Wednesday, July 10, 2013

Born Contaminated - Our Toxic World

A study, Pre-Polluted by Canada's Environmental Defence examines the contaminants that are found in the blood of newborns in two of Canada's largest urban centres.

Let's first put our chemical world into perspective.  At this point in time, there are 84,000 chemicals in use in North America. Around the globe, an estimated 143,000 chemicals are in use.  In Canada, only 200 of these chemicals have been reviewed for their impact on human health and the United States EPA has reviewed only 200 chemicals since 1976.

Scientists tested the umbilical cord blood from three newborns whose mothers live in the Greater Toronto/Hamilton areas and found a rather surprising cocktail of contaminants.  While the actual sample size is very small, the results mimic those found in larger studies undertaken in various nations.   The chemicals that were screened for in this study include the following groups:

1.) Dioxins and Furans: byproducts of waste incineration and manufacturing processes including the bleaching of paper and production of steel, in herbicides and pesticides and in the processing of oil.  These chemicals are ingested through food because they accumulate in the food chain and are both persistent (they do not break down substantially over time) and accumulative (they accumulate in our bodies over our lifetime).

2.) PBDEs (polybrominated diphenyl ethers): used as flame retardants in furniture, mattresses and electronic goods.  These chemicals build up in the body's fat tissues and are highly persistent in the environment.

3.) PFCs (perfluorocarbons): used as non-stick coatings, food packaging and water resistant fabric treatments (i.e Gore-tex and Teflon).  These chemicals are extremely persistent.

4.) Organochlorine Pesticides: legacy chemicals that were used in agricultural operations (DDT is an example).  The use of these chemicals was banned in Canada in 1970.  They are highly persistent and highly toxic and are accumulative through the food chain.

5.) PCBs (polychlorinated biphenyls): used as coolant fluid in electrical transformers and electric motors.  The production and importation of PCBs has been banned in Canada since 1977.  These chemicals also build up in the body's fat tissues.  These chemicals are highly accumulative, highly toxic and are very persistent.

6.) Lead: byproduct of paint, tire weights, metal smelters and impurities in products including lipstick.

7.) Methylmercury: byproduct of coal burning, mining and manufacturing as well as compact fluorescent light bulbs and thermometers.
Now, let's look at the results of the in utero exposure to these chemicals.  Keep in mind that a fetus absorbs more of a given chemical per unit of body weight because of their small size.  As well, since the fetus' organs are in a constant state of development while they are in utero, their organs are not as efficient at flushing the chemicals out of their system and their blood - brain barrier is incompletely developed, meaning that chemicals can pass into the brain fluid.

Here are the results showing the number of chemicals of each family found, how many samples of the three contained these chemical families and the potential physiological impact of the chemicals :

1.) Dioxins and Furans: two chemicals were found in all three samples.  These chemicals can cause problems with reproduction, the immune system, skin disorders (choracne), elevated levels of diabetes, heart and kidney disease and cancer.

2.) PBDEs (polybrominated diphenyl ethers): twenty-two chemicals were found in all three samples.  These chemicals are thought to be endocrine disruptors, can cause cancers, reproductive and development disorders and can damage the thyroid gland which regulates the development of the fetal brain.

3.) PFCs (perfluorocarbons): two chemicals were found in one sample.  These chemicals can cause cancer and disrupt hormones.

4.) Organochlorine Pesticides: ten chemicals were found in all three samples.  Considering that the use of these chemicals was banned in 1970, their persistence in the ecosystem is nothing less than shocking.  Chronic exposure can cause damage to the reproductive system, skeletal abnormalities and neurological damage.  They are also classified as carcinogenic.

5.) PCBs (polychlorinated biphenyls): ninety-six chemicals  were found in all three samples.  Again, considering that the production and importation of these chemicals has been banned in Canada since 1977, it is surprising how persistent they are.  PCBs are reported to cause many kinds of cancer, nervous system damage, birth defects, immune and cardiovascular system damage.

Of the 137 chemicals that were found in the umbilical cord blood as noted above, 132 are reported to cause cancer in animals or humans, 133 cause development and reproduction difficulties in mammals and 110 are considered toxic to the brain and nervous system.  On top of that, the synergistic impact of the chemicals acting in combination has not been studied but could make the situation substantially worse.

6.) Lead: was found in all three samples.  Lead is a neurotoxin and can damage nearly every organ in the body, particularly the nervous system.  Lead contamination can also result in decreased mental ability, reproductive defects and developmental delays.

7.) Methylmercury: was found in all three samples.  Mercury is transformed by micro-organisms into methylmercury which accumulates in the bodies fatty tissues, particularly in fish.  Mercury is a developmental toxin, neurotoxin, respiratory toxin and reproductive toxin.  Minamata Disease is an extreme example of mercury contamination. 

The present and future impact of many of these chemicals is frightening.  We are already seeing elevated levels of cancer in hormone-sensitive body tissues including testicles, thyroid, prostate, ovaries and breasts, possibly related to increased exposure to endocrine-disrupting chemicals.  Actions by government to ban the use of some of these chemicals is needed, particularly in the case of flame retardant PBDEs.  Experience with the persistence of both PCBs and organochlorine pesticides tells us that these chemicals will long outlive us and that actions taken now may provide us with a very limited measurable environmental response for decades to come.

No comments:

Post a Comment