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A Global Contamination: Persistent Organic Pollutants

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For personal reasons, I have been investigating environmental toxins and their effects on hormonal, neurological and reproductive health. The bioaccumulation of Persistent Organic Pollutants (POPs) within our bodies and the proliferation of POPs across the entire planet is frightening, but like most, I was not aware of the dangers. Despite the abundance of research linking POPs to many of the health epidemics we face here in the United States, such as Type II Diabetes and obesity, the public’s attention has not been directed to this man-made creation. Here is some of the research I found on persistent organic pollutants and what is being done to control our exposure to them.

What are Persistent Organic Pollutants?

Persistent Organic Pollutants, or POPs, are a number of organic (mostly man-made) compounds resistant to degradation by natural environmental processes. A number of POPs became widely utilized during the increase in industrial production post-World War II, a time when thousands of chemicals were introduced into commercial use. Many of these chemicals were proven effective in pest and disease control, crop production, manufacturing and industrial processes. Also in existence are a number of POPs which are “unintentionally produced chemicals” as the result of combustion (e.g., trash burning or municipal/medical waste incineration).

Why are Persistent Organic Pollutants So Bad?

Since they cannot be broken down via natural degradation in the environment, they are transported by wind and water. POPs are known for bioaccumulation in human and animal tissue and have become a part of the food chain, affecting all life on earth. Isolated communities, such as indigenous populations in the Arctic Circle, have a particularly high exposure risk to POPs.  POPs have been linked to disruption of our endocrine, reproductive and immune systems, neurological problems, diabetes, obesity and cancer. According to The United Nations Industrial Development Organization (UNIDO), the international community has been calling for “urgent global actions to reduce and eliminate releases of these chemicals.” A number of POPs are compounds the reader may be familiar with, such as DDT, PCBs, and HCH.

“The Dirty Dozen” and the Stockholm Convention

Coordinated by the United Nations Environment Programme (UNEP), The Stockholm Convention serves as “a global legally-binding instrument for targeting persistent organic pollutants.” The purpose of the Convention is to direct us toward a future free of POPs and re-shape the global economy in order to eliminate reliance on such dangerous pollutants.

The Convention initially identified twelve POPs (“The Dirty Dozen”) considered to be the most detrimental to the well-being of humans, animals and the environment. This measure created a system that allows for a greater number of chemicals to be identified as “unacceptably hazardous.” In accordance with the Convention, governments are obliged to eliminate or reduce the introduction of POPs into the environment. Such is done by channeling resources into “cleaning up existing stockpiles and dumps of POPs that litter the world’s landscapes.” The Convention was ratified May 17, 2004, with 150 signatory countries. As of February 20, 2013, Afghanistan acceded to the Convention as its 179th party. According to Kyoto Energy, the Convention aims to prohibit the production of POPs, with the exception of equipment currently in use; they have set a deadline for the elimination of the remaining usage for 2025.

Destroying and Transforming POPs in the Environment

The UNIDO website suggests that POPs stockpiles “must be destroyed in a manner which does not further degrade the environment by generating or releasing POPs.” The Convention calls for community participation, safety of the community, full disclosure of information, monitoring and release of data.

Details regarding the destruction process on the UNIDO website are vague; they suggest that traditional methods use “landfilling, ground storage, deepwell injection and combustion by open burning, incineration or in cement kilns or metal furnaces.” UNIDO stresses that there are “serious limitations” to the “normal incineration process,” considering that incineration can lead to the creation of dioxins, PCBs and HCBs. The quantities of POPs are rather difficult to estimate; almost no inventory exists. Kyoto Energy estimates that one million tons of PCBs and 100,000 tons of obsolete pesticides exist within countries that are not member to the Organization for Economic Co-operation and Development (OECD).

Are We Burying POPs for Future Generations?

Many of these methods do not entirely eliminate the problem. Rather, we are, quite literally, burying them for future generations to deal with – if we don’t burn this stuff and release it into the atmosphere first.

The United Nations Environment Programme (UNEP) suggests that high temperature incinerators, incineration in cement kilns and chemical treatment are proven methods of destruction. There is no evidence of this being true, and most research indicates that POPs are created as a result of incineration.  

