spent 8 days at Caroline Atoll, Kiribati, a remote coral atoll at 

 9°59.09"S, 150° 14.04" W. Neuston sampling of the lagoon 

 water of Caroline Atoll was done using a stationary 102 u. 

 (0.5 x 1 ml neuston net placed in the tidal currents of the 

 entrance to the lagoon. The stationary net was left in position, 

 with the opening facing toward the lagoon, over a 7-day period, 

 during both flood and ebb tides. Also, one additional location 

 in the central lagoon was sampled during two 30-min tows 

 using two neuston nets ( 102 |i) towed alongside an inflatable 

 boat. 



Three different types of sampling methods were used in 

 the open ocean. These included /. surface sampling using a 

 1 x 2-m tucker trawl (in the open position) equipped with a 

 94 u. net; 2. surface sampling with a 102 U. neuston net with a 

 0.5 x 1- m opening; and 3. subsurface water sampling at the 

 pycnocline horizon by deploying and hauling the tucker trawl 

 in the closed position and fishing at depth in the open position. 

 The pycnocline was determined using Soviet equipment 

 installed aboard the research vessel to determine temperature, 

 salinity, and density. Each net apparatus was equipped with a 

 flow meter to determine the linear distance sampled that was 

 later expressed on a surface area basis for surface sampling and 

 a volume basis for sampling at depth. 



Surface water trawls from the ship averages 15 min with 

 half of the rectangular opening of each net below the surface. 

 The tucker trawl was towed off the bow of the ship at speeds 

 between 82.0 and 280.6 cm/s. Neuston trawls were done from 

 the stern of the ship while drifting at speeds from 

 5.4 to 55.0 cm/s. At the end of each tow the sample was 

 removed and passed through a series of acetone/hexane rinsed 

 stainless steel sieves with pore sizes of 4 mm, 1 mm, 500 |i, and 

 106 u to fractionate the sample. Each fraction was examined 

 under magnification for the presence of plastics; marine 

 organisms were separated from the sample for storage. Plastics 

 recovered from the sample were immediately characterized as 

 to size, type (raw pellet, fragments of plastic objects, fishing 

 gear), and frozen in chemically-clean glass jars. 



Chemical Analysis 



All plastics (fragments and pellets) were removed from 

 I lie fractionated sample, weighed, and extracted by shaking the 

 sample three times in separate 5-ml rinses of hexane. Hexane 

 extraction was used to remove nonpolar organics from the 

 surface of the plastics and to avoid chemically dissolving the 

 plastic samples. The extracts were combined and concentrated 

 to a volume of I ml using a stream of dry nitrogen. Sample 

 extracts were analyzed for chlorinated hydrocarbons using a 

 Hewlett-Packard (HP)589()A gas chromatograph equipped 

 with a "'Ni electron capture detector and a 30m DB1 column. 

 An IIP 5890A interfaced with an HP 5970 mass selective 

 detector, in the full scanning mode from 50 to 450 atomic mass 

 units, was used to detect the presence of other halogenated 

 hydrocarbons and petroleum hydrocarbons. 



Plastic Adsorption and Chemical Release Experiment 



1 o assess the possible chemical hazards of plastic to 

 marine life two experiments were conducted. Theseexperiments 

 were designed to evaluate the potential adsorption of organic 



compounds from surface water and to determine if the 

 gastrointestinal environment of birds could cause the release of 

 organic compounds from raw polyethylene pellets. 



To determine the adsorption potential of plastics 

 from surface water, 100 g of new polyethylene pellets 

 were placed in a 1-m-diameter brass-wire mesh enclosure in 

 Baltimore Harbor. Chesapeake Bay. After 24 h. the pellets 

 were collected, handled, and analyzed according to 

 the procedures described above. At the same time the plastics 

 were collected, a sample of the surface microlayer was collected 

 by contact and adhesion of surface water to a glass plate. 

 The plate was dipped repeatedly and rinsed with methylene 

 chloride to obtain a sample volume of approximately 1-1 

 of water from the microlayer. Water microlayer samples 

 were extracted with methylene chloride and analyzed using 

 the same methods as the plastic extracts. The purpose of 

 the microlayer sample was to facilitate the comparison 

 between compounds found in the surface microlayer and 

 what was potentially adsorbed to the plastic pellets. 

 This experiment was conducted to assess the possible 

 adsorption characteristics of plastics under environmental 

 conditions. 



To determine if chlorinated or petroleum hydrocarbons 

 could potentially be released from polyethylene pellets in the 

 digestive system of birds, a simulation experiment was 

 conducted. The experiment was patterned after those of 

 Kimball and Munir ( 1 97 1 ) using a 42 C HC1 bath to simulate 

 the physicochemical conditions in the digestive system of 

 waterfowl. Hydrochloric acid was added to 1 N saline solution 

 to yield digestive solutions with pH"s of 1.4 and 2.8. Two 

 50-g samples of polyethylene pellets were added to glass jars 

 containing either a 1 N saline only (controls). pH 1.4 solutions, 

 pH 2.8 solutions, or a hexane (without saline). These solutions 

 were agitated in a water bath at 42°C. At the end of 8 days, the 

 plastics and the digestive solutions were extracted with 

 methylene chloride and these extracts were analyzed for 

 chlorinated and petroleum hydrocarbons using the methods 

 described above. 



Results and Discussion 



Over 80,000 m : of surface water and 93.000 m 3 of 

 subsurface water were sampled during the course of the 

 expedition (Table 1 ). The total number of stations sampled 

 using either the 947 \i tucker trawl, the 102 |i neuston net. or 

 both at a single location was 28 and 8 for the Pacific Ocean and 

 South China Sea. respectively. Sampling at Caroline Atoll was 

 done at only two locations. Plastics were recovered from 219i 

 of the sample collected in the Pacific Ocean; five of six positive 

 samples contained opaque polyethylene pellets. The sixth 

 sample contained plastic fragments, not raw pellets. The 

 concentration of plastics at positive stations varied considerably. 

 with a maximum of 0. 1 8566 mg plastic/m : (Table 2 1. Although 

 sampling was done along the cruise track from as far north as 

 10°N to as tar south as 10°S. plastics were only recovered from 

 stations near the ION latitude area (Fig. I ). Tar balls were 

 found at only two of the stations sampled in the open waters of 

 the Pacific (Table I). 



194 



