Savannah River Ecology Laboratory

Low Dose Irradiation Facility (LoDIF)

The LoDIF is a unique facility designed to evaluate the impact of chronic, low-level radiation exposure on aquatic organisms. The facility is an array of 40 outdoor mesocosms equipped with cesium-137 irradiation sources or unexposed controls. Irradiation sources provide three biologically relevant levels of exposure: 2, 20, and 200 mGy/d mean exposure. Mesocosms are arranged into eight blocks, with five mesocosms per block (three levels of irradiation and two controls). Because dose rates within each mesocosm are greatest directly under the radiation source, mesocosms may also be partitioned to take advantage of this spatial heterogeneity if additional dose levels are required. Thermoluminescent dosimeters placed within the exposure field allow accurate dose rate estimates to be made for all mesocosms. Each mesocosm holds approximately 965 L of water, with a maximum depth of 41 cm. Mesocosms are flow-through, with water cycled from a nearby lake.

The primary model organism is Japanese medaka (Oryzias latipes). Medaka have been used as comparative models for a variety of human and environmental research, including carcinogenesis, mutagenesis, DNA repair, aging, developmental biology, endocrine disruption, and genetics. Short generation time (6-8 weeks), high reproductive output (6-30 eggs per day, with up to 3000 per female per breeding cycle), and well-characterized genetics and developmental biology make this species very suitable for experimentation.

The LoDIF is located adjacent to SREL's Par Pond Radioecology Laboratory, a 3,500-ft2 facility for sample preparation, sequential extractions, and radiochemical analyses.

For more information about the Low Dose Irradiation Facility see SREL publication #2797:
Hinton, T.G., D.P. Couglin, Yi Yi, and L.C. Marsh. 2004. Low Dose Irradiation Facility: initial study on chronic exposures to medaka. Journal of Environmental Radioactivity 74: 4355. (PDF)