Ecological and social costs of single use plastic bags

Seekiefer (Pinus halepensis) 9months-fromtop.jpg
This conservation resource was created by Carmen Kam, Rebecca Li, Brian Ramirez, and Hechuan Wu. It is shared under a CC-BY 4.0 International License.
Don't throw me away - re-use me! By Philip Halling via Wikimedia Commons. CC BY-SA 2.0.

Following the rise of the industrial revolution, single-use plastic bags have become a common household item and appear in nearly every restaurant and store as a convenient way for consumers to carry purchased goods. Plastic bags, however, have been proven to have a major, destructive impact on both the ecological environment and our society. Plastic bags take between 500 and 1000 years to degrade, and the biggest concentration of them in the ocean is twice the area of the state of Texas while also outnumbering sea life a whopping six to one. [1] Due to their shape and structure, many marine creatures fall victim to these plastic bags through entanglement and ingestion. [2] However, ecosystems are not the only victims; humans are also affected by the negative impacts of plastic bags on a gradual basis, evident in the inflated prices of products driven to break even with plastic bag taxes. [3] Nonetheless, with growing environmental concern, more people are taking action in reducing plastic bag use around the world. For instance, California’s Senate Bill 270, a law that bans the use of single-use plastic bags, declares that most grocery stores must not provide customers with single-use plastic bags unless they are made of recycled material, in which case consumers must be charged a minimum of 10 cents per bag. [4] By establishing legal regulations, providing education about the impacts of single-use plastic bags and enacting management practices to limit the usage of them, we can reduce the negative effects they have on the environment and transform societal costs into a symbiotic relationship with the planet.


Plastic Bag Industry

The plastic bag manufacturers simultaneously benefit from the production of plastic bags through financial gain and suffer from the backlash of environmentalists due to the unsustainable aspect of plastic bags. Observing the positive aspect, plastic bag companies bring in over $100 million every year in California alone. [5] In perspective, the companies ironically find it financially beneficial to challenge California’s ban on plastic bags with no expectation of winning just to prolong their sales. [5] The response, however, to plastic bags has grown increasingly negative, and the plastic bag industry has been facing increasing pressure from environmental groups to put production to a halt. One CEO of a plastic bag manufacturing company defends the industry and resents the fact that the plastic bag industry has been “painted as the Great Satan and the evil empire”. [6] The pushback against plastic bags has been so severe that a group called Save the Plastic Bag Coalition was formed which includes a number of plastic bag manufacturers to defend the industry and to retaliate against plastic bag bans. [6] While it may appear that the industry is solely benefiting from plastic bags, the negative effects of plastic bags can also impact the industry’s reputation and social standing within society.

Consumers

Consumers play an important role in the prevalence and persistent usage of single-use plastic bags, although they themselves are often negatively affected by the damage that is wrought upon the environment by the irresponsible disposal of them. Perhaps this is due to the plastic bag being so easy to dispose of that it fits in so well with the capitalist consumer culture and feeds into the toxic approach to material value. Where convenience is of the utmost importance, plastic bags are able to become so popular because once it has been used, it can be thrown away and forgotten as rubbish. As the next plastic bag comes around, the cycle repeats. To be good consumers, we are often encouraged to consume as much as we can, because it is widely viewed that a measure of our wealth is dependent on what we can afford and how much of an excess we have. In fact, plastic bags are frequently used as a symbol for the “throwaway” consumer culture. [7] In a society fixated on consumerism, plastic bags have perpetuated the disposable and wasteful mindset of consumers that helped to create a city of litter and landfills.

Governments have the power to invoke change. By Jebulon via Wikimedia Commons. Public Domain


Government

The role that governments play in the issue of single-use plastic bags is quite significant in the power they hold to enforce policies and legislation regarding the usage of the bags. This is evident by Canberra, Australia’s effective ban against plastic bags which reduced the overall influx of landfill waste by 36%. [8] Moreover, the policy against plastic waste has also been internalized by some Australian citizens who choose to not use plastic bags while grocery shopping even while they are travelling in a different city that has not implemented the ban. [8] When citizens are willing to follow the policy without enforcement and supervision, the ban against plastic bags becomes a part of the institution and makes the policy highly effective. While governments may not be directly affected by the usage of plastic bags, they hold immense power to decrease it and the damage it has on our environment.

Single-use plastic bags cause ecosystem degradation through its negative impacts on marine life, the greenhouse gas emission from the manufacturing process, and its gradual breakdown and release of toxic material. The ecological costs of plastic bags to the environment is detrimental and not justified by their ease and convenience for consumers.

