Phenol and the Importance of Dose Thomas D. Crute Augusta College, Augusta. GA 30910 One of t h e goals of a chemistrv course for nonmaiors i s to promote sciekific literacy (1).Recent highly publikzed incidents underscore t h e need for informed citizens. The most recent of these high profile alarmist stories spurred a public reaction t h a t l e d to a b a n on t h e u s e of A l a r (daminozide) on apples (2).The adoption i n many states of new Right-to-Know acts regarding hazardous materials in the wo;kplace also makes h i s a timely issue. It is our responsibility to talk about chemical safety a n d instill a sense of perspective. I have found t h a t a discussion of phenol is relevant. Early in my basic organic and biochemistry course, aromatic compounds a r e introduced. On this day, I bring a Merck Index (3) a n d t h e Materials Safety D a t a Sheet (MSDS) for phenol (4). After relating some properties of aromatics such a s benzene and toluene. I read selective portions of t h e Merck Index and MSDS regarding phenol. Some of the toxicitv data from the phenol MSDS follows. A similar list is f o u n i i n t h e Merck Iidex.
Phenol:Highly toxic by inhalation, toxic by ingestion and dermal absorption. corrosive~neumtoxin/nareotic Acute inhalation. Inhalation may cause profuse sweating, headache, intense thirst, nausea and vomiting, abdominal pain, diarrhea, salivation, eyanosis, tinnitus, twitching, tremors and convulsions. The central nervous system may initially be stimulated followed by severe, profound depression progressing to coma. The hean rate may increase then becomc slow and irrrkwlar The blood pressure mny inerrare shghtly and then fall markedlv wcth dvsonra and fnll in bndv tcmoerature. Stertomus breaihing, i u k s rales, and fmthing at'the mouth and nose may indicate the presence of pulmonary edema, which may be followed by pneumonia. Methemoglobinemia and hemolysis have been reported occasionally. Death may occur fmm respiratory, circulatory or cardiac failure. If death is not immediate, jaundice and oliguria or anuria may occur. Acute skin contact. Vapors and liquid may be readily absorbed thmueh the skin to cause svstemic effectsas detailed in amtp inhalatmn expusure. There have been srveral reports of cardm arrhythmia* associated with application nfsoluoonsnf phcnol, hruachlomphene, and crown uil w ihe skin. Profound coma and death have been reported to occur within 10 minutes following skin contact. Acute ingestion. Ingestion may cause immediate intense burning of the mouth and throat ...marked abdominal
pain ...systemic effects may oaur as detailed in acute inhalation exposure Approximare lethal dose in man is 140 mgkg. Death from as lmle as one gram has been reported. An understandable grimace can usually be observed on student faces during the reading of this impressive list. In the ensuing discussion of how awful phenol is, I ask them whether thev would aeree that it's use in the food or d r u e industry should be banned. I also a s k if they would f e z comfortable eating phenol or rubbing some on their skin.. The reaction to these questions i s quite predictable. Immediately afWr reading t h e health effects but before t h e discussion. I clear m v throat. coueh.. ~. u l al box of Chloraseptic lozenges out of my poc'ket, place a lozenge in mv mouth. and ~ u the t box on the front desk. This series of events draws l i k e reaction from t h e class at the time, but a n interesting reaction later when I pick u p the box and read thc act& ingredients a s phcnoiand sodium phenolate. I also point out that phenol is used in calamine lotion 10.lmOto 1'2) a s a n antioruritic (to relieve itchinel. ". Solutions of have a ~ s been d used as antiseptics a n d disinfectants (5). T h e importance of dose i s a n often neglected point. Chemicals considered by t h e public to be perfectly safe are dangerous i n large doses. Likewise, studies reporting the dangers of large doses of a chemical should not automatically lead to its demise as a useful product. The banning of Alar on apples illustrates how a useful compound can fall due to public pressure. As chemists, we need to relate these points to our students. Phenol is one example t h a t can be used i n a n orE ~ N Cor allied health chemistrv course. General chemistrv courses can bring up phenol i d sodium phenolate i n coniunction with acidmase chemistnr. Other e x a m ~ l e smav also be used to reinforce this impokant concept. '
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Literature Cited 1. I(loU, I. M.J. C k m . Ed. 1992.69.225. 2. Chiinid, M.h w r , lssO,11(1).14. 3. Windholz, M., Ed. Memk I&, 10th 4.; M m k : Rahway, NJ,1983. 4. M=tehlsSafefyDolaS k t for phenol supplied by Fiaher Sdentif~, Fairlaam, NJ. 5. M h . A R.1" Wllsona"d0ia"oldS Tertb~okofO~mlcM&indMdPhohohoho". flml Chamratry, 9th 4.Delgado, : J. N.; Rernem, W.A, Eds.; UppinmU:Philadeiphia, 1991; p
132.
Volume 6 9 Number 7 July 1992
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