302 



Economic Aspects 



Hyperion outfall the benthos in 1956 was 

 much changed, with the development of an 

 impoverished pollution-tolerant fauna com- 

 posed mostly of detritus feeders. Between 

 3 and 6 km the benthos were enriched, par- 

 ticularly in detritus feeders, predators, and 

 scavengers, probably because of the greater- 

 than-normal food supply there. At 6 to 9 

 km away the benthos present a gradual tran- 

 sition to the normal faunas of the shelf and 

 slope. Bottom fishes were found to reflect 

 the changes in benthos, with maximum 

 catches over the area of enriched benthos, 

 evidently in response to an increase in their 

 own food supply. At Whites Point a marked 

 decrease in the abundance of kelp has been 

 attributed to sewage discharge, and a de- 

 crease in abalone may be related to loss of 

 their food supply, the kelps. 



Wastes considered too harmful to be 

 pumped to sea through outfalls are barged 

 farther out and dumped. Such materials in- 

 clude overage military explosives and used 

 acids and caustics from oil refineries. The 

 explosives are dumped by Navy ships, pre- 

 sumably mostly in the prescribed areas: San 

 Diego Trough 30 km west of Point Loma and 

 Santa Catalina Basin at its west end. In 

 northern California other dumping areas are 

 located 30 km west of the Farallon Islands 

 and, formerly, 75 km west of Pigeon Point. 

 Most chemical wastes in southern California 

 are dumped in Santa Cruz Basin or en route 

 to it from San Pedro. One company weekly 

 disposes of a barge load of acid, mostly sul- 

 furic, and a barge load of caustic, mostly 

 sodium hydroxide. Since most of the mate- 

 rial is easily soluble in water, it is usually 

 slowly dumped at the surface as the barge is 

 being towed, in order to avoid forming large 

 spot concentrations. 



Potentially more dangerous to man than 

 sewage discharge, although invisible, is the 

 disposal at sea of radioactive materials. A 

 small quantity of these have been and will 

 continue to be introduced intentionally as 

 tracers to aid in the study of movements of 

 water and sediment. Only radioisotopes of 

 short half-lives and low intensity are selected 

 so as to constitute no nuisance or danger. 

 One example is the introduction of 20 curies 



of 85-day scandium 46 into 5 million gallons 

 of sewage at the Los Angeles Hyperion Sew- 

 age Treatment Plant to permit tracing the 

 discharge from the outfall and to measure 

 its dilution with sea water to about 1 part in 

 10,000; a single such experiment combined 

 with other field studies served to evaluate the 

 reduction in concentration of discharged 

 coliform bacteria by dilution, sedimentation, 

 and mortality (Nuclear Science and Engi- 

 neering Corporation, 1956; Rittenberg, 

 1956). Another example is the irradiation 

 of sand from Scripps Beach at La Jolla and 

 its replacement on the beach to learn the rate 

 and direction of movement (Inman and 

 Chamberlain, in press). About 5 millicuries 

 of the radioisotope, phosphorus 32, that was 

 formed had a half-life of 15 days but could 

 be detected even after several months with 

 a sensitivity of 1 grain in 1 million by using 

 photosensitive paper. Waves caused the 860 

 grams of irradiated fine sand to be dispersed 

 over an area of about 2 sq km in only 24 

 hours. 



Of far greater importance than tracer tests 

 is the disposal at sea of radioactive wastes. 

 Some disposal is indirect — the fallout from 

 bomb bursts. Since all explosions before 

 1959 were at least several hundred kilo- 

 meters distant from the coast of southern 

 California, the fallout has doubtlessly been 

 reasonably uniform throughout the area ex- 

 cept probably nearshore where some concen- 

 trations must be produced by stream dis- 

 charge. Measurements by the Los Angeles 

 Department of Water and Power (Ree, 1958) 

 show that counts in streams and rains imme- 

 diately following Soviet bomb bursts are 

 higher by a factor of about 10 than prior to 

 them. Little or no eff"ect is noted for the 

 much closer but smaller American tests, ex- 

 cept for one in October 1958. Because the 

 beta gamma activities are reduced in about 

 60 days to one-tenth of their original values, 

 the radioactivity supposedly represents no 

 known danger to users of the water. How- 

 ever, it is conceivable that a single large 

 widespread rainstorm coming during the first 

 week or two after a large dirty test would 

 bring as much as a thousand curies of fission 

 products down to the ocean throughout the 