Effects on Marine Life

Plastic debris in the ocean. By Kevin Krejci via Wikimedia Commons. CC BY 2.0.

Many of the plastic bags that consumers dispose of often end up in the ocean where they prove to be an endangerment to marine life through ingestion and entanglement. Ingestion of plastic bags is due to versatile nature of their shape and form and their resemblance to prey which can prove fatal to many marine lives. Turtles are especially susceptible to making this mistake. They are often found washed up on shore, dead with evidence of ingestion of plastic bags that have an uncanny resemblance to jellyfishes as they flow through the waters. [2]

The breakdown of plastic bags can also produce a variety of fragmented pieces that can each resemble a different food source. [2] Because of this, plastic bags have the potential to be ingested by any number of marine organisms in the ecosystem and contribute to a greater bio-accumulation of plastic along the food chain. In addition to ingestion, entanglement is also a majorly devastating role that plastic bags play within the marine ecosystem through choking, abrasions and a debilitated feeding and hunting efficiency. [9] Sea lions are often the victims of entanglement as the handles of plastic bags can evoke their playfulness and curiosity and their necks or limbs may get caught in the loops. [10] This can pose a problem over time as the plastic handles cut into their skin and cause infections, or the extra plastic attached to their body may slow them down and require them to expend more energy to move around. [10] Due to the ambiguous and flexible structure of plastic bags, they hold a significant impact on the mortality and health of marine life.

Effects on the Environment

Plastic bags are abundant in landfills. By Eric Guinther via Wikimedia Commons. CC BY-SA 3.0.

The entire life span of the single-use plastic bag begins its damage on the environment from its manufacturing state and continues onto its “death” in landfills. This can include the air pollution and soil and water contamination from the toxic chemicals it eventually breaks down into. [7] Producing plastic bags involve both inputs and outputs in its process, where the input of resources to create the bags are consumed during production and environmentally detrimental outputs are distributed. This creates an imbalance of a “take and waste” relationship with the environment. It offsets not only the health of the environment, but also the species living within within the ecosystem as well as we take more than our share of the resources from the environment. [11] From the time of its production to its degradation, plastic bags prove to be harmful to the environment.

Greenhouse Gas Emissions

In the manufacturing stage for plastic bags and throughout its life span, there is a high emission of greenhouse gases put into the atmosphere that is then trapped in the air and contribute to climate change. A study estimates that greenhouse gas emissions from the life cycle of plastic bags in Hong Kong and China reach 12.8 kg, which is more than half of its more sustainable counterpart of reusable cloth bags. [12] Interestingly, carbon emission is found to decrease in response to a prolonged life span and usage of the plastic bag. From the same study, they found that even a 5% increased reuse of plastic bags in different countries can result in 22 kg less of greenhouse gas emissions. [13] The effect on the atmosphere of single-use plastic bags is significant issue because of how much greenhouse gas emitted that can be prevented.

Contamination During the Decomposition Process

As the slow degradation of plastic bags begin, toxic chemicals are released in response to climatic factors and contaminate the soil and waters. Heavy metals are often added to the production of plastic bags in an effort to give the bags more durability and colour and often leach out into the environment in response to temperature and sunlight. [14] This means that as the plastic bag tries to break down, the heavy metals come away from the plastic and into the environment. The potential hazardous effects of this is concerning as the leaching of the heavy metals from plastic bags into our waterways can be damaging to the health of organisms and humans alike.

Laysan albatross with plastic filled stomach. By Claire Fackler via Wikimedia Commons. Public Domain.

In addition to the toxic chemicals released during degradation, plastic bags are also unable to fully break down and rather fall apart into smaller and smaller fragments that are unknowingly consumed by many organisms. These fragments can be mixed into the soil, with up to 1.2% of plastic fragments in the soil when a little less than half of the ground is covered by plastic bags. [15] This can be damaging to organisms that are not able to distinguish the plastic from natural food sources. In fact, some soil organism are found to have a decreased weight and increased rate of mortality due to ingestion of these fragmented plastics. [15] Plastic bags prove to be hazardous to the environment because of its hazardous chemical make up and inability to be fully broken down.

