Seasonal variations in deposition and retention of cerium-141 and cesium-134 in cool desert vegetation

• Published in: Journal of environmental radioactivity 1993, Vol.21 (3), p.203-212
• Main Authors: Fraley, Leslie, Chavez, Gloria, Markham, O.Doyle
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Applied ecology; Artemisia tridentata; Biological and medical sciences; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on plants and fungi; Elymus elymoides; Fundamental and applied biological sciences. Psychology
• ISSN: 0265-931X; 1879-1700
• DOI: 10.1016/0265-931X(93)90042-6

Deposition velocities and retention half-times were measured for 141Ce and 134Cs aerosols on big sagebrush ( Artemisia tridentata) and squirreltail bottlebrush ( Elymus elymoides). These aerosols were released over a native community in southeast Idaho during each of three seasons—spring, summer, and winter—to study the effects of plant development and growth on deposition velocity and retention. Air concentration during the release and vegetation concentration after the release were measured to determine deposition velocity. Friction velocity, roughness length, and particle size were measured. Vegetation concentration as a function of time was measured to determine retention half-time. There was no significant difference between nuclides for deposition velocity and retention half-time. Species differences were significant ( P < 0.05). Squirreltail bottlebrush deposition velocities were 220, 700, and 820 μm s −1 in spring, summer and winter, respectively. Big sagebrush values were 1·6, 1·6, and 1·0 mms −1. Retention data indicated a rapid initial loss (half-times of 1–2d) followed by a slower loss (half-times of several weeks).