PVC AND ADDITIVES
PVC, an environmental poison of Greenpeace Australia on the Internet.
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 to 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.
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.
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 consumption in Sweden in 1992 was:
All figures expressed in tonnes/year.
|Lead consumption in Sweden|
|Lead cable sheathing less than:||3,000|
|Fishing weight, nets:||600|
|Plastic additives, excl. PVC pipes:||400|
|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?
The annual emission of lead to the environment was calculated to be:
All figures expressed in tonnes/year.
|Lead emissions in Sweden|
|Fishing weights, nets:||600|
|Rust protection paint:||90|
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.
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.
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 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.
A recent comprehensive review and an IARC consensus report conclude that effects caused by peroxysome proliferators in rodents are of negligible relevance to humans.
Only two phthalates, dibutylphthalate (DBP, also naturally found in selery 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    . All the more common phthalates like DEHP, DINP and DIDP (diisodecylphthalate) have been tested and found to be negative .
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 .
In addition, exposure to rats to DINP  and DIDP  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.
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 , it was only stated by Dr. R. Sharpe, that it could not be reproduced . 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
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.
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.
You are at level two of the Chlorophiles pages
Created: June 2, 1996.
Last update: March 7, 1999.
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