In first-world societies, plastic bags are the most used when grocery shopping. From its convenience to its low cost, plastic bags have dominated the post-industrial revolution developing an unsightly reliance on this plastic carrier. Aside from its environmental costs, it intertwines a series of issues, beneficial and detrimental, that are specific to that of the human-race. As plastic bags continue to reign in the realm of convenience, it is creating another layer to the controversy of plastic bag use, varying between job losses and the expenditure of social resources.

Job Loss

Plastic bags are seemingly an inexhaustible source to many consumers. Reliance on the lightweight carrier has shaped our understanding of convenience and practicality. Society has risen to a level where there is an over-reliance on plastic bags. A study done by the National Center of Policy Analysis (NCPA) on grocery stores in Los Angeles demonstrates that bans on plastic bags can have an adverse effect on the business that imposes the ban, whereby sales significantly decrease and inversely promote an increase on surrounding businesses. [16] With the ban in effect, it is difficult for consumers to have incentive to purchase items from stores that cannot conveniently provide a carrier for their groceries. Consumers will often leave to other stores that are willing to give them free, convenient, and disposable bags. As a result, the business will not have sufficient funds to employ many workers which can lead to unemployment for many able workers. Such effects are demonstrated in a NCPA study that found a 10% decrease in employment in stores that actively enforce the plastic bag ban. [16] On a larger scale, if the decreasing need for plastic bags continue, factories manufacturing plastic bags may also require less workers, therefore creating more unemployment that could affect 30,000 people working in these factories across the United States. [16]

Lowering Standards of Living

Increased crime rates. By Skitterphoto via Pixabay. CC 0

Job loss is not only a significant economic impediment, especially to those who have to provide for their families, but it can also cause problems for both the individual and the society. For instance, it can lead to lower rates of volunteering and higher rates of crime due to great amounts of stress and frustration during times of unemployment. [17] Those who are unemployed may turn to stealing in hopes to provide for families or may find themselves in a emotional state that may cloud judgement. As a result of higher rates of crime, the standard of living in the area would decrease and become a place that is not ideal for growth, as it can become a place that exposes the residents to danger that may cause a decline in the desire for families to thrive in the neighbourhood.

Expenditure of Social Resources

Plastic waste in storm drains. By dankeck via Wikimedia Commons. Public Domain.

The increasing use of plastic bags would result in an increasing number of disposed plastic bags, especially within urban life. As such, accumulation of plastic bags may be found in the drains and sewage systems. Cities that have such a problem may have to enforce cleaning teams that are funded by tax money which may not be a wise method of spending of taxpayer money when such funds could be used toward improving livability, such as building schools or infrastructure. [18] Similarly, machinery that is used in the process of recycling can actually contribute to this problem. Many cities and recyclers spend countless dollars and hours in removing plastic bags that are jammed in the plastic-recycling machinery. The extent of this problem is can be demonstrated in a city, San Jose, in which spent nearly $1 million per year on repairing plastic bag related damages. In a similar case, a recycling factory had to close down up to six times a day in order to remove the trapped plastic bags in the machinery. [19]

Switching to Paper Bags

Oji Paper Tomakomai Factory. By pakku via Wikimedia Commons. CC BY 3.0

A great concern entailed with the use of plastic bags is its non-degradable material that affects the environment. As a solution to the problem, paper bags may come into the equation and become a more beneficial alternative to plastic bags. However, it can only be said that the benefits of paper bags do outweigh that of the plastic bags, but the environmental costs of production of paper bags are actually more detrimental. For instance, many people do not factor in the resources required to make paper bags but are only focused on the aftermath of how its disposal affects the environment [13] Paper bags are sourced from paper, which come from the process of logging. As such, in order to even produce the bags would mean that we need to remove the carbon sinks in the ecosystem, thereby destroying habitats of animals. [13] Not only are animals affected, the process of creating pulp from the trees in order to make the paper bags emits plentiful amounts of greenhouse gases due to the burning of fuel for powering machinery and factories. [13] Though paper bags are sourced from a renewable resource unlike plastic bags, the detrimental effects seem to outweigh the results of beneficial disposal.

Using Reusable Bags

Cotton Shopping Bag from Trader Joe's. By Francinegirvan via Wikimedia Commons. CC 1.0.

Likewise, cotton shopping bags may seem like one of the definite solutions in the plastic bag problem. The idea that reusable shopping bags are more environmentally friendly becomes an incentive for consumers to use them as an alternative to plastic. However, studies show that unless the cotton shopping bag is used over 100 times, they are not more environmentally beneficial than plastic bags and could possibly be even more detrimental to the environment. [20] As cotton bags used in grocery shopping are often exposed to raw meats and other produce, bacteria can accumulate, and resources, such as water, are used in order clean and maintain the cotton shopping bags. [20] If the amount practical use does not equate to the use of resources overtime , then it is not justified that cotton shopping bags are a good alternative to plastic bags.

