PVC AND ADDITIVES
FAIRY-TALE
This Vinyl House: Hazardous Additives in Vinyl Consumer Products and Home
Furnishings.
Greenpeace
toxics campaign on the Internet.
FACTS AND FIGURES
The environmental and health impact of PVC and additives
The health and environmental impact of chlorine and PVC can be compared
in life cycle analyses. That can be found in our Complete
Life Cycle Analyses of PVC and alternatives pages. Phthalates, the
main additives for soft PVC are mentioned in our Chlorine
and hormonal changes pages, but here follows a complete reaction. The
use of heavy metals as PVC stabilisers is another main item here.
Parts of this page
Lead as stabilisers in PVC
Because of concerns of the use of lead as a stabiliser in PVC drinking
water pipe, the Nordic Pipes federation (Nordic = Norway, Sweden, Denmark,
Finland) prepared a paper for a scientific debate on health and environmental
impact, compared with other lead uses. It can give you a feeling of the
ratio of problems of lead in PVC to lead in other uses.
Lead leaking to drinking water
Drinking water and pipe materials were tested for lead migration from PVC
to the water. Except for the first five days, when lead of the surface
can migrate to the water, there are no migrations seen and the water contains
no more lead at the tap than the natural lead content at the source. In
the first days, the pipe is tested for leakage and thouroughly flushed
and desinfected.
The surface of PVC pipes was tested with the same test, used for ceramics
in contact with food.
The first test did give 0.13 and 0.20 mg/dm2 lead.
The second test did give less than 0.01 mg/dm2 that means that no lead
is migrating from the inside of the plastic.
The tightest EU test limit is 0.80 mg/dm2.
Lead uses in Sweden
Lead consumption in Sweden in 1992 was:
All figures expressed in tonnes/year.
| Lead consumption in Sweden |
| Application: |
Consumption |
|
|
| Accumulators, batteries: |
22,000 |
| Lead cable sheathing less than: |
3,000 |
| Crystal glass: |
1,300 |
| Electronics: |
1,300 |
| Ammunition: |
1,200 |
| Weights: |
1,000 |
| Metal alloys: |
900 |
| Fishing weight, nets: |
600 |
| Chimney plates: |
500 |
| Plastic additives, excl. PVC pipes: |
400 |
| Leaded petrol: |
340 |
| PVC pipes: |
225 |
| Other usages: |
150 |
| Rust protection, paint: |
90 |
Interesting, if lead in PVC pipes is a problem, why should the use of
lead in crystal glass be allowed, just for enjoying the art of glass blowing,
with no environmental benefit?
Lead emissions in Sweden
The annual emission of lead to the environment was calculated to be:
All figures expressed in tonnes/year.
| Lead emissions in Sweden |
| product |
emission |
|
|
| Accumulators: |
3,000 |
| Ammunition: |
1,200 |
| Fishing weights, nets: |
600 |
| Leaded petrol: |
340 |
| Rust protection paint: |
90 |
| PVC pipes: |
0.08 |
When incinerated, the amount of any metal used as stabiliser in PVC
will nearly not change the total amount of heavy metals that has to be
washed out of the stack gases.
No leaching has been seen from PVC pipes in soils or landfills, neither
any breakdown of rigid PVC itself. But, if we assume that PVC anyway will
breakdown in 100,000 years or so, that extra risk of lead leaching would
be neglible:
Natural lead content of soil: 20-50 mg/kg.
Maximum allowed by different countries: 200-1000 mg/kg
When the lead content from one meter of 110 mm (4.3") PVC pipe migrates
in the adjacent soil that would augment the background lead content of
soil with:
0.4 mg/kg if only the surface layer breaks down and lead migrates within
0.5 m of the pipe.
7 mg/kg if the entire lead content migrates in the adjacent 1 m3 of
soil.
The migration speed of metals in general is less than 1.5 m in more
than 600 years, with sandstone as exception: 4.5 m in 690 years.
Phthalates as softeners in soft PVC
Phthalates and toxicity
Because of the scare that Greenpeace started against the leaking of "toxic"
chemicals out of children's toys, here follows the toxicological background
of phthalates.
