Radionuclides in bees and honey within and around los alamos national laboratory

Abstract

Honeybees are effective monitors of environmental pollution. Los Alamos National Laboratory (LANL), in fact, has maintained a network of honeybee colonies within and around LANL for 17 years (1979 through 1995); the objectives for maintaining this honeybee network were to (1) determine the bioavailability of certain radionuclides in the environment with respect to LANL operations (3H, 57Co, 60Co, 1S2Eu, 40K, 7Be, 22Na, 54Mn, 83Rb, 137Cs, 238Pu, 239Pu, 90Sr, 241Am, and totU) and (2) estimate the committed effective dose equivalent (CEDE) and the corresponding risk of excess cancer fatalities (RECF) to people who may consume honey from hives located around the perimeter of the Laboratory (Los Alamos [LA] and White Rock/Pajarito Acres [WR/PA], New Mexico). Based on the 17‐year average, bees from nine out of eleven hives and honey from six out of eleven hives on LANL lands contained 3H that was significantly higher (p <0.05) than background. The highest average concentration of 3H in bees (434 pCi mL−1) collected over the years was from LANL's Technical Area (TA) 54—a low‐level radioactive waste disposal site. Similarity, the highest average concentration of 3H in honey (709 pCi mL−1) was collected from a hive located near three 3H storage ponds at LANL TA‐53. The average concentrations of 3H in bees and honey from background hives was 1.1 pCi mL−1 and 1.6 pCi mL−1, respectively. Although the concentration of 3H in bees and honey from most LANL and perimeter (WR/PA) hives were significantly higher than background, most areas, with the exception of TA‐53 and TA‐54, generally exhibited decreasing 3H concentrations over time. Also, all other radionuclides in honey collected from perimeter hives around LANL were not significantly different from background. Overall, the maximum total net positive CEDE—based on the average concentration plus two std dev of all the radionuclides measured over the years after the subtraction of background‐from consuming 11 Ib of honey collected from LA and WR/PA, was 0.031 mrem y−1 and 0.006 mrem y−1, respectively. The highest CEDE was <0.04% of the International Commission on Radiological Protection permissible dose limit of 100 mrem y−1 from all pathways and corresponds to a RECF of 1.6 × 10−8 (0.016 in a million)—far below the Environmental Protection Agency's guideline of 1 × 10−6 (one in a million).