By Thi Xuan Hieu Ngo
Course: Science Planet and Earth SCI291E
Professor Denise Baines
2 Dec. 2008
AGENT ORANGE CONTAMINATION IN BIEN HOA – BIEN HUNG (VIETNAM)
Bien Hoa City and its surrounding area (Bien Hung Lake), with a population of almost four hundred thousands, are one of the environmental hot spots in Vietnam due to severe dioxin contamination (Schecter et al., Recent Dioxin). They are located in southern Vietnam, approximately 32 km north of Ho Chi Minh City, and are near a former air base used for “Operation Ranch Hand” fixed-wing aircraft Agent Orange spray missions. Agent Orange is a herbicide, which contains high concentration of persistent and very toxic chemical called dioxin or “TCDD” (2,3,7,8-tetrachlorodibenzo-p-dioxin). It was sprayed in Vietnam between 1962 and 1971 by the US Army to defoliate inland hardwood forests, coastal mangrove forests, and cultivated land (Arison III ). Although the war ended over 30 years ago, the adverse effects from dioxin still continue on this territory. By looking at various studies, this paper concludes that dioxin levels in soils, sediments, food, and humans in Bien Hoa – Bien Hung are relatively high; residents are at risk of health problems; and that urgent plans for adaptation and mitigation must be drawn to tackle the problem.
According to The US Department of Defense, an estimated release of 5000 to 7000 gallons of Agent Orange from underground storage tanks at this location occurred just right after the spraying ended. Dioxin can transfer from soil into organic matter in sediment in lakes or rivers despite being highly lipophilic and significantly hydrophobic. It then moves up the food chain from phytoplankton to zooplankton, from zooplankton to fish, and then into humans (Schecter et al., Recent Dioxin).
With this knowledge, a study was conducted in 2004 by the Technical University of Berlin (Germany) to examine soil and sediment in the region. The study concludes that dioxin levels in soil samples of Bien Hoa Airbase and in different sediment layers of Bien Hung Lake are much higher than standard values suggested by Canadian Environmental Quality Guideline. In soil samples of Bien Hoa Airbase, the dioxin level, on average, is 46 times higher than the standard value for safety of agricultural, residential, commercial and industrial use. In sediment of Bien Hung Lake, dioxin level is up to 20.4 times higher than (probable effect level) PEL value. In fact, the results are relatively high with respect to the dioxin concentrations in soil/sediment of some developed countries (Germany, United Kingdom, Luxemburg, and Belgium). Because dioxins are extremely persistent and bio-accumulative, they have the potential to accumulate in the tissue of aquatic organisms, which can lead to the bioaccumulation of chemicals in higher levels of the aquatic food web. As a result, wildlife species, bird, and humans who rely on these organisms for food tend to suffer from health problems (Mai et al.). According to an official assessment on consequences of the toxic chemical to biodiversity and alteration of ecosystems in the Bien Hung Lake, conducted by the Ministry of Natural Resources and Environment of Vietnam, species structure is poor: imbalance and lack of some species, particularly amphibian, reptile, shrimp and crab (Nguyen).
There seems to be positive relationship of high dioxin levels in contaminated soils and sediments, and in food. In 2002, the University of Texas Houston School of Public Health conducted a study for food collected in Bien Hoa-Bien Hung. The study concludes that there is elevation of TCDD in some of the food products. For example, the levels of wet weight for ducks were from 276 ppt to 331 ppt, chickens from 0.031 to 15 ppt, fish from 0.063 to 65 ppt, and a toad with 56 ppt while the usual TCDD levels in food are less than 0.1 ppt (Schecter et al., Food).
There also seems to be positive relationship of high dioxin levels in food consumed, and in human blood. A recent study reports that 95% of 43 selected residents of Bien Hoa City experience elevated dioxin levels of over 5 parts per trillion (ppt) TCDD while typical blood TCCD levels in normal Vietnamese people are less than 2 ppt. In fact, the highest blood TCDD level found in Vietnam, 413 ppt, was recently measured in a Vietnamese person living in Bien Hoa City (Schecter et al., Food). This suggests that dioxin-contaminated food is responsible for the elevation of dioxins in humans in this region. According to EPA’s Dioxin Reassessment Report in 2006, TCDDs are carcinogenic to humans and can cause immune system alterations. People who are exposed to the toxic dioxin can suffer reproductive, developmental, and nervous system damage such as endocrine disruption (altered lipid metabolism; liver damage, and skin lesions) over several generations (qtd. in Schecter et al., Food). Therefore, urgent solutions are obligatory for people who are living and will be born in this region.
However, there are many difficulties in mitigating the perpetuating problem because of high cost involved and political issues in and between both Vietnam and the United States. Mitigation requires extensive data and intensive studies and programs to track, interdict, and monitor the movement of TCDD and remove the contamination. The cost involved is a significant challenge for Vietnam. In addition, there has not yet been a clear mitigation road map of what dimensions of the problem need to be solved, in what order, when and how to solve them, what steps, and at what cost due to political obstacles. Although the third annual meeting of the Vietnam-US Joint Advisory Committee on Agent Orange/dioxin last month agreed on an allocation of $3 million (from the US Government), this fund will have to be shared among the most competitive mitigation projects, in which Bien Hoa – Bien Hung is just one candidate. Moreover, despite the fact that international organizations (e.g. the Ford Foundation, UNDP, UNICEF, and the Czech Republic) have committed donations, no precise funds are yet declared (Remarks by Ambassador). This leaves us no choice but prompt plans for adaptation while waiting for further plans. They include substituting clean food for the contaminated, informing the local residents about the toxic level of dioxin and its consequences, isolating and evacuating the residents of the territories with high risk (Schecter et al., Food; Mai et al.).
In conclusion, it is clear that the deadly effects of dioxin on environment and human health in Bien Hoa-Bien Hung have not reduced over time but increase in some residents. Soils and sediments in the area are proved to have elevation of dioxin, which leads to high dioxin level in food and human blood. As a result, residents living in this territory are at risk of various cancers, reproductive, developmental, and nervous system disturbance. This calls for urgent plans for adaptation and mitigation to tackle the problem. However, since mitigation face many difficulties, quick adaptation schemes are urgent.
Arison III, Lindsey H. “Executive Summary: The Herbicidal Warfare Program in Vietnam, 1961 – 1971.” 22 Oct. 2008 <http://www.utvet.com/agentorange2.html>
Mai, Tuan Anh, Thanh Vu Doan, Joseph Tarradellas, Luiz Felippe de Alencastro, Dominique Grandjean. “Dioxin Contamination in Soils of Southern Vietnam.” Chemosphere 67.9 (2007): 1802-1807.
Nguyen, Xuan Quynh. “Assessment on Consequences of the Toxic Chemical to Biodiversity and Alteration of Ecosystems in Ma Da area (Dong Nai, Binh Duong, Binh Phuoc) and Lake Bien Hung (Bien Hoa City) from 2002-2004.” 22 Oct. 2008 <http://www.office33.gov.vn/PrintPreview.aspx?ID=4713>
“Remarks by Ambassador Michael W. Michalak: Ambassador Michael Michalak, Press Conference Agent Orange/Dioxin Joint Advisory Committee Results, The American Center, Hanoi, Vietnam.” Embassy of the United States. 16 Sept. 2008. 22 Oct. 2008 <http://vietnam.usembassy.gov/ambspeech091608.html>
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