The utilization of plant growth promoting rhizobacteria (PGPR) is a potential strategy to ameliorate the rhizoremediation effect in the heavy metals (HMs) contaminated soil. In this study, a new heavy metal tolerant PGPR, Sphingomonas sp. PbM2, was isolated from the rhizosphere of maize. The siderophore production and 1-aminocyclopropane-1-carboxylic acid deaminase activity of PbM2 were superior to that of Novosphingobium sp. CuT1, an HM-tolerant PGPR, while the indole-3-acetic acid productivity of PbM2 was inferior to that of CuT1. The inoculation effect of the PGPR (PbM2 alone or a mixture of PbM2 and CuT1) on the rhizoremediation performance of HM-contaminated soil planted with maize was compared. Cu bioavailability was enhanced with PGPR treatment, while the bioconcentration factor significantly increased or remained steady depending on the HM concentration (200, 500, or 1000 mg/kg-soil) and remediation period (20 or 60 d). PGPR inoculation significantly enhanced soil PGP activity except for siderophores but was not statistically associated with improved plant growth. The dynamics change in the bacterial communities during rhizoremediation was similar for all soil conditions regardless of PGPR inoculation. Network analysis revealed that both the inoculated PGPR and indigenous rhizobacteria contributed to Cu bioavailability and soil PGP activity. These results suggest that the inoculation of PGPR is effective in the remediation performance of contaminated soil in which autogenous PGPR is inhibited.

Man and the Biosphere Program (MaB) was established by UNESCO in the early 1970s to resolve the conflict between humans and nature. The biogeography representative was determined by UNESCO/MaB as one of the main criteria for registering an area as a biosphere reserve (BR). Therefore, countries require selecting appropriate areas for BRs to complete the criterion of representativeness of the global biogeography protection network. This study aimed to analyze the study process of biogeography representatives at the global and national levels based on the research objectives. The results revealed the necessity of combining the map of Iran’s biogeography produced at the global level with the map of the macroecosystems of national production to identify the representative ecosystem units (REUs). The production of this map led to the identification of 112 REUs in the country. The compliance maps of BRs and REUs showed that 13 BRs of the country have covered only 23% of Iran’s REUs. The results of the studies of biogeography provenances, biological hot spots and ecoregions led to the definition of 5 quantitative indicators for screening and prioritizing the country’s REU. The description of this issue, which is very brief in the abstract, is given in the text of the article. A total of 18 REUs were specified with priority for selecting new BRs using identified indicators and Entropy Shannon VIKOR models. Based on the results, 27% of the REUs proposed can be covered by modifying existing BRs boundaries. All proposed BRs could select more than one REU. In addition, 15 REUs with about 17% of the country’s area may be covered with the registration of seven new priority BRs.

Niobium is considered to have a good resistance in various chemical environments. However, during the corrosion process, a dense product that forms on the surface was used here as a catalyst for the degradation of the methylene blue dye. The niobium catalyst was formed at room temperature (28°–30 °C) by simple precipitation using immersion of sample in an alkali medium. X-ray diffraction spectroscopy and scanning electron microscopy confirmed the synthesis of Na8Nb6O19.13H2O and its octahedral shape, respectively. Thermogravimetry analysis indicated the thermal stability of the synthesized catalyst. X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and Raman spectroscopic data show the presence of sodium, niobium and oxygen elements in the prepared catalyst. Methylene blue was degraded effectively (90%) and the process obeys the pseudo-first-order kinetics and the degradation was completed in 0.9934 min−1.

