Journal of Hazardous, Toxic, and Radioactive Waste

The ecological integrity of several freshwater ecosystems has been disrupted by the rapid and unrestrained accumulation of toxic heavy metals (HMs) from various sources. Changes in land use and land cover, in the form of urbanization and industrialization, have significantly affected the surface-water quality of freshwater ecosystems by causing an upsurge in pollutant loads. In addition, agricultural runoff has contributed to the decrease in water quality. Almost 70% of India's surface-water resources have become polluted owing to the discharge of untreated sewage and industrial effluents, according to a recent report by the Central Water Commission (CWC) of India, with 42 rivers containing at least two HMs in concentrations above the permissible limit. The aquatic biota inhabiting contaminated sites can accumulate HMs from the surface water. In high concentrations, these HMs can damage biotic components, predominantly by triggering oxidative stress and becoming bioaccumulated in different trophic levels of freshwater ecosystems. Heavy metal contamination in the aquatic environment can also cause direct potential hazards to humans, mostly through their consumption of fish and waterfowl. Thus, it is recommended that the untreated wastewater discharge from industry, agricultural fields, and households be curtail to improve surface-water quality. In this systematic review, we investigated the probable sources of the HMs, the HM contamination in the important rivers and wetlands of India, the effects of HM toxicity on freshwater food chains, and potential remediation measures. The findings of the present study will improve our knowledge about the spectrum of HM toxicity and the effects of HM contamination on the biota in freshwater bodies throughout India, and will also aid policymakers in building strategic and sustainable freshwater management plans around the globe.

Plastics, often known as synthetic polymers, have become an essential workhorse element in the contemporary marketplace due to their availability in a wide range of forms and adaptability. Despite its many advantages, the present plastic business has problems that are becoming more obvious by the day. Between 2000 and 2019, global waste plastic production more than quadrupled to 460 million metric tonnes. Only 9% is recycled, 12% is burned, and the rest is disposed of in the waste stream. As per the Down to Earth 2018 figures, India consumes over 16.4 million metric tonnes of plastic. In that, single-use plastics are made up of nearly 43% and were disposed of in landfills. Recycling possibilities include converting waste into raw materials for industry, producing fuel, and using it as construction material. Since buildings are intended to last for several decades, adding such waste materials into them helps to extend their life. It is thus conceivable to reduce both the amount of plastic waste put in landfills and the amount of natural resources mined for the production of conventional materials. This comprehensive review intends to logically analyze the findings of numerous researchers who introduced waste plastic in various forms (flakes, fibers, pellets, granules, pellets, and molten forms) into different building materials. This article supports the discussion of using waste plastic for sustainable building by offering details regarding the physical, mechanical, and durability strength properties of building materials containing various forms of plastic waste. The review analysis indicates that adding plastic waste, regardless of shape or particle size, tends to reduce the workability and mechanical properties of the resulting material. However, introducing plastic particles in small amounts, such as 2%–20%, helps to obtain threshold strength properties. The study also suggests that the addition of smaller particles with irregular forms helps to obtain better results than larger particles with uniform shapes and smooth surfaces.

Groundwater plays a pivotal role in water management worldwide as a renewable natural resource. The issues with water management are multifaceted and are associated with quality assessment, augmentation, distribution, reuse or recycling, pollution, and its protection from depletion and degradation. To address this issue, near the newly developed region of Dwarka, New Delhi, India, this study investigates the hydrochemistry and groundwater quality for drinking and irrigation. To assess the quality of these, several water quality parameters, such as electrical conductivity (EC), total dissolved solids (TDS), sodium (Na⁺), calcium (Ca²⁺), magnesium (Mg²⁺), and other ions were determined. Based on the previous parameters, the water quality index (WQI) was determined, which indicated that 87% of samples were undesirable for drinking purposes. A very high value of some parameters, such as TDS and nitrates, was of major concern. The suitability of groundwater for irrigation was estimated using parameters such as the sodium adsorption ratio (SAR) and percent sodium (Na%), which showed a low alkali hazard and indicated that the water resources were suitable for irrigation. The Piper trilinear and Chadha diagrams that are used to understand the evolution of the hydrochemistry of groundwater showed the presence of permanent and temporary hardness in the groundwater. The Wilcox and Gibbs classification inferred that the majority of groundwater samples fall under the evaporation–crystallization category, partly influenced by the water–rock interactions and aquifer materials. The results of this study are significant for drinking and irrigation purposes and indicate the need for water quality control before use. This study could be helpful for local farmers, authorities, and policymakers to interpret the current groundwater conditions of the newly developed Dwarka Region. It will help in the sustainable management and implementation of water quality control programs and make them more resilient.

