CHLORINE AND CANCER
FAIRY-TALE
Of more than a hundred chlorine containing organic materials, the carcinogenic
effect has been proven.
Greenpeace leaflet 'Chlorine is everywhere' (in Dutch) - summer 1994.
FACTS AND FIGURES
Statement
There are no carcinogenic materials, there are only carcinogenic doses.
Source: A free interpretation of a statement of Paracelsus, one of the
pioneers of medical science, about toxins some 400 years ago.
Parts of this page
Causes of cancer
Although, there are still wide interpretations of the possible causes of
cancer, here we give an indication of magnitude of the different possible
causes:
Expectance of premature cancer:
All figures expressed in percent:
| Expectance of premature cancer |
| cause |
average rate |
|
|
| Unbalanced diet: |
35.0 |
| Tobacco: |
30.0 |
| Infections: |
10.0 |
| Sexual behaviour: |
7.0 |
| Occupational: |
5.0 |
| Alcohol: |
3.0 |
| Geophysical factors: |
3.0 |
| Environmental problems: |
2.5 |
| Medical operations: |
1.5 |
| Food additives: |
1.0 |
| Industrial products: |
1.0 |
| Unknown: |
1.0 |
Source: 'MENS' NR. 13: Cancer and the environment (Dutch), Belgium.
Too many rodent carcinogens
Bruce
N. Ames, the world famous toxicologist, found that when a lot of materials,
chlorine containing or not, natural or not, are tested for carcinogenity
at MTD (maximum tolerated dose) in rodents, about 50% are found to be positive.
According to him, most of this carcinogenesis is due to the high dose,
not the carcinogenic potential of the material itself. If the dose is lowered,
the results are vanishing rapidly, in general a quadratic dose-response
curve can be seen and below a certain dose there is no effect at all. See:
Too
many rodent carcinogens (not a popular scientific chat!).
Other materials are carcinogens, even at lower dose, but then the carcinogenic
effect lowers more in proportion with the magnitude of the dose.
Everybody will have cancer, if he/she will become old enough. The possibility
of having cancer is growing exponential with age with 10^4 to 10^5. For
mice and rats, that results in about 40% natural cancer deaths at an average
two years of age. For humans, who have a different metabolism, this results
in a 25% of natural cancer deaths on an average seventy-five years of life.
One of the most common carcinogens, indispensable for life, which is
responsible for 10,000 oxidative DNA-adducts (faults in the cell kernel,
which can induce cancer) per cell per day, is oxygen. In fact most of this
DNA-faults are repaired by some mechanism, but not all. The fear of many
people that even one molecule of a carcinogen will cause cancer, can be
true, but misses relevance, if you compare that with this natural damage
and the enormous amount of natural carcinogens we do digest with our food.
See: Dietary
Pesticides (99.99% All Natural). If you think that the body treats
natural carcinogens differently to synthetic carcinogens, you are wrong.
A lot of natural carcinogenic chemicals are introduced only a few hundred
years ago to recently in our diet, so our body had not the time to evolve
some counteraction. Our body defences are in fact general in nature and
treat natural and synthetic chemicals in the same way. See: Nature's
Chemicals and Synthetic Chemicals: Comparative Toxicology.
What amount is carcinogenic?
The same material can be an anti-carcinogen at low dose and a carcinogen
at high dose. A typical example is vitamin A. At normal dose in food, it
is indispensable for growth, night-sight and the immune system. It also
seems to help in the prevention of (lung)cancer, because it is an anti-oxidant.
At higher dose, about four times the daily average, it augments
the possibility of having lung cancer by smokers. At much higher dose it
is very dangerous for the unborn child: children are born without brains!
And it seems to be carcinogenic itself at very high dose.
There are, just like in the case of toxins (see Chlorine
and toxicity) enormous differences between the carcinogenic potency
of different materials. If you drink one beer or one glass of wine a day,
that can be beneficial for your hart and will not influence your possibility
to develop cancer. If you drink more than a hundred grams of alcohol a
day, that is five or more glasses, you will raise the possibility of liver
cancer. On the other side of the scale, we have nitrosamines (can be formed
by too much nitrate in our food) of which a few milligrams a day can be
enough to form colon cancer.
