How is lead typically introduced into drinking water?

Lead is typically introduced into drinking water primarily through the corrosion of lead pipes or plumbing fixtures. This corrosion can occur when water is in contact with lead-containing materials, especially if the water is acidic or has a low mineral content, which can enhance the leaching of lead into the water supply.

Over time, lead pipes, fittings, and solder can deteriorate, releasing lead particles into the drinking water system. This situation is particularly problematic in older homes and buildings where lead plumbing materials may still be present. The public health concerns regarding lead in drinking water are significant because lead is a toxic substance that can cause a range of health issues, particularly in children.

The other possibilities listed, such as treatment processes, agricultural runoff, or water softening, do not commonly introduce lead into drinking water. Treatment processes are designed to remove contaminants, agricultural runoff generally involves pesticides or fertilizers rather than heavy metals like lead, and water softening typically addresses calcium and magnesium without introducing lead.