Access to waste management services is crucial for urban sustainability, impacting public health, environmental well-being, and overall quality of life. This study employs logistic regression analysis on survey data collected from 1,032 household heads residing in Nouakchott, the capital of Mauritania. The survey investigated key household factors that determine access to waste management services. The findings reveal a significant interplay among waste service provision, the presence of cisterns, housing type and size, and access to electricity. Socioeconomic disparity in service access, with poorer housing formats like shacks receiving substandard services. In contrast, areas with robust electrification report better service access, although inconsistencies remain amid power outages. The research highlights the challenges faced by Riyadh municipality, particularly rapid growth and inadequate infrastructure, which hinder waste management efficiency. Overall, the results not only illuminate Nouakchott’s unique challenges in service provision but also propose actionable recommendations for a sustainable urban future. These recommendations aim to inform and guide targeted policies for improving living conditions and environmental sustainability in urban Mauritania.

We reviewed economic and environmental studies on global plastic pollution and we estimate the global cost of actions toward zero plastic pollution in all countries by 2040 to be US$ 18.3–158.4 trillion (cost of a 47% reduction of plastic production included). If no actions are undertaken, we estimate the cost of damages caused by plastic pollution from 2016 to 2040 to be US$ 13.7–281.8 trillion. These ranges suggest it is possible that the costs of inaction are significantly higher than those of action. Plastic product sales will also generate a global benefit in the form of incomes (salaries, dividends etc.) estimated to be US$ 38.0 trillion over 2016–2040 in the case of inaction, and US$ 32.7–33.1 trillion in case of action. Calculating benefit minus costs provides the net benefits: US$ −120.4 to 19.7 trillion in case of action and US$ −243.8 to 24.3 trillion in case of inaction. Net benefit ranges suggest action and inaction will both be beneficial when considering the high estimates. However, the low estimates show net benefits might be negative, which suggests inaction might generate a net cost for society that will be twice the cost of action. Our estimates are preliminary (several cost and benefit data are lacking).

Geological disposal is the preferred option for the final storage of high-level nuclear waste and spent nuclear fuel in most countries. The selected host rock may be different in individual national programs for radioactive-waste management and the engineered barrier systems that protect and isolate the waste may also differ, but almost all programs are considering an engineered barrier. Clay is used as a buffer that surrounds and protects the individual waste packages and/or as tunnel seal that seals off the disposal galleries from the shafts leading to the surface.

Bentonite and bentonite/sand mixtures are selected primarily because of their low hydraulic permeability in a saturated state. This ensures that diffusion will be the dominant transport mechanism in the barrier. Another key advantage is the swelling pressure, which ensures a self-sealing ability and closes gaps in the installed barrier and the excavation-damaged zone around the emplacement tunnels. Bentonite is a natural geological material that has been stable over timescales of millions of years and this is important as the barriers need to retain their properties for up to 106 y.

In order to be able to license a final repository for high-level radioactive waste, a solid understanding of how the barriers evolve with time is needed. This understanding is based on scientific knowledge about the processes and boundary conditions acting on the barriers in the repository. These are often divided into thermal, hydraulic, mechanical, and (bio)chemical processes. Examples of areas that need to be evaluated are the evolution of temperature in the repository during the early stage due to the decay heat in the waste, re-saturation of the bentonite blocks installed, build-up of swelling pressure on the containers and the surrounding rock, and degradation of the montmorillonite component in the bentonite. Another important area of development is the engineering aspects: how can the barriers be manufactured, subjected to quality control, and installed?

Geological disposal programs for radioactive waste have generated a large body of information on the safety-relevant properties of clays used as engineered barriers. The major relevant findings of the past 35 y are reviewed here.

Although studies suggest that wastewater treatment plants (WWTPs) are the main pathway for plastics into receiving waters, studies on the origin and fate of plastics entering WWTPs are imprecise and largely unexplored. The analysis of plastics in samples from WWTPs is also a relatively young and growing field compared with the marine environment. Furthermore, recent studies have shown that plastics are not uniformly distributed in WWTPs due to environmental factors and the inherent properties of plastics. Accordingly, this review article attempts to describe the current state of knowledge on plastic pollution in WWTPs and identify future research areas. In particular, this study describes the sources of plastics entering WWTPs and the analytical techniques used for the occurrence and properties of plastics in WWTPs. It also defines the role of these plastics as a possible source of microplastics and discusses the problems they can cause in WWTPs. The factors that can influence the variations in the number of plastics are defined. Furthermore, the policy needs for managing plastic pollution as a contribution to achieving the United Nations Sustainable Development Goals are assessed.