Polluter's Pay Principle

Often, the most effective solution to a problem is driving the one in charge to take responsibility. As such, a solution to the plastic bag problem would be to push toward a polluter pays principle, whereby the one inflicting the environmental harm must take responsibility of their acts and pay for the costs of the activity. In this case, it can be easily achieved by pressuring plastic bag manufacturers to recycle and dispose of their own garbage bags. [21] Not only will this place pressure on the companies in producing less in order to dispose of less, it may bring awareness to the consequences of their production activities. However, it must be noted that this method may often run into complications due the unbreakable plastic that can damage disposing machinery. [19] Nonetheless, it is an approach that can tackle both a sustainable disposing alternative and raising awareness of the detrimental consequences of the product.

Switching to Biodegradable Bags

Biodegradable bags have increasingly become a positive alternative to traditional single-use plastic bags. Typically, these bags can be used to dispose of organic food waste (or other waste) properly in order to diminish the harmful affects of plastic mixed with biodegradable substances. These bags can degrade much faster than traditional plastic which is noted above to take 500 to 1000 years. However, research has shown that biodegradable bags might also be just as harmful to the environment, especially marine life. Studies showed that after six months in exposure to sediment, the bags retained a huge amount of their mass and "reduced sediment pore-water oxygen concentration and pH". [22] The relationship between these bags and the imbalance created in aquatic environments is worth noting in order to create better plans of disposing them properly. The importance of the degradation and recycling processes is just as important as implementing new technologies to protect the environment.

The solution to the problem of disposable plastic bags is a long-term process. The following is addressed to each of the main categories of actors.

Governments

The general ideal the government should hold is simple: anti-plastic bags. First, the government would need to publicize their opposition to plastic bags through public relations social media while following up by issuing a decree restricting the use of plastic bags from free use to paid use. Second, the government can gradually convert the government spending budget for recycling plastic waste into encouraging the use of environmentally safe bags by the public. During this time, the revenue accumulated from purchasing of these bags can be used to fund community-led, environmental cleansing operations and research and development of alternative products. Finally, the government must completely ban the use of disposable shopping bags by a proposed target year. For example, in England, forced plastic bag charges have been implemented for large businesses, but not small businesses. All fees collected are then donated to charitable and environmental protection agencies. [23]

Plastic Bag Industry

The plastic bag industry should respond to the government's call to action by undergoing an industrial transformation while minimizing unemployment. This can be done through the discovery of new technologies and recycling methods that will be more biocentric. The plastic bag industry can also gain additional artistic value through product innovation and new shopping bags through art processing all while maintaining maximum sustainability.

Consumers

People are used to a free plastic bag. However, a switch to paid use of plastic bags will not fundamentally change consumer dependence on plastic bags. Instead, the focus should be on consumers fundamentally understanding the hazards of plastic bags on the entire ecological environment and the need to limit their mass use. This education will help consumers develop the habit of using economically friendly and biodegradable shopping bags.

Plastic bags have become a product humanity has been the extremely reliant on. From groceries to clothing, plastic bags serve as a mean to hold our items conveniently in the most cost efficient way. However, with the use of non-renewable sources to create this product that has been permanently etched into consumerist lives, there comes a series of costs that have a negative effect on our planet and society. From ecological costs such as marine life degradation and greenhouse gas emissions to societal costs such as job losses and social spending's, plastic bags continue to exhaust resources from different sectors. Consumerist attitudes and the role of government regulations becomes one of the most important factors in this debate. The goal of this wiki page is to bring forth such issues into public awareness, providing an outlook on what problem we have at hand and how we can find its solution. In order to solve the problem of plastic bags in our society, we must find a way to provide incentive to consumers to no longer feel the need to use plastic bags. No matter how many non-plastic options institutions put forth, there will always be businesses that will continue to use plastic bags. As a whole, institutions and governments need to work together to find an alternative that is more favourable than that of plastic bags. Such an alternative can also be accompanied by raising awareness on the adverse costs of plastic bags and what society can do to change this issue. With knowledge and incentives, consumers can easily find the drive to stray away from the use of plastic bags.

