Contaminants refer to substances that are present in the environment in concentrations high enough to pose a threat to human health, wildlife, or the ecosystem. These substances can come from a variety of sources, including industrial processes, agricultural activities, vehicle emissions, and waste disposal. Common contaminants include heavy metals, pesticides, industrial chemicals, and sewage. Research in this area focuses on identifying sources of contamination, measuring levels of contaminants in the environment, assessing their potential health and environmental impacts, and developing strategies to mitigate their presence. This research is essential for protecting human health and the environment from the harmful effects of pollution.