sewage (Zhang et al., 2020)
Concentrations and isotopic compositions of mercury in surface water and surface sediment of the Jiulong River Estuary (JRE) were measured. Differences in total mercury (THg) concentrations in surface water between dry and wet seasons were insignificant, which was also the case with surface sediment THg levels. Large variations in Hg isotopic compositions were observed both in surface water (δ²⁰²Hg: − 1.53 to 0.61‰; Δ¹⁹⁹Hg: − 0.22 to 0.20‰) and surface sediment (δ²⁰²Hg: − 2.64 to − 0.96‰; Δ¹⁹⁹Hg: − 0.27 to 0.25‰). Concentration correlations between mercury and dissolved inorganic nitrogen (DIN) implied that mercury in surface sediment may undergo resuspension and be re-emitted to the water surface. The negative Δ¹⁹⁹Hg in most of the surface sediments and the correlation between mercury and DIN in the wet season indicate that soil erosion is the major source of mercury. The main sources of mercury in surface water are precipitation and natural soil. The correlation between mercury and dissolved inorganic carbon, perfluoroalkyl substances, polycyclic aromatic hydrocarbons, and dissolved Cd indicates that the contribution of underground water and industrial and urban waste cannot be ignored, which is supported by the positive signature of Δ¹⁹⁹Hg. The results of the isotopic analysis also indicate that atmospheric dry deposition is another source of mercury in surface water. The study suggests that the mercury distribution in the estuary is related to some other pollutants. Both using mercury isotope signatures and the distribution links between mercury and other pollutants can be used to better understand the processes and sources of mercury in the estuary.
Urbanization leads to changes in the natural state of the environment, including changes in natural aquatic habitats within urbanized zones. In the present study, the impact of urbanization on the water quality of urban streams, which are important sources of drinking water and recreational areas for the urban population, was investigated along two streams in the Croatian capital Zagreb. The upper reaches of the two urban streams are largely pristine (located within a nature park), whereas their downstream reaches are physically altered and impacted by anthropogenic (residential, municipal, industrial, agricultural) activities. Several physico-chemical parameters were measured in the streams using standardized methods, while concentrations of 30 dissolved metals/metalloids in the water were measured using a high resolution inductively coupled plasma-mass spectrometer. Although the water quality of the streams studied was rather good, the influence of urbanization was evident. Different contamination levels were observed along the two streams, depending on the specific anthropogenic activities and contamination increase in the stream reaches closer to the city centre. Furthermore, the summer season of low water levels and water discharges proved to be the most critical time, with significant increases in many metals/metalloids in the water. Since stream quality evidently reflects urbanization, continuous monitoring of urban streams is recommended, especially during the warmer seasons. The results of this study could help to understand the effects of the “urban stream syndrome” along urban streams and its seasonal characteristics.
(a) Location map of the study area (Chhattisgarh, India); (b) initial stage of P. guajava plantation; (c) restored waste dump after 7 years of P. guajava plantation
Phytorestoration strategy of solid waste dump (A. regrading of waste dump; B. topsoil blanketing and coir matting; C. grass-legume seeding; D. guava plantation)
Phytorestoration efficiency of P. guajava grown in restored waste dump
Solid wastes generated from industrial sponge iron plants (ISP) are categorized as hazardous waste due to their extremely fine, loose texture, toxic metal concentrations, and being wind borne in summer; their unscientific disposal leads to severe land degradation and environmental pollution. In the present study, phytorestoration of such a hazardous waste dump in central India was carried out through blanketing with forest soil (substratum for vegetation growth) followed by plantation with Psidium guajava (L.) saplings (2500 saplings/ha). The present study aimed to assess the efficiency of fruit orchards in restoring the soil health of waste dumps (WD) without causing