The analysis of this topic comes to a close in an open-ended conversation. Despite the battling pros and cons of this issue, the most rational solution to combat this situation is to create incentives to decrease the need for plastic bags while creating sustainable job opportunities that can be derived from the absence of these plastic carriers. Higher taxes imposed upon plastic bags should be implemented to penalize unsustainable manufacturing of plastic bags as well as for consumers that choose to use plastic bags. This in turn will hopefully encourage consumers to reuse the plastic bags and prolong the life span of "single-use" plastic bags. Recycling programs can also be set up to make it easier for consumers to recycle plastic bags that have reached the end of their life span should also be created. On the other hand, subsidies can be provided for companies that choose to ban the usage of plastic bags to support the use of more sustainable options like reusable cloth bags. Government regulations and committed action of raising awareness can easily be a step toward these goals. Through responsible disposal and raising awareness of the plastic bag effects, we may be able to win against the plastic bag war and gain our independence from them.

  1. D'Alessandro, N. (2014). 22 Facts About Plastic Pollution (And 10 Things We Can Do About It). EcoWatch. Retrieved 5 February 2018, from https://www.ecowatch.com/22-facts-about-plastic-pollution-and-10-things-we-can-do-about-it-1881885971.html
  2. 2.02.12.2 Moore, C. J. (2008). Synthetic polymers in the marine environment: A rapidly increasing, long-term threat. Environmental Research, 108(2), 131-139. Retrieved April 11, 2018, from https://www-sciencedirect-com.ezproxy.library.ubc.ca/science/article/pii/S001393510800159X
  3. Nilsen, A. (2010). An Economic Evaluation of Plastic Bag Regulation, 1-54. from https://www.duo.uio.no/bitstream/handle/10852/16927/FINALCOPY.Sept.24.8amAndersNilsenThesis.pdf?sequence=1
  4. Ban on Single-Use Carryout Bags (SB 270 / Proposition 67) Frequently Asked Questions. (2018, January 12). Retrieved April 12, 2018, from http://www.calrecycle.ca.gov/plastics/carryoutbags/FAQ.htm
  5. 5.05.1 Matier, P., & Ross, A. (2015, March 1). Plastic bag industry profits as it faces tough battle over ban. San Francisco Chronicle. Retrieved April 12, 2018, from https://www.sfchronicle.com/bayarea/matier-ross/article/Plastic-bag-industry-profits-as-it-faces-tough-6109021.php
  6. 6.06.1 Verespej, M. (2009). Plastic bag industry in flight of its life, learning to cope with pressure groups. Plastics News,21(2), 16-18. Retrieved April 12, 2018, from http://web.b.ebscohost.com.ezproxy.library.ubc.ca/ehost/detail/detail?vid=0&sid=759db2f5-12b0-40e1-9f1d-d1f4b741dda5@sessionmgr102&bdata=JnNpdGU9ZWhvc3QtbGl2ZSZzY29wZT1zaXRl#db=8gh&AN=37559183
  7. 7.07.1 Ritch, E., Brennan, C., & Macleod, C. (2009). Plastic bag politics: Modifying consumer behaviour for sustainable development. International Journal of Consumer Studies, 33(2), 168-174. Retrieved April 12, 2018, from http://web.b.ebscohost.com.ezproxy.library.ubc.ca/ehost/pdfviewer/pdfviewer?vid=1&sid=c4634131-7956-4030-b1c1-be9b93343b8d@sessionmgr101
  8. 8.08.1 Waste360 Staff. (2017, April 11). The Impact of Canberra, Australia's Plastic Bag Ban. Waste 360, p. 1. Retrieved April 12, 2018, from http://web.a.ebscohost.com.ezproxy.library.ubc.ca/ehost/detail/detail?vid=0&sid=1da8f548-c8b6-40ec-8118-a6cf0c44e67c@sessionmgr4008&bdata=JnNpdGU9ZWhvc3QtbGl2ZSZzY29wZT1zaXRl#AN=122443005&db=8gh
  9. Sigler, M. (2014). The Effects of Plastic Pollution on Aquatic Wildlife: Current Situations and Future Solutions. Water, Air and Soil Pollution, 225(11), 1-9. Retrieved April 11, 2018, from https://search-proquest-com.ezproxy.library.ubc.ca/docview/1628460563/fulltextPDF/7C2C3E90F9B2441CPQ/1?accountid=14656.