Textile industries are water intensive and the effluent generated contains salts, dyes, and heavy metals as well as having a high biological oxygen demand (BOD) and chemical oxygen demand (COD), therefore it must be treated before being discharged into the aquatic environment to prevent its contamination. Electrocoagulation (EC) is a promising technique to treat domestic and industrial effluent, where in situ coagulants are produced by sacrificial dissolution of the anode by application of an electric current across the electrodes. The effect of punched-hole electrodes on the performance of EC—color removal efficiency (CRE), electrical energy consumption (EEC), and operating cost (OC)—was studied by varying the number and diameter of holes in the electrode. It was observed that the use of punched electrodes resulted in higher CRE, lower EEC, and lower OC as compared with plane electrodes. The difference in CRE obtained using plane and punched electrodes was found to increase with an increase in current. The effect of punched-hole electrodes on the treatment of real dye effluent was studied and COD removal of 78.79% was obtained using punched-hole electrodes as compared with 69.30% using plane electrodes. The EEC and the OC were found to be 0.5 kW·h/m³ and US$0.424/m³, respectively, for punched-hole electrodes.

The increasing market share of light emitting diode (LED) lamps shows that there will be a surplus of LED lamp waste in the future. LED lamps contain base, critical, and precious metals, and these metals are associated with resource depletion and toxicity impacts. To develop effective recycling and disposal programs, updated metal concentration data are crucial. Evaluating the toxic impacts of metals on LED lamp waste is essential for informed decision-making in metal selection and substitution in future LED lamp design. This study aims to evaluate the metal substances in LED lamp models consumed in Thailand, representing the ASEAN region, using standardized leaching tests. It compares the obtained metal concentration data with existing literature and threshold total metal concentration (TTLC) standards to determine the potential hazard status of LED lamp models. Additionally, the study applies the USEtox life cycle impact assessment (LCIA) model to develop a comprehensive toxicological impact data set based on metal concentrations in different LED lamp types. The results showed that copper, aluminum, and iron were the most abundant metals in LED lamps. The average mass concentrations of copper, nickel, silver, lead, and zinc were found to have exceeded the TTLC limits, classifying the waste LED lamps as hazardous. Of the metals found in LED lamp waste, nickel and lead carried the highest cancer risk, zinc and lead the highest noncancer toxicity, and aluminum and iron the highest ecotoxicity. These results indicate that stronger enforcement is needed to reduce toxic impacts. The findings lead to the development of a new data set for recycling/recovery and provide recommendations for making eco-friendly designs in the manufacture of LED lamps.

Abstract

This research study aims to investigate the moderating effect of the perceived privacy risk and the mediating role of perceived convenience on the relationship between perceived awareness and e-waste disposal behavior among smartphone users. Using the theory of planned behavior (TPB), the authors have proposed that perceived awareness, convenience, and privacy risk would impact e-waste disposal behavior. An online questionnaire has been sent to Pakistani millennials using a convenience sampling method. The collected data have been analyzed with the SmartPLS 4 software using partial least squares–structural equations modeling (PLS–SEM) and a moderating effect of perceived privacy risk and a mediating effect of perceived convenience in the relationship between perceived awareness and electronic waste disposal behavior among smartphone users has been found.

