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Wednesday, December 18, 2013

The terrible legacy of Agent Orange and dioxin

Exposure to TCDD (dioxin)

There are two different health effects that must be considered when dealing with dioxin. One is the effect of direct exposure to the individual and the second is the effects on the germline of the individual, both maternal and paternal. The latter is far worse as it signifies there is a permanent effect on the human genome and all future generations. This is one of the horrific legacies of dioxin, only now being understood. (It will be dealt with in a later article). 

History of poisonings by dioxins

There is a history of accidental poisoning by dioxins in both animals and humans in many places in the world and the precautions taken by governments to cover this up or underplay its significance. It should be noted that although some of the poisoning events refer to Polychlorinated Biphenyls, a close relative of dioxin, these would also contain small amounts of TCDDs or dioxins (White and Birnbaum 2009). 

  • GREAT LAKES REGION:  The Great Lakes region of US and Canada saw the greatly diminished reproduction among trout and mink, which has persisted to this day, due to dioxin contamination. Multiple species of birds, fish, reptiles and mammals have exhibited reproductive impairment, immunologic dysfunction, hyperplasia of the thyroid and adrenal glands, porphyria, congenital malformation, growth retardation amongst others (Fox, 2001).

  • LUDWIGSHAFEN, GERMANY:  On November 17, 1953, an uncontrolled decomposition reaction occurred in a trichlorophenol (TCP) production unit owned by BASF AG and located in Ludwigshafen, Germany. Byproducts that escaped from the damaged autoclave contaminated surfaces throughout the immediate work area of the enclosed production building. Within days, workers who were engaged in clean-up efforts developed severe acne as well as other signs and symptoms, and some were taken into hospital. The agent most likely to have caused these responses was not identified until 1957 when high TCDD levels were found in the blood lipids. Employees were exposed to residues contaminated with TCDD during the clean-up and repair activities that lasted for about four to five months, during incidental maintenance work in the building after completion of the restoration work, and finally during demolition of the reactor portion of the building in 1968-69. Some 30 years later TCDD could still be detected in the survivors. Workers died from lung cancer, stomach cancer, liver cancer and cardiovascular disease (Ott and Zober 1996)

  • SEVESO, ITALY:  The most famous case occurred in Seveso, Italy, when an explosion occurred in 1976 at an Italian chemical plant producing 2,4,5 trichlorophenol, an intermediate in 2,4,5-T synthesis. Because of the nature of the uncontrolled reaction that produced the explosion, not only TCDD was released but the levels were far higher than the normal range of 1 ppm and could have reached 100 ppm. Immediately after the accident, those exposed had skin lesions consistent with chlorache. Later studies revealed that TCDD could increase the risk of many cancers, as well as diabetes, adverse cardiovascular effect and altered endocrine and immune function and early death (Bertazzi et al. 1997; Bertazzi et al. 2002; Baccarelli et al. 2002; Mocarelli et al. 2008). It is this case that has indicated that the effect of TCDDs can be passed on to the next generation. The sperm count in children exposed in Seveso has been measured now that they are adults. Those children of an age before puberty have shown a much lower sperm count as adults but those exposed at an age after puberty have higher sperm counts. So the effect of TCDDs depends not only on the dosage but also on the timing of exposure.

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