any health hazards, allowing the possibility for an economically viable after use of the degraded land. Heavy metal concentration (Mn, Zn, Cu, Cr, Ni) in blanketed topsoil, plant tissues (roots, leaves, fruits), and its associated risk due to consumption of guava fruits were analysed. Soil health with reference to organic carbon (1.7%), total nitrogen (1727.7 mg kg⁻¹), and exchangeable potassium (162.3 mg kg⁻¹) at the 7-year-old restored site was significantly higher than that of the initial stage of revegetation. No probables of health risk was found due to consumption of guava fruit (growing on WD) as the target hazard quotient (THQ) of all the metals in fruit was <1. Restoration cost analysis of the present study showed that only 5% of total costs were responsible for the development of fruit orchards. Therefore, the study concluded that fruit orchards could be a sustainable alternative for phytorestoration of WD, which will also provide socio-economic return to stakeholders. Graphical abstract
Severe droughts and mismanagement of water resources during the last decades have pro�pelled authorities in the Kurdistan Region to be con�cerned about better management of precipitation which is considered the primary source of recharg�ing surface and groundwater in the area of interest. The drought cycles in the last decades have stimu�lated water stakeholders to drill more wells and store uncontrolled runof in suitable structures during rainy times to fulfll the increased water demands. The optimum sites for rainwater harvesting sites in the Qaradaqh basin, which is considered a water-scarce area, were determined using the analytical hierar�chy process (AHP), sum average weighted method (SAWM), and fuzzy-based index (FBI) techniques. The essential thematic layers within the natural and artifcial factors were rated, weighted, and ntegrated the northern and around the basin’s boundary, while unsuitable areas cover northeastern and some scat�ter zones in the middle due to restrictions of geology, distance to stream with the villages, and slope crite�ria. The total harvested runof was 377,260 m3 from all the suggested structures. The proposed sites may provide a scientifc and reasonable basis for utiliz�ing this natural resource and minimize the impacts of future drought cycles.
Map of the study sites in the northern Gulf of Mexico
A simplified diagram of the N cycling experimental design
The A) Observed alpha diversity, B) Chao1 alpha diversity, C) PCoA of select HC degrading groups, and D) total relative abundance of the nine HC degrading groups. Different letters indicate statistical differences (p < 0.05)
The A) Denitrification potential rates, B) DNRA potential rates, and C) percent dissimilatory NO3.⁻ reduction (denitrification + DNRA) attributed to denitrification. Different letters indicate statistical differences (p < 0.05)
Coastal marshes provide valuable ecosystem services including the removal of excess nitrogen (N) prior to reaching coastal waters. Crude oil contamination can disrupt N cycling processes, and while the impacts of crude oil on marsh structure and function are well studied, less is known about the effects of different oil components. The objective of this study was to determine how water accommodated fraction (WAF) of oil impacts marsh sediment N cycling capacity from three marshes with differing characteristics. One site was previously oiled following the Deepwater Horizon (DWH) oil spill while the other two sites had no known history of oil spills. We measured 16S rRNA gene composition from sediments collected from each marsh then conducted a laboratory incubation experiment on sediments treated with different concentrations (0%, 25%, 100%) of WAF. The DWH impacted site had a lower number of observed microbial taxa and lower Chao1 diversity, but a higher relative abundance of putative hydrocarbon degraders compared to the other sites. While there was no treatment effect of WAF on sediment denitrification, denitrification potential rates were 2.4 × higher in the DWH impacted sediment compared to the other sites. There were no differences in dissimilatory nitrate reduction to ammonium (DNRA) potential rates across sites, but 100% WAF treatments increased rates nearly twofold at one of the unoiled sites. These results suggest oil contamination alters the microbial community structure and impacts N cycling processes in salt marsh sediments.
