128 CALIFORNIA FISH AND GAME 



STREAM AND BAY POLLUTION STUDIES 



By Paul A. Shaw 



INTRODUCTION 



In order to deal intelliofently with the iiiiportaiit problem of 

 maintaining California waters free from detrimental pollution, it 

 is essential to have a clear picture of present conditions, based on 

 accurate data collected in all areas aifected. Such a picture would be 

 valuable in formulating a general policy relative to i)ollution control, 

 and in dealing justly with individual cases. The purpose of the present 

 outline is to indicate the need of certain studies and the general 

 program of activity that will be conducted relative to pollution. 



ORGANIC WASTES 



Wastes containing oxidizable organic matter include discharges 

 from dairies, tanneries, fibre board and paper plants, canneries, win- 

 eries, domestic sewage, slaughter houses, etc. While the relation of 

 this important class of wastes to fish life has been the subject of exten- 

 sive investigation in various eastern States, it has been given but slight 

 attention in California. 



The most dangerous feature of organic wastes lies in their ability 

 to consume large quantities of dissolved oxygen. This process is rela- 

 tively slow and the detrimental effect on fish life may pass unobserved, 

 due to the fact that fish will avoid the area and fatalities occur only 

 when high temperatures and bacterial activity result in a rapid deple- 

 tion of oxygen. Thus, while heavy fatalities may be rare, the average 

 condition of dissolved gases, bottom enviromnent and aquatic life may 

 be altered sufficiently to make the area undesirable for fish. With an 

 increasing density of industries and municipalities discharging organic 

 wastes, important water areas may become unsuitable for fish, reduc- 

 ijig the normal incoming runs as well as causing tlsh within the area to 

 seek a more suitable environment. 



The ratio between the oxygen available from the diluting water 

 and the oxygen demand of the waste is particulai'ly valual)le as an 

 indicator of the intensity of pollution. When this factor is sntficiently 

 high, natural purification will iirogress without appreciable oxygen 

 depletion and beneficial nutrient material is furnished for aquatic life. 

 In such instances, the streams and bays should probably be recognized 

 as a legitimate means of disposal. However, where this factor is low, 

 a detailed study of the intensity and extent of pollution may be 

 required, while in certain cases immediate steps to abate the condition 

 may be indicated. 



The program for study of pollution from oxidizable organic wastes 

 Avill include the following: 



1. Inspect and list industries according to watershed, obtaining 

 data on the quantity and kind of product, character of discharge, 

 treatment if any, and point of disposal. 



2. Obtain corresponding data on high and low stage stream or 

 tidal dilution. 



