An Evaluation of Plastic

Most adult Americans know that plastic is made from petroleum, which is an nonrenewable, increasingly expensive resource, and that plastic fills up landfills for centuries. However, what most Americans know may be wrong.

Plastic can be made from natural gas and can be easily disposable under proper conditions. Plastic has often been under a dark spotlight, but some of the more in depth arguments against plastic no longer can stand on their own with today’s new evidence. There are also many types of plastics, some of which have been scrutinized more than others.

Despite its negative publicity, number three plastic is safe to manufacture, use, and dispose of because the dangers of the past are not the dangers of the present. People have changed procedures dealing with this plastic so that it is no longer the threat it once was.

Polyvinyl Chloride (PVC) is a plastic labeled as number three in the “resin identification coding system developed by the Society of the Plastics Industry, Inc.” (www.greenyour.com, 2009). PVC has some basic components. PVC, also known as vinyl, is a polymer, like all plastics, that will neither rust, nor decay, nor be heavy, nor will stain.

An inexpensive material that is manufactured to make cling wrap, jars for cooking oil and peanut butter, containers for detergent and window cleaner, and some squeeze bottles, PVC can only be used effectively with additives. This is because this polymer is “a tough, horny, rigid material” (Burdick & Leffler, 2001, p. 349) and cannot be molded into items such as cling wrap without assistance from additives.

PVC has a dangerous reputation because of these additives and how it has been created. This means that polyvinyl chloride itself has not been proven harmful. The other chemicals involved in its manufacturing and composition are what all of the alarm has circled around. This alarm stems from the fact that PVC manufacturing facilities have incorporated lead, mercury, vinyl chloride, and other toxic and inflammable chemicals in its processes.

In the past, there has been worry about the individuals who work in the manufacturing industry. Awareness of the dangerous chemicals prompted in depth investigations into the effects of various compounds. The PVC industry has had a dangerous reputation among workers since some of the investigations into the chemicals have indicated significant negative effects from constant extreme exposure of these chemicals (Emsley, 1994).

The first stage of manufacturing usable polyvinyl chlorine requires retrieving raw materials. Chlorine gas and ethylene gas, both toxic, must be combined. The chlorine is obtained by separating sodium and chloride in sodium chloride with mercury. Chlorine has been used in wars before mustard gas, and has been used in the infamous DDT’s. By burning ethane, propane, butane, or naphtha (from oil), ethylene gas is formed (www.onelook.com, 2009). Other burn-offs are methane, hydrogen, and propylene (Emsley, 1994).

Methane is a notorious ozone destroyer, and all of these burn-offs are inflammable. All of these burn-offs from the first stage have their own degrees of dangerousness. The first stage of manufacturing is meant to finish with a combination of chlorine gas and ethylene gas to create ethylene dichloride, another toxic gas, which can damage kidneys with long-term exposure.

The second stage of manufacturing changes ethylene dichloride to vinyl chloride, also referred to as chloroethene, by using radiation. Vinyl Chloride also has been shown to play a part in a rare, deadly cancer of the lungs (Emsley, 1994).

In stage three of making the number three plastic that is sold to companies, the monomer VC is either placed in suspension, emulsion, bulk, or in solution. Suspension is usually the method (Burdick, 2001). By placing VC into water, the molecules began to bump into each other to form a polymer.

In this stage, polyvinyl alcohol is used as a dispersing agent so that the VC molecules bump into each other more frequently. This is how VC is polymerized into PVC. In stage three, additives are mixed into the PVC depending on what properties the manufacturing company wants it to have, such as flexibility instead of rigidity. After some of these controversial additives have been mixed into the plastic, the PVC is steamed and dried.

The PVC itself has no toxicity and is not inflammable (Emsley, 1994). These chemicals, chlorine gas, ethylene gas, methane, hydrogen, propylene, mercury, ethylene dichloride, and vinyl chloride have all been viewed as dangerous. They have been considered dangerous either with their associations with toxicity or with inflammability.

This means that the PVC itself is not about what people have been worried. People have distressed over the other chemicals involved in its manufacturing or its additives. Some of the negative histories of these chemicals are easier for the average person to grasp than the fact that there have been changes, in fact, solutions.