Plastic has infiltrated every ecosystem on the planet, making encounters between this anthropogenic pollutant and fauna inevitable. Abiotic environmental breakdown involving light, oxygen, temperature and mechanical forces is well-characterized, while biotic degradation mechanisms are less well-understood. Reports of the role of macrofauna in the fragmentation of plastic debris are increasing. This review explores the driving factors for macrofaunal fragmentation, as well as the physiological mechanisms by which plastic items are fragmented. The presence, and access to plastic within an organism’s habitat are the key determinants of macrofaunal plastic degradation. Foraging strategies, along with burrowing and nesting behaviors increase the likelihood of macrofauna interacting with plastics. Though this type of fragmentation can occur externally, it often follows ingestion, which in itself can be driven by resemblance to food. Four physical mechanisms of macrofaunal plastic fragmentation were identified, namely biting, drilling, grazing and grinding. Biting, restricted to the mouthparts of an organism, was the most common form of macrofaunal fragmentation reported in literature. Similarly, the use of specialized mouthparts for drilling or grazing can produce secondary plastic particles. Lastly, grinding, through manipulation by the gizzard or gastric mill following ingestion can significantly reduce the size of the plastic material. Prolonged and/or repeated interactions with plastics pose the risk of increased wear on the mouthparts and digestive organs involved. Through mechanisms that directly affect the plastic’s structural integrity, physical fragmentation by macrofauna can amplify overall plastic degradation rates and the formation of micro- and nanoplastics in the environment, while long internal retention times can contribute to their dispersal, trophic transfer, and the organism’s exposure to plastic additives. To more fully understand the extent of macrofaunal plastic fragmentation and allow predictive modeling, we suggest the reporting of evidence in a unified and systematic way. Our findings further highlight the urgency for the implementation of a global plastic waste management system to reduce the burden of micro- and nanoplastics.

Although the awareness of the environmental damage caused by plastic pollution has recently increased, few steps have been taken to confront its consequences. These consequences are often most severe in the Global South where countries often lack proper waste management infrastructure. Unless the market value of plastic waste increases, it will simply be discarded, eventually making its way to the environment. It has been established that polyolefin plastic can be converted to a sulfur-free fuel oil by pyrolysis, suitable for use in diesel engines or as a clean cooking fuel. However, carrying out this chemistry in the Global South is challenging. Any process intended for use in the Global South must be safe, robust, efficient, simple to operate, low cost, and most importantly profitable for the operator. When the average daily wage in sub-Saharan Africa is less than 3 USD, an income provided from plastic waste fuel can be significant. The research presented herein focuses on the optimization of a plastic-to-fuel processor that can be built using the principles of appropriate technology. The results of this optimization and profitability assessment will be described. This research has been conducted in collaboration with the NGOs Empowered Solutions for Environmental Sustainability and UpCycle Africa.

We present a series of experiments to illustrate the dynamics of positively or negatively buoyant particle-laden plumes in a cross-flow, with relevance for the discharge of sediment into the ocean during deep-sea mining operations. In an unstratified ambient fluid, our experiments identify three different regimes, corresponding to (i) a dense particle-laden plume, host to relatively dense saline fluid, in which the particles separate from the descending plume as the flow speed falls below the particle settling speed; (ii) a dense particle-laden plume, host to buoyant fluid, in which the fluid gradually rises from the sinking plume of particles, to form a second rising plume of source fluid; and (iii) a buoyant particle-laden plume, host to buoyant fluid, which rises from the discharge pipe, and from which particles gradually sediment. Classical models of single-phase plumes describe the initial motion of the plumes in cases (i) and (iii), but as the flow speed falls below the particle fall speed, sedimentation leads to a change in the averaged buoyancy, and, hence, the plume speed. Our data also suggest that the sedimentation leads to a reduction in the rate of entrainment of ambient fluid, compared with the classical single-phase plumes. We also show that with a density stratified ambient fluid, the stratification may arrest the plume prior to significant particle sedimentation, and in this case, the plume tends to spread downstream at the level of neutral buoyancy where particle sedimentation proceeds. The bulk density of the residual plume fluid may then remain intermediate between the density of the upper and lower layer fluid, or may become less dense than the upper layer fluid, in which case, following sedimentation, the plume fluid rises through the upper layer. While the dynamics of deep-sea mining plumes in the ocean are more complex, for example, owing to background turbulence and mixing, the results of our new laboratory experiments highlight the range of flow processes which may influence the initial dispersion and sedimentation of particles in such plumes following release into the water, depending on the initial conditions, the ambient density and the particle fall speed. We also discuss the relevance of our work in the context of ash dispersal by volcanic plumes.