Practical Applications

This study has several practical applications for nonacademics or practitioners, such as the findings could be used to prepare effective e-waste management strategies that encourage responsible disposal behavior among smartphone users in Pakistan. In addition, the results from this study could be used to raise awareness of the environmental importance of e-waste and promote information on safe disposal options that could change consumer behaviors. Smartphone companies could use this study’s insights to develop more user-friendly recycling initiatives and highlight their benefits. In addition, this study’s findings could be used to advise smartphone and app developers to resolve privacy concerns that are connected to data deletion during disposal. Organizations could win trust and encourage users to recycle their old devices correctly. Government officials might find this study’s findings helpful when developing data privacy and e-waste management rules and regulations. The findings could be used by nongovernmental organizations to create regional e-waste collection and recycling centers. In addition, e-waste management could be incorporated into sustainability projects by companies that operate in Pakistan.

The present study focuses on recovery and removal of phosphate in the form of hydroxyapatite (HAP) from a phosphate-rich secondary-treated effluents. Synthesis of HAP has been done at different operating parameters and statistical analysis was carried out using response surface methodology (RSM). Initial ${\mathrm{PO}}_4^{3-}-\mathrm{P}$ concentration (mg/L), pH, and stirring speed (rpm) have been used as the input parameters for the RSM process. Optimization and interaction between the factors (initial ${\mathrm{PO}}_4^{3-}-\mathrm{P}$ concentration, pH, and rpm) were performed using the Box-Behnken design (BBD) of RSM. The model obtained from the RSM-based BBD statistical study has given pH: 12, ${\mathrm{PO}}_4^{3-}-\mathrm{P}$ initial concentration: 400 mg/L, and rpm: 100 as optimized parameters for the synthesis of HAP. Maximum removal of 79% phosphate removal/recovery was achieved (as HAP) in this study for the experimental runtime of 3.5 h. The effect of pH, ${\mathrm{PO}}_4^{3-}-\mathrm{P}$ initial concentration and stirring speed on HAP formation/phosphate removal were also briefly discussed. ANOVA and the fit statistics generated for the model has identified that the model is significant. The validation study conducted using both synthetically prepared and secondary-treated effluent revealed their reasonable agreement with the predicted results (less error). Scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) characterization was performed for the HAP produced in this to discover the morphology and elemental composition.

Leakages from fuel tanks and fuel transport pipelines are common occurrences that affect the environment and the geotechnical properties of geomaterials, which is of significant relevance in the case of unstable soils. In this work, experimental and numerical analyses were conducted to study the effect of kerosene on the mechanical behavior of collapsible soils. The compressibility tests on undisturbed loess samples were performed at natural water content, flooded with water, and flooded with a nonaqueous phase liquid (NAPL), such as kerosene. Numerical models were developed to reproduce and analyze the experimental results. The results show that the extended basic Barcelona model (EBBM) can successfully represent the stress–strain behavior of the soil under zero-lateral displacement conditions, as well as the higher compressibility developed by the specimens flooded with water than with kerosene. The presence of kerosene on tested loess produced negligible changes in swelling indexes and was not able to trigger collapse. The effect of particle–fluid interaction on the obtained results is discussed and analyzed to identify the main responsible mechanisms for soil collapse.

The natural environment consists of flora and fauna, providing valuable services for human livelihood, termed ecosystem services (ES). These ES consist of four significant biomes, of which water is one of the subbiomes. Due to anthropogenic activities, visible changes are seen in land patterns, which has a diverse effect on these water bodies. Monitoring these changes plays a vital role in the present-day scenario. The water availability at the upper Ganga basin (UGB) has the potential to develop the state economy by producing hydropower. Hence, the main aim of this work is to estimate the annual water yield and understand the quantity of water yield produced from each Land Use Land Cover (LULC) class in the study area using the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model. The study captures the impact of LULC changes on water yield for three decades from 1985 to 2014. The results are obtained in pixel-level computations, which are incorporated with the spatial variation of parameters in the model application; it shows that the Evergreen needleleaf forest (ENF) plays a significant role in boosting water yield. The outputs obtained by the model are in good agreement with pixel-level formation. This study helps decision-makers take proper steps to increase water yield of the study area and is ideal for application in mountainous regions and other river basins where quality and quantifying ES are critical.