Fast growing coastal population centers face an increasing vulnerability to several emission sources of anthropogenic and industrial pollutants. The ongoing industrialization in emerging countries increases the environmental and human risk for people living in coastal megacities, especially in the global south of Asia. Extreme weather events, such as heavy rainfalls and resulting flood events, are projected to increase in frequency in the foreseen future, facing an increasing vulnerability to monsoon-induced floods and the release and distribution of xenobiotics causing harm to communities and the environment along a river’s pathway. To endeavor the unknown risks posed by these toxic floods and to assess the associated contamination distribution, the preserved organic geochemical signature from floodplain sediments is studied. This investigation evaluates the inorganic and organic pollutant assemblage in ten surface sediments along the Adyar and Cooum river in the urban areas of Chennai (southern India). Potentially toxic elements (Cr, Ni, Cu, Zn, Pb) show a continuous concentration decrease downstream. Four main groups of persistent organic pollutants have been detected: petrogenic pollutants (hopanes, PAHs), urban wastewater pollutants (LABs, DEHA, methyl-triclosan, octocrylene), technical compounds (Mesamoll ® , DPE, NBFA), and pesticides (DDX). While most organic compounds show source specific properties, the definite sources for others remain vague based on the multitude of potential sources and diffusiveness of anthropogenic emissions. The chosen approaches have shown that urban wastewater pollutants and several technical compounds are suitable to assess the anthropogenic-induced contamination in floodplain sediments. However, sedimentary archives in fast-growing, urbanized environments are influenced and superimposed by anthropogenic alterations.
The location map of the Reyhanlı District, Hatay
The map of sample locations of drinking water samples and geological structure of Reyhanlı District, Hatay
The variation of the gross alpha and gross beta activity concentrations in drinking water samples
The graph of annual effective dose (AEDα/β) for adults and infants in drinking water samples
The distribution of the excess lifetime cancer risk (ELCRα/β) values for adults in drinking water samples
The natural gross radioactivity concentrations in drinking water collected from the Reyhanlı District, Hatay, were measured. The gross alpha/beta radioactivity levels were measured in August 2021. A proportional counter was used to determine gross alpha/beta radioactivity levels in drinking waters. The activity levels of gross alpha/beta in drinking waters ranged from 0.001 ± 0.000 to 0.020 ± 0.002 Bq/L and 0.015 ± 0.003 to 0.715 ± 0.126 Bq/L, respectively, according to results obtained from the activity measurements. The results of the gross beta radioactivities were found reasonably high compared to the results of the gross alpha activity levels. The measured gross alpha/beta activity concentrations are smaller than the 0.5-Bq/L and 1-Bq/L limit values recommended by WHO and EPA. The annual effective dose and excess lifetime cancer risk parameters were calculated using gross alpha/beta radioactivity concentrations.
Laponite nanoparticles have been proposed for soil densification to reduce the negative impacts of seismic hazards. However, the effects of laponite on the aquatic ecosystem are lacking. In this study, different concentrations (0.1, 0.2, 0.3, 0.4, and 0.5%) of laponite were used to investigate the growth and total chlorophyll content of microalgae: Chlorella sp. This study examined the potential toxic effects of laponite on the growth characteristics of freshwater green algae Chlorella sp. isolated from northern Ontario. The experiments were carried out in a 500-ml glass flask with 300 ml working volume and placed under white fluorescent lights for 16 h: 8 h day-night cultivation cycle in a constant orbital shaker. The results revealed that the lower concentration of laponite can enhance microalgae growth, while the higher laponite concentration had a growth inhibitory effect. The total chlorophyll content increased by 33% at 0.1% treatment group than that of the control group. Based on the SEM images, aggregation of microalgae was significantly noticeable at the lower concentration of laponite (0.1% treatment) whereas, in the higher laponite concentration (0.4 and 0.5% treatment), algal cells were embedded in laponite gel and also noticed some physical impairment.
