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Plastic: Not so inert and harmless after all

Posted on December 7th, 2010 by Alf | Print

The late twentieth century will no doubt be remembered as the period in which a revolution in information technology really began to transform the world with the advent of the internet, satellite technology, mobile phones and lap top computers, communication with almost any part of the planet was now possible. At around the same time, another revolution, perhaps not as technologically impressive, but nevertheless of great significance, was also taking place. The plastics revolution has resulted in the substitution of simple materials such as paper, cardboard, wood, and aluminium, with plastics. Indeed, such is the pervasiveness of plastic, it is hard to find any area of human activity where plastic is not used. And of course there are good reasons for this. Plastics are easy and cheap to manufacture (if environmental and energy costs are not included), stable, unbreakable, and light.

Most people are unaware of the extent to which plastics have really revolutionized our lives. The carpets, floor coverings, furniture, light fittings, kitchen utensils and aids, and mattresses, may contain plastics. Much of our clothing may be made of polyester or nylon which is a type of plastic. It does not end there because when we get into our car, we find plastic in a sizable proportion of the interior (eg floor coverings, front panels), the exterior, and under the bonnet. When we drive to the supermarket, we find plastic in the food packaging, in the shelving, refrigerators, light fittings, and floor coverings. And, of course, when we pay for what we have bought we may take our plastic card out of a plastic wallet or plastic handbag, and carry what we have bought to the car in plastic bags, perhaps even walking to the car in shoes with plastic uppers and soles. Back home, we find plastic everywhere both inside the house and in the garden. If we have children or grandchildren, we find it increasingly difficult to find a toy that is not made of plastic.

But, as with any new technology, while there may be benefits, there are also costs. Quite apart from the impact of the release of millions of tons of slowly degraded waste material on the environment, and its concomitant effect on animal and plant life, it is also very likely that our exposure to plastics has an impact on our health and wellbeing. But how can something that seems so inert and indestructible, affect our health? Surely, in order to do this, the components of plastic have to be taken up into our bodies?

Well, there are numerous reports in scientific and medical journals that show precisely that because some of the components are detectable in our blood and urine (1,2). Even more alarming is the fact that plastic components have been detected in amniotic fluid, the fluid surrounding the developing foetus, as well as breast milk (1,2). In a recent television interview with Lateline, the eminent environmentalist David Suzuki, even claimed that we each had around a pound of plastic (450 grams) in our bodies.

It is believed that plastic components are taken up into our bodies through the skin, mouth, or nose. Skin contact is very easy as it involves simple handling, something we do without thinking many times in a day with the many different plastic items that are now such an integral part of our life. If some of the plastic components do rub off onto our skin, particularly our hands, they can also find their way into our mouth, then into our stomachs and, finally, into our blood. Skin is not a complete barrier to the entry of foreign substances in our bodies and it is likely that some plastics components enter our bodies directly through the skin.

Perhaps the most surprising way they can enter our bodies is through the air we breathe. Some of the plastics components, most notably the plasticizers and the flame retardants are relatively volatile and can be detected in air, particularly indoors where they are probably released from all sorts of items including floor coverings, furniture, floor polish etc (3) and so can enter our bodies in this way. Another source of air exposure possibly occurs in motor vehicles. With the sun beating down, temperatures can rise to in excess of even 50 degrees Centrigrade (122 degrees Fahrenheit) and, under these conditions, fire retardants and plasticizers present in plastics can vaporize and be breathed into the lungs. The release of something into the air is obvious to anyone getting into a car that has been left in the hot sun for al long time.

While there is absolutely no doubt that plastic components find their way into our bodies, the million dollar question is – are they harmful? There is plenty of evidence from experiments with animals, that some of the plastic components, most notably bisphenol A and the phthalates, can affect reproduction, may contribute to cancer, and interfere with action of insulin, the hormone that regulates blood levels of the principal fuel in our blood ie glucose. Effects on humans are much more difficult to prove. However, the US National Toxicology Program (NTP) Center for the Evaluation of Risks to Human Reproduction (CERHR) has indicated that it has concerns of the potential of bisphenol A to affect effects on “the brain, behavior, and prostate gland in fetuses, infants, and children at current human exposures to bisphenol A” (4). Similar concerns have been expressed by the US FDA (5). The principal source of exposure for children of bisphenol A is through baby bottles, feeding cups, and metal cans.

Promoting Good Health has long had concerns about the impact of environmental pollutants, including the plasticizers, monomers, UV stabilizers etc that are present in plastics. That is why we have published a book, “The Silent Threat” which describes in some detail what plastics are, how they are made, what the various chemicals are that are added to plastics during their manufacture (additives), how these additives get into our food, whether they are harmful, and how we can avoid them. The good news is that we can reduce our exposure. The Silent Threat is available for purchase from this website.

Until next time, stay happy and healthy!

(1) Wittassek M., et al (2009) “Fetal exposure to phthalates – A pilot study“.  Int. J. Hyg. Environ. Health212(5), 492-498.
Abstract available online at:  http://www.ncbi.nlm.nih.gov/pubmed/19423389
(2) Lin S
et al (2010) “Phthalate exposure in pregnant women and their children in central TaiwanChemosphereNovember 12: Epub ahead of print.
Abstract available online at: http://www.ncbi.nlm.nih.gov/pubmed/21075419
(3) Marklund A., et al (2005) “Organophosphorus flame retardants and plasticizers in air from various indoor environments.J. Environ. Monit.7(8), 814-819.
Abstract available online at:  http://www.ncbi.nlm.nih.gov/pubmed/16049584
(4) National Toxicity Program (2008) “NTP-CERHR Monograph on the Potential Human Reproductive and Developmental Effects of Bisphenol A.NTP CERHR MON., Sep; (22), i-III1.
Abstract available online at:  http://www.ncbi.nlm.nih.gov/pubmed/19407859
(5)  US FDA News and Events (2010) “Update on Bisphenol A for Use in Food Contact Applications: January 2010 “
Available online at: http://www.fda.gov/NewsEvents/PublicHealthFocus/ucm197739.htm