POLLUTION 



Chemical Observations 



The second season's chemical observations were 

 extended to include the alongshore areas and harbors, 

 since detectable pollution was not found in the open 

 waters of the lake in 1928. Eight major sources of pol- 

 lution were found, the products of trade waste and sew- 

 age entering the lake from rivers and harbcars. Most 

 critical conditions were found in enclosed harbors pro- 

 tected from wave and current action. Conditions could 

 be considered critical to animal and plant life in only 



4 of these areas. Dilution renders the water harmless 

 within a very short distance from shore, usually within 

 a mile. Detectable traces of waste were observed at 

 greater distances at Fairport, 3 1/2 miles, and Toledo, 



5 miles. It may therefore be safely stated that pol- 

 lution at the present time in Lake Erie is a problem 

 only in the immediate vicinity of the shore. Spawn- 

 ing grounds located more than 2 miles from shore are 

 probably in no way influenced by outwash during the 

 production seasons, except possibly in the vicinity of 

 larger cities, and even here the danger is questionable. 



Chloride forms an important indicator of some 

 types of industrial pollution. There was very little 

 vertical difference in chloride values throughout the 

 lake but great fluptuations occurred in horizontal dis- 

 tribution. The bulk of the chloride in the lake origi - 

 nates from the rocks in the drainage area, and the 

 average values for most of the stations serve as an 

 index of this supply. The high values in the vicinity 

 of cities, however, indicate industrial waste. Extreme 

 values were encountered along the western margin of 

 the area investigated. Unfortunately, the program 

 could not be extended sufficiently to determine the 

 significance of these high values extending from Lorain 

 toward Point Pelee. 



Bacteriological Observations 



Bacteriological collections were made at each 

 station in the area east of Long Point in 1928. To con- 

 tinue this work in 1929, when the cruises were ex- 

 tended to approximately 2 weeks' duration, would have 

 necessitated the establishment of a bacteriological 

 laboratory on the vessel. For this reason and also be- 

 cause the conclusive results of the first season were 

 substantiated by previous findings in Ohio waters, the 

 work was not repeated in 1929. The present report 

 is therefore based solely on the observations made in 



1928 (Fish et a^. 1929) but in view of the absence of 

 chemical pollution over the Central Basin as well as 

 the eastern sector, the bacteriological results are be- 

 lieved to be applicable to the whole area. 



The objects of the bacteriological investigations 

 were to determine the sanitary condition of the water 

 and the extent to which sewage pollution might be a 

 factor in the decline of the fisheries. Reports by 

 fishermen of heavy pollution in different parts of the 

 lake were common. 



Collections were taken at approximately 6 inches 

 below the surface and 12 inches above the bottom. The 

 samples were immediately placed on ice and trans- 

 ferred for testing to the laboratories of the Buffalo City 

 Health Department, except in the case of the more 

 distant stations where inoculation and plating was car- 

 ried on in an improvised laboratory on the vessel. The 

 analyses were made by Andrew M. Zillig, Buffalo City 

 Bacteriologist, as specified in Standard Methods of Water 

 Analysis (Amer. Pub. Health Assoc. 1925). 



Of 94 samples the average bacterial count was 34, 

 the lowest 1, and the highest 210 per cubic centimeter 

 of water (fig. 66). B. coli and B. aerogenes were 

 absent in all one -tenth and 1 cc. counts and of 470 

 10 cc. counts only 20 gave positive results. These posi- 

 tive tests were always found in low total bacterial counts 

 and (fig. 66) indicate outflow into the lake from nearby 

 sources of pollution. The highest values were found in 

 bottom samples during calm weather. The churning 

 action of the water quickly eliminates pollution, and the 

 small numbers prevailing during the calm warm weather 

 may be considered maximum for the area in summer. 



These results can not be interpreted as indicative 

 of conditions throughout the year. The records of the 

 Buffalo City Health Department covering a period of 

 35 years show a marked increase in bacterial counts 

 following heavy rain storms in spring. These observa- 

 tions, however, were made close to the shore at the 

 entrance of the Niagara River and do not indicate con- 

 ditions prevailing at the time in the open lake. Since 

 bacterial growth is greatly accelerated by high summer 

 temperatures, and as the only effect of summer storms 

 in the open lake seems to be a more even vertical dis- 

 tribution of bacteria, and not any significant increase 

 in numbers, it is believed that winter conditions will not 

 be more severe. 



Therefore, in view of the repeated absence of 



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