September 20, 2011

The Water Bottle Debate: Plastic or Metal?

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While students debate prohibiting plastic bottles on campus, disagreement continues for the best method of transporting your water.

Stainless steel water bottles, which have been popularly dubbed as one of the most eco-friendly consumer products, use a large amount of fuel in the creation process. The New York Times reported that manufacturing a 300-gram stainless steel water bottle uses “seven times as much fossil fuel, releases 14 times more greenhouse gases … and causes hundreds of times more toxic risk to people and ecosystems” as compared to producing a 32-gram plastic bottle. These figures take into account the extraction process, manufacturing, distribution, use and disposal of the steel bottle. However, the bottle becomes eco-friendly with repeated use. The Times calculated that when used 500 times, one steel bottle “beats plastic in all the environmental-impact categories studied in a life cycle assessment.”

Chemical leaching is another pertinent problem in reusable bottles because it poses a significant risk to the drinker’s health. Bisphenol A, more commonly known as BPA, is a hotly controversial molecule that has been implicated in several disorders, like heart disease, diabetes, sterility and altered childhood development. BPA is an organic compound that acts as the sex hormone estrogen and is used in the making of polycarbonate plastics, like compact disks, baby bottles and water bottles. Despite reports, there is controversy still over the chemical’s role in declining health. Prof. Geoffrey Coates, chemistry and chemical biology, said, “My personal bias is that until we really know we should act in caution.”

BPA isn’t the only chemical that has been recently investigated. Environmental Health Perspectives published a study earlier this year examining chemical leaching in BPA-free products, concentrating on baby bottles and water bottles. The researchers discovered that, despite not containing any BPA, these products still leach chemicals that mimic estrogen. The study found that more than 70 percent of the products, after being diced and soaked in an alcohol or salt solution, released estrogenic chemicals. More than 95 percent of the tested products released estrogen-like compounds after coming into contact with daily exposures like simulated sunlight, dishwashing, and microwaving.

Finding a replacement for BPA has been a difficult endeavor for researchers, although there are a few viable options.

“There is a replacement for Bisphenol A water bottles and that is a material called Tritan,” Coates said. “It has many of the nice properties of the polycarbonate water bottle, namely that you can drop it on a rock when you’re camping and it doesn’t break. It’s clear, so you can see what’s inside. It has a very high softening temperature.”

Overall, he said, “It’s a great, great material. There have been a few materials that can take the place of Bisphenol A polycarbonate and Tritan is one of them.”

Tritan is an Eastman Chemical creation designed to compete against other polycarbonate plastics in durability, clarity and, significantly, protection against temperature change which can disrupt the polymer building blocks in the plastic and cause leaching. According to an article published Monday Sept. 19 by Chemical & Engineering News, Tritan surpassed Eastman’s expectations, “proving to be more dishwasher-durable than polycarbonate, which tends to develop cracks, called crazing, at molded-in stress points.”

Despite the development of new petroleum-based materials like Tritan and other biobased plastics,  intrigue still surrounds reusable water bottles’ energy consuming production rates and the adverse chemical effects due to leaching. However, Tori Klug ’14, co-president of Cornell’s Sustainability Hub, thinks that these factors should not prevent people from using one and said utilizing a “green” bottle gives “the added benefit of knowing that you are being a more ethical consumer and reducing your negative impact on the world.”

However, living sustainably requires more than purchasing a reusable water bottle, according to Linda Taimina ’12 and Cara Schwartz ’13, co-presidents of Cornell’s Take Back the Tap. Taimina and Schwartz strongly encourage that students purchase reusable bottles and commit to keeping and reusing the bottle so that it “serves its purpose after all.”

“If the bottle is lost or thrown away quickly, the purpose of buying the reusable bottle in the first place was defeated,” Schwartz added.

Original Author: Jessica Harvey