DIOXIN: It’s cancerous, it’s in your food, and your children are probably being exposed at higher levels during breast feeding.
Since the 1960s, and for more than five decades thereafter, the Houston Ship Channel has been hiding a dark environmental reality: buried beneath its waters lies waste pits that are holding and releasing dioxins, a type of chemical known to cause cancer and birth defects. See Houston Chronicle. Also see TCEQ webpage.
What is Dioxin?
Dioxin is a term used to describe hundreds of chemicals that share a similar chemical structure. The shared chemical structure is marked by two benzene rings connected by a pair of oxygen atoms, otherwise known as “aromatic compounds.” These chemicals look like white crystalline needles under a microscope, and they are primarily produced as a byproduct of manufacturing chlorinated organic compounds, such as herbicides, and also from outdoor burning. According to the Environmental Protection Agency (EPA), there are three families of these aromatic compounds:
How is Dioxin toxic?
Dioxin is toxic to humans because of its ability to bind to particular receptors on the cells in our bodies, leading to the cell becoming inept at producing much needed proteins. Although dioxin was heavily manufactured in the United States for decades, by the 1980s cancer clusters appeared heavily in residential neighborhoods adjacent to areas known to have been contaminated by the improper disposal of dioxin waste. Finally, in 1997, the International Agency for Research on Cancer (IRAC) came forward and decided to formally add Dioxin to its list of chemicals known to cause cancer in humans – a Group 1 carcinogen.
Risk of Exposure to Dioxin?
What makes Dioxin unique from many other chemicals is the fact that humans are likely exposed to it regularly through our food chain. This is particularly true for people consuming a western diet, which is heavier in meat and processed food consumption compared to non-industrialized countries. The fact remains that so much dioxin was poured into our environment in the 1950s, 60s, 70s, and 80s, that our fresh waters and food supplies have been heavily exposed to these substances. Dioxins are lipophilic – they are attracted to fats in water – so animals and humans absorb them faster and more readily compared to most other carcinogens, making the exposure highly toxic, as these substances bio-accumulate over a lifetime.
This is especially concerning given the fact that the environmental distribution of dioxin is global, regardless of its origin – where it is produced. So even though production in the U.S. is virtually nonexistent today, its production in countries like China exposes all of us through the food supply. In most instances today, Dioxin is being introduced to our animals through contaminated animal feed. Not all countries monitor their food supply chains, but for those that do, there have been many instances where dioxin contamination has been documented. For example, as noted by the World Health Organization, in late 2008 Ireland had to recall many tons of its pork meat due to testing that revealed levels of dioxin contamination at 200 plus times recommended health limits.
Dioxin Levels in Human Breast Milk
In 1987, the New York Times published an article that referenced a study of breast milk from 50 mothers throughout the United States which found higher than average levels of Dioxin. At the time the EPA was not surprised, since higher than average levels are expected in industrialized nations. In 2013, the International Journal of Environmental Research and Public Health published a paper titled, “A General Model of Dioxin Contamination in Breast Milk: Results from a Study of 94 Women from Caserta and Naples Areas in Italy.” See study. The study was significant because it demonstrated that the greatest indicator of high human levels of dioxin was age. The older women had the highest levels of dioxin in their breast milk, indicating bioaccumulation over time was the greatest indicator of toxicity.
Dioxin in Our Food Supply
It was not until 2001 that a comprehensive study was performed on levels of Dioxin in the U.S. food supply. The study, performed by scientists at the University of Texas Public School of Health, produced a shocking conclusion: “Americans are getting 22 times the maximum dioxin exposure suggested by the EPA.” The study went so far to conclude that “among U.S. nursing infants, that level is 35 to 65 times the recommended dosage.” See University of Texas study.
These conclusions were not surprising, considering a 1995 study by Dr. Arnold Schecter, Paul Cramer, Kathy Boggess, John Stanley, and James R. Olson. The study, “Levels of Dioxins, Dibenzofurans, PCB and DDE congeners in pooled food samples collected in 1995 supermarkets across the United States”, concluded that dibenzofuran and PCB cogeners “significantly contribute to the total TEQ value in the butter, beef, chicken, pork, hot dog, bologna, ocean fish, and cheese samples.” To measure risk of exposure by food, the study produced a chart, showing the highest levels of dioxin within the food supply coming from freshwater fish, followed by butter, and then hot dogs and oceanic fish. See Schecter study.
All studies are clear that there dioxin s bio-accumulating in our bodies over our lifetime. Where the exact source of this dioxin is remains unclear. However, as more comprehensive studies of dioxin levels to edit.
This blog was authored by Alexander Forrest on 5.6.2018
Alex Forrest is currently the chief prosecutor for the Harris County Environmental Crimes Division of the Harris County District Attorney's Office in Houston, Texas. This blog is intended to keep the public informed on recent changes in environmental law.