This study was performed to determine the effects of soil and building materials on indoor radon concentration. Short-term measurements were made in the underground soil of a building along with the radon emanation rates from the phosphogypsum board used as the interior wall. The radon measurements in the soil were 9,213 Bq/m3 in the B3 level, and 3,765 Bq/m3 in the B4 level. Soil radon concentration in the B4 level was 2.4 times higher than in the B3 level. Indoor radon measurements in 50 different locations in the underground of the building, averaged from 144.3 Bq/m3 (B1), 177.0 Bq/m3 (B2), and 189.2 Bq/m3 (B3) to a high of 210.1 Bq/m3 (B4). Indoor radon concentration was increased from the lower level to the upper level. The radon emanation rates from phosphogypsum were 4,234.1 mBq/m2/h and, 450.4 mBq/kg/h. The measurement results indicated that the phosphogypsum board used as building materials as well as the soil could affect the indoor radon concentration.

The resistance of maize weevil(Sitophilus zeamais), an important agricultural pest of stored grain, on aluminium phosphide fumigant(PH3) has been reported recently in Korea. Many researchers reported that ethyl formate(EF), a potential methyl bromide alternative fumigant, showed good efficacy on several grain pests. In this trial, based on CTP (concentration × time products), we evaluated efficacy of EF on phosphine resistant and susceptible maize weevil. Each of insect strains were collected in grain storehouses and examined the PH3 resistance according to FAO method (Busvine, 1980). L(Ct)90 of PH3 resistant and susceptible strain was 48.3 and 0.3 g h m-3, respectively. When treated with EF, L(Ct)90 of PH3 resistant and susceptible strain was 90.0 and 110.9 g h m-3, respectively. In the case of EF, there was no difference between resistant and sucsecptible strain compare with PH3. These results indicates that EF is a potential alternative for aluminium phosphide resistance management in grain storehouses.