The development of silver nanoparticles (AgNPs) for the colorimetric assessment of dangerous metal ions in water and environmental samples is discussed in this chapter. Metal ion poisoning in the ecosystem increased quickly as a result of anthropogenic activities, seriously illening both humans and coastal life. A quick and easy test is urgently required to scanner the presence of metallic ions in the natural world and aquatic bodies. The nanoparticle colorimetric-based approaches have been widely employed for quick noticing, but there are several drawbacks that can be avoided or controlled by knowing the key variables that govern these reactions. Due to their simplicity in synthesis, high level of surface functionalization, biocompatibility and tunable physicochemical properties, noble metal nanoparticles (NPs), especially those derived from gold and silver, have garnered a lot of awareness. Noble metal nanoparticles have made it possible to rapidly and multiplexed notice metal ions with exceptional sensitivity and selectivity. Colorimetric metal detection is made possible by the optical properties of Au-Ag NPs and noble metal-based nano enzymes. These metal nanoparticles' color changes in response to lead ions are caused by changes in surface modification and interparticle interactions (aggregation/disaggregation). The enormous implicit of noble metal nanoparticles as the upcoming generation and on-site sensing aid have been examined for the fast identification of lead ions in ecosystem matrices. As a result of their size, shape, and aggregation conditions, silver nanoparticles (NPs) exhibit a variety of colors in the visible area of the electromagnetic spectrum. The term "localized surface plasmon resonance" (LSPR) refers to this occurrence. LSPR provides an attractive framework for the evolution of an innovative, affordable, bare-eye assay for on-site monitoring of many analytes. In this paper, we latest assessed the most recent developments in the colorimetric assay for hazardous metal ions based on silver nanoparticles. Each method's mechanism and its uses were also discussed.