Predicting the occurrence of 228Ra in ground water

Area of Science:

• Environmental Science
• Geochemistry
• Radiological Science

Background:

• Elevated radium-228 (228Ra) in public drinking water poses health risks.
• Understanding the occurrence of 228Ra in groundwater is crucial for public health protection.

Purpose of the Study:

• To develop a conceptual model for predicting the probability of elevated 228Ra in public drinking water supplies.
• To classify aquifers based on their geochemical and radiological properties related to 228Ra and 232Th.

Main Methods:

• Developed an aquifer classification scheme based on geochemical and radiological behavior of 228Ra and its parent 232Th.
• Classified aquifer types into low, medium, and high probability categories for elevated 228Ra.
• Applied the model nationwide to classify US counties and map 228Ra occurrence probability.

Main Results:

• Nationwide classification revealed 71% of counties as low probability, 18% as medium, and 11% as high for elevated 228Ra.
• Summarized available data on actual 228Ra concentrations within different aquifer types.
• Presented a map illustrating the geographical distribution of the three probability classes across the United States.

Conclusions:

• The conceptual model provides a framework for assessing 228Ra occurrence in public water supplies.
• The nationwide classification offers a valuable tool for prioritizing water quality monitoring and risk assessment.
• The majority of US counties exhibit a low probability of elevated 228Ra, suggesting localized areas of concern.