FISHERY BULLETIN: VOL. 72. NO. 2 



CC 

 LU 

 Q- 



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3.5- 



3.0 



2.5 



2.0 



1.5 



1.0 



0.5 



0.0"- 



DDE 



DDT 



-DDD 



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1950 



1955 



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I960 

 YEAR 



1965 



1970 



Figure 10.— Trends of p.p'DDE (squares), p.p'DDT (circles), 

 and p.p'DDD (triangles) in the ocean off southern California, 

 1949-72, at a theoretical station 20 nautical miles from the point 

 source of pesticide contamination. Computed lines show persistant 

 DDE increasing until dumping of DDT wastes ceased in 1970. 

 Both DDT and DDD increase for several years and then level off 

 when metabolism, excretion, and dispersion equal input. Points are 

 based on calculated total value of the three analogs distributed 

 among them on the basis of the observed ratios of the three analogs 

 to each other for each year. The 1972 ratios were affected by sewer 

 cleaning operations that caused large quantities of DDD to enter 

 the ocean. 



From the calculated values of DDT and the 

 DDD:DDT ratios we may estimate values for 

 DDD. From these it appears that DDD accumu- 

 lates in the fish up to 0.303 ppm where input 

 equals metabolism. From this we may calculate 

 that Frf = 0.303(1 - 0.525^). However, this for- 

 mula is based on a constant input equivalent to 

 0.189 ppm. The actual input from metabolism of 

 DDT was only 0.028 ppm the first year and in- 

 creased to 0.181 by the 10th year, and 0.188 by the 

 20th year. By adjusting for these increasing in- 

 puts we obtain accumulative values for DDD, for 

 DDMU, and other metabolites of DDD (Table 2, 

 Figure 10). 



The percent distribution of total DDT among 

 p,p'DDT,p,p'DDE, andp,p'DDD did not appear to 

 change in myctophids with distance from the 

 sewer outfall. Therefore the percent distribution 

 which is based on large numbers of fish in most 

 years can be used to prorate the total p.p'DDT 

 obtained from the curves to obtain "observed" val- 

 ues ofp,p'DDT,p,p'DDE, andp.p'DDD (Table 1, 

 Figure 10). Both the curves and their observed 

 values are based on observed percent changes in 

 the composition of total DDT transformed to ppm 

 values of the three constituents at a theoretical 

 station 20 nautical miles from the sewer outfall. 



It should be emphasized that the above descrip- 

 tion of metabolism is only an indication of what is 

 taking place in the ocean. It neither describes the 

 metabolism of DDT in the myctophid fish nor the 

 metabolism in the marine environment, but 

 rather refiects selective storage of DDT and its 

 environmental metabolites in one species offish. 



Three factors determine the amount of CHC 

 found in myctophid fishes: 1) The CHC present in 

 the fish's environment during its brief life span; 2) 

 the selective absorption of CHC through the gills 

 and the ingestion of selected food particles; 3) and 

 the selective storage, metabolism and excretion of 

 CHC. Factors 2 and 3, above, should remain con- 

 stant for each generation of fish. Therefore, the 

 changes in composition of total DDT probably 

 reflect changes occurring in the environment. 

 However, the percent composition found in the 

 myctophids may not represent the percent com- 

 position in the environment because of the selec- 

 tive nature of intake and excretion. 



Some of the DDT was changed to DDE and DDD 

 before entering the ocean. Sixteen samples of 

 sewer discharge from the Montrose Chemical 

 Corporation taken between 14 August 1970, and 

 12 May 1971, averaged 74%DDT, 209^^ DDE, and 

 6%DDD (Redner and Payne, 1971). Although 

 these samples represented discharges averaging 

 less than 0.5 lb (0.23 kg) a day, samples taken 

 earlier in 1970 when dumping was estimated at 

 640 lb (290 kg) per day also had ratios of 73:25:2. 

 These percent ratios are very much like the 

 74:23:2 distribution in the myctophids in 1949 and 

 the 70:23:7 distribution in 1950. 



Although some DDT was converted to DDD and 

 DDE before it left Montrose, most of the 

 metabolism took place after it was discharged 

 from the plant. This is indicated by the percent 

 distribution of DDT, DDE, and DDD in the myc- 

 tophids in 1970, 16:75:9, by the bottom fish taken 



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