Is the statement true: Groundwater usually contains more dissolved minerals and gases than surface water?

Is the statement true: Groundwater usually contains more dissolved minerals and gases than surface water?

• A. True
• B. False
• C. Not sure
• D. Not applicable

Answer: (A)

Groundwater spends a long time moving through soil and rock, which gives it plenty of opportunity to dissolve minerals from the surrounding material. That extended water-rock interaction raises the total dissolved solids, so groundwater tends to have a higher mineral content than surface water, which is more quickly formed from rain and runoff and often diluted by various surface inputs. Gases behave similarly: underground, gases produced by soil and microbial activity can stay dissolved under the pressure and cooler temperatures found there, while surface water is in more direct contact with the air and tends to equilibrate with atmospheric gases, limiting the amount of dissolved gases that remain. Because of these factors, groundwater typically contains more dissolved minerals and certain dissolved gases than surface water.

Groundwater spends a long time moving through soil and rock, which gives it plenty of opportunity to dissolve minerals from the surrounding material. That extended water-rock interaction raises the total dissolved solids, so groundwater tends to have a higher mineral content than surface water, which is more quickly formed from rain and runoff and often diluted by various surface inputs. Gases behave similarly: underground, gases produced by soil and microbial activity can stay dissolved under the pressure and cooler temperatures found there, while surface water is in more direct contact with the air and tends to equilibrate with atmospheric gases, limiting the amount of dissolved gases that remain. Because of these factors, groundwater typically contains more dissolved minerals and certain dissolved gases than surface water.