Climate change is a key threat to biodiversity and ecosystems. The impacts of climate change on vegetation must be evaluated to control the sustainability of the ecosystem. Precipitation and temperature are the most important climatic parameters affecting vegetation growth. It is important to analyze the spatial and temporal variations of vegetation under changing climatic parameters to envisage the response to the regional ecosystem. In this study, variation of the Normalized Difference Vegetation Index over five different agro-climatic zones in the Upper Bhima Sub-basin from 2003 to 2013 was analyzed to find the effect of climatic and hydrological variables on vegetation dynamics. The correlation analysis has been performed by using the Pearson correlation method and Geographical Detector Model. Taylor diagrams are generated to highlight the variation in the correlation values of NDVI with other variables. Results show that precipitation and temperature are key parameters for the growth of the vegetation, but Western Ghat Zone shows contradictory results. To identify the reasons behind contradictory results in the Western Ghat Zone, hydrological parameters such as soil moisture, terrestrial water storage and groundwater levels are analyzed. NDVI shows a positive correlation with precipitation in Water Scarcity Zone, and Assured Rainfall Zone with correlation values 0.37, and 0.462 respectively, but, in the Western Ghat Zone, NDVI has a negative correlation (− 0.38) though more than average precipitation occurs in that region. The result of the Geographical Detector Model reveals that the terrestrial water storage and precipitation are dominant factors affecting vegetation in WGZ and WSZ, respectively.

The global carbon dioxide in the atmosphere is predicted to rise due to fossil fuel emissions during the next century. Carbon dioxide is soluble in water and partially dissociates into bicarbonate and carbonate, releasing protons that decrease the pH. This change in pH is expected to play a critical role in some earth systems, such as the hydrosphere, where ocean acidification affects the survival of marine organisms. This study used aqueous solutions consisting of water with sodium bicarbonate, Miller’s lysogeny broth, Roswell Park Memorial Institute 1640 medium, and Dulbecco’s Modified Eagle Medium to develop a colourimetric method for the quantification of dissolved carbon dioxide. Various environmental testing conditions were studied using a fluorescent microplate spectrophotometer. The temperature varied between 27 and 42 °C, and the carbon dioxide levels ranged from 0.20 to 10% v/v in the air. The data showed that the amount of dissolved carbon dioxide decreased by 50% in broth solutions, while the reduction in water samples was approximately 18% when the temperature rose from 27 to 42 °C. Furthermore, the composition of the solutions impacted the amount of gas dissolved. The highest amount of dissolved carbon dioxide was observed in the water sample with the lowest salinity, which reached 20,000 ppm CO2 at 27 °C. The lowest amount of dissolved carbon dioxide concentrations was obtained in Miller’s lysogeny broth with the highest salinity level, which reached 1200 ppm under the same conditions. The results obtained can be considered a robust estimation method to calculate the amount of dissolved carbon dioxide under different conditions.

The case studies are introduced in this study, highlighting freight transportation via road and road rail between satellite cities in Pakistan’s Punjab and Sindh provinces. The case study analysis contributes to developing environmentally friendly and cost-effective transportation solutions and reducing nitrous oxide (N2O) and carbon dioxide (CO2) emissions associated with road and intermodal freight transit. We developed a mixed-integer linear programming (MILP) model to formulate the bi-objective problem, including real-life constraints, emissions at starting nodes, ending notes, and between the arc. In the mathematical model, the cost and emissions functions are developed to minimize the primary and secondary objective functions in the road and intermodal transportation. Furthermore, five distinct sets (locations, starting stations, ending stations, transport orders, and transport service) with parameters relating to container movement between the starting and ending nodes are a necessary part of the MILP formulation. The multiobjective optimization problem is solved by metaheuristic techniques such as the multiobjective genetic algorithm as the goal of applying a metaheuristic algorithm is to find the search space to search the near to optimized solutions. The Pareto front solutions are provided for balancing the costs and emissions of transporting supplies from Punjab to Sindh using the MATLAB solver toolbox. We gathered data from one of Pakistan’s most well-known logistics service providers in the paper industry. According to the findings, intermodal transportation is 72% more cost-effective than road transportation. Additionally, by substituting intermodal transportation for road transportation, N2O, and CO2 emissions can be reduced by 74% and 57%, respectively.

