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Scientific proves of adverse effects caused by herbicide/dioxin on humans in Vietnam

(Bqp.vn) - A basic in toxicology is "any chemicals can be toxic and nontoxic. Importance is exposure dose". That means, in the other words, any chemicals can become toxic if being used with overdose.

Common herbicides will cause toxic effects on environment and humans if they are used with overdose. In the War in Vietnam, US army frequently used herbicides with concentration dozen times higher than acceptable levels. Therefore, only herbicides are enough to cause adverse effects on environment and human health in sprayed areas.  

Herbicides used by US army in the war in Vietnam contain, mainly 2,4,5-T (an organic compound contains chlorine). Agent Orange is a mixture of 2,4,5-T and 2,4-D. Besides, Agent White, Agent Green, etc also contain 2,4,5-T and thus where 2,4,5-T can be found, dioxin is also present because dioxin is a byproduct formed during production of 2,4,5-T. The older technology used for manufacturing the herbicide, the more dioxin being formed. In order to increase production of the herbicides to meet demand from US army, companies increased temperature in manufacturing processes of 2,4,5-T and thus more dioxin was formed.  

Dioxin is the most dangerous among toxic chemicals. This is perhaps unarguable fact. With concentration of few part per billion of gram, dioxin can cause reproductive abnormalities and birth defects in in-vivo experiments. There are thousands scientists in the world work on identifying dioxin's effects. Twenty-six international symposiums have being held for debates on dioxin. Dioxin has become a priority research topic for ecologists, toxicologist and environmentalist in the world. The higher development of industry and living standard, the more concerns are arisen for prevention of dioxin exposure. Elimination of dioxin from environment is very difficult work because dioxin is a "product of fire and organic matters".  

How much dioxin was contained in 80 millions liter of herbicides used by US army in the war in Vietnam? There are several different scientific estimations. Scientist in Columbia University, US estimated approximately 366 kg. Scientists in Russia and Vietnam estimated a figure about 2-3 times higher than that. Assuming the figure of 366 kg, this is already extremely high volume and enough to cause adverse effects on environment and humans of Vietnam.  

Dioxin can cause several diseases. The list of dioxin-related diseases is longer and more severe by time. This is resulted by more and more research from scientists from all over the world including Vietnam and US. Unfortunately, so far, neither specific clinical symptom nor biological test have been found in order to determine toxic effects of dioxin.

Quantification of dioxin is only used for reference and determination of dioxin exposure. Low or non-detected levels of dioxin in people who previously exposed to herbicide/dioxin doesn't eliminate the possibility that dioxin may cause health effects to them because dioxin has been reduced over the past few decades. Therefore, epidemiological studies are necessary in this case. These studies should be carried out in large scale, making comparison of diseases pattern in dioxin exposed group with those who did not expose to dioxin. So that basic difference in disease pattern between two groups could be clarified. This is a conventional methodology which is always true and being widely recognized by international scientists. This methodology is applicable not only for dioxin but also for other occupational toxic exposure in case of lacking specific signs for medical examination.

Scientists in Vietnam have a number of epidemiological studies in this field, especially there is a larges-scaled study on over forty-seven thousands Vietnamese veterans and their offspring. Differences in disease patterns are clarified. It should be noted that ratio of birth defects in children of those who exposed to dioxin is significantly higher than the control group of dioxin non-exposed people.

Even though, in a particular patient, examination of diseases caused by dioxin is not a simple work. Clinical examination and biological test should be sufficient for determination of effects. Historical exposure to dioxin has to be considered as a vital criterion. Throughout questionnaire to eliminate other interfering factors is necessary. With this approach, there is no misuse of examination for dioxin-related diseases, and no misunderstanding for disabilities and birth defects caused by dioxin exposure.   

In studies on dioxin "there is neither simple question nor simple answer" (cited from speech of ex-ambassador of US to Vietnam, Buckhardt in opening ceremony of Vietnam - US scientific conference in 2002). Simple examination for dioxin exposure is unscientific. However, it will be even more unscientific if ones deny the link between herbicide/dioxin exposure with disabilities and birth defects in children of Vietnam because above arguments is far enough to identify consequences of dioxin on humans of Vietnam.

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