(This appeared in Plating & Surface Finishing, 92, 34, May 2005)
We spend billions of dollars in an attempt to minimize pollutants such as formaldehyde, 1,4-dioxane, trichloroethylene, chloroform, cyanide, hydrochloric acid, radiation, hypochlorite, hydrogen peroxide, ozone, and nitric oxide. What do all of these have in common? One answer is that they all bring to mind scary, perhaps carcinogenic agents, created in most part by industry. Another answer is that these are all created by ourselves, within our own bodies, without any help from outside forces such as industry or the environment. They are all unintended consequences of pollution. So here’s the dilemma if you’re one of those folks who dream of a pristine place, free of industry and other pollution created by humans—you can’t get away from these contaminants. By virtue of being human you create them every day. There’s more: the average human body contains enough sulfur to kill all fleas on an average dog, carbon to make 900 pencils, potassium to fire a toy cannon, fat to make 7 bars of soap, phosphorus to make 2,200 match heads, water to fill a ten gallon tank, and enough iron to make a 3 inch nail.(1)
Science writer James Trefil sums our body pollution problems quite succinctly, “Surprisingly, the greatest number of carcinogens facing human cells do not come from outside the body, but are normal by-products of human metabolism.”(2)
As a result of metabolism, formaldehyde is present in our blood at concentrations around 3 ppm. Many organic compounds of concern to the EPA are normal byproducts of mammalian metabolism. At least 15 of these products, including 1,4-dioxane, trichloroethylene (TCE), and chloroform are on the “List of Hazardous Air Pollutants” regulated under Section 112 of the Clean Air Act. The EPA concerns itself at ambient air concentrations less than one-ten thousandth the level found in normal intestinal gases.(3) Think about this for a moment; if EPA were to regulate our metabolism we would be out of compliance by a factor of about 10,000!
Human metabolism itself is capable of providing the body with 70 mg of nitrate per day, equivalent to that coming from outside sources. Cyanide and thiocyanate are naturally present in urine and blood but this does not necessarily indicate poisoning. Courtney Young reports that potassium cyanide reacts with water and ammonia under pressure to produce adenine, which is a building block to DNA. Hydrogen cyanide promotes polypeptide formation from amino acids; polypeptides than complex to form proteins. In this regard, cyanide is necessary to all forms of life and its presence does not mean imminent illness or death.(4)
At the concentration secreted by the stomach lining, hydrochloric acid (pH less than 1) is deadly to living cells and powerful enough to dissolve zinc. This raises the question, why don’t we just corrode ourselves from the inside out? The answer isn’t really known but the acid and accompanying enzymes are kept at bay by an alkaline lining of mucous on the stomach wall. If this lining is breached, the acid and enzymes go to work on the stomach, and the result is a gastric ulcer.(5)
Each of us excretes a minimum of 1.5 grams of phosphorus per day, so that the annual input to the environment is more than one-half billion pounds as phosphorus pentoxide. It was this fact that led the Soap and Detergent Association to investigate economical treatment techniques for the removal of phosphates from sewage.(6)
Our blood contains potassium 40, from which we get an internal dose of around 30 millirems of radiation in one year. For comparison purposes, some other radiation exposures include, 40 millirems per year from annual medical X-rays, 65 millirems per year for living in the mile-high city of Denver, and 5 millirems for every transcontinental round trip by air. The yearly safe limit of radiation exposure has been set at 5000 millirems per year, so all of these exposure are not problematic. Further, as James Muckerheide notes, “the damage to cells from metabolism is millions of times more damaging than that of radiation.”(7)
Ozone is a familiar component of air in industrial and urban settings where the gas is a hazardous component of smog. Guess What? Recently, investigators at The Scripps Research Institute (TSRI) reported that the human body makes ozone. One hypothesis is that we do this as part of a mechanism to protect ourselves from bacteria and fungi.(8)
Lastly, nitric oxide, an industrial gas and environmental pollutant, is extremely important to our bodies. It regulates our bodily activities from our head to our toes. Every moment of our life, our body generates a constant supply of nitric oxide molecules, none of which last more than a few seconds.
So there you are. We continue to try and remove pollution from the world around us, and yet our own bodies are serious culprits in creating some of the very pollutants we strive to eliminate.
1. “The Incredible Human Body, Part 2,” www.bibleufo.com/humanbody2.htm; accessed September 9, 2004
2. James Trefil, Human Nature, (New York, Times Books, 2004), 99
3. Jane M. Orient, “Microorganisms, Molecules, and Environmental Risk Assessment: Assumptions and Outcomes,” Chapter 12 in Standard Handbook of Environmental Science, Health, and Technology, J. H. Lehr, Editor, (New York, McGraw-Hill, 2000), 12.50
4. Courtney A. Young, “Cyanide: Just the Facts,” in Cyanide: Social, Industrial and Economic Aspects, Courtney A. Young, Larry G. Tidwell and Corby A. Anderson, Editors, (Warrendale, Pennsylvania, The Minerals, Metals & Materials Society, 2001), 97
5. Philip Ball, Life’s Matrix: A Bibliography of Water, (New York, Farrar, Straus and Giroux, 2000), 247
6. William McGucken, Lake Erie Rehabilitated, (Akron, Ohio, University of Akron Press, 2000), 75
7. James Muckerheide, “The Beneficial Effects of Low-Dose Radiation,” 23rd Annual Meeting, Doctors For Disaster Preparedness, Las Vegas, NV, July 17, 2005
8. “Scientists at The Scripps Research Institute Make Strides in Addressing Mysteries of Ozone in the Human Body,” The Scripps Research Institute, February 28, 2003, www.scripps.edu/news/press/022703.html