This study aims to gain a better understanding of how climatic and anthropogenic factors have affected the Aral Sea Area (ASA). The dynamic changes of the ASA from 1920 to 2020 were investigated, and then the relationship between the water area and its drivers was evaluated using different regression analyses. The results demonstrate that the water surface area exhibited minor fluctuations with an upward trend of 0.04 km2/year from 1920 to 1960. Since then, the water area decreased dramatically. It reduced by 88% in 2020 compared to that in 1920, and the decreasing rate slowed significantly after 2010. The multi-factor analysis determined that human activities are the root cause of declining in water area. The multiple stepwise regression results suggest that the water withdrawals from rivers (dam capacity > domestic water consumption > agricultural water consumption) could be responsible for most of the variation in ASA, and 82% of total withdrawal water was used for agricultural consumption. The diversion of rivers (for irrigation) that historically fed the Aral Sea, resulting in a decrease in inflow entering the sea, is another cause of the ASA's shrinkage.

In this research, recycled plastic wastes and unexploited natural rice straw (RS) are used as raw materials to produce a new type of wood plastic composite. Recycled high-impact polystyrene (HIPS) and mechanically fiberized RS (without any chemicals) were mixed together twice through a single extruder followed by a press process using a flat press to produce an eco-friendly synthetic wood called rice straw plastic composite (RSPC). Samples with different densities (950, 1100, and 1250 kg/m3) and different RS fiber ratios (40, 50, and 60 wt%) were produced. The effects of the RS fiber ratio and the RSPC density on flexural properties and water uptake characteristics were investigated. It was found that the modulus of elasticity and modulus of rupture reached maximum values of 4917 MPa and 25.2 MPa at 1250 kg/m3 of composite density with 60% and 50% fiber ratio, respectively. The highest values for water absorption and thickness swelling were recorded at 1250 kg/m3 composite density and 60% fiber content to be 3.96% and 2.64%, respectively. Comparison of the results with other RSPCs indicated the feasibility of fabrication of the investigated RSPC. Moreover, the use of additives like coupling agents could further enhance the properties of the produced RSPC.

Aerobic composting (AC), anaerobic digestion (AD), and anaerobic manure storage tank (AMST) are conventional systems for treating liquid swine manure (LSM). In this study, life cycle assessment (LCA) was used to evaluate environmental impact in both construction and operation phases to compare AC, AD, and AMST systems. The results were obtained using SimaPro® with ReCiPe impact assessment method. The system boundary was from cradle to grave, and the adopted functional unit was 10.0 m3 of LSM. LCA results showed that steel and cement were the inputs with higher environmental impact in construction phase in AC and AD with average percentages of 74.25 and 24.56%, and 57.17 and 17.30%, respectively. For AMST, high-density polyethylene (HDPE) was more significant with average impact of 83.37%. The comparison between the construction and operation phases of each system individually showed that the construction causes the higher impact in AC and AD, while in AMST was the operation phase. The comparison between the construction phases of the systems showed that AC resulted in higher environmental impacts than in AD and AMST in all impact categories. In relation to operation phase, AMST system causes higher impact compared to AD and AC. Finally, the global comparison of systems showed that the AD with energy use has the better environmental performance. The high use of steel and cement in construction phase and methane production in operation phase have a significant impact on the global life cycle.

The explosive rate of population growth demands a revision of existing protective measures to address water scarcity that urges water body monitoring models to be developed using satellite image-based change detection approaches. And the main objective of this proposed work was to investigate the spectral indices for spatial object extraction in satellite images with respect to water body extraction. The Landsat 8 coastal/aerosol band (0.433–0.453 μm) is still an unexplored band with spectral signatures that favor water extraction, and it has been used in the proposed deep blue normalized difference water index (DBNDWI). The multi-temporal Landsat 8 data products of three lakes with distinct geographical importance from India and Iran are chosen for assessment. Widely used spectral indices for water body extraction such as the normalized difference water index (NDWI), modified normalized difference water index, and automated water extraction index are the benchmark results used for comparative assessment. Along with these conventional water indices, the most recent water indices weighted normalized difference water index (WNDWI) and Wavelet-based normalized difference water index (WAWI) are also compared for extended validation. The use of standard image quality analysis and statistical histogram distance measures justifies the significance of coastal band in extracting water bodies. The experimental results tabulated show that proposed DBNDWI outperforms the most recent WNDWI and WAWI with higher accuracy, even in moderate-resolution images.

