137Cs concentration in soil, prairie plants, and milk from sites in southern Chile.

Soil, prairie plants, and milk samples were collected at 39 dairy farms in the 9th and 10th Region in Southern Chile (38 degrees 44'-41 degrees 08' S) between 1982 and 1990. 137Cs concentrations found in soil, plant, and milk samples ranged from 3.8-17.1 Bq kg-1 for soil, from < 0.3-20 Bq kg-1 dry mass for plants, and from 0.10-0.71 Bq kg-1 for milk. Cesium concentration levels resulting from soil sample measurements exhibit a close similarity with corresponding values found in soils from Central Europe before 1986. The concentration ratio prairie plants:soil ranged from 0.05-0.62, 0.52-5.0, and < 0.02-0.40 corresponding to Dystrandepts, Placandepts, and Palehumults soil groups, respectively. At seven selected dairy farms in the vicinity of Valdivia city (10th Region), soil, prairie plant, and milk samples were taken yearly during the grazing period between 1982 and 1990. Results obtained from soil samples taken after April 1986 show no significant increase of the 137Cs concentration. Concentrations in plants and milk for 137Cs decreased during the observation time. 134Cs (as an indicator of Chernobyl fallout) was not found in soil, plant, or milk samples during 1986-1990.