Water pollution occurs when harmful physical, chemical, or biological substances enter water bodies such as rivers, lakes, groundwater, oceans, and reservoirs, reducing water quality and making it unsuitable for human consumption, agriculture, industry, and aquatic ecosystems. The sources of water pollution are both natural and anthropogenic, but human activities are the dominant contributors in the modern world. Physical pollutants include suspended solids, sediments, silt, plastics, microplastics, and thermal discharges. Excessive sediment from deforestation, mining, and construction increases turbidity, reducing light penetration and affecting photosynthesis in aquatic plants. Plastic waste accumulates in rivers and oceans, where it persists for decades and fragments into microplastics that enter the food chain. Thermal pollution, mainly from power plants and industrial cooling systems, raises water temperature and reduces dissolved oxygen levels. Chemical pollutants comprise organic and inorganic substances. Industrial effluents often contain heavy metals such as mercury, lead, cadmium, chromium, and arsenic, which are toxic even at low concentrations. Agricultural runoff introduces fertilizers rich in nitrates and phosphates, along with pesticides, herbicides, and insecticides. Domestic sewage contributes detergents, oils, pharmaceuticals, and personal care products. Petroleum spills from offshore drilling and shipping release hydrocarbons that contaminate marine environments. Acid mine drainage introduces sulfuric