Environmental pollution is a pressing global issue that requires urgent action. To address it, we must first understand the impact of pollutants on ecosystems, especially on vital resources like water. Over 1.2 billion people suffer from water scarcity, a growing problem driven by pollution. This chapter explores advanced methods for detecting and quantifying pollutants, including optical biosensors, remote sensing, and biomarkers. Optical biosensors offer a quick, sensitive, and specific way to identify various pollutants, such as pesticides, pharmaceuticals, and heavy metals, in water. Remote sensing provides a broader view, measuring vegetation, microhabitat, and habitat structure. Biomarkers, including biomarkers of exposure, susceptibility, and effect, offer insights into the health of ecosystems. Together, these tools empower us to monitor pollution, assess its effects, and take timely action to protect our planet.