MONITORING DIOXINS RESIDUE IN SURROUNDING AREA OF BIEN HOA AIRBASE

Abstract

Bien Hoa Airbase is the military airport where the defoliants such Agent Orange, Agent White and Agent Blue were storaged during Ranch Hand Operation and Pacer Ivy Campaign. There was also happened some large chemical leakages in 1970 with total about 28,000 L. Nowadays Bien Hoa Airbase is named as one of three “hot spots” of Dioxin contamination and it is decontaminating by the national/international programs. However the risk caused by Dioxins/Furans residue spreading out through runoff and sewage from inside the area is still affecting on surrounding ecosystems as well as on the health of local population. Our monitoring result in dry and rainy seasons in 2010 has detected the residue of TCDD in soil (6/28 samples) with maximum concentration of 0.687 ng /g dry weight; in sediment (3/20 samples) with maximum concentration of 0.442 ng /g dry weight; and in fish sample with maximum concentration of 18.4 ng/kg wet weight. Compared with current Vietnamese and international standards these values are greater than the allowed standards (TEQ was 3-4 times higher than PEL value, max TEQ was up to 50 times higher than PEL value) and can cause adverse effects to ecosystems and human health if exposure long and continuous. Furthermore, the area around Bien Hoa Airbase were converted into residential areas with high population density, thus the need for research as well as warnings about this potential risk to health to residents in the area.