Health and environment: a closer look at plastics
While researchers are still at the early stages of assessing the risks to human health posed by plastics use, negative impacts on the environment have been a growing concern for many years. Over 300 million metric tons of plastics are produced worldwide each year. Roughly 50 percent of this volume is made up of products disposed of within one year of purchase.
Plastics today represent 15-25 percent of all hospital waste in the U.S. Some newer plastics are biodegradeable, but the rest must be incinerated, disposed of in landfills, or recycled. All of these methods have drawbacks and carry environmental risk, as the new study explains.
Biodegradeable plastics may break down in the environment into smaller polymer constituents, which may still pose a risk to the environment. Incineration liberates greenhouse gases associated with climate change. Landfilling of plastics, particularly in the enormous volumes now produced, may be an impractical use of land resources and a danger exists of plastics constituents entering the ground water. Finally, recycling of plastics requires careful sorting of plastic material, which is difficult. Recycled plastics tend to be of lower quality and may not be practical for health care and other applications.
Infographic on dangers of plastics
As Halden explains, the problems posed by plastics need to be addressed on several fronts, and current research offers significant hope for improvements to human and environmental health. Better biodegradeable plastics are now being developed using carbon dioxide and carbon monoxide compounds and applying metal complexes as catalysts.
Plastic recycling can be very confusing. One way to think about the different types of plastic is to compare plastic to fruit. Not all fruit is the same. An apple is not an orange. Not all plastic is the same. Plastic #1 is not plastic #5. Even within the same plastic group there are differences. Consider apples. A red apple is not a green apple. A plastic #2 narrow neck milk jug is not the same as a plastic #2 wide mouth yogurt cup. Keep the value of plastic high by placing only those types that are accepted for recycling in your recycling container.
There are many types of plastic in use. Plastic must be sorted by type for recycling since each type melts at a different temperature and has different properties. The plastics industry has developed an identification system to label different types of plastic. The system divides plastic into seven distinct groups and uses a number code generally found on the bottom of containers. The following table explains the seven code system.
Plastic #1: Polyethylene Terephthalate
Common uses: 2 liter soda bottles, cooking oil bottles, peanut butter jars.
This is the most widely recycled plastic and the only one with redemption value under the California “Bottle Bill.” Many recycling programs and centers request that you remove caps and flatten the bottles.
Plastic #2: High Density Polytheylene
Common uses: detergent bottles, milk jugs, grocery bags.
Most curbside recycling programs accept rigid narrow neck containers. Contact your curbside recycling service provider about whether they take plastic #2 and if containers need to be sorted by color.
Plastic #3: Polyvinyl Chloride
Common uses: plastic pipes, outdoor furniture, shrink wrap, water bottles, salad dressing and liquid detergent containers. Recycling centers rarely take #3 plastic. Look for alternatives whenever possible.
Plastic #4: Low Density Polyethylene
Common uses: dry cleaning bags, produce bags, trash can liners, food storage containers.
Recycling centers rarely take #4 plastic. Look for alternatives whenever possible.
Plastic #5: Polypropylene
Common uses: aerosol caps, drinking straws
Recycling centers rarely take #5 plastic. Look for alternatives whenever possible.
The technique provides a double benefit, binding unwanted greenhouse gases, while avoiding the competition with the human food supply. (Conventional bioplastics are made with plant sources like corn and molasses.) One application would be to replace BPA-containing epoxy resins lining metal food cans, thereby dramatically reducing BPA exposure while also sequestering 180 million metric tons of carbon dioxide (greenhouse) emissions.
The use of disposable items is also undergoing a reevaluation, in light of the potential environmental toll. In some cases, reusable plastic products are gaining ground, and estimates suggest the potential for a 50 percent reduction in medical equipment costs. Almost a quarter of all U.S. hospitals are now using reprocessing to decrease disposable waste.
Nevertheless, the largest source of plastics-related environmental damage stems from the overuse of items whose long-term harm outweighs their short-term benefit. Typically, these are consumer convenience items, often quickly discarded after a short use-life, including plastic water bottles, grocery bags, packaging, Styrofoam cups, Teflon-coated dental floss and other products. Halden recommends a thorough life-cycle assessment of plastics-based products, to identify safer, more sustainable replacement materials that reduce adverse effects to the environment and human health from plastic consumption.
“Many current types and consumption patterns of plastics are unsusustainable, as indicated by harmful plastic components circulating in our blood streams and multiple giant garbage patches of plastic debris swirling in the world’s oceans. Continued use of plastics into the future will require us to redesign these indispensible materials of daily life to make them compatible with human health and the ecosystems we rely on,” says Halden.
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Rolf Halden has been appointed to lead a new effort to protect human health and critical ecosystems, called the Center for Environmental Security (CES) at Ariziona State University. The goal of the Center is to protect human populations and the planet by detecting, minimizing and ultimately eliminating harmful chemical and biological agents through engineering interventions.
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Additionally, Halden is a professor in the Ira A. Fulton Schools of Engineering, School of Sustainable Engineering and the Built Environment, Co-Director of the Center for Health Information Research and Senior Sustainability Scientist at ASU’s Global Institute of Sustainability
Written by: Richard Harth
Science Writer: The Biodesign Institute
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