Human–carnivore interactions are on the rise globally, and often take the form of damage to property and livelihoods, human injuries or fatalities, and retaliatory killing of carnivores. Potential conflict situations are rarely recognized early, and circumstances are often complicated by mismatches between people's perceptions and reality. Following media reports of sloth bear Melursus ursinus attacks on people, we evaluated the situation in a tourism-dominated town in southern Rajasthan, India. Using a spatially explicit survey design, we interviewed 241 residents of Mount Abu to record recent bear sightings and attacks, prevailing attitudes towards bears, and respondents’ understanding of bear ecology. We obtained independent secondary information on tourism levels and bear attacks to verify information received during interviews. We used recursive partitioning to identify factors that explained residents’ attitudes towards sloth bears, and multi-model inference to identify land cover and other features that influenced bear presence. Respondents perceived increasing bear presence and attacks, and secondary data supported these perceptions. Respondents’ insights regarding bear ecology, particularly bears being attracted by rubbish bins, were supported by multi-model inferences. Mount Abu's residents, especially women and younger men, had negative attitudes towards bears, independent of their education level or occupation. Our findings suggest a novel situation in Mount Abu, with sloth bears habitually accessing rubbish bins, which leads to increased bear–human interactions and negative attitudes among residents. We recommend immediate action focusing on waste management, which could help prevent an escalation of the situation and reduce attacks by bears that could otherwise lead to retaliatory killings.

The US Department of Energy Office of Nuclear Energy is conducting a brine availability heater test to characterize the thermal, mechanical, hydrological and chemical response of salt at elevated temperatures. In the heater test, brines will be collected and analyzed for chemical compositions. In order to support the geochemical modeling of chemical evolutions of the brines during the heater test, we are recalibrating and validating the solubility models for the mineral constituents in salt formations up to 100°C, based on the solubility data in multiple component systems as well as simple systems from literature.

In this work, we systematically compare the model-predicted values based on the various solubility models related to the constituents of salt formations, with the experimental data. As halite is the dominant constituent in salt formations, we first test the halite solubility model in the Na-Mg-Cl dominated brines. We find the existing halite solubility model systematically over-predict the solubility of halite. We recalibrate the halite model, which can reproduce halite solubilities in Na-Mg-Cl dominated brines well.

As gypsum/anhydrite in salt formations controls the sulfate concentrations in associated brines, we test the gypsum solubility model in NaCl solutions up to 5.87 mol•kg–1 from 25°C to 50°C. The testing shows that the current gypsum solubility model reproduces the experimental data well when NaCl concentrations are less than 1 mol•kg–1. However, at NaCl concentrations higher than 1, the model systematically overpredicts the solubility of gypsum.

In the Na+—Cl–—SO42–—CO32– system, the validation tests up to 100°C demonstrate that the model excellently reproduces the experimental data for the solution compositions equilibrated with one single phase such as halite (NaCl) or thenardite (Na2SO4), with deviations equal to, or less than, 1.5 %. The model is much less ideal in reproducing the compositions in equilibrium with the assemblages of halite + thenardite, and of halite + thermonatrite (Na2CO3•H2O), with deviations up to 31 %. The high deviations from the experimental data for the multiple assemblages in this system at elevated temperatures may be attributed to the facts that the database has the Pitzer interaction parameters for Cl–—CO32– and SO42–—CO32– only at 25°C.

In the Na+—Ca2+—SO42–—HCO3– system, the validation tests also demonstrate that the model reproduces the equilibrium compositions for one single phase such as gypsum better than the assemblages of more than one phase.

