Radiochemistry Unit
The Radiochemistry Unit (RCU) of DWRLB is the only State laboratory conducting radiological testing on environmental samples. RCU is capable of measuring alpha, beta, and gamma radioactivity in water, wastewater, sea water, air, biota, vegetation, milk, soil and other matrices and is certified by the US EPA to test regulated radioactive contaminants in drinking water. Radiochemistry services are provided to the Radiologic Health Branch (RHB), the Environmental Management Branch (EMB) and public health authorities and emergency responders at the local, State and Federal level.
RCU provides analytical support to the Radiologic Assessment Unit of RHB in monitoring environments surrounding the nuclear power plant sites in California by analyzing environmental samples for fission productsā which can reveal accidentalā releases. RCU monitors air samples throughout the State for ambient radiation. Air sampling stations are located in Eureka, Diablo Canyon, Livermore, Long Beach, Richmond, San Diego, San Luis Obispo, and San Onofre. Weekly air samplings detect airborne radionuclides that could be released anywhere around the globe, for example, elevated radioactivity was measured for six weeks after the Chernobyl accident in 1986, and after the Tokaimura (1999) and Fukushima (2011) incidents. Another major area of work is enforcement/compliance and decommissioning/decontamination. Radioactive materials are used widely in manufacturing, research and hospitals throughout California, and these facilities require periodic testing for surface contamination. As sites are decommissioned, analyses of environmental samples are performed to demonstrate that radioactivity does not exceed background levels before these sites are released for unrestricted use.
RCU provides analytical support to the EMB in the cleanup of radiological materials at former military facilities prior to release from federal ownership. Currently soil samples from Treasure Island Naval Station and Hunters Point Naval Shipyard are being tested. Other sites McClellan Air Force Base, Alameda Naval Station and Mare Island Naval Shipyard have been tested for radioactive radium and strontium isotopes.
RCU is part of California's Nuclear Power Plant Emergency Response Program (NERP) and is ready to receive environmental samples during the re-entry phase after a nuclear incident (e.g., accidents, dirty bombs, nuclear detonation). For this purpose, the lab is equipped with a special Semi-hot laboratory where moderately radioactive samples can be handled.
Research and method development is an important part of RCU's activities. Currently a rapid method for radioactive strontium in soil measurements as part of emergency preparedness expansion program is being developed. Other achievements include the development of methods for the detection of lead-210 and polonium-210 in water sources and detection of gross alpha and gross beta activities in water by liquid scintillation spectroscopy.