fused-quartz capillary column, length 30 m, and inside diameter 

 .•I 0.32 mm; chromatographic phase DB-1 (0.25 urn). The 

 temperature program lor the column was initial temperature. 

 1 20 C" ( I mini, rising to 250 C at the rate of 5°C/min. The 

 chromatographic analysis time was 40 min. the injector 

 temperature. 225°C, and the electron-capture detector 

 temperature. 300°C. 



The sediment samples were centrifuged for 20 min at a 

 speed of 2,000 rpm to achieve total deposition of the silt. The 

 residue was extracted with acetone, then doubly extracted with 

 a 3:1 hexane-acetone mixture. The combined extract was 

 washed by mixing with an equal volume of 29? sodium sulfate 

 solution. The hexane layer was separated off, and the aqueous- 

 acetone solution reextracted with additional hexane. The 

 combined hexane extract was concentrated, then purified, first 

 with sulfuric acid (to remove extracted organic compounds), 

 then with tetrabutylammonium sulfate (to remove any sulfur 

 compounds). The purified solution was concentrated down to 

 I ml in a stream of pure nitrogen and chromatographically 

 analyzed. The biological samples were crushed to obtain a 

 homogeneous mass, defatted with acetone, then treated, 

 following the procedure used, with sediment samples. 



In order to investigate the effect of photochemical processes 

 on the behavior of CH's in background ecosystems of the 

 Pacific, experiments were conducted on the decomposition of 

 a standard Aroclor 1232 solution in waters drawn from the 

 equatorial Pacific and around Caroline Atoll under the action 

 of sunlight. 



The experiment was run in two 5-1 reactor vessels, one 

 exposed to sunlight, the other shielded using light-blocking 

 foil. The surface area involved was 400 cm 2 . The sterilized 

 seawater in the reactors were spiked with an acetone solution 

 of Aroclor 1232 to yield PCB concentrations in the water of 

 100 ng/1. The samples were extracted with n-hexane (twice. 

 50 ml each time), then concentrated to a volume of 2 ml in a 

 rotary evaporator. They were then purified with concentrated 

 sulfuric acid and chromatographically analyzed. Microbial 

 degradation of the PCB under the same conditions was 

 investigated for control purposes. 



Results and Discussion 



Data on CH levels in Pacific Ocean waters are presented 

 in Tables I and 2. 



Analysis of these results clearly demonstrated the 

 dependence of the distribution of various PCB components on 

 their molecular structure. 



The distribution of hcxachlorocvclohexanc (HCII) is 

 noteworthy since its total concentration was fairly high, though 

 it was still several times lower than in the Bering and Chukchi 

 Seas (Chernyak ci al., 1002). which arc just as far removed 

 from areas where this compound continues to be used. The 

 composition of the IICH mixture (containing as much as 90' - 

 of the (/.-isomer) indicates thai the sources of pollution are 

 probably equatorial countries that employ \ast amounts of 

 technical-grade hexachloran on their crops. The relatively low 



TABLE 1 



Chlorinated hydrocarbon levels in the surface waters 

 of the Pacific (ng/1). 



Chlorinated Hydrocarbon Levels 

 Station Total 

 Number HCH DDT DDD DDE PCB 



TABLE 2 



Distribution of chlorinated hydrocarbons over the water column in 

 Pacific Ocean waters. 



ISO 



