Study of Soil Properties in Relation to Radionuclides in Coffee Samples from Thailand and Japan

Abstract

Coffee is widely popular and essential to economic growth¹⁾. This study evaluates radionuclide levels in soil from Agricultural Innovation Research, Integration, Demonstration, and Training Center (AIRID), Chiang Mai, Thailand, and The Okinawa Orchid Society (OOS), Okinawa, Japan, as well as commercial coffee beans, using an XRF spectrometer and an HPGe gamma spectrometer. Exchangeable K and extractable P were determined via the ammonium acetate and Bray methods. In AIRID soil samples, ⁴⁰K activity ranged from 316.3-937.1 Bq kg^-1 before and 403.4-851.3 Bq kg^-1 after fertilization. For OOS soil, average concentrations were 570.7 Bq kg^-1 and 508.9 Bq kg^-1, respectively. The average of ⁴⁰K concentration in the soil samples is higher than the global average of 420 Bq kg^{-1 2)}. The coffee beans samples show the average concentrations of natural radionuclides such as ²²⁶Ra less than 1 Bq kg^-1 and ⁴⁰K slightly higher than the global average.