After looking through the papers I’ve read and the notes I’ve written, I realized I have a ton of info about beach debris. Let’s see if I can bang out a couple paragraphs about this issue…
Debris in the Mediterranean Sea: Types, Quantities, and Behavior by Abraham Golik
Distribution, Type, Accumulation, and Source of Marine Debris in the United States, 1989-1993 by Christine A. Ribic, Scott W. Johnson, and C. Andrew Cole
Beach clean up and survey data are invaluable to the marine pollution problem. Items collected on beaches offer scientists the opportunity to observe not only what types of plastic are the most prevalent but also a chance at identifying the source of the debris. Often times, sources are not clear: most plastic debris found is in the form of fragments or has been so photo-degraded that any text or labeling left is illegible. However, if the type of debris can be determined, inferences can be made as to where it came from. For instance, used food packaging materials found on a beach obviously came from a land-based source.
It is important to distinguish between land-based and marine-based sources, as these are the two broad categories used when identifying marine debris. Quantifying what exactly is land-based versus marine is again often difficult (Golik, 1997) but for the terms of this paper, the following definitions will suffice. Land-based sources of marine debris encompass any item originating on-land; marine-based sources, on the other hand will include any item disposed of at sea, whether it be accidentally or on purpose. After going through data for a few regions around the world (major coastlines in the US and the Mediterranean) from the early 1990s, it is abundantly clear that land-based sources were most prominent, with man-made packaging material and miscellaneous items (mostly pre-production plastic pellets) ranking highest among plastic debris.
One study found that quarterly accumulations rates for the three major coastlines of the US (Atlantic, Gulf and Pacific) were 716 pieces/km, 544 pieces/km and 1,729 pieces/km, respectively. One reason why the Pacific Coast had such a high accumulation rate could be due to the fact that the Pacific Ocean is bordered on both sides (east and west) by highly populated areas (Ribic, 1994). The Mediterranean faces a similar problem in that it is an enclosed sea surrounded by 18 countries, and its beaches are some of the worlds largest tourist attractions (Golik, 1997).