112 Conservation Department 



The shore studies showed that there are points where entering 

 pollution exerts appreciable effects upon localized areas about the 

 points of entry, but that it is soon assimilated by the great volume 

 of lake waterl In places such as Dunkirk harbor the exuberant 

 weed beds doubtless aid greatly in the assimilation, and directly 

 outside the harbor no effect of pollution could be detected. Between 

 the New York-Pennsylvania State line and the city of Lackawanna 

 the two most noteworthy entries are Cattaraugus and Rush creeks. 

 The former discharges a load of unassimilated organic matter 

 into the lake, but it is the effect upon the stream itself rather 

 than the lake which is the occasion for greatest concern. 



Rush creek discharges into the lake wastes from the iron and 

 steel works just above. On two occasions the stream was found 

 to have an acidity of about .03 normal, or roughly about three 

 times as strongly acid as the reagent which we use in determining 

 a water's alkalinity. This stream carries a load of iron which it 

 holds in solution by virtue of its acidity, but when neutralized by 

 the alkalinity of the lake water the solution becomes a suspension, 

 reddish brown in color because of the oxide of iron which separates 

 out. And so on occasions the adjoining shore waters present a 

 study in color shades, the reddish brown at the edge fading to a 

 lighter hue streaked with clearer lake water as the eye travels 

 outward, until finally the last trace disappears. Such a condition 

 should not be permitted to exist, the more since it might easily 

 be corrected. 



The most easterly point which may be listed as lake proper was 

 inside the breakwater opposite ]\Iichigan slip, and on all three 

 cruises was found to be little affected by pollution. Luxurious 

 weed beds late in the summer brought the dissolved oxygen con- 

 tent above the normal saturation point. 



To show how remarkably free the lake proper is from fluctua- 

 tions due to shore conditions, the profiles in Fig. 2 depict the 

 averages of dissolved oxygen determinations made at the 500 and 

 2000 feet stations throughout the season. The graphs have been 

 extended to include the data on Niagara river, so that all told the 

 picture covers upwards of one hundred and ten miles of shore 

 distance. Because of the character of river flow as opposed to 

 lake, the nearest to shore samples in the case of the former were 

 taken at a distance of 100 instead of 500 feet. 



Niagara River. — The water which sweeps down the main chan- 

 nel of the river to the foot of Squaw island is, under normal 

 conditions, little different chemically from that in the lake itself. 

 Inside the ship channel however the effect of sewage is severe, 

 and just above the international railroad bridge the oxygen con- 

 tent was found at one time to average 3 parts per million, while 

 the ten day biochemical demand showed a value of more than twice 

 this figure. 



