In addition to organic pollutants, sewage water often contains heavy metals such as lead, mercury, cadmium, and arsenic. These metals can originate from industrial discharges, leaching from rusting pipes, or runoff from urban areas. Heavy metals are particularly concerning because they are non-biodegradable and can accumulate in the environment, leading to serious health risks for both humans and wildlife. Chronic exposure to even low concentrations of heavy metals can result in a range of health issues, including neurological disorders, cancer, and reproductive problems.