14 . MARINE AND FISHERIES 



1-2 EDWAnu Vil., A. 1902 

 EXPERIMENTS WITH WASTE WATER FROM NAIL WORKS, ST. JOHN, N.B. 



This pollution was the most deadly one examined. In many experiments J^ per 

 cent was sufficient to kill in a few hours. The most marked peculiarity in all the experi- 

 ments made with this waste was that in a few minutes after mixing it with either fresh 

 or sea water, a reddish brown precipitate began to form, and continued forming for 

 several hours. The suspicion that this precipitate was ferric hydroxide, was confirmed 

 by subsequent chemical analysis. 



Microscopic examination of the gill filaments of fish killed by this waste, showed 

 that death was caused by this adhesive precipitate sticking to the filaments. With a 

 coating of this rust-like substance covering the gills, it is difficult to see how oxygen 

 could pass into the blood and carbon dioxide could pass out, especially as the irritant 

 seemed to cause a mucous or slimy exudation to form on the mouth-parts and gills 



Experiments began with solutions of 6 per cent, 2 per cent and ^ per cent, all of 

 which were found to cause death in from half an hour to an hour. Reduction to \ per 

 cent resulted in the death of the hardy stickleback in about five hours. Specimens were able 

 to survive for two or three days when the solution was reduced to i per cent. In fact, 

 when any of the hardier fish, like Fundulus, the stickleback, or the rock bass were able to 

 survive the six or eight hours during which the ferric hydroxide was being precipitated, 

 they usually lived on for several days or a week. 



More delicate fish like smelt and trout, however, succumbed to weaker solutions 

 ^_i_ per cent) of the poison, in from ten minutes to half an hour. Repeated attempts to 

 resuscitate these fish by artificial aeration in fresh water proved failures. In the case, 

 therefore, of the more sensitive fish, death is apparently caused by the absorption of the 

 free hydrochloric acid and ferrous chloride. That small quantities of the latter were 

 absorbed was proved by treatment of the gill filaments with ferro-cyanide of potassium. 

 This I did at the suggestion of Professor Macallum. This reagent stained the filaments 

 a blue colour, and subsequent examination of sections of these under the microscope 

 showed slight absorption of the iron compound along the surface cells. 



Attention is specially directed to the high specific gravity of this pollution, 1-1150 

 (water ==1). The effect of this would be to cause the pollution to fall to the bottom of 

 a stream into which it might be discharged. This would result in the death of fish that 

 habitually live in deep water, especially if the flow was sluggish. On the other hand, 

 the great density of the pollution would increase the rapidity of difi^usion throughout 

 the fresh water, in accordance with the laws of diffusion of liquids of different density, 

 and this would be followed by the formation of the precipitate already referred to, and 

 ultimately the water would tend to become harmless. 



ACKNOWLEDGMENT re CHEMICAL ANALYSES. 



Before concluding this report I desire to acknowledge my great indebtedness to 

 Mr. Prank T. Shutt, M. A., chemist at the Experimental Farm, Ottawa, for the labour 

 and pains he has spent in making the analysis of the waste water from the gas works 

 and from the pulp mills. 



Mr. J. C. Murray, B. A , School of Mining, Kingston, has placed me under similar 

 obligations for his analysis of the nail waste. 



All the analyses were made at the end of the season, and after my observations 

 had been completed, but I hope to be able to utilize some of the results next season if I 

 continue this investigation. 



As regards sawdust, it seems clear that future observations should be made where 

 large deposits of this pollution occur in river beds. An attempt should be made to as- 

 certain (a) whether adult fish frequent such places ; (h) whether the sawdust affects 

 the laying and development of the eggs, and (c) whether it interferes with the food 

 supply. 



Ottawa city itself might be as good a place as could be found at which to prosecute 

 some of these investiarations. 



