Final answer:
To select a state for groundwater sampling prioritization, factors like known groundwater contaminants, aquifer thickness, and the impact of human activities on water resources should be assessed.
Step-by-step explanation:
To determine which state the data action project should prioritize next for groundwater sampling, there are several factors to consider. The United States Geological Survey provides a list of groundwater contaminants which may guide the decision based on the prevalence of contaminants in each state.
Also, the digital map showing the saturated thickness of the High Plains aquifer in Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming should be considered; states with lesser saturated thickness may be at a higher risk of contamination due to less dilution of pollutants.
The ESRI GEO Inquiry's activity 'Down to the Last Drop' suggests that human activities significantly impact water resources, implying that regions with intensive agricultural or industrial practices might be prioritized for sampling.