[Table of contents | Executive Summary | Sections 1 · 2 · 3 · 4 · 5 · Glossary | Tables | References ]
Over the past few years, public and scientific awareness has increased concerning the aesthetic, economic, and biological hazards associated with persistent manmade debris in the aquatic environment. In response to public and Congressional concerns about the debris, the White House Domestic Policy Council formed an Interagency Task Force on Persistent Marine Debris in 1987. The Interagency Task Force (ITF) was chaired by the National Oceanic and Atmospheric Administration (NOAA) with participation by 12 Federal agencies, including the Environmental Protection Agency (EPA). The ITF was directed to "assess the problem and the need for research, identify potential reduction measures, and consider alternative actions to address the problem of plastic marine pollution" (ITF, 1988).
As a result of increased reports of resin pellet ingestion by aquatic wildlife and evidence that the ingested pellets may be harming the wildlife, the ITF identified resin pellets (also known as plastic pellets) as a debris problem that required additional research. These resin pellets are the raw materials from which plastic products are manufactured. When released into the environment, these pellets either may float on or near the water surface, may become suspended at mid-depths, or may sink to the bottom of a water body. Whether a specific pellet floats or sinks depends on the type of polymer used to create the pellet, on additives used to modify the characteristics of the resin (pellet), and on the density of the receiving water. The pellets most commonly found in the environment are composed of polyethylene, polystyrene, and polypropylene (EPA, 1990a). These compounds are also among the most commonly used resins (Pruter, 1987).
The ITF (1988) and others (e.g., Pruter, 1987; Colton et al., 1974; Ryan, 1988b) listed several suspected sources of pellets in the environment including: (1) pellet manufacturers, (2) ships transporting the pellets, (3) pellet processors, and (4) other pellet transportation vehicles. However, evidence was unavailable to support or confirm the importance of the suspected sources. Therefore, discussions of likely sources were limited to suspicions or educated guesses. As a result, one of the recommendations of the Task Force was for Federal agencies to conduct research to determine land-based and water-based sources of marine debris including plastic pellets.
The Task Force did not address whether plastic pellets in the environment and resulting environmental problems were associated with historical releases or were related to current releases. However, in the late 1980s, the Society of the Plastics Industry, Inc. (SPI), had reported that plastic pellets in the environment may have been the result of historical inputs and that the industry had addressed these releases (SPI, as cited in CMC, 1988). In contrast, Heneman (1990) reported a 200% to 400% increase in the numbers of pellets present in the North Atlantic Ocean between 1972 and 1987. In addition, recent results from EPA studies conducted in several U.S. harbors (EPA, 1990b, 1992a,b) found widespread distribution of plastic pellets, most of which were not weathered and were probably released recently. The EPA studies found that
Plastic pellets are present in harbor areas that are inaccessible to cargo ships and other major ship traffic, implying that these vessels are not the only source of plastic pellets in the environment (EPA, 1990b, 1992a,b).
Harbors of cities with older combined sewer overflow (CSO) systems contained significant percentages of pellets in the floatable debris (EPA, 1990b, 1992a,b).
Harbors near known production, transport, and processing centers had higher concentrations of pellets (EPA, 1990b, 1992a,b).
Pellets are present in CSO and storm water outfall discharges and solids collected in sewage treatment facilities (EPA, 1992c).
These findings suggest that the plastics industry remains a likely source of pellet releases into the environment and indicate that significant land-based pellet sources currently exist.
Additionally, in its 1990 Report to the Congress, Methods to Manage and Control Plastic Wastes, EPA identified plastic pellets as an item of particular concern (EPA, 1990a) due to increasing evidence suggesting ecological impacts from these materials. EPA also included an action item to determine the source(s) of plastic pellets to the environment and to evaluate control options.
1.1 Study Objectives
As part of EPA's response to the action item included in the Report to the Congress (EPA, 1990a), a study was initiated to determine possible land-based sources of plastic pellets within the plastics industry, including pellet manufacturers (producers), transporters, and processors. The objectives of this study were to (1) identify and locate possible sources of pellet releases into the environment, (2) evaluate the significance of each source as a pellet release pathway, and (3) recommend mechanisms for controlling or preventing the release of pellets.
To obtain the information necessary to meet these objectives, EPA implemented several investigations. These investigations were to
Review the literature on plastic pellet characteristics.
Summarize pellet producing and processing methods used in the plastics industry.
Determine the procedures used to transport the pellets between the various manufacturing sectors.
Summarize the literature on the environmental effects of plastic pellets when released into the environment.
Conduct site visits to selected facilities in the various sectors of the plastics industry to observe and evaluate all potential release points to the environment and to evaluate the techniques for controlling pellet releases.
Continue marine debris studies in the U.S. harbors.
Evaluate potential sources of aquatic debris into coastal waters.
Maintain an ongoing dialogue with SPI.
This report presents the study findings and recommendations. Included are discussions of the following major topics.
Chemical and physical properties of pellets, including additives and their effects on pellet behavior in the environment (Section 2).
Geographical distribution of pellets and the known and suspected impacts of pellets in the aquatic environment (Section 3).
Generic descriptions of manufacturing and transport operations of each plastics industry sector (pellet producing, transporting/packaging, and processing operations) (Section 4).
Summaries of observations made during the visits to several facilities in each industry sector (Section 4).
Identifications of likely pellet release points in each sector of the industry (Section 4).
Existing regulatory framework and other government and industry efforts to address the pellet problem (Section 5).
Recommendations for controlling pellet releases (Section 5).
1.2 Acknowledgment
The study was completed with the assistance and cooperation of the Society of the Plastics Industry, Inc., which is a major trade organization representing the plastics industry. Information was gathered through discussions at SPI meetings in Washington, DC, and through site visits to seven different companies (two pellet producers, two transporters/packagers, and three processors), which were arranged by SPI in response to a request for voluntary study participants. Information gathered at and supplied by these companies was invaluable to this study.
source: http://www.epa.gov/owow/OCPD/PLASTIC/sect1-.html 12apr03
(February 11, 1997)
[Table of contents | Executive Summary | Sections 1 · 2 · 3 · 4 · 5 · Glossary | Tables | References ]
|
If
you have come to this page from an outside location click
here to get back to mindfully.org |