The increasing concern over soil and water contamination has accelerated the development of advanced technologies for the detection and remediation of environmental pollutants. This chapter explores the application of electrochemical sensors and nanotechnology as innovative tools for the monitoring and mitigation of harmful substances in agricultural and aquatic environments. Emphasis is placed on the use of electrochemical sensors, which operate through redox reactions between analytes and electrodes, providing high sensitivity and selectivity for detecting pesticides, heavy metals, and other contaminants. The chapter discusses the classification and health risks of various pesticide groups (organochlorines, organophosphates, carbamates, and pyrethroids) as well as the toxic effects of heavy metals such as cadmium, lead, and copper. In response to these challenges, various remediation techniques are examined, including adsorption with nanomaterials such as carbon nanotubes, graphene, magnetic nanoparticles, and metal oxide nanostructures. Additionally, the chapter highlights the potential of nanotechnology in precision agriculture, particularly in the detection of soil contaminants, pathogens, and the optimization of agrochemical use. Overall, the integration of sensor technologies and nanomaterials offers a promising approach to improving environmental sustainability and food safety in agricultural systems.