This investigation quantifies the advantages of transitioning from a cash to electronic toll collection (ETC)/open road tolling (ORT) system in an Indian setting. The real-world driving emissions approach, which is considered more suitable at locations with frequent acceleration and deceleration events, was adopted for actual onroad emissions data. Observations demonstrated that, unlike diesel vehicles, emissions generated during the waiting phase in gasoline vehicles were relatively minor when compared with acceleration and deceleration phases. As a result, for queues of equivalent length, the benefits of ETC were not pronounced for gasoline vehicles. Simulations were also carried out using a traffic simulation model VISSIM under three separate regimes – a 100% cash-based system, ETC, and ORT. Results revealed that the emissions generated by the ETC and cash-based systems were respectively 2 and 4 times greater than those generated by ORT. Likewise, the cumulative weekly time-delay experienced under the cash system was 2.5 times greater than that experienced under ETC. Furthermore, a comparison of efficiency of the cash and ETC systems was carried out by assessing the time-headway between transactions of both toll collection systems. The same was found to be approximately 21 s for the cash and 13 s for the ETC system in India. These results provide ample justification for the Indian government to contemplate a shift to ORT.

Northeast India, home to a population of 46 million, has the highest infant mortality rate in the country. Some of these infant mortalities might be attributed to exposure to toxic air pollutants, especially heavy metals. To explore this, seasonal changes in the source contributions of these metals were studied, using a positive matrix factorization model, in a residential area in the largest city in the region. The mean particulate matter with aerodynamic diameter ≤ 10 and ≤ 2.5 µm (PM₁₀ and PM_2.5) concentrations were found to be 90 and 69 μg/m³, respectively. Particles from biomass burning, coal mining, Dust emissions types 1 and 2, and industry and vehicular emissions were found in both PM₁₀ and PM_2.5. A comparison between the source contributions to PM₁₀ and PM_2.5 during clean and pollution days revealed that the highest concentrations were not only due to stagnant weather conditions, but also to changes in emissions from the different sources. Further analysis was carried to estimate the overall health risk associated with each source and the carcinogenic risk from the metals. The results revealed that more emphasis should be given to the health effects associated with each source when designing control strategies, rather than just concentrating on the source that contributes the maximum mass.

In the long-term operation of any deep geological repository (DGR), microbial species can grow within and biological activity may take place. The presence of microbes can result in the production of small organic acids and siderophores that may change the properties of the buffer material and corrode the metal canisters. In the current study, the bacterial population of Bikaner and Barmer bentonites was investigated through the plate culture technique. For detailed analysis, 16S ribosomal RNA (rRNA) gene sequencing technique was carried out. The results showed that Bacillus tequilensis KTCT 13622(T) and Lysinibacillus fusiformis NBRC 15717(T) were present in the Bikaner bentonite, whereas Burkholderia contaminans LMG 23361(T) and Staphylococcus pasteuri ATCC 51129(T) were present in the Barmer bentonite. Bacillus tequilensis and Lysinibacillus fusiformis are rod-shaped, gram-positive, nonmoveable bacteria of phylum Firmicutes. Burkholderia contaminans is a gram-negative, rod-shaped, moveable bacterium of phylum Proteobacteria. Staphylococcus is a genus of gram-positive bacteria in phylum Firmicutes. Bacteria belonging to the phylum Firmicutes can restrict the mobility of toxic radionuclides by the process of biosorption; and bacteria belonging to the phylum Actinobacteria have the ability to change their shape by extending out branches, or filaments, and destabilizing the compactness of the backfill material. The identified bacteria would be helpful for designing DGRs, considering the long-term safety aspects.