Human impacts of the garbage patch 

 

Chemical exposure

            About 10% of plastic in the ocean is nurdles, pre-production plastic pellets about 5 mm in diameter.[1] Harmful chemicals that aren’t water-soluble cling to the nurdles. The small size and high surface area-to-volume ratio makes nurdles exceptionally efficient carriers for chemicals.[2] For example, bisphenol A (BPA), an estrogen-related compound, sticks to nurdles and has been linked with feminization of male sea creatures. 

            Bisphenol A is an industrial chemical used primarily to make polycarbonate plastic and epoxy resins found in bottles and metal based food and beverage cans. It has been used since the 1960s[3] . BPA can act on human tissues even when it is undetectable in serum. Unlike natural hormones, BPA is not bound by serum protein-binding globulins. This leaves it free in the bloodstream to act on tissues[4].   Human consumption of animals exposed to BPA and other nurdle-borne chemicals is an obvious hazard to human health.

            As previously stated, chemicals are attracted to nurdles due to their high surface area. Therefore, the concentration of chemicals such as polychlorinated biphenyls on a nurdle may be a million times the concentration in the surrounding water. Blood levels of PCBs in humans correlate with the amount of fish consumed. Because the general population consumes low levels of fish compared to other meats, PCB exposure through this route is minimal. However, prenatal exposure to PCBs can lead to impaired neurological development[5]

    Nurdles are a a frighteningly efficient means of chemical transfer via ingestion. While plastics absorb contaminants more readily than water and sediment, sediment releases contaminants much more quickly than plastics. A study of small marine organisms showed that organisms at the bottom of the food chain, when exposed to chemical-impregnated plastic, showed increases in tissue concentrations of that chemical. Naturally predators (like us humans) will have higher concentrations of the chemicals found in their prey’s flesh, leading to a concentration of pollutants.[6]  Further studies need to be performed on the extent of the impact on humans from chemical exposure secondary to ingestion of contaminated fish.  However, it is clear that a potential exists that these chemical could be causing us great harm.

 

Economic cost

            Countries within and bordering the Pacific Ocean are suffering great economic impact from the garbage patch. Marine debris causes economic harm through direct economic costs, indirect economic costs, and non-market values. A direct economic cost is the damage done to fishing vessels by floating garbage. The impact of ocean plastic on fish and humans eating those fish is an indirect economic cost. Non-market values include the impact of garbage-strewn beaches on tourist dollars. Marine debris cost Asia-Pacific Economic Cooperation (APEC) member countries $1.265 billion in 2008. [7]      Fishing, shipping, and tourism industries bore the brunt of these economic costs. In 2007, a phenomenon known as “ghost fishing,” entanglement of marine life in garbage, killed $250 million worth of lobsters. Shipping vessels may lose a propeller when it becomes caught in garbage. Annual damage to fishing equipment and private boats is worth $800 million. Tourism suffers lost tourist dollars but also added costs of cleanup. In the United States, beach litter incurs $28 million in annual costs to the tourism industry. Taken together, the APEC countries suffer $622 million in annual tourism losses due to marine debris. Cleanup cost ranges from less than $100/ton for volunteer labor to $25,000/ton for repair of fishing gear and mechanical debris removal. Of course, cleanup is more expensive than prevention. [4]



[1] CDNN. (2007). Plastic Ocean: The Great Pacific Garbage Patch. Retrieved on November 6, 2010 from http://www.cdnn.info/news/article/a071104.html

[2] Barnes DK, Galgani F, Thompson RC, Barlaz M. (2009). Accumulation and fragmentation of plastic debris in global environments. Philos Trans R Soc Lond B Biol Sci. 364(1526):1985-1998.

[3]Update on Bisphenol A fr Use in Food Contact Applications: January 2010. Retrieved on November 29, 2010 from http://www.fda.gov/newsevents/publichealthfocus/ucm064437.htm

[4] Welshons WV, Nagel SC, vom Sall FS. (2006). Large Effects from Small Exposures. III. Endocrine Mechanisms Mediating Effects of Bisphenol A at Levels of Human Exposure.  Endocrinology.  147(6):s56-s69. 

[5] Committee on Nutrient Relationships in Seafood: Selections to Balance Benefits and Risks. (2007). Health Risks Associated with Seafood Consumption. In M.C. Nesheim and A.L. Yaktine (Ed.), Seafood Choices: Balancing Benefits and Risks. (pp. 121-194). Washington D.C.: National Academies Press.

 

[6] Teuten EL, Rowland SJ Galloway TS, Thompson RC. (2007). Potential for Plastics to Transport Hydrophobic Contaminants. Environ Sci Technol. 41(22):7759-7764.

[7] Asia-Pacific Economic Cooperation. (2009). Understanding the Economic Benefits and Costs of Controlling Marine Debris In the APEC Region. Retrieved November 7, 2010 from http://publications.apec.org/src-browsegroups.php?groupselected=Marine%20Resource%20Conservation%20Working%20Group%20%28MRCWG%29&groupid=30

[8]Image retrieved on November 10, 2010 from http://reference.findtarget.com/search/Marine%20debris/

[9]Image retrieved on November 10, 2010 from  http://www.coastal.ca.gov/ccbn/images/propeller.jpg

[10]Image retrieved on November 10, 2010 from http://www.alexhoffordphotography.com/node/2300?page=3