Specific environmental issues related to the polymer-related industry have been raised from time to time by the general public as well as the scientific community. More often than not, the quantitative data that supports the concerns and estimates the magnitude of the impacts have not been available. Consumer interest in plastic-related environmental concerns, however, continue to increase. This has unfortunately lead to the inaccurate information and indefensible arguments in the press (and at times even in technical literature34). A newspaper article,35 for instance, may question the recyclability of plastics, or speculate on the hundreds of years that polymers take to degrade in the soil environment. Surprisingly, the plastics industry has done little to educate the public and to promote an unbiased technical discussion on the environmental stature of plastics. It is crucial for the plastics industry of the future to play a much larger, more emphatic, role in public education and dissemination of unbiased technical information relating to the industry. All criticism leveled against plastics as a material, however, is not unjustified; several valid, concerns relating to plastics and the environment do exist.
Environmental issues of today are conveniently discussed within two broad classes; global issues and regional or local issues. Table 1.2 summarizes the various issues in each category that impact the polymer industry. The following discussion examines each of these environmental concerns in an effort to understand the extent to which the plastics industry potentially contributes to it. Serious environmental problems that do not involve the polymer industry directly, such as the loss of biodiversity or the increase in urban population density, are excluded from the present discussion.
34 In Plastics: The Making of a Synthetic Century by Stephan Fenicell, Harper Business (1996), the author makes the incredible statement "plastics owe its bad rap and its bad rep to the undeniable fact that so many of its most fundamental applications are so chintzy and sleazy."
35 San Francisco Bay Guardian, 02-28-1996, "Epicenter: The Plastics Inevitable," by Leighton Klein: "... so producing plastic requires the constant extraction of oil, coal, and natural gas. Repairing anything made of plastic is nearly impossible, and the notion of recycling it is a robust fallacy at best."
Table 1.2 The Major Global Environmental Issues and their Relevance to the Plastics Industry
Relevance to Plastics
1. Depletion of fossil-fuel energy and raw-material resources
2. Global Warming
Use of fossil fuels as a source for energy as well as raw materials
The release of greenhouse gases such as C02, methane, NO* and CFC's into the atmosphere
1. Contributing to future energy crisis
2. Contributing to future shortage of critical raw materials
1. Direct health impacts due to increased temperature.
2. Sea-level rise and possible displacement of populations
3. Unstable weather conditions
4. Increase in vector-borne and infectious diseases
5. Loss of agricultural productivity.
Polymers are synthesized for the most part from fossil fuel resources such as crude oil.
But the resource consumption by the industry is relatively small (less than about 4%).
All industries, including the plastics industry release some greenhouse gases. Polymer industry does not produce a disproportionate share of the emissions.
Table 1.2 (continued)
Environmental Issue Identified Cause Effects Relevance to Plastics
3. Depletion of stratospheric ozone
4. Acidification of the environment
Release of ozone depleting substances (ODS) such as CFCs and CHFCs into the atmosphere
Acidic gas (NOx and SOx) release mainly from the burning of fossil fuels
Depletion of the ozone layer results in higher levels of UV-B radiation reaching the earth's surface. Following consequences are reported.
1. Higher incidence of skin and eye damage due to increased UV-B radiation
2. Other impacts on human health
3. Changes in agricultural productivity as well as marine and in fresh water ecosystems.
4. Possible changes in the bio-geochemical cycles.
1. Damage to freshwater ecosystems including inland fisheries.
2. Impairment of the fertility of agricultural soil due to acidic leaching.
3. Crop and forest damage by direct acidification and biotoxicity due to solubilized metals
Plastics industry in the US does not use any significant levels of CFCs. Worldwide the use of HCFCs in plastic foams is also being phased out.
Polymer industry uses fossil fuels, but not at a disproportionate level The incineration of PVC has been claimed to result in the release of HC1 into the environment contributing to acidification. But this is considered a negligible contribution to acidification.
Table 1.2 Major Regional or Local Environmental Issues and their Relevance to the Plastics Industry
Relevance to Plastics
1. Solid Waste
2. Urban litter
Municipal solidwaste (MSW) stream grows each year. The plastics waste content of MSW is small, but it is not biodegradable.
Disposable products, particularly plastic and paper packaging materials, are not disposed of properly by the consumers.
1. Lack of sufficient landfill space requiring transportation of waste over long distances.
2. Possible contamination of potable water supplies by leachate.
3. Need to explore alternative solid waste disposal strategies
1. Negative aesthetic impact in urban areas.
2. Pollution of the world's oceans due to at-sea disposal of plastic waste
3. Some products pose a hazard to marine mammels, reptiles and birds.
4. Wash-up on beaches of improperly disposed medical waste.
Polymers represent only about 8% by weight of the MSW stream. The non biodegradability of plastics in a landfill is not particularly a disadvantage.
Litter is a real problem in urban areas. Some plastic products such as non photodegradable varieties of six-pack yoke or even plastic bags are can pose a danger to marine life. Resin prills entering the ocean during transport is also claimed to create a hazard to birds who feed on them.
(continued overleaf )
Table 1.2 (continued)
Relevance to Plastics
4. Hazardous air pollutants
Volatile organic compounds (VOCs) emitted from solvents, paints and adhesives.
Industrial processes emit volatile chemicals. These include some of the VOCs mentioned above.
1. Creates urban smog which is unsightly and presents a health hazard.
1. Negative health effects from overexposure to these chemicals
Solvents used in the polymer industry and in applications such as paints and adhesive formulations can contribute significantly to the problem of urban smog. This is particularly true in regions with high solar UV levels.
1. Solvents in paints and adhesive systems include HAPs.
2. Monomers can often be HAPs.
3. In thermoset systems or in-situ polymerization technologies, a small fraction of HAP reactants might be released to the environment.
4. HAPs (in this case dioxins) are claimed to be created in the incineration of polymers such as PVC.
• Global Concerns These environmental problems have adverse impacts that are felt far beyond the location where environmental mismanagement occurs. Their effects are transnational and can even threaten the very survival of global ecosystem in the long term. Issues such as global warming or the stratospheric ozone layer depletion fall into this category. Addressing problems in this category is complicated by the fact that the multiple perpetrators (or the polluters) are not always readily discernible. Resolution of these requires an international effort, nations acting in concert toward a common goal to ensure the rights of future generations.
• Local and Regional Concerns The more familiar environmental problems have to do with local or regional impacts of pollution such as the release of toxic chemicals into the environment, management of municipal solid wastes, or the disposal of spent nuclear fuel. The impact of these problems is generally limited to specific geographic regions and often results in short-term consequences to a well-defined population. The polluters are generally easy to identify and legislative or other remedies are available to address these types of issues.
The two categories might be further subdivided into environmental concerns with long-term and short-term implications. This two-dimensional approach allows the additional dimension of time to simple geographic categorizations of environmental impacts such as that by Hauschild and Nuim . This yields an interesting matrix of environmental problems in which the cells are differentiated in terms of testability of hypotheses and by the perception of severity of the problem. Testing as used in the matrix refers to field experimental verification of hypothesis that address the causes, impacts, and mitigation of the environmental problems. Examples of each type are given in parentheses.
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