Program: Collaborative Research for Common Regional Issues (CRC)

Field: Environmental Engineering

Principal Investigator: Dr. DANG Thuong Huyen

Sending University: Ho Chi Minh City University of Technology (HCMUT)

Japanese Co-Investigator: Prof. Dr. Toshifumi IGARASHI

Japanese University: Hokkaido University

Year: 2013


During the Vietnam War, Bien Hoa airbase was utilized by the US military in the storage and transport of Agents Orange, White, and Blue, which are herbicides/defoliants used during the war. These chemicals used were highly contaminated with dioxins, which were still unknown at that time as carcinogenic chemicals. Thus, accidental spills as well as deliberate disposal of contaminated items within the airbase caused the advertent dioxin problem of the airbase. The relationships of soil properties and dioxin distribution have not yet been considered at this site. Therefore, the objective of this paper was to clarify these relationships using soil samples from boring cores drilled from three areas of the airbase. Based on results, we analyzed the dioxin concentration up to 10 meters. At depth of 3,5 m, the highest concentration was found. Silty clay with higher TOC of 0.49 % presented the highest toxicity equivalency quantity (TEQ) of 3300 pg-TEQ/g-dw at borehole BH01. Similarly, at BH02, silty clay with the highest TOC of 0.42 % showed the highest TEQ of 760 pg-TEQ/g-dw. The analyzed results of this research also presented a relationship between the TEQ and particle size. It seems to show that the higher concentration of dioxins was found with a ratio of coarse grain size to fine grain size approximately 1:1. However, correlation between dioxins and LOI was not clearly observed. This indicates that mobility of dioxins is sensitive to the TOC of soils. We also assessed the movement ability of dioxin in the vadose zone. strengthen the network between Hokkaido University and HCMUT. We got emails from several insitituation would like to do more colaboration in the dioxin contamination We enhanced our skills of research. Students know how to do real research: field trip, lab skill, communication Encourage our government considering more detail about dioxin contamination volumn in the study area. We contribute our knowledge for mangroves which affected by the war, particularly in the south of Vietnam