Some chlorinated chemicals are found to be carcinogenic, but with the
exception of TCDD-dioxin, they are all between the above limits. VCM, the
building block for PVC, was found to be a carcinogen around 1970. Before
that, a lot of workers had been exposed to massive doses (even more than
1000 ppm - parts per million) of VCM, during years. This resulted in about
170 workers all over the world, who died from angiosarcoma, a specific
liver cancer. Immediately after this discovery, the concentrations of VCM
in air were rapidly reduced to less than 1 ppm at the workplace, resulting
in a possibility of developing cancer of less than 1:100,000.
And what about dioxins, the most toxic product ever made by man (and
nature: see Sources of dioxins) That seems
to be the same story as for vitamin A: low doses seems to be cancer inhibiting,
higher doses are cancer promoting. See How dangerous
are dioxins. But that being said, we do not promote the use of small
doses of dioxins to prevent cancer!
Recently, the WHO has declared the Seveso type dioxin (2,3,7,8 TCDD)
as a human carcinogen, based on the consequences of severe accidents in
several chemical works, where workers received extreme high levels of this
dioxin type. The rise of cancer incidences in a life time was app. 40%
for the highest exposed people. That has to be compared with a 20 times
(or 2,000%) rise in cancer incidence for smokers...
The other 209 types of chlorinated dioxins and furans are not classified
until now, because of lack of reliable data.
Carcinogenic substances in industry
Here we can give you an idea of the relative (possible) carcinogenic potency
of different materials. The maximum allowed concentration in air on the
working place for 8 hours a day, 5 days a week, 50 weeks a year and 40
years long, which causes less than one extra case of cancer on 100,000
workers is:
(suspect) carcinogenic substances in industry:
maximum allowed at the work environment, all figures expressed in mg/m3
in air
| (suspect) carcinogenic substances in industry |
| material |
maximum |
use, occurrence |
|
|
|
| pure (hydro)carbons: |
| 1,3 butadiene: |
34 |
cracking, synthetic rubber |
| benzene: |
16 |
crude oil, petrol, cracking |
| carbon black: |
3.5 |
dye, anti-oxidant |
| diesel soot: |
0.6 |
diesel exhaust |
| PAH's (#): |
0.1 |
see benzo(a)pyrene |
| benzo(a)pyrene (#): |
0.0005 |
diesel exhaust, cracking, crude oil, asphalt, burning of
organic materials, tar from wood and coal |
| carbon-oxygen: |
| propylene oxide: |
6 |
PET bottles and packing |
| ethylene oxide: |
2 |
PET bottles and packing |
| carbon-oxygen-chlorine: |
| epychlorhydrin: |
12 |
epoxy resins, coatings, glues |
| TCDD-dioxin: |
0.00000005 |
all incineration, all processes |
| carbon-nitrogen: |
| nitropropane |
18 |
|
| acrylnitril |
7 |
ABS-rubber/plastic, yarns |
| acrylamide: |
0.06 |
|
| nitrosamines (10 types) |
0.0025 |
synthetic rubber, nitrates in food |
| carbon-halogen: |
| 1,2 dichloroethane (DCE)(*): |
40 |
PVC, amines |
| vinylchloride (VCM): |
8 |
PVC |
| dibromomethane: |
0.8 |
|
| carbon-sulphur: |
| diethylsulphate: |
0.2 |
|
| dimethylsulphate: |
0.1 |
|
| oxygen: |
| ozone (since June 1995): |
0.1 |
bleaching, disinfectant |
| metal/metalcombinations: |
| cobalt: |
0.5 |
catalyst for phthallic acids and linoleum |
| nickel: |
0.5 |
stainless steel |
| antimonytrioxyde: |
0.3 |
fire retardant |
| chromium(VI)salts: |
0.2 |
leather tannery |
| beryllium: |
0.005 |
|
| organic material: |
| wood dust (general): |
2 |
construction, floors, furniture, based on wood dust from
oak and beach |
Source: Deutsche Forschungsgeselschaft, Germany, 1994.
(#) Benzo(a)pyrene is the most potent carcinogenic
PAH.
The potency of a mixture of PAH's is compared for total toxicity by multiplying
quantities with toxicity factors, compared to this compound.
(*) expected
As you can see, almost all human activities have to do with carcinogenic
substances. On toxicological grounds, even many more materials are suspect
carcinogens, but have no certain highest allowable concentrations yet.
