The Harmful Effects of Plastic on Human Health and the Environment
Design, craftsmanship and environmental impact are important to Jacob Deva Racusin and Ace McArleton, authors of The Natural Building Companion(Chelsea Green Publishing, 2012). This comprehensive guide to integrative design and construction focuses on natural building materials that leave a gentler footprint than current practices. While the industrial development of plastic in many ways made life easier, plastic production impacts every phase of the life cycle. Learn about the harmful effects of plastic on human health and the environment in this excerpt from chapter 2, “Ecology.”
Harmful Effects of Plastic
A sea change in building technology arrived in the 1950s with the “Age of Plastic.” Industrial development of fossil fuels into a wide array of plastics changed formulations in everything from insulation to mechanicals to paint, and plastic is still a ubiquitous component of every building assembly. Unfortunately, the impacts of plastic production in its many forms are heavy in every phase of its life cycle. While there is a common general understanding that plastics have negative ecological associations, a closer understanding of what types of plastics create what types of impacts will empower us to improve the toxic footprint of our buildings.
Plastics are not inherently bad, and they have many redeeming ecological features; in fact, many of the techniques we utilize in our designs involve targeted use of plastic products. Their durability and low maintenance reduce material replacement, their light weight reduces shipping energy, their formulation into glue products allows for the creation of engineered lumber and sheet products from recycled wood, and their formulation into superior insulation and sealant products improves the energy performance of our structures.
The feedstock of plastic is primarily petroleum- or natural-gas-derived, although bio-plastics are making inroads in the overall market share of plastic products. Obvious issues emerge regarding the finite amount of available petroleum resources, as well as the pollution associated with oil extraction and refinement; the massive Gulf Coast oil spill of 2010 is only one of the more notorious of the many ecologically devastating accidents that are not frequently considered in addition to the standard pollution impacts of extraction and refinement, which are extensive.
Toxic chemical release during manufacture is another significant source of the negative environmental impact of plastics. A whole host of carcinogenic, neurotoxic, and hormone-disruptive chemicals are standard ingredients and waste products of plastic production, and they inevitably find their way into our ecology through water, land, and air pollution. Some of the more familiar compounds include vinyl chloride (in PVC), dioxins (in PVC), benzene (in polystyrene), phthalates and other plasticizers (in PVC and others), formaldehyde, and bisphenol-A, or BPA (in polycarbonate). Many of these are persistent organic pollutants (POPs)–some of the most damaging toxins on the planet, owing to a combination of their persistence in the environment and their high levels of toxicity. These are discussed in greater detail later in this chapter as a consideration of human health; however, their unmitigated release into the environment affects all terrestrial and aquatic life with which they come into contact.
It is in the use phase that the benefits of plastics in durability and effectiveness are most evident. Though most plastics are benign in their intended use form, many release toxic gases in their in-place curing (such as spray foam) or by virtue of their formulation (as with PVC additives off-gassing during their use phase). Occupational exposure during installation, such as inhalation of dust while cutting plastic pipe or off-gassing vapors of curing products, is also a great concern for human health and the environment.
The disposal of plastics–the “grave” phase, if you will–is one of the least-recognized and most highly problematic areas of plastic’s ecological impact. Ironically, one of plastic’s most desirable traits–its durability and resistance to decomposition–is also the source of one of its greatest liabilities when it comes to the disposal of plastics. Natural organisms have a very difficult time breaking down the synthetic chemical bonds in plastic, creating the tremendous problem of the material’s persistence. A very small amount of total plastic production (less than 10%) is effectively recycled; the remaining plastic is sent to landfills, where it is destined to remain entombed in limbo for hundreds of thousands of years, or to incinerators, where its toxic compounds are spewed throughout the atmosphere to be accumulated in biotic forms throughout the surrounding ecosystems.