To estimate the cesium sorption by the bentonite and to obtain the isotherms, some batch-adsorption experiments are being carried out, being the Kd (retardation coefficient) calculated from these isotherms. One-dimensional flow cell was constructed to measure the bentonite permeability regarding to a cesium solution, which results will be used to evaluate the diffusion coefficient – D. It will be used the PHREEQC software to model the transport of the cesium radionuclide through this bentonite with the Kd and D data. The modelling of radionuclide transport in the Brazilian materials will contribute to evaluate the efficiency of multi-barriers system of the national repository, because it is one of its safety criteria.

Samples of real irradiated (i-)graphite from bushings of RBMK reactor after several types of decontamination treatments were put in contact with aqueous solutions modelling underground water of Nizhnekansky massif (Russia) equilibrated with bentonite for periods up to 1.5 years. Leach rates of radionuclides and evolution of graphite surface morphology and oxidation state were monitored using nuclear spectroscopy, SEM and XPS. After the experiment, less than one third of surface carbons remains unoxidised. Extensive precipitation of secondary phases (alumosilicates, carbonates) was observed on some samples and is possibly correlated with surface oxidation extent. The leach rates of dose-forming 14C and 36Cl are comparable with the leach rates of radionuclides in glassy waste forms. According to the current study i-graphite could be regarded as a waste form, which is suitable for near-surface disposal.

Energy recovery from waste treatment and growing biomass is of great significance for the energy management and sustainable energy supply. It is shown that biomass and various wastes containing carbon are able to significantly contribute to the energy sector.

We describe a possible scenario for the energy development of an European country of the future. In addition to solar, wind, and hydrogen energy, priority should also be given to generating energy using small-sized gasifiers. First, it is sustainable energy since biomass and household waste are always available. Second, this approach will allow us to launch local electric power grids instead of the unified state and interstate grids, which will reduce up to three times the consumption of energy raw materials and financial resources. Third, a new design of electric motors, namely torus motors, will allow one almost halve electricity consumption and open a gateway to new technologies.

New data on microstructure of 16 years old (La, Pu)PO4 monazite ceramics doped with 8.1 wt% of 238Pu are presented. It is shown that the sample consists from at least two phases differing in La/Pu ratio and small precipitates of Pu-phosphate. Possible mechanisms of the compositional heterogeneity are discussed. Formation of Pu-containing rhabdophane after sample storage in air is observed. This phenomenon together with gradual mechanical destruction of the ceramic pellet formation of submicron particles will likely increase rate of radionuclides loss from the monazite-based waste form. X-ray emission lines produced by recoil uranium ions from Pu decay are analysed. It is suggested that careful examination of their relative intensities may provide important information about behaviour of "hot" recoils in nuclear waste forms.

It is pertinent to the safety case for geological disposal in the UK that the behaviour of vitrified wastes in proximity to cementitious materials is understood. In this study, vitrified simulant intermediate level nuclear waste (ILW) was subject to dissolution in a synthetic cement water solution to simulate disposal conditions. Results show that the presence of alkali / alkaline earth elements in the cementitious solution can be favourable, at least in the short-term, leading to lower dissolution rates associated with incorporation of these elements into the altered layer of the glass.

The low-level nuclear wastes such as decontamination waste from Fukushima are disposed in near-surface underground, where the intermittent recharge of rain and groundwater causes spatial distribution of water content. Therefore, pores of soils are not filled with water, that is, an unsaturated zone will be formed. In such a condition, since the water flow path are detoured by clogged gas in pores of soil in the unsaturated zone, the migration path of radionuclide would be different from the saturated zone. So far, the one-dimensional advection-dispersion equation (ADE) model has been widely used in order to explain experimental results under an unsaturated condition. However, the detouring of local flow-paths remarkably affects the mass transfer. The one-dimensional ADE evaluates such a detouring effect by using Peclet number and retardation coefficient as fitting parameters. In other words, the one-dimensional ADE model is difficult to explain mass transfer under an unsaturated condition. Therefore, the purpose of this study is explaining such complicated transport of radionuclides using a multi-path model based on phenomena in underground. The proposed multi-path model considering both water saturation and permeability distributions showed good agreement with the experimental data under an unsaturated condition.