Groundwater quality, determined by taking ten samples from fourteen wells within a watershed throughout one calendar year, was related to land use and geology. The wells were found in forested and cropland areas within three different geologic zones. Nitrate, chloride, and phosphate concentrations were much higher in the groundwater underlying cropland. The mean concentrations ranged from five to seven times higher than those observed under forested land. The higher concentrations were consistent with acidic nutrients found in both the fertilizers and manure used on the croplands. The groundwater quality under the forested area was variable and was highly influenced by the amount of rainfall. With increasing rainfall, the nitrate, chloride, and phosphate levels were very low. In one geologic area downstream from the agricultural land, the concentrations of nitrates, chloride, and phosphates were also low due to mixing and dilution with the stream waters.

Question

Which statements about groundwater quality are true? (Choose 3)
Responses
A The more available water, either from precipitation or stream flow, the lower the concentration of fertilizer chemicals.The more available water, either from precipitation or stream flow, the lower the concentration of fertilizer chemicals.
B Agricultural lands have a lower pH than forested lands.Agricultural lands have a lower pH than forested lands.
C The concentrations of nitrates, chloride, and phosphates were much higher in groundwater under cropland than anywhere else.The concentrations of nitrates, chloride, and phosphates were much higher in groundwater under cropland than anywhere else.
D Chemicals such as nitrates, enter ground water as a result of fertilizer and manure use.Chemicals such as nitrates, enter ground water as a result of fertilizer and manure use.
E The validity of the experiment was questioned since only fourteen wells were tested.The validity of the experiment was questioned since only fourteen wells were tested.

Answer 1

The three true statements about groundwater quality based on the provided information are:

A. The more available water, either from precipitation or stream flow, the lower the concentration of fertilizer chemicals.
C. The concentrations of nitrates, chloride, and phosphates were much higher in groundwater under cropland than anywhere else.
D. Chemicals such as nitrates enter groundwater as a result of fertilizer and manure use.

Statements B and E are not supported by the information given in the passage.