What is the primary source of mercury pollution in waterways?

The primary source of mercury pollution in waterways is largely attributed to industrial emissions, particularly from coal burning. When coal is burned for energy, it releases mercury into the atmosphere. This mercury can then settle into water bodies through precipitation or atmospheric deposition. Once in the water, mercury can undergo chemical transformations and bioaccumulate in aquatic organisms, leading to elevated levels in the food chain and posing significant health risks to both wildlife and humans.

The emphasis on coal burning is important as it represents a significant contributor to global mercury emissions. In contrast, while agricultural runoff, household waste disposal, and oil spills can lead to various forms of pollution, they are not the primary contributors to mercury levels in waterways. Agricultural runoff may introduce pesticides and fertilizers but is not linked to mercury. Household waste generally does not contain notable amounts of mercury, and while oil spills can harm aquatic environments, they do not significantly introduce mercury into the water. Hence, the connection between coal burning and mercury pollution establishes industrial emissions as the primary source in this context.