The problem of water pollution persists and, in some cases, has been getting worse since many of the industries that are currently installed in developing countries do not comply with established standards. In order to reduce water pollution, various environmental standards have been established that aim to regulate the introduction of contaminating agents into water and, thereby, control the degree of alteration of the quality of the vital liquid. Adsorption allows minimizing the generation of toxic waste and the recovery of the metal. The objective of the work was to study the bioadsorption of Cr (VI) and Pb (II) using the dry peel of <i>Tamarindus indica</i>. We worked at different pH values and concentration levels. The determination of the chemical-physical parameters was carried out at the Empress Geominera Oriente. Adsorption isotherms were performed using the Langmuir, Freundlich and Dubinin-Radushkevich models, resulting in the maximum bioadsorption capacity of Cr (VI) and Pb (II) by biomass being 3.83 and 15.63 mg/g, respectively. reaching maximum removal percentages of 90.8%. The values of mean free energy of adsorption obtained from the Dubinin-Radushkevich model in Cr (VI) and Pb (II) were 10,000 kJ/mol, respectively, showing that, for these experimental conditions, the adsorption process is of a chemical nature.

The context, which allowed to write this article is the fact that we have noticed an increase in the environmental impact caused by the poor management of car parks and fuel sellers as well as the proliferation of service stations that do not respect any standards. The illegal storage and marketing of petroleum products, especially gasoline, in the city of N'Djamena is the main factor of vulnerability and criticality of air pollutants, thus demonstrating the growing environmental impact in the city of N'Djamena. The presence of Polycyclic Aromatic Hydrocarbons (PAHs) as well as that of fine particles which are part of the Persistent Organic Pollutants (POPs) and characterize by their toxicities, their persistence in the environment, their bioaccumulation in living tissues, and their long-distance transport. Thus, the main objective of this work is to determine and evaluate the physical properties of gasoline and the presence of fine particles in the ten districts of the city of N'Djamena. These are the species sold on the street and presenting a danger to users. The main idea would be to look for gas stations and points of sale that comply with the regulations in force and those that do not. Then physical analyses were carried out on different types of gasoline consumed and then the air quality was measured with a Purple Air sensor. In conclusion, a complete structure of the ten districts with their degrees of pollution as well as the number of gas stations and fuel sellers on the street will be listed.

Rapid urbanization and population growth with its associated Solid Waste Management issues are at the moment the front burner challenges of the 21<sup>st</sup> century, more especially in developing countries of the world of which Nigeria is inclusive. However, the majority of past research in Solid Waste Management has mostly concentrated on the institutional capability and resources required to handle the problems associated with solid waste management, with little attention paid to the attitudes of city inhabitants. Therefore, this research article examines the trends and applications of solid waste management (SWM) in the rapidly urbanizing Kano Metropolis, looks at how the attitudes of city dwellers have contributed to the problem of SWM, and then goes on to review new applications that have been used to manage solid waste in the study area. The study report, which draws on secondary and empirical data sources, finds that just 20.5 tons of the 330 tons of solid waste produced every day are properly managed. The results therefore imply that two factors—bad attitudes of city inhabitants and insufficient institutional capacity—influence the city's poor SWM. While these urban citizens' negative views towards solid waste management (SWM) have contributed to the current indiscriminate garbage disposal, weak institutions have also made it difficult to handle solid waste concerns in the city and prevented timely solutions. In order to ensure effective solid waste management in the Kano Metropolis of Nigeria, the research article now suggests public awareness education programs on solid waste management, public-private partnerships, increased stakeholder engagement, and the creation and implementation of new solid waste management plans.

Groundwater resources that are increasingly being cherished for most socioeconomic development are exposed to varied pollutant sources. Studies have shown that they are vulnerable to various impacts such as climatic change, human impacts and also pollution from seawater intrusion in coastal areas. The susceptibility of a groundwater body to pollution indicates extent to which its quality is at risk of being compromised by contaminants. Assessments of this vulnerability are classified based on scale (site, local, regional) or objective (such as risk management or protection zoning) and also distinguish between source and resource vulnerability maps, as well as specific and intrinsic vulnerability maps. Groundwater vulnerability assessment methods differ based on several factors, including the availability and spatial distribution of quantitative and qualitative data, the objectives and scale of the mapping, the costs of model development, and the particular hydrogeological characteristics of the aquifer under investigation. The National Research Council has classified these methods into three primary categories: process-based methods, statistical methods, and overlay/index methods. Among these, the overlay/index method is widely employed for conducting large-scale assessments of aquifer sensitivity and groundwater vulnerability. It is especially advantageous in developing countries due to the easily accessible data required for its implementation.

The retail industry is an integral part of the service sector. In the context of the booming development of the service industry and digital technology, this paper explores the low-carbon transformation path for traditional retail enterprises empowered by digital technology. Initially, a literature review reveals that as the overall scale of the service industry continues to expand, its negative impact on the environment is also intensifying. Reducing energy consumption and carbon emissions has become a rigid constraint faced by the service industry; Meanwhile, digital technology is becoming an important means to empower traditional service enterprises in their low-carbon transformation. Subsequently, through case study analysis, it is pointed out that digital technology can empower the low-carbon transformation of traditional retail enterprises from three aspects: reducing energy consumption, decreasing emissions, and saving resources. Finally, in response to the existing obstacles in implementing low-carbon transitions such as insufficient motivation for transition, constraints on investment costs in low-carbon technologies, and difficulties in managing energy and carbon emissions, practical paths for digital technology to empower the low-carbon transformation of traditional retail enterprises are proposed. These include enhancing the motivation for enterprise low-carbon transition, overcoming constraints on capital and talent, and improving technical support capabilities for the transformation.