Which type of water is vulnerable to pathogens and contaminants?

Surface water is particularly vulnerable to pathogens and contaminants due to its exposure to environmental factors and human activities. It includes streams, rivers, lakes, and reservoirs that are directly impacted by rainfall, runoff, and other forms of water movement. Because surface water is often in contact with the atmosphere and surrounding land, it can easily become contaminated by various pollutants, including microorganisms from animal waste, agricultural runoff, and industrial discharges.

In contrast, groundwater, which is stored in underground aquifers, typically has a natural filtration process as it passes through soil and rock layers, providing some protection from surface pollutants. Saltwater, while it has its own set of challenges, primarily pertains to oceanic waters and is less applicable in the context of pathogen exposure relevant to human consumption. Drinking water, which is treated for safety, is designed to be a secure source; thus, it is not inherently vulnerable to contamination in the same way that untreated surface water is.