Monitoring river systems is crucial for understanding and managing water resources, predicting natural disasters, and maintaining ecological balance. Assessment of heavy metal pollution derived valuable data which are critical for the environmental management and regulatory compliance of the Jukskei River. Heavy elements were evaluated in the Jukskei River for seasonal impact, potential health risks, and contamination level with concentration levels ranging from 6900 mg/kg iron (Fe) to 0.85 mg/kg cadmium (Cd) in the dry sampling season and 6900 mg/kg Fe to 0.26 mg/kg Cd in the wet season. Enrichment factor analysis indicated high contamination levels of Fe and Pb in both dry and wet seasons. Moreover, pollution indicators revealed extremely high contamination of geo-accumulation and enrichment factors in the downstream to upstream in both seasons with a mild contamination factor for mercury (Hg). Principal Component Analysis revealed anthropogenic sources of arsenic (As), Cd, and Pb due to wastewater and agricultural pesticide application while Thorium (Th), uranium (U) and Hg were attributed as a results of gold mining activities. ANOVA and Pearson correlation analysis showed a high and moderate link between As–Pb, Cd–Pd, and As–Hg, which are significantly correlated. The potential ecological risk index assessment revealed a significant impact of heavy metals on the freshwater ecosystem.

The increasing population has subjected rivers and streams to high levels of both industrial and domestic pollution. Significant environmental challenges have been brought about by their effects, particularly with regard to biota, ecosystem processes, soil quality, and groundwater pollution. This study examined the effects of human activity by applying pollution index models to evaluate the input of toxic elements in river sediments. Prior to sediment quality analysis, the total amount of arsenic (As), lead (Pb), cadmium (Cd), mercury (Hg), thorium (Th), and uranium (U) was determined in the concentration range of 1.09–10.0 mg/kg, 8.53–475 mg/kg, 0.12–0.16 mg/kg, 4.85–77.5 mg/kg, 3.14–5.9 mg/kg and 0.93–2.86 mg/kg, respectively. The enrichment factor, contamination factor, pollution load index, and geo-accumulation index revealed alarmingly high levels of Pb and Hg contamination at some sampling points, which are related to possible human input, ranging from severe enrichment to considerable contamination. The low ranges of pollution indices of some toxic elements suggest enrichment through the natural weathering process and atmospheric deposition. The Pearson correlation coefficient revealed a significant correlation between Pb-Fe and As-Fe, suggesting the possibility of acid mine contamination. Continual monitoring of river sediment is essential to minimize the impact of toxic elements to sustain sediment health and quality.

Value-added base metals such as copper, nickel, lithium, and manganese are critical for energy applications due to their intriguing properties for catalytic and other modern energy applications. These materials play a significant role in energy storage and energy conversion, including supercapacitors, batteries, and fuel cells. The efficient separation, extraction, and analysis of metals from mineral ores is crucial for meeting the exponential growth demands for sustainable renewable energy solutions. This chapter explores the various dissolution approaches to recover these metals from complex mineral ore matrices. Additionally, the main focus of this chapter will be on acid digestion, the alkaline fusion dissolution method combined with classical chemistry, and advanced spectroscopic techniques that ensure the effective utilization of value-added base metals. This chapter will also provide an in-depth discussion of the mineralogical analysis for the mineral association of these metals using analytical characterization such as scanning electron microscopy (SEM), X-ray diffraction, petrographic microscope, and mineral liberation analysis (MLA). Furthermore, this chapter also discusses the economic viability of value-added base metals, policies and strategies for commercialization, and future gaps of critical minerals in energy conversion development and water purification. High-value base metals are crucial for energy applications, battery technologies, catalysts, and renewable infrastructure. Research and technological advancements indicate that they can bridge the gap between mineral characterization and energy sustainability, ensuring a sustainable materials supply.