A number of countries have continued to produce POPs such as DDT, with a staggering 3,314 tons (7,306,119 pounds) produced globally in 2009. On the bright side, this signifies a 43% reduction in DDT production from 2007. Considering the stability of POPs (i.e., resistant to degradation), it’s difficult to imagine any concerted effort can “undo” the damage that has already been dealt to the planet, especially since a number of POPs like DDT continue to be produced and exported in such exorbitant quantities.

It’s time to rethink our reliance on dangerous chemicals and the industries that use them. Though, many of these chemicals were developed before we understood their dangers, now that we know, it is difficult to support their continued use. With all of the advances in science, one would think we could design better, safer tools for industry, than the non-degradable, persistent organic pollutants we have now.

The Bottom Line: BPA and Endocrine Disruptors

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Unless you have been living under a rock for the past ten years, you probably know about BPA. Bisphenol A is a chemical used in the manufacturing of some hard plastics and liners for canned foods, including infant formula. In recent years, more and more plastic products, especially items like baby bottles, have adopted the “BPA-free” label. Why? It turns out that BPA mimics some effects of estrogens in the body.  BPA and chemicals like it, known collectively as endocrine disruptors, have been implicated in a disturbing variety of health problems, ranging from early puberty to cancer. The U.S. Food and Drug Administration banned the use of BPA in manufacturing of baby bottles and sippy cups in July, 2012. However, its use in can liners and other plastic products is still essentially unregulated. The science of endocrine disruptors is still in its infancy, and consumers are left to decide what constitutes an acceptable level of exposure. So, how concerned should we be?

Is BPA Safe?

This turns out to be a complicated question. The vast majority of studies on BPA and other endocrine disruptors have been done in rodents, whose endocrine systems are not equivalent to those of humans. Many of the early studies of these compounds exposed animals to doses much higher than humans might ever experience or administered the compounds via routes that were unlikely in humans (e.g. intravenously). There was also a widespread lack of consistent methodology across studies, with different labs examining different endpoints, so that results were nearly impossible to compare and interpret. Recent efforts by the FDA, National Institutes of Health and Centers for Disease Control have helped to coordinate multiple, large scale studies and improve methodology.

The Good News and the Bad News about BPA

Based on these more recent studies, there’s good and bad news. The good news: recent estimates of exposure levels for infants are 10-fold lower than previous estimates (0.24 micrograms/kg body weight/day vs. 2.4 micrograms/kg body weight per day) [1]. This may be partly due to increased inaccurate assumptions about how parents prepare bottles. Also, studies in primates, whose endocrine metabolism is closer to humans, suggest that most orally-administered BPA is rapidly metabolized to an inactive form and excreted [2].

Now, the bad news.  A recent study, in which pregnant rhesus monkeys were exposed continuously to low concentrations of BPA, similar to those found in human tissues, found that the ovaries of female fetuses had more unenclosed follicles [3]. This could mean that the female offspring of exposed monkeys would have fewer viable eggs and diminished reproductive success as adults, though this study did not follow the offspring to adulthood. Another study examined the effects of BPA on human breast epithelial cells grown in culture [4]. BPA increased expression of genes involved in DNA repair, including the BRCA1 and BRCA2 genes. Women who carry specific mutations in these genes are at five times greater risk for developing breast and ovarian cancers than the general population. The study suggests that women who carry these mutations may be unable to repair DNA damage induced by BPA and may be especially vulnerable to its effects on estrogen-sensitive tissues.

How Concerned Should We Be about BPA?

So, back to our original question: how concerned should we be? While exposure levels are probably fairly low, and much of the BPA we ingest is likely metabolized, there are certain populations, including pregnant women, infants and women at high risk for breast and ovarian cancer, who should be especially concerned. In the absence of tighter regulatory controls on BPA use in manufacturing, there are simple steps consumers can take to reduce their exposure. Bottom line, am I going to stop buying canned foods? Not entirely, but fresh is always nutritionally superior to canned anyhow. Do I buy BPA free bottles for my infant son? Absolutely.  Do I spend a lot of time worrying about my family’s exposure to BPA? No. Not because it’s not important, but because there are many other known endocrine disruptors in our environment, and probably many more that haven’t yet come to our attention. BPA is just a small piece of a very complex puzzle.

