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A worker cutting a PVC pipe on a construction site. Image credit: Toa55 / Shutterstock.com
Best known in the form of the ever-present white piping seen in basements of buildings, the domestic use of Polyvinyl Chloride (PVC) could be considered a double-edged sword.
Its reliability and range of uses make it an ideal material for making everything from water pipes to flooring. However, PVC is non-biodegradable and capable of releasing toxins into both the environment and the human body.
History
PVC was actually discovered by accident in the 19th century when it appeared as a white solid by-product in flasks of vinyl chloride left in the sun.
Early PVC was too brittle to use, and it wasn’t until chemists working for B.F. Goodrich in 1926 introduced several additives that PVC was suitable for widespread use. The use of PVC gained even more traction during the Second World War, when the material demands of the conflict left domestic societies with a severe rubber shortage.
Chemistry
The PVC molecule has the chemical formula C2H3Cl. The material itself is made from a polymer of many vinyl chloride molecules linked together: giving it the chemical formula (C2H3Cl)n. At the molecular level, PVC and other polymers look like long chains of repeating units – like strands of spaghetti.
This simple polymer can be altered through the addition of various modifiers and additives to make PVC material rigid, flexible, soft, or give it any other number of desirable qualities. For example, when phthalates are used to make PVC softer, the material can be used as medical tubing, hoses or intravenous (IV) bags.
Household Applications
In addition to medical applications, PVC also has a number of uses around the household. When a house is being built, contractors may use piping, siding, flooring or roofing materials made with PVC. PVC pipes have several significant advantages over metal pipes, including the fact that they do not rust or develop slimy coatings that can host bacteria. They are also lighter and cheaper to produce than metal pipes.
PVC is also used for a number of domestic purposes. It can be used in the production of raincoats, rubber boots, shower curtains or other goods that need to be waterproof. PVCs durability also lends itself to use in toys, upholstery, patio furniture and even credit cards.
Potential Dangers - Household Exposure
The ubiquity of PVC means that we are constantly being exposed to it and while the material is largely considered safe, health officials have raised some concerns about exposure to PVC.
Direct exposure to PVC inside the home can come from pipes, flooring, or even food packaging. Outside, PVC exposure can come from swimming pools or plastic furniture.
This means that PVC exposure can come from almost anywhere and although these products are highly resilient, critics point out that PVC is capable of releasing additives like phthalates, lead and toxic glues. One study involving a PVC shower curtain showed that the phthalates it leaked could cause nausea and even damage to the reproductive system.
PVC also includes vinyl chloride, a combustible sweet-smelling gas. According to the U.S. Environmental Protection Agency, PVC pipes can leach vinyl chloride into drinking water.
In addition to phthalates and vinyl chloride, PVC can also release dioxins and Bisphenol A (BPA).
However, the U.S. Food and Drug Administration (FDA) have recently addressed the public's concerns regarding BPA contamination in food and drink. Whilst accepting that some exposure may occur, they conclude that, based on scientific evidence, the levels to which consumers are subjected to are safe.
Other Exposure Situations
In addition to the risks posed by PVC in domestic situations, the production, land-filling and burning of the plastic can release dangerous toxins.
PVC is desirable as a fire retardant, but this resistance to burning means it can smolder for a long time, all the while releasing hydrogen chloride gas. HCl gas is highly toxic, capable of causing skin burns and long-term damage to the respiratory system.
Smoldering PVC also releases large amounts of dioxin, which can persist in soil for long periods of time.
The U.S. National Institutes of Health (NIH) recommend contacting a health care professional if someone thinks they are suffering from the effects of PVC exposure. If the situation is urgent, such as the inhalation of PVC fumes, the NIH suggests contacting a local poison control center or emergency center.
Recycling and Sustainability
Critics of PVC state that the material gradually finds its way into landfills where it can easily smolder or break down and release a considerable quantity of toxic compounds. PVC producers counter this point by mentioning that PVC's long life makes it appear in landfills less than more eco-friendly options, and that some landfill liners are made of PVC.
There are a number of methods used to dispose of or recycle PVC materials. Mechanical recycling of PVC is considered an uncomplicated and common practice. This involves identifying post-use products and separating them from the waste stream.
Feedstock recycling is another option that can be seen as supplementary to mechanical recycling and it requires a process less sensitive to unsorted or contaminated waste products. Feedstock recycling does boost the overall recycling capacities ahead of the larger quantities of PVC waste expected in the future.
Thermal de-polymerization has also been utilized to transform used PVC into other functional materials, but this method is rarely applied.
Generally speaking, the large number of additives used to generate PVC make large-scale recycling troublesome and costly, so much so that suppliers typically find it more feasible to make new PVC rather than recycle it. Only 0.5 percent of PVC plastic is recycled, according to the Healthy Building Network.
However, the plastics industry has been taking note of the general public’s desire to recycle PVC as opposed to landfill it. Recovinyl and Recofloor are two European based schemes dedicated to collect and recycle PVC products.
Making Consumer Choices about PVC
PVC is a durable material that finds uses all around the typical home. Consumers need to educate themselves about the potential dangers and responsible disposal of the plastic. Before conducting research, consumers should know that the sustainability and dangers of PVC use are politically-charged and contentious issues. This means that the source should always be considered for bias when reading about PVC.
Sources and Further Reading
Disclaimer: The views expressed here are those of the author expressed in their private capacity and do not necessarily represent the views of AZoM.com Limited T/A AZoNetwork the owner and operator of this website. This disclaimer forms part of the Terms and conditions of use of this website.