  10. 10.010.1 Li, W. C., Tse, H. F., & Fok, L. (2016). Plastic waste in the marine environment: A review of sources, occurrence and effects. Science of The Total Environment, 566-567(1), 333-349. Retrieved April 12, 2018, from https://www-sciencedirect-com.ezproxy.library.ubc.ca/science/article/pii/S0048969716310154?_rdoc=1&_fmt=high&_origin=gateway&_docanchor=&md5=b8429449ccfc9c30159a5f9aeaa92ffb.
  11. Nilsen, A. (2010). An Economic Evaluation of Plastic Bag Regulation(Master's thesis, Thesis / Dissertation ETD, 2010) (pp. 1-74). Oslo: University of Oslo. Retrieved April 12, 2018, from https://www.duo.uio.no/bitstream/handle/10852/16927/FINALCOPY.Sept.24.8amAndersNilsenThesis.pdf?sequence=1.
  12. Muthu, S. S., Li, Y., Hu, J. Y., & Mok, P. Y. (2011). Carbon footprint of shopping (grocery) bags in China, Hong Kong and India. Atmospheric Environment,45(2), 469-475. Retrieved April 12, 2018, from https://www-sciencedirect-com.ezproxy.library.ubc.ca/science/article/pii/S135223101000840X#!
  13. 13.013.113.213.3 Muthu, S. S., Li, Y., Hu, J. Y., & Mok, P. Y. (2011). Carbon footprint of shopping (grocery) bags in China, Hong Kong and India. Atmospheric Environment,45(2), 469-475. Retrieved February 8, 2018, from
  14. Alam, O., Billah, M., & Yajie, D. (2018). Characteristics of plastic bags and their potential environmental hazards. Resources, Conservation and Recycling, 132, 121-129. Retrieved April 12, 2018, from https://www-sciencedirect-com.ezproxy.library.ubc.ca/science/article/pii/S0921344918300375.
  15. 15.015.1 Hodson, M. E., Duffus-Hodson, C. A., Clark, A., Prendergast-Miller, M. T., & Thorpe, K. L. (2017). Plastic Bag Derived-Microplastics as a Vector for Metal Exposure in Terrestrial Invertebrates. Environmental Science & Technology,51(8), 4714-4721. Retrieved April 12, 2018, from https://pubs-acs-org.ezproxy.library.ubc.ca/doi/ipdf/10.1021/acs.est.7b00635.
  16. 16.016.116.2 Caliendo, H. (2013, February 6). The economic effect of plastic bag bans. Retrieved from https://www.plasticstoday.com/content/economic-effect-plastic-bag-bans/35843076718443
  17. Simpson, S. D. (2017, May 5). The Cost of Unemployment to the Economy. Retrieved from https://www.investopedia.com/financial-edge/0811/the-cost-of-unemployment-to-the-economy.aspx
  18. Boyle, L. K. (2015, May 21). Plastic Pollution: A Social Justice Perspective. Retrieved from https://www.huffingtonpost.com/lisa-kaas-boyle/plastic-pollution-a-socia_b_7184298.html
  19. 19.019.1 C. (n.d.). California's Statewide Single-Use Plastic Bag Ban. Retrieved from https://www.cawrecycles.org/the-problem-of-plastic-bags/
  20. 20.020.1 Bourne, R. (2014, June 7). Plastic bags – why should we care? Retrieved from https://iea.org.uk/blog/plastic-bags-–-why-should-we-care
  21. Tattrie, J. (2018, January 21). Plastic debate bags the question: What to do with all our junk? Retrieved from http://www.cbc.ca/news/canada/nova-scotia/plastic-debate-bags-the-question-what-to-do-with-all-our-junk-1.4496435
  22. Balestri, E., Menicagli, V., Vallerini, F., & Lardicci, C. (2017). UBC Library | EZproxy Login. Www-sciencedirect-com.ezproxy.library.ubc.ca. Retrieved 11 April 2018, from https://www-sciencedirect-com.ezproxy.library.ubc.ca/science/article/pii/S0048969717316698
  23. Smithers, R. (2016, July 29). England's plastic bag usage drops 85% since 5p charge introduced. Retrieved April 13, 2018, from https://www.theguardian.com/environment/2016/jul/30/england-plastic-bag-usage-drops-85-per-cent-since-5p-charged-introduced
source: http://wiki.ubc.ca/Course:CONS200/Ecological_and_social_costs_of_single_use_plastic_bags_and_what_can_be_changed

Post image:  By Philip Halling via Wikimedia CommonsCC BY-SA 2.0.