References

[1]Department of Health and Human Services. Memorandum: Exposure to Bisphenol A (BPA) for infants, toddlers and adults from the consumption of infant formula, toddler food and adult (canned) food. 2009

[2]Doerge D.R., Twaddle N.C., Woodling K.A., Fisher J.W.  Pharmacokinetics of bisphenol A in neonatal and adult rhesus monkeys, Toxicology and Applied Pharmacology 2010; 248: 1–11.

[3] Hunt P.A., Lawson C., Gieske M., Murdoch B., Smith H., Marre A., Hassold T., Vandevoort C.A. Bisphenol A alters early oogenesis and follicle formation in the fetal ovary of the rhesus monkey. PNAS USA;  2012 Sep 24. [Epub ahead of print].

[4] Fernandez S.V., Huang Y., Snider K.E., Zhou Y., Pogash T.J., Russo J. Expression and DNA methylation changes in human breast epithelial cells after bisphenol A exposure. International Journal of Oncology 2012; 41(1): 369-77.

BPA in Plastic Bottles: What’s the Big Deal About ‘Little Beards’?

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“The only thing that I heard is if you take plastic and put it in the microwave and heat it up, it gives off a chemical similar to estrogen. And so, I mean, in the worst case, some women might have little beards”   

~Paul LePage, Governor of Maine

Long ago, I cut a deal with my best friend: if one of us is on our death bed unable to care for ourselves, the other will tweeze her friend’s “man hairs.”  It may sound vain to some, but there is dignity even in death. When my mom lay dying in her hospice bed, I plucked the dark hair from her chin and upper lip, trimmed her nails, and brushed her hair, because I knew she wouldn’t want to “be seen like that”.  It was the least I could do after all those years she spent caring for and grooming me.

So I took great offense when Maine Governor Paul LePage–exhibiting astounding ignorance (even for a politician) of the delicate balance of human chemistry–made his remark about “women might have little beards.”  As if a woman having a little beard was no big deal, right?

Now before you go accusing me of over-reacting to media and environmentalist hype about the side effects of BPA–or bisphenol A- a compound added to plastic bottles and other packaging materials to increase flexibility, transparency, durability–first consider what a “big deal” it is in the scientific community.Two recent studies in Italy and Germany show that suboptimal storage conditions—such as prolonged exposure to sunlight and high temperatures—can cause leaching of BPA in plastic bottles into fluid contents resulting in high levels of estrogenic activity in plastic-bottled water. In other words, plastic bottles can leach chemicals that disrupt the endocrine system.

The endocrine system is responsible for making our hormones. Hormones are substances that help to control activities in your body. Different types of hormones control reproduction, metabolism (food burning and waste elimination), growth and development, and yes, even facial hair. Hormones also control the way you respond to your surroundings, and they help to provide the proper amount of energy and nutrition your body needs to function.While too few studies have been conducted to know with certitude about potential human health effects of drinking plastic−bottled beverages, as Lisbeth Prifogle of Hormones Matter reported previously, investigators have found that BPAs combined with the xenoestrogens in our environment cause male fish to grow eggs in their testes, female deer mice to pick males who weren’t exposed to BPA in a controlled environment, hyperactive rats (some scientist speculate that endocrine disruptors could be linked to the rise in ADHD amongst school children) and many other strange behaviors in the animal kingdom.

The National Toxicology Program’s Center for the Evaluation of Risks to Human Reproduction, suggests, in response to the European studies, that people move away from polycarbon−ate plastics [due BPA concerns].

In women with PCOS or other hormone problems, BPA can be especially problematic. Researchers from Athens report:

“Blood levels of BPA were nearly 60 percent higher in lean women with PCOS and more than 30 percent higher in obese women with the syndrome when compared to controls. Additionally, as BPA levels increased, so did concentrations of the male sex hormone testosterone and androstenedione, a steroid hormone that converts to testosterone.”

So Governor LePage, if you’re reading this, let me see if I can help you understand what the “big deal” is. Suppose you were exposed to an everyday chemical that made your breasts “a little” larger or your testes produce eggs. Or what if BPA led to sexual dysfunction in men? No big deal, Right? What’s a little Viagra between friends.Sources:

International Journal of Hygiene and Environmental Health, March 2009
Environmental Science and Pollution Research, March 2009

Environmental Health Perspectives, “Estrogens in a Bottle?”, June 2009

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