There is now a law in the United States that requires all traces of VC to be removed from PVC, and workers must be exposed to no more than one part per a million (1ppm) of VC per air molecules if possible. Companies have implemented procedures such as sanitary suits that limit contact with VC.

Also VC is removed from PVC by the steaming process after suspension. There is still a little tidbit of VC left in the finished PVC product, but it cannot leach out. This tidbit is not harmful since cancer from VC in PVC contact never happens. Also, since a large amount of PV is required for dangerous effects, even a high amount of the nutrient iron in the blood is dangerous, being exposed to only a maximum of 1ppm VC is not harmful to workers.

Not only have solutions been implemented, but there have been over-reactions to mild dangers such as methane, hydrogen, and propylene formed as burn-off from creating ethylene gas. Inflammability is not as bad as it may sound. Wood, clothing, and paper are all inflammable. These items are used in everyday American lives. Americans will not stop using them just because of inflammability.

Plus, methane, hydrogen, and propylene are often recycled. They usually are sold to companies that want them despite the decreasing demand for some of it. They can also be used to provide energy to an industrious nation.

Another point to make is that just because something is toxic, like snake-venom, does not mean it is a common end to all life. For instance, “Chlorine has [only] killed…eighty-one people throughout the world” from 1960 to 1994 (Emsley, 1994, p. 154). That is, about 2.4 people dying annually from chlorine gas around the world. 1 to 2 people die annually from venomous snakebites in Texas alone (www.dshs.state.tx.us, 2009). A naturally made creature sounds more dangerous than chlorine gas.

One of the other chemicals aforementioned in the manufacturing process, mercury, has yet to have its toxicity explained.

Mercury has been known to annihilate neurons without failure. One such event that demonstrated this fact is when mercury entered fish in Minamata Bay, Japan in the 1950’s. Innocent Japanese people ate the fish. These people either died or suffered brain damage from their poisoned food.

Now “[I]n some plants…[mercury escaped] as little as a quarter of a gram for each tone of chlorine produced” (Emsley, 1994 p. 156). Even if that still seems too much mercury to people. They can relax because asbestos has been replacing mercury as a separator, and by 2010, no mercury will be used as a separator. In addition, the asbestos is in a solid form so that no asbestos can escape.

There are other parts of PVC that people have worried about. Some additives have caused cancerous side effects in rodents who have been exposed to dense long-term doses (Emsley, 1994). The group of these additives that have shown this effect are plasticizers.

Some of the most common plasticizers are adipates, phthalates, and organophosphates.

Di(2-etylhexyl)phthalate (DEHP) was fed to rats for twenty hours a week for fifty weeks. Many of these rats developed cancer. DEHP is a phthalate, and phthalates are in cling wrap. If cling wrap touches fatty food, its phthalates cling to the food.

Di(2-ethylhexyl)adipate (DEHA) clings to food also and has been said to be bad for the liver, kidneys, spleen, and bones (Smart Plastics Guide Healthier Food Uses of Plastics: For parents and children).

Lead is also an additive used to strengthen PVC plastic, which can cause nerve damage, but lead additive is only used for polymer that will be used underground.

There has also been leaching from the chemicals in PVC into our bodies (Smart, 2005). Leaching, a process in which the chemicals from a plastic separate from the plastic and enter a nearby substance such as the food under a cling wrap, increases in rate if the plastic is in contact with oily or fatty foods when heated. Leaching occurrences also increase if the plastic is old or scratched.

There are plasticizers that do leach from plastic (Emsley, 1994). There has been fear that if these chemicals leach into food and drink that people consume over long periods of time, those people could become ill.

The truth is, DEHP and DEHA plasticizers are not actually toxic. Experts are not afraid to use them in medical-related and food-related containers. Some people may have worried about these chemicals because there were rats that exhibited cancer from exposure to DEHP, but there is an interesting phenomenon with studies using rodents.

There was a study that proved that rodent studies are not accurate or reliable when connected with humans. There were several diseases given to rats and mice. A handful of six rodent diseases were the same in rats in rodents, while the other diseases showed up in only one, rats or mice, or neither of them. This means that rats do not contract all of the diseases as mice do. When these six diseases, that affected both types of rodent, were tested on primates (non-human), no disease showed up.

