How can heavy metals enter drinking water supplies?

Heavy metals can enter drinking water supplies through multiple pathways, which include industrial discharges, leaching from pipes, and surface runoff. Industrial activities often release heavy metals into the environment, and wastewater containing these metals can be improperly managed or discharged into nearby water sources. This can lead to contamination of both surface water and groundwater.

Leaching from pipes is another significant pathway, especially in older infrastructure where pipes may corrode or degrade over time, allowing metals such as lead or copper to seep into the water supply. Surface runoff can wash heavy metals from soil or urban areas into water bodies, especially during rain events.

This multifaceted approach highlights the various ways heavy metals may be introduced into drinking water, making the option encompassing these pathways the most comprehensive and accurate choice.