That is the case for wood dust of all types (oak and beach are already
proven human carcinogens), the products from pyrolyses of any organic material,
ethylene which reacts in the body like ethylene oxide, but at a 30 times
higher concentration in air, formaldehyde, and many more...
Chlorine, alternatives and cancer
Greenpeace is right when they say that more than a hundred chlorine containing
compounds are proven carcinogens. In fact this is not much, because average
half of the more than 10,000 chlorinated materials will be found to be
carcinogenic at some (high) dose.
But the same is true for non-chlorinated materials. If you see the
complete list of known carcinogens, the lists of far more potent carcinogen
hydrocarbons and nitrogen compounds are much longer.
As far as we know, not one industrial or natural material can be produced
without release of carcinogens or other dangerous substances. Sand for
glass gives silicosis, crude oil contains hundreds of carcinogenic materials,
like benzene, waxes and PAH's. So all from
crude oil derived products and the use of oil for energy, releases some
carcinogenic materials. Ethylene for polyethylene (PE),
butadiene for synthetic rubber, benzene for polystyrene (PS),
ethylene oxide for polyethylene terephthalate (PET),
wood dust for furniture, tannins and chromium salts for leather, all are
dangerous if not carefully treated...
How carcinogenic is a PVC-factory?
If you look at the air releases of a chlorine-VCM-PVC-factory, there is
(in Europe) less than 100 g of VCM that
is emitted per ton of PVC. A factory that
makes 500,000 tonnes of PVC gives a maximum emission of about 50 tonnes
of VCM per year. This seems to be rather much, but this is in fact only
6 kg/h, widespread over a large factory. This is within the factory below
all concentration limits for the workers and outside the factory far below
all limits for the inhabitants.
Compare this with a truck: a diesel motor emits about 4 kg of soot
per ton of fuel. A full loaded truck uses approximately 33 kg of fuel per
hour and emits 100 g of soot (into the smallest streets of towns). The
carcinogenic potency of soot is in fact 13 times higher than of VCM, but
the limits for soot outside factories are 4 times stricter. That means
that a large chlorine-VCM-PVC factory is not more carcinogenic for the
general public than about one truck...
PVC in food packaging and cancer
There are always traces of monomers remaining in polymers. The possibility
that the users will develop cancer by migration to food of these quantities
is negligible in all cases.
The amount of VCM in PVC-bottles, used for water, is so low that, even
if you drink two litres a day all your life and all VCM was migrating to
the water, the total amount of VCM in a lifetime reaches the amount of
VCM a PVC-worker may have during one working day. This gives a pure theoretical
extra possibility of one to a hundred million to develop cancer.
Professor Maltoni of Bologna (Italy), who discovered the carcinogenity
of VCM, did prove that PVC is neither as powder, nor as packaging a carcinogen.
The latter was done in a mega experiment with 2000 rats, 1000 fed with
water from glass bottles, 1000 fed with water from PVC bottles, were even
PVC pellets were added. All rats were fed from before they were born until
theirs death. All movements and sexual behaviour were controlled, and when
they died, the cause of death was controlled too.
The results were, that there was no difference in behaviour, nor in
average age and a non significant difference in the amount of cancer deaths,
in fact the PVC-water drinkers had 1.9% less cancer!
For other packaging materials, the situation is not different: in all
cases some very small quantities of possible carcinogens migrate to the
packed food. For glass these are silicates and lead, for stoneware: lead
and cadmium, for polyethylene (PE): ethylene and waxes, for polyethylene
terephthalate (PET): acetaldehyde, etc., etc... In all cases the effect
is negligible.
THE ALTERNATIVES
No alternatives for chlorinated chemicals or products are carcinogen-free,
or can be produced carcinogen-free. Neither synthetic materials, nor natural.
So the use of carcinogens itself is no reason for an exchange to non-chlorinated
materials.
CONCLUSION
There is no reason to treat chlorinated carcinogens different from non-chlorinated.
And there is no reason at all to accuse chlorine in general to be the origin
of cancer in the environment.
LINKS TO CANCER RELATED WEB SITES
If you want to find out more about cancer and possible cures, look at Cancer
News on the Net
You are at level two of the Chlorophiles pages.
Created: March 9, 1996.
Last update: September 18, 2001.
Welcome page
Home page of the Chlorophiles
Chlorine and risk
Chlorine and toxicity
Chlorine and hormonal changes
For any comment on this or other pages, especially on cancer effects:
chlorophiles@pandora.be