TCEQ Class D Water Operator License Practice Exam 2025 – Complete Study Resource

Surface water typically has lower concentrations of certain minerals and gases compared to groundwater and other water sources. In many cases, surface water is more exposed to atmospheric conditions, which can lead to lower levels of dissolved gases, including oxygen and carbon dioxide, particularly in warmer temperatures or during calm weather when there is minimal mixing and aeration.

Minerals, on the other hand, can vary in concentration depending on the geology of the surface area and the surrounding soil. However, compared to deeper groundwater sources—which often has higher mineral content due to leaching from soil and rock layers—surface water may display lower overall mineral levels.

Options such as nutrients and pollutants often vary based on surrounding land use and runoff. Chlorine and sulfur are specific chemical elements that might be present due to particular conditions, but they do not characterize surface water in a general sense like minerals and gases do. Therefore, lower levels of these components signify conditions typical to surface water, making the selected answer the most appropriate choice.