It can be concluded that diseases that affect humans likely will affect rodents, but diseases that affect rodents will not likely affect people.

These chemicals are still present in the plastic when it is disposed in the trash or in the recyclables, but since they are not harmful there are no worries about DEHP and DEHA.

Plastic is disposed of by incineration. There have been arguments against incinerating plastic, because there is fear of dioxins. Even when manufactured, trace amounts of dioxins exist.

Dioxins, poisonous compounds, can appear in smoke from incinerators and can coat grass. If individuals eat the animals that eat this grass, they put dioxins directly into their bodies.

Dioxins might also manage to enter rain and snow. Even burning off the plastic coating on copper wiring might allow dioxins to form.

They are “known human carcinogens” (Screening Evaluation of Dioxins Pollution Prevention Options, 2001, p. 2) and have a TEF, toxicity equivalency factor, of 7, which is a high toxicity rating.

Specifically, the most dangerous dioxin is 2,3,7,8-tetraclorodibenzo-p-dioxin (TCDD). TCDD stays inside the body for extended periods of time and causes a multitude of health problems, from the youthful to the geriatric, from small animals to humans (Veterans and Agent Orange: Update 1996, 1996).

There were a few serious health consequences from exposure to TCDD in some American occupations and some operations in Vietnam as stated, “[T]he committee found…an association with herbicides and/or TCDD of five diseases: soft-tissue sarcoma, non-Hodgkin’s lymphoma, Hodgkin’s disease, chloracne and porphyria cutanea tarda (in genetically susceptible individuals)” (p. 5).

In this updated book, porphyria cutanea tarda was moved down to “limited evidence” to support a connection with TCDD exposure.

Soft-tissue sarcoma is a disease that affects organs and the tissue between organs. Non-Hodgkin’s lymphoma is the name for any malignant cancer in lymphoreticular cells. Hodgkin’s disease is an enlargement of general lymphoid tissue, and Chloracne is a skin disorder, and certain types can persist in individuals for up to thirty years.

TCDD may be the most toxic of the dioxins, but all classified dioxins have similar toxicity (Screening, 2001). This means that dioxin contact is a serious issue. People have condemned PVC because of many chemicals, including dioxins.

Despite the condemnations, dioxins are actually not an issue.

There was an unlikely event that gave scientists data that proved that plastic users do not have to worry about dioxins (Emsley, 1994). There was a wooden warehouse filled with two hundred tons of PVC and five hundred tons of other types of plastic. The warehouse was incinerated along with the plastic. Due to uncommon weather conditions, the smoke from the fire was trapped in snow that encircled the warehouse for a mile around. Testing the snow, scientists found 3mg of dioxins.

There is a possibility that those dioxins came from the wood, but even if they did come from the plastic, 3mg out of seven hundred tons of plastic is an extremely low amount. This is almost as if three people died from breast cancer in a state with a population of six million people causing required breast cancer vaccines to come into existence.

This analogy was used because dioxins are dangerous, like breast cancer, but there was an extremely small amount of dioxins from that warehouse. Approximately 998 kg is required to make a ton, and this was seven hundred tons of plastic and three milligrams of dioxins. A mathematician is not required to figure out that panic over this small percentage is illogical. PVC is not a dioxin dispenser.

PVC should not continue to be placed in the same negative light, because not only are conditions different now than in past, but some dangers never existed.We have taken steps that have increased our safety, even to the effect that some dangers no longer exist at all, and discovered that some dangers have never existed.

For instance, the methane, hydrogen, and propylene, formed as burn-off from creating ethylene gas, are usually recycled. Asbestos, as a harmless solid, has been replacing mercury as a separator.

Also, workers may not be exposed to more than one part per a million (1ppm) of VC per air molecules if possible. In addition, any traces of VC in PVC do not affect people, even if it is in drinking bottles.

Products that do have dangerous additives that can still affect people are kept away from people, and not all additives are toxic, like DEHP and DEHA

As for the concern over dioxins, they do not form in significant numbers from plastic incineration. PVC is no longer as dangerous as it once was and was never as dangerous as it was once thought.The dangers of the past are not the dangers of the present.

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