Radionuclides in redistributed sediments and ash from the Las Conchas fire in Northern New Mexico

The 2011 Las Conchas fire burned 632 km² of ponderosa pine forests and piñon–juniper woodlands in the Jemez Mountains in north central New Mexico. In the weeks following the fire, heavy rainfall caused extensive flooding and erosion of surface soil and ash from the affected areas. Samples from mud and ash flows were collected and analyzed for ¹³⁷Cs and Pu, which were originally deposited as global fallout during the era of atmospheric nuclear testing. The mean concentrations for ²³⁸Pu, ^239,240Pu and ¹³⁷Cs were 0.18 ± 0.05, 4.16 ± 1.95, and 111 ± 56 mBq/g, respectively. ^239,240Pu and ¹³⁷Cs are significantly elevated above non-fire affected regional background levels.