Biological Observations and Toxicity Bioassays in the Control of ; '    Industrial Waste Disposal
¦       :    ¦•^   :,..;'" PETER  DOUDOROFF •\,       . .    ,
Fisheries Research Biologist '¦>¦   '         .' .
¦~   '"              Environmental Health Centre ''   '
U. S. Public Health Service ;   •'
Cincinnati, Ohio .,
In order that the disposal of industrial vpastes into surface vraters may be properly controlled, the pollutional nature of these wastes and their influence on aquatic life must be considered. The value of bio¬ logical indices and measures of water pollution has been pointed out and discussed repeatedly in the past. Very recently Van Horn i^, Patrick^^ and Henderson ^^ have published interesting data and discussions of various phases of this subject, with especial reference to industrial pol¬ lution. Biological indices of pollution with industrial wastes and domestic sewage (which has eiifects similar to those of some organic industrial wastes) have been considered in a general way also by Bartsch^, Butcher*, Brinley^, Lackey^*, Campbell^, Ellis^, Claassen^ and Whipple^o. Ellis, Westfall and Ellis^, Hart, Doudoroff and Greenbank^" and Anderson^ have recently described bioassay methods for the evaluation of the toxicity of industrial wastes to aquatic animals, as a helpful index of their pollutional potency. Important contributions of other workers have been cited by the authors mentioned above.
Many established facts and valid conclusions pertaining to biological criteria by which the intensity of polution can be judged already have been fully and clearly presented and need not be restated here. However, some striking contradictory views are frequently encountered. Therefore, the present general discussion, based on a critical survey of pertinent literature and personal experience in the field of pollution control, may be helpful in the planning of biological studies. Bacteriological investi¬ gations and methods are not considered here.
OBJECTIVES  OF   BIOLOGICAL   STUDIES
The practical objectives of biological studies of water pollution first must be carefully considered. It seems that some authors have failed to  recognize  or have lost sight of  these  objectives.   This may have
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