The acute toxicity of several commercial phthalates is so low that enormous
quantities must be fed to animals to reach the MTD
(maximum tolerated dose), equivalent to 500 g/day for an adult. DEHP,
the most common phthalate is considered as non-toxic and non-iritant. DEHP
is approved for use in food packaging materials by the US FDA and the EU
Scientific Committee for Foodstuffs. PVC plasticised with DEHP is the only
flexible material approved by the European Pharmocopoeia for use in blood
and plasma transfusion equipment.
Phthalates and cancer
Of course if you continuously administer doses as high as the MTD,
you will find effects, caused by the dose, not the toxicity of the product.
See "Too
many rodent carcinogens" of Bruce
N. Ames.
In the case of DEHP, feeding high levels
of phthalates, fats and other substances to rodents over their lifetime
causes "peroxisome proliferation", leading to the formation of liver tumours.
The same effects were NOT observed in primates (marmosets and monkeys).
This species difference is en_reflected in the EU Commission decision of
25 July 1990 which states that DEHP shall
not be classified or labeled as a carcinogenic or an irritant substance.
In February 2000, also the IARC (International Agency for the Reseach
of Cancer), a part of the WHO (World Health Organisation) reclassified
DEHP from possible human carcinogen to not classifiable as to carcinogenicity
to humans.
A comprehensive review and an IARC consensus report conclude that effects
caused by peroxysome proliferators in rodents are of negligible relevance
to humans.
Phthalates and hormones
Only two phthalates, dibutylphthalate (DBP,
a similar product, bytylphthalide is found in celery and lovage) and butylbenzylphthalate
(BBP) mainly used in printing inks, showed
very weak oestrogenic activity (one millionth of the strength of the natural
female hormone oestradiol) in SOME in vitro tests (in the laboratory),
but showed no effect in other tests [21] [22]
[23] [24]. All
the more common phthalates like DEHP, DINP
and DIDP (diisodecylphthalate) have been
tested and found to be negative [21].
The most recent in-vivo studies (in living animals) specifically intended
to look for oestrogenic effects, showed no effect for all phthalates, ranging
from DBP to DIDP
[22].
In addition, exposure to rats to DINP
[25] and DIDP
[26] in utero,
during lactation, puberty and adulthood in multi-generation tests didn't
affect testicular size, sperm count, morphology or motility neither produced
any reproductive fertility effects.
Reproductive effects of phthalates at low doses not
reproducable
Some phthalates (like DEHP) do give reproductive
effects at very high doses. These doses are much higher than the doses
where no observed adverse effects (the NOAEL level) of any kind occurs
in rats, the most vulnarable species. The maximum allowed limit for intake
by humans is set 100 times lower than the NOAEL in rats.
There was one study that did found adverse effects of one phthalate,
BBP, on the reproductive tract at very low
levels, only 10-100 times higher than the intake by children from food.
This study by Dr. R. Sharpe e.a. of the Medical Research Council Biology
Unit in Edinburgh, couldn't be reproduced by two other laboratories, although
these were carefully replicates of the original study. Although it was
announced that the study would be retracted [34],
it was only stated by Dr. R. Sharpe, that it could not be reproduced [36].
While nobody involved could offer an explanation for the differences in
results obtained, this makes it quite clear that BBP can not be the origin
of the differences and hence does not have adverse effects at low levels.
See also the comment of Dr. Sharpe at the time that his study had fueled
a scare about the amounts of phthalates found in baby food in the UK: How
my work triggered the milk fiasco (somewhere halfway the page).
Possible explanations for these differences in results could be that
sometimes bisphenol A is used as anti-oxydant in phthalates but not in
other cases, or there can be differences in the food that the rats have
had in the different tests. It is known that e.g. soya contains strong
oestrogenic isoflavones like genistein.
THE ALTERNATIVES
All alternatives use almost always additives to give the properties wanted
for a specific purpose, PVC not being an exception. Anti-oxydants, pesticides,
fungicides, stabilisers, dyes, plasticisers, etc... are used in paper,
plastics, paints, etc...
As long as that doesn't give unacceptable impacts on environment or
health, that is not a problem. If certain additives give problems, they
should be phased out and replaced by others.
CONCLUSION
There is no reason to ban (heavy) metal stabilisers in PVC, the environment
and health impacts are neglible. There are other real problems if you compare
the impact of lead in PVC with its use in a lot of other purposes. Neither
is there a real risk from the use of phthalates in soft PVC.
You are at level two of the Chlorophiles pages
Created: June 2, 1996.
Last update: September 18, 2001.
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