To evaluate the concentrations of iodine (I) and bromine (Br) in agricultural soils of Japan in relation to soil type and region, we collected 180 soil samples from the surface layer of 96 paddy fields and 84 upland fields. Samples were extracted with tetramethylammonium hydroxide solution for determination of total I by ICP-MS, and with alkali solution for determination of total Br by the analysis of 2-bromo-3-pentanone by HPLC. The arithmetic means were 7.18 mg I and 14.7 mg Br kg^<-1>, and the geometric means were 3.12 mg I and 7.38 mg Br kg^<-1>. Total I concentrations were relatively high in Dark Red soils (21.8 mg kg^<-1>), Andosols (18.8 mg kg^<-1>), Red soils (18.3 mg kg^<-1>), and Wet Andosols (17.1 mg kg^<-1>). Total Br concentrations were relatively high in Non-allophanic Andosols (39.0 mg kg^<-1>), Andosols (36.6 mg kg^<-1>), and Wet Andosols (26.1 mg kg^<-1>). In general, concentrations of both were higher in Andosols and lower in Lowland soils and Dune Regosols. Total concentrations of both were higher in the Kanto, Kyushu, and Hokkaido regions and lower in the Shikoku, Chugoku, Kinki, and Hokuriku-Chubu regions. These trends corresponded well with the trends of soil organic matter content, redox condition (reflecting land use), and contents of iron and aluminum oxides.
