It may be noted that the total content and mix of PAH's 

 present in the tissues of South China Sea sponges was not much 

 different from those established for the same aquatic organisms 

 in the Bering Sea (Table 4). The predominant PAH's 

 (in percent by weight) for South China Sea and Bering Sea 

 sponges were BbF (54 and 59) and BaP (36 and 33.6), 

 respectively. 



Concentrations of PAH's in livers of sharks ranged from 

 1.2 to 10.2 (ig/kg of fresh weight (Table 4). The predominant 

 compounds were the following four- and five-ring PAH's 



(in percent by weight): Chr, 53.7; BPer, 24.7; BaA. 8.7; BaP, 

 8.7; BbF, 2.3; and BkF, 1.9. 



For comparison we note that the levels and distribution of 

 PAH's in aquatic organisms of the Bering Sea (sponges and 

 walleye-pollack liver) also indicate relatively high total PAH's 

 in fish livers and the buildup of the strong carcinogens BbF, 

 BaP, and BkF as the dominant PAH's in sponges (Table 4). 



Analysis of the findings of the present study points to 

 severe petroleum hydrocarbon pollution of the sea and to the 

 buildup of the carcinogenic PAH's — BbF and BaP — in some 

 aquatic organisms. 



2.3 The Occurrence and Microbial 



Transformation of Benzo(a)pyrene in the 

 Waters of the Tropical Pacific (Caroline 

 Atoll, Line Islands, Phoenix Islands 

 Transect, South China Sea) 



YURIY L. VOLODKOVICH and OLGA L. BELYAEVA 



Institute of Global Climate and Ecology, State Committee for Hydrometeorology and Academy of Sciences, Moscow; USSR 



Introduction 



Among the numerous organic pollutants working to 

 produce dangerous and undesirable changes in the chemical 

 and biological status of the marine environment, polycyclic 

 aromatic hydrocarbons (PAH's) of both natural and human 

 origin must be singled out as being particularly noxious. 

 Exhibiting considerable molecular stability, as well as 

 pronounced carcinogenic and mutagenic properties, compounds 

 of this series are a serious hazard to marine life. At present, 

 researchers have been choosing ben7.o(a)pyrene (BaP) as an 

 indicator of environmental pollution by PAH's. 



Benzo(a)pyrene and other PAH's have been found to 

 occur in many marine ecosystem components from the arctic 

 latitudes (Volodkovich & Belyaeva, 1987) all the way to the 

 Antarctic, affecting mariculture and other activities. 



The proximity of human sources of pollution has a powerful 

 impact on the marine environment, increasing BaP levels in 

 waters by factors ranging from tens to hundreds (Tsyban et ai, 

 1985b; Tsyban ef a/., 1986). 



For example. BaP levels in some parts of Los Angeles 

 harbor have reached, and even exceeded. IIS ng/1. while 

 concentrations in the top 0.5 m of the water column in the 

 equatorial Pacific have been reported in the 1-6 ng/1 range 

 (Shilina, 1982). 



In view of the fact that elevated PAH levels in seawater are 

 due largely to the proximity of a given sea area to pollution 

 sources, the study of BaP circulation and elimination processes 

 (including microbial transformation) in as yet unimpacted 

 open sea and open ocean areas is of considerable interest and 

 value. 



Microorganisms, which are virtually ubiquitous in the 

 World Ocean, play a major role in the functioning of marine 

 ecosystems and in the biochemical cycling of various 

 compounds, including pollutants such as petroleum crude and 

 PAH's (Izrael & Tsyban, 1989). The processes involved in the 

 microbial transformation of aromatic hydrocarbons and 

 heterocyclic compounds have been investigated in sufficient 

 detail. On the other hand, the rates of microbial degradation of 

 BaP in the marine environment, as well as the local and 

 regional scale of these processes, have thus far been neglected 

 (Tsyban et ai, 1986). 



Integrated studies of biogeochemical cycling of PAH's. 

 using BaP as an example, were performed in 1988 during the 

 cruise of the R/V Akademik Korolev as an extension 

 of work begun in 1981 in the South China Sea and the 

 Marianas sector. The research represented the first time that 

 such work has been undertaken in the tropical Pacific (in the 

 Caroline Atoll area and the Line Islands/Phoenix 

 Islands transect). 



186 