To localize high-density polyethylene membrane leakage in operating landfills, a leakage localization method based on the wave velocity inversion model is proposed in this study. A double-layer acceleration sensor and elastic wave generator are placed under the high-density polyethylene membrane. First-arriving wave extraction is performed using a short-time average/long-time average method and an Akaike information criterion joint algorithm. When a high-density polyethylene membrane breakage signal is received, parameter information is extracted. An elastic wave with the same frequency as the breakage signal is emitted by the generator. The mean value of the wave velocity of the clay layer is calculated as the time-difference positioning wave velocity to determine the breakage point location. If no breakage signal is received, the generator emits a fixed-frequency elastic wave to invert the wave velocity of the leakage area, and a wave velocity tomography map is generated for leakage point localization. Leaky point shapes are identified in combination with soil moisture migration principles. The experimental results demonstrate that the error between the actual leakage coordinates and positioning coordinates meets the engineering requirements and that the inversion model can effectively identify block and slit leakage points.

A high photoluminescence (PL)-based nanosensor based on graphene quantum dots (GQDs) is fabricated for the detection of toxic ions Ag+, Ce2+, Cd2+, Cu2+, Cr2+, Pb2+, Sn2+, and Fe3+, p-nitrophenol, and thioacetamide in water. The quenching of PL spectra indicates that the complex of GQDs/Fe(III) shows a high florescent quenching efficiency (~ 75%) toward the hydrophobic surface of the GQDs. The limit of detection for Fe(III) concentration 40 \(\pm\) 2 nM, with high linearity and sensitivity. The change of the zeta potential value proves the attachment of Fe (III) ions to the surface of the GQDs. The GQDs/Fe(III) complexes can be utilized as a turn-OFF or turn-ON type fluorescence probe for p-nitrophenol (turn-OFF) detection with 5 \(\pm\) 1 pM concentration and the sulfur (turn-ON) detection with 7.6 \(\pm\) 1 pM. The proposed method is facile, sensitive and fast, which makes it ideal for nanosensors to detect water quality of rivers, ponds, or industrial wastes.

United Nations (UN) Sustainable Development Goals (SDG) of 2030 emphasizes the wastewater industry should seek more energy-efficient measures for wastewater treatment. Since many wastewater retrofit projects normally do not have the flexibility to adopt most cutting-edge technologies, any retrofit plan that can reduce system energy and resource usages deserves attention. In this study, the advantage of step-feed Anoxic–Oxic (AO) is explored by a model-based approach for a retrofit project treating low C/N influent. Results indicate the success of step-feed AO is to optimize the spatial–temporal match between electron donors and acceptors along the process train, and an optimum influent distribution profile exists for each influent C/N level. However, since influent C/N determines the maximum system attainable N removal, influent step-feed can only improve the usage efficiency of influent bCOD (biologically degradable COD) for denitrification by reducing unnecessary aerobic loss of influent bCOD. Distributing influent too much toward either upstream or downstream will break such balance. Furthermore, by changing the system operation from high DO (dissolved oxygen) mode to low DO mode, the main N removal route can be shifted from full nitrification–denitrification to partial nitrification–denitrification which requires less bCOD and aeration, and thus can further enhance the efficiency of step-feed AO. Although low DO operation mode can have a smaller system operational cost, system robustness is reduced in against influent fluctuations and environment seasonal variations, along with increased N2O emissions. Overall, this study demonstrates the usefulness of step-feed AO for wastewater engineers in responding to the UN SDG 2030 campaign.

