FISHERY BULLETIN: VOL. 72, NO. 2 



s 



Z 



9780 .75 .70 .65 .60 .55 50 45 10 35 .30 



ColCOFI STATION NUMBERS 



Figure 8. — Average total DDT at CalCOFI stations off southern 

 California for the 6 yrl% 1-66. 



increase inp,p'DDE relative top,p'DDT for the 

 years 1950-51 through 1965-66 in the myctophids 

 was: 



These data show a 12-fold increase in the amount 

 of DDE relative to DDT from 1950-51 to 1965-66. 

 The ratio for the fish taken in 1970, 65-70 nautical 

 miles southeast of the sewer outlet (in La Jolla 

 Canyon) indicates a continuing increase in the 

 ratios, although there were only two fish in the 

 sample. The 1972 sample, consisting of only five 

 myctophids, was taken west of Santa Catalina 

 Island and about 25-30 nautical miles south 

 southwest of the sewer outfall about 2 yr after the 

 dumping of DDT into the sewer system had 

 stopped. The high ratio may reflect in part con- 

 tinued metabolism of DDT without replenish- 

 ment. 



Because there are no data on the amount of DDT 

 discharged into the ocean through the White Point 

 sewer outfall each year, I have assumed that it 

 was constant and discharged continuously 

 throughout the year. Under these circumstances 

 the amount of DDE (and DDD) entering the 

 marine environment should gradually have in- 

 creased in the earlier years until the input of DDT 

 equalled the amount of DDT metabolized, when 

 the input of DDE (and DDD) would also be con- 

 stant. This is indicated by the initial slower in- 

 crease in ratios of DDE to DDT. 



If we assume that the same amount of pesticide 

 is released into an environment each year and 

 that it is released continuously throughout the 

 year we may empirically represent the accumula- 

 tion of the pesticide in the environment by the 

 formula 



Y =Ka -S^) 



in which Y equals the amount of pesticide accumu- 

 lated at the end ofX years; /^ equals the maximum 

 amount of pesticide that could be accumulated by 

 the organism under the prevailing conditions; and 

 S equals the "survival" rate of the pesticide for 1 



yr- 



In some of the years from 1949 to 1966, Cal- 

 COFI cruises were limited, and fewer samples 

 were taken. Also the fish were not uniformly sam- 

 pled with respect to distance from the sewer out- 

 fall in each of the years. But, by averaging the 

 p,p' DDE content of all fish taken in each year and 

 grouping years by twos, a rough indication of the 

 increase in p,p 'DDE was obtained to compare 

 with theoretical values of the formula, Y = K 

 (1 - SX) (Figure 9). 



The almost linear increase inp,p'DDE indicates 

 that its metabolism is very low. In fact, 

 metabolism in this case would include p,p' DDE 

 lost by removal from the area under study, and, 

 therefore, the data indicate that very little was 

 lost from this area during the years in which 

 dumping occurred. 



Because of the apparent lack of metabolism of 

 p,p' DDE, this metabolite of p,p 'DDT should give 

 the best picture of areal and temporal buildup of a 

 CHC in the ocean as a result of the sewer dis- 

 charge. 



Data on p,p'DDE content of the myctophids, 

 year of capture (with 1949 equal to year 1), and 

 distance in nautical miles from the sewer outlet to 

 the place of capture were fitted to the formula: 



284 



