2.5 Quantity and Distribution of Plastics: 

 An Analysis of Chemical Hazards to 

 Marine Life 



GREGORY J. SMITH' and CHARLES J. STAFFORD ; 



"Wildlife International Ltd., Easton, Maryland, USA 



f US Environmental Protection Agency, Analytical Chemistry Laboratoiy, Beltsville, Mankind. USA 



Introduction 



In recent years, plastics in the marine environment have 

 been recognized as important pollutants of marine ecosystems 

 (Laist, 1987; Prater, 1987; Wolfe, 1987). Medical waste, 

 plastic debris, and other types of refuse have washed ashore on 

 Atlantic Coast beaches at alarming rates. These events have 

 created new public awareness of the critical nature of the 

 plastic waste disposal. Plastics present a unique disposal 

 problem because the same attributes that make many types of 

 plastics useful also enhance their longevity and buoyancy in 

 the world's oceans. 



The distribution of plastics has been studied in various 

 estuarine. coastal, and oceanic waters of the world. 

 Concentrations of plastics in surface waters have been associated 

 with oceanic convergence zones or the proximity to shipping 

 lanes (Colton et ai. 1974; Wong et ai. 1974; Wolfe, 1987). 

 Although the distribution and abundance of plastics in the 

 oceans have been studied almost exclusively in surface water, 

 it is well known that many types of plastics do not float and 

 must occur in marine sediments (Shaw, 1977). Gradual sinking 

 of those plastics that do float is also possible as bacteria, 

 diatoms, hydroids. and other marine life grow on the surface of 

 floating plastics (Carpenter et al., 1972; Colton et ai. 1974; 

 Winston, 1982). Morris (1980) indicated that floating plastics 

 gradually sink to the bottom or to a denser horizon where they 

 attain neutral buoyancy and remain in suspension. Because the 

 stratum of the pycnocline represents a marked change in water 

 density, this would appear to be a likely area for subsurface 

 accumulation of plastics with the appropriate neutral buoyancy. 



Potential adverse effects of plastics in the marine 

 environment include aesthetic, physical, and chemical. Clearly, 

 floating plastic debris or litter that occurs on beaches is visually 

 unpleasant. Physical impacts of plastics have been well 

 documented. Entanglement and ingestion of floating plastics 

 by sea turtles have been found in several areas (Balazs, 1985; 

 Carr, 1987). Fish have been found to ingest plastic pellets 

 (Carpenter et ai. 1972), as have seabirds (Connors & Smith, 

 1982;Furness, 1985; Day & Shaw, 1987; Fry etai. 1987). In 

 several studies seabirds were found to have consumed massive 

 quantities of plastics (Day et al.. 1985: Furness. 1985; Fry 

 etai, 1987; Ryan. 1987). The physical ingestion of plastics has 

 been detrimental with respect to causing digestive system 

 impaction, ulcerative lesions, and reducing meal size 



(Day etai. 1985; Fry etai. 1987; Ryan, 1988a). However, 

 there continues to be much speculation regarding the potential 

 chemical hazards of plastics to seabirds and other marine 

 organisms. 



Raw plastic pellets have generally been considered to be 

 biologically inactive, although manufactured plastics often 

 contain additives known to be toxic (van Franeker, 1985). 

 Moreover, since Carpenter et al. (1972) published the first 

 account of polychlorinated biphenyls (PCB's) adsorbing to 

 plastic spherules in seawater. there has been concern for the 

 potential for PCB exposure to fish and wildlife that ingest 

 plastics. Ryan et al. ( 1988b) found evidence to suggest that 

 seabirds assimilated PCB's from ingested plastic particles. 

 However, Fry etai ( 1 987 ) suggested that plastics were unlikely 

 to pose a significant toxic hazard to birds compared to the 

 physical impaction effects that may result. Polychlorinated 

 biphenyls are commonly found in certain types of plastics and 

 the potential for plastics to adsorb PCB's from ambient water 

 would suggest two possible sources of PCB contamination 

 from marine plastics. One potential source would be intrinsic: 

 PCB's incorporated into the plastic during manufacturing. A 

 second source, extrinsic, represents PCB' s adsorbed or absorbed 

 from contaminated water. To date, there is still little known 

 about the association of environmental contaminants occurring 

 both in and on plastics in the marine environment and their 

 potential toxic hazard to marine organisms. 



In this paper we report the abundance and distribution of 

 plastics in areas of the central Pacific Ocean and the South 

 China Sea. Both surface water and water at the level of the 

 pycnocline were sampled. Chemical extractions of the plastics 

 recovered were analyzed for several organic pollutants and 

 subsequent field and laboratory experiments were conducted 

 to elucidate potential toxic hazards that plastics may pose to 

 fish, seabirds, and other marine organisms. 



Methods 



Field Sampling 



Sampling was conducted during the Third Joint 

 US-USSR Bering & Chukchi Seas Expedition to the two seas 

 and the central Pacific Ocean, along the segment from Hawaii 

 to Singapore. Trawls for plastics were made from 15 September 

 to 30 October 1988, along the 18,400-km cruise track of the 

 Soviet R/V Akademik Korolev. During the cruise, the vessel 



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