Chlorine: Serious Threat To Human Health, Environment.

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Subject:Chlorine: Serious Threat To Human Health,

Environment.--Leading Scholar

 

 

 

 

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Chlorine: Serious Threat To Human Health,

Environment.--Leading Scholar

By Terrence Collins, Thomas Lord Professor of Chemistry

Oct 19, 2004, 17:50

 

 

Chlorine. The word evokes pleasant images of swimming

pools and clear blue water sparkling in the summer sun. For most

people, in fact, the familiar smell of the chemical is linked with the

reassurance that the water we use every day has been rendered pure.

 

But critics have brought forth another image of chlorine

and chlorinated compounds that are used in many products and

industrial processes, including ubiquitous polyvinyl chloride

plastics. For them, chlorine is inextricably accompanied by the dark

shadows of dioxins and PCBs--polychlorinated biphenyls. They blame

chlorine and chlorine chemistry for unleashing some of the most

serious threats to human health and the environment.

 

 

--

 

 

The chlorine industry has made foundational contributions

to modern civilization, including much safer drinking water,

inexpensive bleached paper for education's biggest-ever growth burst,

and solvents and reagents for synthesizing life-improving medicines.

 

However, many serious pollution episodes are attributable

to chlorine products and processes. This information also belongs in

chemistry courses to help avoid related mistakes. Examples include

dioxin-contaminated 2,4,5-T, extensively used as a peacetime herbicide

and as a component of the Vietnam War's agent orange;

chlorofluorocarbons (CFCs); polychlorinated biphenyls (PCBs); the

pesticides aldrin, chlordane, dieldrin, DDT, endrin, heptachlor,

hexachlorobenzene, lindane, mirex, and toxaphene; pentachlorophenol

for wood preservation; and dioxins-producing wood pulp bleaching with

elemental chlorine.

 

Regulations have partially resolved these problems. Still,

the properties of leading chlorine products call for more change

before the chlorine industry can be compatible with a sustainable

civilization.

 

 

 

Global chlorine production exceeds 40 million tons

annually. Approximately one-third goes into manufacturing polyvinyl

chloride. PVC's low cost, adaptability, and high technical performance

seem impressive. But beneath the attractive veneer, PVC is extremely

hazardous for multiple reasons. Space permits me to consider only the

dioxins hazard associated with PVC combustion.

According to the National Academies, the most toxic of the

dioxins, tetrachloro-p-dibenzodioxin (TCDD, often called dioxin),

elicits a diverse spectrum of cancer and noncancer effects.1 The

noncancer disorders are far more troubling than cancer itself. Cancer

destroys lives. But a broad base of evidence indicates not only that

childhood intake of dioxins impairs development at infinitesimal body

burdens (parts per trillion), but also that dioxins lie in wait in the

tissues of parents-to-be, threatening children with a diminished

humanity before their conception even occurs.

 

Dioxins are implicated in birth defects, impaired

neurological development and related cognitive or behavioral deficits,

immune suppression leading to increased susceptibility to infectious

disease, cardiovascular disease, diabetes, and other effects on or

injury to the liver, thymus, spleen, teeth, bone and bone marrow, and

skin. Female reproductive disorders include decreased fertility,

inability to maintain pregnancy, ovarian dysfunction, endometriosis,

hormonal changes, and problems in breast development. Male

reproductive disorders include reduced sperm count, testicular

atrophy, abnormal testis structure, reduced size of the genital

organs, reduced testosterone levels, changes in sexual behavior, and

fewer male babies.

 

With this in mind, consider all the windows, siding,

flooring, automobile components, packaging, and innumerable other PVC

products where accidental or inadvertent fires could (and do)

contaminate neighborhoods with bioaccumulative dioxins, putting

children and people of reproductive age at risk of exposure. Some

people discard plastic food wraps and containers on their barbeques

while cooking. This practice could lead to dioxins-contaminated food

when the plastics contain organochlorines such as PVC. Saran,

polyvinylidene dichloride, also produces dioxins upon pyrolysis. Thus,

it is heartening that S. C. Johnson & Son has recently removed Saran

from Saran Wrap in its " initiative to look for more sustainable and

environmentally acceptable plastic. "

 

On a related matter, chlorine industry supporters too

often argue that concern over anthropogenic dioxins is overstated

because a very small amount can be generated naturally. This non

sequitur is like conjecturing that it is okay to add, say, arsenic to

the water supply because a trace is often present naturally.

 

The U.S. chlorine industry claims, via the Environmental

Protection Agency's Toxics Release Inventory, to be reducing releases

of dioxins from industry facilities. Releases from incinerators have

also been falling in some parts of the world. As wider prohibitions

are imposed on backyard incineration, this major dioxins source will

diminish. And the Centers for Disease Control & Prevention has

reported that body levels of TCDD have been dropping significantly in

most of the U.S. population.

 

These are encouraging trends, to be sure. But there are

more than 1 million accidental fires each year in the U.S. alone. As

more PVC accumulates in our civilization, it is hard to believe that

children are not being compromised in increasing numbers by dioxins

from chance PVC combustion.

 

Some chlorine companies (or alliances or spin-offs) are

developing new genuinely " green " products. Let me highlight two of my

personal favorites. In contrast with PVC, Dow Bioproduct's WoodStalk

building material is both safe and technically superb. This

alternative to wood-based products is composed of renewable wheat

straw fiber, an agricultural discard, bound with a formaldehyde-free

polyurethane resin. It is light, strong, moisture-resistant,

cost-effective, and available in hardware stores. Also, Cargill-Dow

has moved assertively into polylactic acid, which it makes from

biomass for use in industrial packaging and

biocompatible/bioabsorbable medical devices. These inventive uses of

renewable feedstocks are helping to build the technological dimension

of a sustainable civilization.

 

Perhaps the chlorine industry will one day find a way to

reformulate PVC to eliminate dioxins formation upon combustion. Until

then, I believe PVC should be restricted to those uses where

uncontrolled combustion cannot occur; for example, in buried piping.

In a sustainable civilization, the fetus and the child in every nation

will be fully protected from all anthropogenic compounds where there

is proven causation or reasonable suspicion of developmental impairment.2

 

1. Committee to Review the Health Effects in Vietnam

Veterans of Exposure to Herbicides, Division of Health Promotion &

Disease Prevention, Institute of Medicine. " Veterans and Agent Orange,

Update 1996, " Washington, D.C.: National Academies Press.

 

2. For an easy-to-read review of the neurobiological

effects of anthropogenic toxicants, see " In Harm's Way: Toxic Threats

to Child Development, " report by Greater Boston Physicians for Social

Responsibility (prepared for Joint Project with Clean Water Fund),

http://psr.igc.org/ihw-download-report.htm.

 

Terrence Collins, Thomas Lord Professor of Chemistry at

Carnegie Mellon University and director of the Institute for Green

Oxidation Chemistry there, is a member of C & EN's advisory board. He

contends that the dangers of chlorine chemistry are not adequately

addressed by either academe or industry and that alternatives to

chlorine and chlorine processes must be pursued.