Dr. Glaser's "Chemistry is in the News"
To Accompany Bruice, Organic Chemistry 3/e.
Chapter 14. Aromaticity. Reactions of Benzene.

Editorial Comments

POPs (Persistent Organic Pollutants) are certain toxins that the EPA and other state and federal regulatory agencies have been cracking down on.  When found in high amounts in the environment, these chemicals are dangerous to humans and cause numerous different maladies.  The EPA's list of POPs includes:  aldrin/dieldrin; mercury and compounds; benzo(a)pyrene; mirex; chlordane; octachlorostyrene; DDT, DDD, and DDE; PCBs (polychlorinated biphenyls); hexachlorobenzene; dioxins and furans; alkyl lead; and toxaphene.

In this article, the author is attacking Washington State's environmental regulators for their work at a recent conference.  She says the "envirocrats" are going too far with their efforts to ban the Terrible 27 (a list of 27 toxins that the agency considers dangerous).  However she exaggerates on what we believe the agency means by "virtually eliminate." Perhaps she is unaware that some of these chemicals are released into the environment by tons each year in industries around the United States.  For instance, look at this graph of the mercury released each year in the U.S.  In the article, Malkin states that mercury is "manufactured naturally."  However this is misleading.  Although mercury is manufactured naturally, it is artificially emitted into the air by industries as seen in the chart.

She writes about how eliminating these toxins could cause great economic hardships in several industries.  However she does not take into consideration that Washington's plan takes gradual steps over the course of 25 years to lessen economic strains.  For instance, in the EPA's Multimedia Strategy for Priority Persistent, Bioaccumulative, and Toxic (PBT) Pollutants the agency is outlining a plan to eliminate POPs, but it emphasizes collaborating with industries to do so by developing safer alternative chemicals.  After all, this kind of gradual planning has worked in the past when the EPA banned DDT and related chemicals without a great deal of harm to the agriculture economy.

Although Malkin has a good point, she has taken it overboard.   The regulating groups are simply trying to reduce the huge amounts of these toxins from industry, not eliminate them completely from the environment.  Besides we have not seen any legislation banning bread, tea, coffee, or pumpkin pie because of the benzo(a)pyrene it contains.  It is true, however, that many of these chemicals are extremely depended upon in industry.  Each one of us has probably advantageously used these chemicals several times in our daily life.  It is up to each individual how much they want to expose themselves to the chemicals, but it is important that the individual is educated on the specific risks involved.  One can probably find evidence defending and attacking each of these chemicals, but this evidence's integrity must be evaluated.  For instance, coffee, which is attacked in Malkin's article as a carcinogen, is defended in an article, "Coffee May Combat Cancer."  In such a cases, we believe that it is best to apply the old quote, "everything in moderation."
 
 

Pertinent Text References
Chapter 14. Aromaticity. Reactions of Benzene.
Chapter 15. Reactions of Sunstituted Benzenes.
 
 

Questions
 

Question 1: Look up the structures of the EPA's  POPs on this POPs web page and on ChemFinder.  How are the structures alike?  How do these similarities make them hazardous?

Answer 1: Most of the structures have aromatic rings.  Aromatic rings are known for being carcinogenic.  They are carcinogenic because they alter the nucleotide bases in DNA & RNA by adding and eliminating functional groups on their aromatic rings.  The DNA & RNA in turn alter enzymes in the cells that control growth.  As a result, the cells grow uncontrollably creating tumors.
 
 

Question 2: Check out the bar graph and information on the dioxin page.  How could you best protect yourself against harmful dioxins?  What kind of effect would taking these precautions have on industries such as meat packing or dairy farms?  Are there ways farmers can help lower dioxin levels in meat and dairy products?

Answer 2: One could lower their intake of dioxins by lowering their intake of meats and dairy products and/or eating less fatty meats and dairy products such as skim milk or lean meat  (because dioxins are stored in the fat of animals).  People eating less meat/dairy products would obviously hurt the meat/dairy industry.  They would probably have to come up with ways to lower dioxin levels in their products.  Farmers can help lower dioxin levels by raising stock that is bred to be leaner therefore lower fat in the meat and dioxin levels.  
 
 

Question 3: According to the article, do plants growing in affected soil largely contribute to the uptake of dioxins by humans and other organisms?

Answer 3: No because the dioxins do not transfer from the soil to the plant, but due to runoff, these chemicals are deposited into water sources where they accumulate in the adipose tissue of aquatic organisms.

Question 4: Is the government being realistic in setting its goals to "Zero Tolerance," or the total elimination of these BCC'S and POP's, considering these chemicals occur naturally in the environment?

Answer 4: The government is setting itself up for failure if it tried to do this, since every time a volcano erupts or a forest fire breaks out certain amounts of the "Terrible 27" are released into the environment. Regulating chemical output by major "human sources" may be a more attainable goal with a higher success rate.

Chemistry & Society.
Question 5: There have been international efforts to create worldwide bans on some toxic chemicals.  Do you think that the U.S. and other powerful countries have the right to force other third world countries to ban chemicals that might be advantageous to their economical status?