2.1 Distribution of Chlorinated Hydrocarbons 

 in Ecosystems of the Equatorial Pacific 



SERGEI M. CHERNYAK and VALERIYA M. VRONSKAYA 



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



Introduction 



It is a well-known fact that chlorinated hydrocarbon 

 pesticides (CHP's), which earned their developers a Nobel 

 Prize, have been both a great benefit to mankind by making it 

 possible to rescue up to one-half of the world's cereal-grain 

 harvests from pests and a detriment to the environment by their 

 trait of extreme stability causing them to build up in the 

 environment. In just a few years, their environmental hazard 

 has become apparent. 



The multiplicity of pathways and the high rates of CHP 

 transport led to a situation whereby in the early 1 970' s they had 

 accumulated on a worldwide scale, being detectable in virtually 

 all environments, including mountain-peak glaciers and deep- 

 ocean depressions. Later, the world was to see a no less 

 extensive buildup of other classes of chlorinated hydrocarbons 

 (CH's). namely polychlorinatedbiphenyls(PCB's), chlorinated 

 terpenes, dioxins, benzofurans. et cetera, which were being 

 used not only in agriculture but also in various industries and 

 even in health care fields. 



Despite the fact that most industrialized countries had 

 invoked total or partial bans upon the use of CH's in open-cycle 

 processes, their production on a global scale remains almost 

 undiminished, since no effective alternative for protecting 

 agricultural harvests in tropical countries has yet been devised. 



There is now a considerable body of scientific literature 

 indicating that the World Ocean is the ultimate repository for 

 CH's. According to the most reliable estimates (Tanabe. 

 1 985 ), ocean waters are today the repository of as much as 70% 

 of all the CH's ever released into the environment. Previous 

 studies (Chemyak et al., 1985b) showed that the rates of CH 

 buildup and migration in constituents of the oceanic environment 

 depend first and foremost on the physicochemical and 

 hydrologic-geographic characteristics of various portions of 

 the World Ocean. Hence, predictive estimates of increases in 

 ocean pollution, which are bound to occur globally, require 

 information on the forms and amounts of CH's present in 

 various media and especially in little-studied regions such as 

 the Pacific Ocean, where only a few expeditions have concerned 

 themselves with CH's (Izrael & Tsyban, 1989). Our own 

 recent studies (Chernyak&Mikhaleva. 1985a) were the first to 

 include nearly in situ studies of microbial and photochemical 

 PCB decomposition processes, which are the only processes 

 presently at work to rid the oceanic environment of these 

 xenobiotic substances. We were particularly interested in 

 investigating PCB distribution at Caroline Atoll, a coral island 

 remarkable for its diverse flora and fauna, where these CH's 

 have accumulated, in markedly altered form and at a distance 



of many thousands of kilometers from their sources. Their 

 presence at these locations are probably occurring through 

 atmospheric and oceanic transport. 



The present paper sets out the findings and conclusions of 

 comprehensive studies conducted in 1988 in the equatorial 

 Pacific and at Caroline Atoll, which were obtained during the 

 First Joint US-USSR Central Pacific Expedition aboard the 

 R/V Akademik Korolev. 



Materials and Methods 



The locations of the sampling stations are shown in Fig. 1 . 

 The media sampled in order to establish the specifics of 

 hydrochemical processes involving chlorinated hydrocarbons 

 in background regions of the Pacific and coral-reef ecosystems 

 were seawater, sediment, plankton, neuston, demersal 

 organisms, and fishes. Specific studies conducted at Caroline 

 Atoll also included corals, flora and fauna, and eggs of local 

 bird species. 



Fig. 1 . Expedition route and station locations in the Pacific Ocean and South 

 China Sea (9 September to 3! October 1988). 



Seawater samples, 100 I in volume, were filtered through 

 XAD-2 resin at the rate of 20 1/h. The sorbed CH's were eluted 

 with 80 ml of ethanol mixed with an equal volume of 2% 

 sodium sulfate solution. The water-alcohol solution was 

 doubly extracted with n-hexane ( using 25 ml of hexane in each 

 of the two extractions). The extracts were concentrated to a 

 volume of 4-5 ml using a rotary evaporator, purified with 

 concentrated sulfuric acid, neutralized with a 5% NaHCO, 

 solution, rinsed twice, dried over sodium sulfate, and 

 concentrated in a stream of pure nitrogen to a volume of 1 ml. 

 The concentrate was injected into a Hewlett-Packard gas 

 chromatograph with the aid of an autosampler. The 

 chromatographic analysis conditions were as follows: 



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