2.2 Distribution of Polycyclic Aromatic 

 Hydrocarbons 



EHA R. URBAS. NATALYA I. IRHA, and UVE E. KIRSO 



Chemistry Institute of the Estonian Academy of Sciences, Tallinn, ESSR 



Introduction 



Three distinct regions (Caroline Atoll, tropical Pacific and 

 South China Sea) during the First Joint US-USSR Central 

 Pacific ( BERPAC) Expedition were sampled and analyzed for 

 polycyclic aromatic hydrocarbons (PAH's). Methods for 

 collection and analyses are described in Distribution of PAH's 

 ( Irha et al. , 1 992) in Results of the Third Joint US-USSR Bering 

 & Chukchi Seas Expedition (BERPAC), Summer 1988 (Nagel, 

 1992). The regions that were sampled are identified in the 

 Frontispiece to this volume. 



Polychlorinated aromatic hydrocarbons are important 

 natural and anthropogenic contaminants of marine ecosystems. 

 These compounds are associated with petroleum pollution, 

 including natural oil seepage, and with industrial contamination 

 and many exhibit carcinogenic and mutagenic properties. In 

 this paper, the presence and quantity of PAH's in both biotic 

 and abiotic components of tropical Pacific ecosystems is 

 reported. 



Results 



Caroline Atoll 



Determinations were made of the composition and 

 distribution of PAH's (Table 1 ) present in water and marine- 

 organism suspensions sampled in inshore waters off the atoll, 

 as well as in the following media: bottom sand, island soils, 

 corals, and siphonales algae. The findings (Table 2) indicated 

 that the PAH pollution of this ecosystem was negligible. There 

 were no PAH's in samples of surface sand from the atoll, and 

 the soils taken from a palm tree forest area showed PAH levels 

 below background. 



The total PAH content of coral samples did not exceed 

 9.6 |ag/kg of dry weight. The following representatives of 

 four- and five-ring PAH's were detected: benzo(e)pyrene 

 (BeP), 62.5; indeno( l,2,3-cd)pyrene (IPy), 23; benzo(a)pyrene 

 (BaP). 14.5 (in percent by weight). 



The benthic sand of the atoll lagoons contained four- and 

 five-ring PAH's (Table 2); the major constituents (in percent 

 by weight of the total amount of PAH's present) were 

 benzo(b)fluoranthene (BbF), from 38.7 to 53.6%; and BaP, 

 from 16.8 to 36.6% (Fig. 1). 



The surface waters off the atoll contained six four- and 

 five-ring PAH's, whose total amount did not exceed 

 1.55 ng/1, the dominant constituents being the five-ring 

 carcinogens BbF and BaP (Fig. 2). Suspended matter sampled 



at a depth of 90 m included four kinds of four- and five-ring 

 PAH's, whose total concentration was 0.68 ng/1, with the four- 

 ring IPy and benz(a)anthracene (BaA) predominating (Fig. 2). 



The total PAH level in the gills of Mexican (northern red, 

 Pensacola) snapper {Lutjanus campechanus) specimens was 

 moderate, amounting to 0.08 |ig/kg; the corresponding value 

 for muscle tissue was 1.13 Hg/kg of fresh weight. 



The following five-ring PAH's were identified as present 

 in the gills (in percent by weight): BbF. 62.5; BaP, 33.5; 

 benzo(k)fluoranfhene (BkF), 3.7; moreover, chrysene (Chr) 

 and benzophenanthrene (Bp) were also present. The main 

 constituents of the total PAH mix were four-ring compounds: 

 BaA, 88.5%, and Chr, 1 1.5%; also present were traces of BbF 

 and BkF. 



Polycylic aromatic hydrocarbon levels in various 

 components of the Caroline Atoll ecosystems indicated that 

 this area was only slightly polluted by these specific compounds. 



183 



