Micropollutants, which include organic compounds, heavy metals, and microplastics, are small yet persistent contaminants originating from a variety of sources such as industrial emissions, agricultural runoff, pharmaceuticals, and household products. Due to their widespread presence and potential for environmental accumulation, these pollutants pose significant risks to ecosystems and human health. This chapter offers a comprehensive examination of the different categories of micropollutants, exploring the pathways through which they infiltrate and persist in the environment, whether through air, water, or soil. Special attention is given to their ability to bioaccumulate and transform through processes like biodegradation and photodegradation. The toxicity mechanisms associated with micropollutants, highlighting both immediate (acute) and long-term (chronic) effects. These include cellular damage, endocrine system disruption, and adverse impacts on the immune and nervous systems. Methods used to assess toxicity are also covered, from in vitro and in vivo laboratory testing to advanced computational models and the use of bioindicators to evaluate environmental effects. The challenges in detecting micropollutants at extremely low concentrations and understanding their combined, synergistic effects when multiple pollutants are present. Emerging solutions, such as advanced detection technologies and bioremediation methods, are discussed for their potential to mitigate these challenges.