Unfortunately, because of plastic’s low density, it frequently migrates “downstream,” blowing out of landfills and off garbage barges. For decades, marine biologists and researchers had been witnessing increasing amounts of plastic garbage contamination in the ocean. Then, in 1997, as mentioned in the introduction, Captain Charles Moore discovered widespread plastic garbage contamination in an area larger than the state of Texas that had formed within a cyclonic region, called a gyre, in the North Pacific Ocean. By 2005, the estimated area of contamination expanded to 10 million square miles, nearly the size of Africa. Ninety percent of this garbage was determined to be plastic, and 80% was originally sourced from land, such as construction waste–so Captain Moore found where “downstream” goes. Early sampling determined approximately 3 million tons of plastic on the surface; the United Nations Environment Program reports that 70% of marine refuse sinks below the surface, which would suggest a staggering 100 million tons of plastic in this one area of the Pacific alone–with more entering every day. There are six similar gyres across the planet’s oceans, each laden with plastic refuse (Weisman 2007).
The harmful effects of plastic on aquatic life are devastating, and accelerating. In addition to suffocation, ingestion, and other macro-particulate causes of death in larger birds, fish, and mammals, the plastic is ingested by smaller and smaller creatures (as it breaks down into smaller and smaller particles) and bioaccumulates in greater and greater concentrations up the food chain–with humans at the top. Exacerbating these problems of persistence and bioaccumulation is plastic’s propensity to act as a magnet and sponge for persistent organic pollutants such as polychlorinated biphenyls (PCBs) and the pesticide DDT. So, in addition to ingesting the physically and chemically damaging plastic compounds, aquatic life is also ingesting concentrated quantities of highly bioaccumulative compounds that are some of the most potent toxins found on the planet. Again, this bioaccumulation increases in concentration as it works up the food chain and into our diets.
A final consideration of plastic disposal comes from the release of POPs and other toxic chemicals into the environment from the plastics themselves. These compounds present a host of ecological and human health issues and, like plastic, are also bioaccumulative. Polyvinyl chloride (PVC) is particularly noxious, owing to its formulated inclusion of halogenated compounds (those containing bromine or chlorine), and are particularly dangerous if burned, in which case dioxins are produced, some of which are among the most harmful of all human-made compounds. Consider, then, the terrific health liability of exposure through accidental or unwitting incineration or house fire. Halogens are also sourced from a class of flame retardants that are commonly formulated into a variety of plastic products found in the building industry, particularly polystyrene insulation (XPS, EPS); the effects of flame retardants are discussed in the next section. Collectively, these harmful chemicals are known to cause the following severe health problems: cancer, endometriosis, neurological damage, endocrine disruption, birth defects and child developmental disorders, reproductive damage, immune damage, asthma, and multiple organ damage.
While we recognize the need for plastic products in our homes, in light of the tremendous ecological impact throughout plastic’s life cycle, we are compelled to select plastic alternatives when possible. In many cases, we can elect to utilize a different material altogether; examples of plastic alternatives include using straw or cellulose-based insulation in walls and roofs and mineral board insulation below basement walls instead of foam insulation, using wood or cement-board siding or plaster as an exterior finish instead of vinyl, and using clay, lime, or casein-based finishes instead of acrylic or latex paints. In other cases, our best option may be to replace a more toxic plastic, such as PVC, with a less toxic one, such as polyethylene, ABS, or metallocene polyolefin (a newly developed plastic of lesser environmental footprint) pipe instead of PVC pipe, fiberglass instead of PVC window profiles, polyethylene instead of PVC-jacketed wire, or polyester instead of PVC commercial wall coverings. The field of bio-plastics is also growing rapidly. These products have the benefits of being nonpetroleum in feedstock, supportive of the farm sector (although LCA must also evaluate industrialized farming practices), and, perhaps most importantly, biodegradable. Additionally, vegetable oils such as soy have been proven to effectively replace pthalates as plasticizers in PVC, reducing its POP load.
This excerpt has been reprinted with permission from The Natural Building Companionby Jacob Deva Racusin and Ace McArleton, published by Chelsea Green Publishing, 2012.
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