MICROFLORA OF THE YELLOWSTONE RIVER. II. PERTURBATIONS uH BILLINGS 



Loren L. Bahls 



INTRODUCTION 



The last floristic survey of the Yellov/stone River through Billings 

 was accomplished 20 years ago when the river was receiving a pollution 

 burden much greater than it receives today. In 1955, no bottom organisms 

 occurred in the first 11 miles below waste outfalls at Billings; sewage 

 "fungus" was commonplace; and taste and odor problems were chronic (10). 



Today, due largely to the application of pollution control tech- 

 nology, the situation is much improved and the river is getting cleaner 

 (2). Nevertheless, the Yellowstone River from Laurel to Billings remains 

 water quality limited because of discharges from the Laurel and Billings 

 sewage treatment plants, and wastewater discharges from three oil 

 refineries, a sugar beet factory and a coal-fired steam-electric plant. 

 There are also a number of non-point source sediment and oil problems 

 in this reach of the river (5). 



This paper describes the response of Yellowstone River algae to 

 a variety of waste discharges originating in the Laurel -Billings municipal/ 

 industrial complex. Emphasis is placed on the relationship between the 

 structure of benthic diatom associations and ambient concentrations of 

 selected algal nutrients. This investigation was conducted as a contri- 

 bution to the biological portion of a waste load allocation study being 

 prepared for this section of the Yellowstone by the Montana Department 

 of Health and Environmental Sciences. 



