Polyvinyl Chloride (PVC)
Environmental Sources
Polyvinyl Chloride is a polymer, or large chain-like
molecule, made up of repeating units of Vinyl Chloride
(a monomer) commonly referred
to as Vinyl or PVC. Other common
commercial polymers used for familiar products arepolyurethane
and polystyrene. PVC is manufactured for use in car interiors
and trim, wall coverings, floor tiles, window frames, siding,
water and sewer pipes, shrink wrap, packaging (including blister
packs and food wraps), medical equipment (tubing, transfusion
bags, blood storage bags, respiration tubes), electric and electronic
cable insulation, textiles, both as trim and complete garments
and toys.
Human Health effects
PVC contains phthalates, which accumulate in body tissues, and
can damage liver, lungs, and have been shown in lower mammals
to damage reproductive organs and decrease sperm count. Phthalates
freely migrate from the plastics in which it occurs and, because
it is fat soluble, is found in quantity in meats and cheeses wrapped
in PVC packaging. Although phthalates show almost no toxicity
in adult humans in acute (short term) doses, even at high doses,the
cumulative nature of phthalate toxicity results in toxic effects
even at very low dosage when ingested chronically (over a long
period of time). Very young infants do not metabolise phthalates
as well as adults, and so are at greater risk of harm. The common
availability of phthalates in the consumer environment causes
inevitable chronic ingestion for almost all modern industrial
consumers. The European Union has banned the use of phthalates
in teething rings and toys for babies made from soft PVC containing
phthalates, after it was found that once phthalates mixed with
saliva, it can pose a serious risk to a baby’s health (damage
to the baby’s liver or kidneys). Belgium, France and Italy
have supported this ban.
PVC manufacturing and disposal result in the release of dioxins
when it is incinerated. Dioxin is uniquely harmful to mammalian
biology, causing cellular changes with even an initial exposure
to very small amounts of the toxin (see Dioxins
and Furans).
Vinyl Chloride Monomer (VCM) is a highly toxic
and carcinogenic gas, and has been found to be a trace component
of PVC. There have been reports of VCM detected in drinking water
that has been standing for a period of time in PVC water pipe.
The main risk of VCM, however, has been found to be primarily
to workers in plants producing VCM or producing PVC resin from
the VCM monomer;and also topeople living close to such plants.VCM
is also found in hair sprays and pose a threat to beauty workers.
Exposure hazard to workers, neighbours, and users of PVC products
is not theoretically inherent in the process, but in fact occurs
due to inevitable lapses in production quality
control and housekeeping.
Exposure limits
- The Bay Area Air Quality Management District in San Francisco,
USA documented a background concentration level of <0.3 ppb
for vinyl chloride for the whole bay area in San Francisco.
- The US EPA requires that the amount of vinyl chloride in drinking
water not exceed 0.002 milligrams of vinyl chloride per litre
of water (0.002 mg/L).
- The EPA requires that spills or accidental releases into the
environment of 1 pound or more of vinyl chloride be reported to
the EPA.
- The US Occupational Safety and Health Administration (OSHA)
has set the maximum allowable level of vinyl chloride or (VCM)
in workroom air during an 8-hour workday in a 40-hour workweek
at 1 part vinyl chloride per million parts of air (1 ppm). A short
term exposure limit (15 minutes) is 5ppm. Note that 1ppm= 2.56
mg/m3.
- The US National Institute for Occupational Safety and Health
(NIOSH) identified vinyl Chloride (VCM) as a potential occupational
carcinogen.
Sources & Links:
www.turnertoys.com/pvc9printable.htm
http://www.mindfully.org/Plastic/Polyethylene/Polyethylene-Family.htm
www.mst.dk/default.asp?Sub=http://www.mst.dk/udgiv/publications/2001/87-7944-407-5/html/kap06_eng.htm
www.greenpeaceusa.org/media/factsheets/plastic101text.htm
www2.niwl.se/forlag/en/samm_en.asp?ID=698
www.caw.ca/whatwedo/health&safety/factsheet/hsfssubstanceno35.asp
http://ecologycenter.org/resource_cntr/fact_sheets/plastichealtheffects.html
www.greenpeace.org/~usa/reports/toxics/PVC/cradle/dcgtoc.html
http://europa.eu.int/comm/dg10/publications/newsletters/esf/2000-4/decisions_en.html
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