TABLE 2 



PAH le\cls in particular media of the Caroline Atoll ecosystem 

 (September 1988). 



Medium Units Py BaA Bnf BkF BaP Bep 



Cm- 



Water, surface ng/1 qualitatively tr. 



>5 0.90 0.21 ir. 



06 



2 



(b) 



n 



n 



BaA BbF BkF BaP 



BaA BbF BkF BaP 



Fig. I PAH levels lu/kgi in henlhic sand of lagoons V (a) and 111 (hi "I 

 Caroline Atoll (September 1988) 

 |1 egend:] A = PAH level, u/kg. 



1.0 



u 0.5 

 X 



< 



a. 



1 

 



(a) 



(b) 



n 



n 



Py BaA BbF BkF BaP BeP 



Py BaA BkF BaP 



i l ontentol PAH's (ng/1) and their distribution (in percent bj weight) 



in the surface (0 0.5 m) layer ol watei (a) and inasuspension(b)drawn 

 from a depth <>i 90 m ofl Caroline \toll (September 1988) 

 [Legend:! A = I>AII level, ng/1 



Tropical Pacific 



Polycyclic aromaitc hydrocarbon levels in the surface 

 w aters were not high. In the open ocean, the total concentrations 

 ranged from 0.8 to 43.8 ng/1, with a maximum of 396.6 ng/1 in 

 the Marianas sector. The composition and distribution of the 

 PAH's identified in the surface waters of the open ocean 

 indicated that the main compounds present were the following 

 five-ring carcinogens (in percent by weight): BbF. 86.3: BkF, 

 1 1 .0; BaA and Chr. 1 .2; BeP. 1 .0; BaP. 0.5: and IPy was present 

 qualitatively. 



The total PAH's present in the waters of the Marianas 

 sector were 1 to 1 00 times higher in concentration than in the 

 open ocean. The dominant compounds were four- and five- 

 ring PAH's ( in percent by weight), namely BaA and Chr. 38.7; 

 BeP, 35.2; andpyrene(Py), 22.7. TheBbFandBaPconstnuted 

 3.2% and 0.2% by weight, respectively. 



In areas where PAH levels in the water were below the 

 sensitivity threshold of the liquid chromatography technique 

 employed, a more sensitive method for just BaP was employed. 

 Benzol a (pyrene is useful as a representative tracer of other 

 PAH's (analytical methods described in Irhae/o/.. 1992). The 

 following BaP levels were noted: up to 0.58 ng/1 in the open 

 ocean and up to 1.36 ng/1 in the Marianas sector. 



Unlike the surface layer of water, suspended matter sampled 

 in the tropical Pacific was found to contain as many as 10 lour- 

 to six-ring PAH's. All samples taken at depths of 0, 20. 58, 80. 

 1 30. and 200 m contained the PAH's IPy, BaA, Chr, BbF. BkF, 

 and BaP. the dominant ones being IPy and BaA. which accounted 

 for 30-99% and 30-50%. respectively, of the total amount 

 present. In certain instances, suspensions from \ arums depths 

 also contained IPy and benzo(g,h,i)perylene ( BPen. 



Bottom sediments of the tropical Pacific were found to 

 contain only three kinds of four- and five-ring PAH's. namely 

 BaA, BbF. and BaP. with the total PAH content not exceeding 

 4.5 Ug/kg. The dominant PAH (by weight) was BbF, which 

 accounted for 93% of the total amount of PAH's present. 

 Although the composition of PAH' s in the bottom sediments of 

 the Marianas sector of the Pacific was similar. IPy and BbF 

 were the dominant PAH's (50.7% and 47.3' - . respectively, of 

 the total weight of PAH's present). 



South China Sea 



Polycyclic aromatic hydrocarbon levels in the waters of 

 the South China Sea were much higher than in the open ocean 

 and in the Marianas sector (Table 3). The total amount of 

 PAH's in the water \ aried w idel) : the PAH mixture identified 

 in the surface microlayer consisted largely of four- and five- 

 ring PAH's (in percent by weight): BeP. 45.5: BaA and Chr. 

 28.7: Py . 24.6; BbF, 0.9; and BaP. 0.2. Their weight ratios and 

 composition in the surface layer were somewhat different 

 (Table 3 ). moving tow aids increased fractions of BaA and Chr. 

 and BeP. Considerably higher levels of PAH's. by weight. 

 were delected in the benthic portion of the water column, the 

 dominant I> All being BbF (Table 3). 



In those sea areas where the PAH level fell below the 

 analytical detection limit, the BaP level did not exceed 

 1.58 ng/1. 



184 