The aim of this study, which covers the period from 1991 to 2017, is to analyze the relationships between recovered paper consumption, human development index, urbanization rate, and forest footprint in the framework of the Environmental Kuznets Curve (EKC) hypothesis in the 10 countries that consume the most recovered paper. Considering that wood is the raw material of paper, the study investigates whether the increase in the consumption of recovered paper has a positive effect on the forest footprint. Therefore, unlike other studies, the dependent variable of the EKC model is the forest footprint. The study is original in that it is the first to analyze the effects of recovered paper consumption on environmental degradation in the context of the EKC hypothesis. To analyze the relationships between the variables, we use panel cointegration tests based on AMG and CCE estimators, which allow analysis on both a country and group basis. According to the results, the EKC hypothesis is valid only in the Netherlands. While there is a statistically significant and negative relationship between recovered paper consumption and forest footprint in the Netherlands, there is a statistically significant and negative relationship between urbanization and forest footprint in Italy. Economic and ecological benefits and costs must be considered to measure the net benefit of waste management programs. In addition, to analyze how environmental impacts change over time, ecological footprint and gas emissions during waste generation or disposal should be measured similarly to carbon emissions.

Many urban water bodies in Chennai, India receive untreated sewage that pollutes their waters. An example is the Sembakkam lake, in which water reaches the Pallikaranai marshland, a proposed Ramsar site. In 2019, the city experienced the worst water crisis in 30 years, and many lakes were extremely dry, favoring peaks of heavy metals. Therefore, this study focuses on analysing heavy metal pollution and evaluating its potential effects on biota. In situ parameters were measured and water, sediment, and water hyacinth samples were collected during four campaigns. Al, As, Cr, Cu, Fe, Mn, Ni, Pb, and Zn were measured in all samples. Digestions for total metal content were performed in solid samples and acetic acid extractions only in sediments. The average pH (7.89–8.46) was neutral-alkaline and electrical conductivities (1559–2864 µS/cm) were high. In water, Pb (average: 2.59 µg/l) posed the highest toxicity risk according to the United Nations Economic Commission for Europe, followed by Cu and Cr. In sediment, Cu and Cr reached severe enrichment with respect to continental crust (averages: 19.46 and 13.65) followed by Ni and Zn with moderately severe enrichment. Ni produced the highest toxicity risk (average: 76.18 mg/kg), above the effects range-median, followed by Cr and Cu, between the effects range-low and effects range-median. The highest bioaccumulation factors in the water hyacinth were in the roots. Translocation factors showed similar concentrations in stems and leaves. Proper management of sewage is necessary to diminish the potential deleterious effects of metals on aquatic life and by extension, human health.

The presence of ammonium (NH4+) in wastewater above the permissible limits leads to undesirable ecological impact and public health concerns. In this study, the anaerobic ammonium oxidizing (anammox) bacteria-mediated nitrogen removal was investigated using a sequential batch reactor (SBR). Effects of different salinity levels were evaluated on the bacterial activity at: mild (below 0.2 g NaCl/L), elevated (18.2 g NaCl/L) and suitable salinity (2–0.5 g NaCl/L) levels mimicking the environmental conditions that are present in real wastewater. Within a suitable salinity period of 0.5–2 g NaCl/L, the highest average total nitrogen removal efficiencies (TNREs) and total nitrogen removal rates (TNRRs) of 67 (± 11)% and 37 (± 29) g N/m3/d, respectively, were achieved. In addition to the salinity tests, the effect of relatively high nitrite levels (> 40 mg N/L) was observed in the reactor resulting in the decrease in anammox activity, but increasing biomass potential for the treatment of high nitrite containing wastewater. Interestingly, the supplementation of hydrazine at 7.5 mg N2H4/L indicated enhanced anammox activity with a nitrogen removal rate of 0.7 ± 0.01 mg N/g MLSS/h, while test without hydrazine showed a rate of 0.68 ± 0.06 mg N/g MLSS/h. Therefore, denitrifying activity decreased with the addition of hydrazine, which on the other hand benefits the anammox start-up. Illumina sequencing analysis revealed that the microbial community has changed with the rise of the salinity levels and was dominated with Anaerolineae, Gammaproteobacteria, Clostridia and various key anammox organisms, such as Candidatus Brocadia and Candidatus Kuenenia strains (at 3%).Graphical Abstract

