samples Included "bacteriological examinations, dissolved oxygen, 

 'biochemical oxygen demand, pH determinations, and temperature readings. 



2. Pollution Criteria * The following excerpt from a report hy 

 W. D. Fedde, Acting Chief Chemist in cliarge of the Testing Lahoratories 

 of the Municipal Engineering Division, Miraflores Water Purification 

 Plant, is suhmitted 'becaxise of the valuatle information it contains with 

 reference to pollution at this location. 



Report on 



Pollution Tests on Waters of Balboa Harhor in Vicinity of the U. S. Maval 

 Operating Base» West Bank 



Discussion 



From time to time, various standards have Taeen proposed as "bases 

 for working criteria limiting pollution of watercourses. In this connection, 

 the Royal Commission standard in Great Britain provided that sewage 

 effluents should contain not more than 50 ppm of suspended matter said 

 should have a 5-day B,O.D. at 65° F not exceeding 20 ppm. As the hasis 

 of the sewage effluent standard, the Commission formulated the working 

 rule that the 5-day B.O.D. of a stream of water, after receiving an effluent, 

 should not exceed k ppm in order to maintain satisfactory conditions in 

 the stream at a summer temperature of 65° F and under dry-weather conditions. 



The dissolved oxygen content of a watercourse should not he 

 allowed to fall to a point where a nuisance will he created or where 

 fish life will be destroyed. Recent surveys of the U. S. Bureau of 

 Fisheries, as reported by Ellis, have indicated that the desirable minimum 

 dissolved oxygen content shoiild not be less than 5 ppm in order to provide 

 favorable conditions for the development of a normal variety of native 

 fish life. Furthermore, if the percentage saturation of dissolved oxygen 

 in a watercourse is not permitted to fall below 50 percent, it is likely 

 that no nuisance will exist. 



In connection with the disposal of sewage by dilution in harbors, 

 estuaries, and the sea, it should be pointed out that sea water contains 

 20 percent less dissolved oxygen than fresh water under similar conditions 

 of temperature and pressure. Sea water also exerts a precipitating effect 

 on the colloids in sewage, a condition that favors the formation of sludge 

 banks when sewage is discharged into salt water. As sludge deposits 

 decompose, hydrogen sulphide is formed in greater abundance in salt water 

 than in fresh water, caused by the breaking aown of the sulphates 

 contained in sea water. 



A46.05 Ifarine Borers 



1. Teredlnidae . Teredinidae . including Bankia canaJLis , B. gouldi . 



2llt 