This paper presents a study on orange II sodium salt (OII) degradation based on iron nanoparticles supported by kaolinite clays. The effects of nanoscale iron and initial dye concentration, as well as hydrogen peroxide dosage in a Fenton process, on the degradation of OII were studied. These nanoparticles were synthesized by green methods using coffee bean extract as a natural antioxidant for this process. Aqueous iron chloride was mixed with coffee extract, which is rich in antioxidants, and these antioxidants are responsible for the reduction of metal compounds into nanoparticles. The composite iron nanoparticle-kaolinite composite was synthesized from an aqueous FeCl3 and kaolinite solution with the added coffee bean extract. The results showed that OII removal efficiency increased with the amount of iron nanoparticles (n-Fe) alone and with the amount iron-supported-kaolinite composite. By increasing the amount of composite, the adsorptive surface area increases as well as the number of active sites, which determine the higher removal efficiency. Regarding H2O2 dosage, dye removal was more efficient at lower quantities: 62% removal efficiency with addition of 10 mL H2O2, while for the test conducted with 20 mL H2O2, removal efficiency was 47%. A possible reason for this behavior can be the n-Fe/ H2O2 ratio, which influences the production of degradation products and hinders the degradation. Highlights • Green synthesized metallic iron nanoparticles (n-Fe) using coffee bean extract as a natural oxidant were used for the removal of Orange II • In order to improve the degradation process, a clay-nanoscale iron composite was used, as well as Fenton oxidation using added H2O2. As a support material for the composite, kaolinite was used. The results showed that both reduction and adsorption processes are involved in the dye removal process. Applying Langmuir and Freundlich isothermal models shows monolayer coverage • By comparing the efficiency of the composite alone with the efficiency of the composite with the Fenton process, better results were obtained for the second case which shows the importance of the H2O2/Fe system in the degradation process. Also, we may state that the best results were obtained by using n-Fe only • Since the amount of n-Fe present in the composite is low (0.01 g), further experiments should be held concerning the ratios between n-Fe and clay in the composite. Experiments using wastewater containing dyes from a real industrial process should also be done as well, to confirm the activity of this material containing nanoscale iron made using green synthesis in a real wastewater environment, with all the associated ions and compounds. Graphical abstract
Due to high mercury and arsenic toxicity, post-mining Hg-As-contaminated sites can cause varied and complex environmental and health problems. The aim of the study was to demonstrate the significance of the health risk assessment tool for remediation of post-mining soil contaminated with Hg and As. The aim was achieved via (1) assessing health risk under future land use patterns, (2) determining the extent and level of site remediation, (3) determining the effect of land use change on health risk and (4) suggesting appropriate remediation actions. To exemplify this issue a site of El Terronal in Asturias, Spain, was used. The health risk assessment was conducted under two potential land use scenarios (industrial and recreational). The results showed significant health risks in most of the studied area under both land use scenarios, although they were much higher under the recreational one. The health risk resulted mainly from the exposure to arsenic and mercury, with arsenic being the predominant element. Both the arsenic and mercury site-specific remedial levels differed significantly between the industrial and recreational exposure scenarios. This indicates that the land use pattern will have a significant impact on the choice of the effective remedial approach. The industrial scenario can be regarded as the more favourable. The health risk-based approach implemented in the studied area can be applied to other abandoned mining sites worldwide for conducting remediation actions.
The Rosetta Branch is one of Egypt’s most important Nile River branches, providing freshwater to multiple cities. However, its water quality has been deteriorating, with various wastes containing high loads of heavy metals being discharged into its body of water. Seasonally, water and sediment samples and two native aquatic plants (Ceratophyllum demersum and Eichhornia crassipes) were collected and analyzed from the Rosetta Branch to assess the level of metal contamination (Fe, Mn, Zn, Cu, Pb, Ni, Cd, Cr, and Co) using different metal indices. The levels of some metals in the branch water overstepped those suitable for drinking water and aquatic life. In increasing order, the means of the heavy metal concentrations in branch water (µg/L) were Cd (1.8–4.9) < Co (7.18–28.1) ≈ Ni (9.0–25.1) < Cr (8.56–27.4) < Cu (14–75) < Pb (9.3–67.9) < Zn (22–133) < Mn (68–220) < Fe (396–1640). All the metal indices measured in the sediment confirmed the Ni and Cd contamination, where Ni and Cd in the sediment surpass the sediment quality guidelines in 80% and 53% of samples, respectively, reflecting frequent adverse effects on aquatic organisms. According to the bioconcentration factor, C. demersum and E. crassipes have higher accumulation capacities mainly for Cd than those for other metals considered as major pollutants in the water and sediment of Rosetta Branch, reflecting the role of hydrophytes in the biological treatment of polluted water in aquatic environments.
Top-cited authors
Tony Hadibarata
  • Curtin University Sarawak
Tushar Sen
  • Curtin University
John L. Stoddard
  • United States Environmental Protection Agency
Leslie Felicia Petrik
  • University of the Western Cape
Sharmeen Afroze
  • Curtin University