Chromium pollution in ground water is already very serious and needs to be solved urgently. In the present work, the products of natural pyrite after heat treatment were used as the reactive media for permeable reactive barrier. It found that natural pyrite can progressively convert to pyrrhotite with mixed monoclinic and hexagonal structures or pure hexagonal structure at different heat temperatures in argon atmosphere. The products heated at 600 °C had the highest removal of Cr6+ as compared to pristine pyrite and other heated products. The column experiment showed the service life of the column was 480 PVs. The removal of Cr6+ mechanisms under the batch and column conditions were also investigated in detail and both of them were redox reactions. The present work suggested that heat-treated natural pyrite has good application prospect as an efficient and low-cost reactive media material in permeable reactive barrier for chromium pollution control.

We investigated the removal of the reactive dye Remazol Red from segregated dye bath with an integrated physical-biological approach combining easy applicability and fast kinetics of the sorption process with intrinsic sustainability of biological treatments. The proposed process consists in a first step dye removal by sorption on a cheap commercial polymer (Hytrel 8206) followed by anaerobic polymer bioregeneration. Excellent dye removals were achieved (up to 100%) under acidic conditions with fast kinetics (in most cases, 4 h are sufficient to reach efficiencies ≥ 80%). Experimental sorption data were well correlated with the Freundlich isotherm and pseudo-first-order kinetic model. The sorption process was optimized with response surface methodology. Practically complete removal was achieved with pH of the solution, initial dye concentration and polymer-to-water ratio equal to 4, 50 mg/L and 8.03% v/v, respectively. High desorption performance under neutral conditions makes Hytrel suitable for bioregeneration in a two-phase partitioning bioreactor. Polymer bioregeration reached 82% efficiency with the added value of achieving effective biodegradation (> 50% in 4 days) of the dye desorbed from the polymer. The study demonstrated the two-step process feasibility, which is characterized by the advantage of employing a cheap commercial polymer and has the potential of achieving complete dye mineralization.

Water is a critical issue, especially in developing countries’ cities that are grappling with climate change effects. Given the importance of water infrastructure assets in cities life and functionality, assessing their vulnerability and trying to make it resilient is an essential mission. To this end, this study has attempted to spatially analyze the urban water infrastructure assets vulnerability in Ahvaz, Iran, that has been hit by various climate change-related disastrous events over the past few years. Regarding this, the study has introduced two indicators, namely distribution and adaptation to determine the vulnerability of water infrastructure assets that have been recognized by applying a two-round Delphi survey. Findings indicate that, overall, there is no positive outlook and reliable capacity in terms of water resilience in Ahvaz because of distribution and adaptability of water infrastructure assets in the spatial area of the city and considerable parts of the city are vulnerable in face of any adverse event. This is mostly the case in Regions 1, 7, 3, 4 that feature a centralized and irregular form of water infrastructure assets distribution and proximity to non-adaptable land uses. Moreover, final spatial vulnerability map highlighted by two critical (hotspot) points, which shows the most vulnerable parts of the city for water infrastructure assets. The study highlights the need to make improvements urban water resilience due to reducing vulnerability, especially considering the spatial distribution and adaptation of water infrastructure assets in Ahvaz.

Poor water quality and its significant adverse impact on the environment in the Addington Brook catchment has long been realised in Christchurch, New Zealand. Contaminants generated from impermeable surfaces such as roadways, rooftops and parking lots produce high rate of dissolved zinc and copper in this catchment. Hence, this research provides a long-term solution for zinc and copper removal. The main idea of this research is to develop and compare different planter box raingardens for the removal of zinc and copper. A planter box raingarden prevents stormwater pollution from entering the stream and rivers. Twelve raingarden modules were constructed and set up using four different media to be tested by three individual stormwater sources. Several water quality tests were undertaken on the influent and effluent sample followed by monitoring the volume of discharge. The results show that a combination of ART3 media, crushed mussel shells and lime chips performed the lowest vertical hydraulic conductivity rate and achieved the highest removal rate for zinc and copper. The planter box P3 achieved the highest removal rate (98%) for both total and dissolved zinc.