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149  We're So Accustomed to Using Chlorine
     That We Tend to Overlook Its Toxicity
     The Washington Post  May 3, 1969

     Chlorine is a poisonous gas.  Its chemical reactivity is so high
that it cannot long persist in nature, being rapidly converted to the
innocuous chloride ion, the form in which it is most abundantly found
as, for example, in common salt.  It is an extremely important
industrial chemical playing an indispensable role in the production
of plastics, drugs, pigments and many other organic materials.

     In the form of sodium hypochlorite, domestic bleach solution, it
is a well-known household article.  It also plays an indispensable
role in the purification of our water supplies.  We are so accustomed
to meeting it in our environment that we hardly notice it except when
someone has zealously overdosed his swimming pool.

     The chlorination of water supplies in the United States began
just 60 years ago in Jersey City.  Its use spread very rapidly and
today it is undoubtedly the major bulwark against typhoid fever,
dysentery and cholera.  It would be conservative to say that it has
saved millions of lives.  In fact, concentrated urban settlement
would be impractical without chlorination or some equivalent means of
removing polluting bacteria from water.

     Chlorine has been used for the treatment of sewage since 1835,
long before Pasteur and Koch showed that infectious disease was an
attack upon the human body by living microbes .  The rationale was
the dissipation of foul orders, which were long blamed for contagion.

     Chlorine was first introduced in the waterworks of Jersey City in
response to potential contamination by sewage from some small towns
about it.  The city demanded that the water company install expensive
filtration equipment or pay for diversion of the sewage.  After
considerable litigation, the court found that chlorination was both
safe and effective for the production of potable water.

     It is difficult to reconstruct the arguments that would support
the safety of chlorination by contemporary standards.  A few tests
of acute toxicity did show that chlorinated water could be
administered in concentrations to 50 to 100 parts per million,
compared with the 1 to 2 PPM generally required for water
purification.  Furthermore, during World War I, chlorine, under the 
name of Dakin's solution, was the only available disinfectant for
contaminated wounds, and it did a heroic job by the standards of the
day.

     This article is not a scare story about a newly discovered hazard
of an ingredient to which most of us have been constantly exposed to
since birth.  It is, rather, a reminder that almost no attention
has been given to the subject of chronic toxicity from chlorine.

     Perhaps we sense such a dependence on the chlorine disinfection
of water that we prefer not to be embarrassed by information about
relatively minor side effects.  This view is not, however, likely
to be defended as a rational basis for social policy.

     The only serious contribution to the subject that I could find
was from a German scientist, Dr. H. Druckrey of the Max Planck
Institute for Immunobiology at Freiburg.  He reared a group of
laboratory rats for seven generations on drinking water supplemented
with 100 PPM of chlorine.  The treated animals showed no obvious
pathology or shortening of the life span compared to the controls.
This is an impressive demonstration that should have been made at
least 50 years earlier.

     Many theoretical suspicions nevertheless remain.  One argument
for chlorine is its rapid removal by reaction with organic material
in body fluids.  These reactions have, however, not been studied
with modern methods.  We have no clear picture of the place, manner,
intermediate products or rate by which chlorine is converted into
chloride ion within the body.  These experiments would not be very
difficult to carry out with the help of radioactive tracers.

     What little we do know of the chemistry of chlorine reactions is
portentous.  It should sometimes react with nitrogenous groups from
various sources to form substances that may eventually reach and react
with the genetic material, DNA, of body cells.  This is only a
speculation so far.  In any case, it would probably be applicable
only to heavily contaminated waters needing heavy doses of chlorine.

     The reactions of chlorine with DNA have been remarkably little
studied.  In my own search in the literature, I found only a single
oblique reference.  Chlorine, casually compared with iodine, rapidly
inactivated DNA that had been isolated from bacteria.

     We know little more of the mechanism by which chlorine kills
bacteria.  The scanty data suggest that the most likely mechanism
is precisely by attack on the DNA of the microbe.

     That chlorine is also intended to inactivate viruses should
provoke questions about the production of mutations in view of the
close chemical similarity between viruses and genes.  Many geneticists
have raised cautions about chemicals that may cause mutations, and I
will join them by adding chlorine to the lengthy list that cry out for
close scrutiny.

     Science is under broad attack today for creating an unmanageable
technology that swamps human individuality, fouls the environment and
imperils the survival of the species.  More often than not, however,
science may be blamed for carrying the bad news that we know too little
rather than too much to support the growing numbers of people who
proliferate themselves and their wastes over the planet.
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