An attempt to evaluate dry deposition velocity of airborne²¹⁰Pb in a forest ecosystem

Abstract

Atmospheric concentration and total (wet plus dry) and dry deposition of²¹⁰Pb and⁷Be have been measured at our laboratory in Ishikawa Prefecture in Japan which faced the Sea of Japan during 1993–1994. At the same time inventories of excess²¹⁰Pb in soil samples were measured from a mixed pine forest. On the basis of the data obtained, an attempt was made to evaluate the dry deposition velocity as a result of the interception by the canopies of airborne²¹⁰Pb in a pine stand The dry deposition velocity of²¹⁰Pb in the pine stand was roughly estimated to be 0.9–0.8 cm/s, higher by a factor of about 10 than the value (mean: 0.12±0.09 cm/s; range: 0.06–0.28 cm/s) in the open area measured on the roof of our laboratory.