Sandia National Laboratories geochemist Mark Rigali and his colleagues are developing and deploying apatite-based technologies to protect groundwater at sites contaminated by radionuclides and heavy metals.

Apatite is currently being used at the U.S. Department of Energy's Hanford Site in southeastern Washington State and the Fukushima Dai-ichi nuclear plant, "and, there are numerous other potential applications we are exploring," Rigali said.

Crystals of apatite, a calcium-phosphate compound commonly used in fertilizer, can capture and hold a variety of radionuclide and heavy metal contaminants from groundwater. The compound forms a barrier when pumped into the ground.

"Apatite is a very versatile material. It can be deployed as a precipitated permeable reactive barrier in the subsurface or in a column as a granular solid for pump and treat remediation applications," Rigali said.

Sandia, Pacific Northwest National Laboratory (PNNL), and Savannah River National Laboratory evaluated calcium apatite-based barrier technologies and recommendations for apatite barrier design, implementation and monitoring at the Fukushima site to reduce groundwater contamination. Tokyo Electric Power Co. funded the research effort.

Thousands of sites throughout the world are contaminated with radionuclides, heavy metals and natural contaminants that threaten groundwater, surface water and food supplies. According to a 2012 U.S. Geological Survey report, about half the global population relies on groundwater as their primary drinking water supply.

Source: - see full article