396 THE SALMON RIVERS OF SCOTLAND 



have their joint entrance to the sea in the centre of Troon 

 Bay, have been ruined by pollution, and are not mentioned 

 separately in consequence. The Girvan a few years ago came 

 very near to sharing the same fate. In the two rivers 

 mentioned the main source of pollution is from ironworks. 

 In the Girvan the pollution has also been iron, but in the form 

 of the sulphate, impregnating water pumped from coal-pits. 



It was in February 1902 that the most serious pollution 

 occurred. A large coal-pit had, eighteen months previously, 

 taken fire and been flooded and shut down. In the year 

 mentioned the pit was re-opened and a commencement made 

 in pumping out the water. The discharge was carried into a 

 burn near Dailly, which was immediately turned a bright 

 orange colour. The burn discharges into the Girvan at a point 

 about 8|- miles from the mouth, and so strong was the pollution 

 that every fish from this point to the sea died. The water 

 of the river was like pea-soup. All the kelts which had not 

 descended and attempted to do so perished, and the smolts 

 fell easy victims to the poisoned water when they attempted 

 to migrate in late spring. Clean fish were unable to ascend, 

 and the nets near the mouth of the river had a rich harvest. 

 The pumping was continued month after month, and although 

 six settling ponds were hastily constructed and the effluent 

 treated with lime, little good seemed to result, since pit pumps 

 were throwing more water than could be coped with. The 

 bottom of the burn between the pit and the river became deeply 

 crusted with the iron deposit. I could push my stick in about 

 half a foot in many places. The result was that the Girvan 

 became void of migratory salmonidae. 



An analysis of the water showed enormous quantities of 

 metallic salts (569-9 grains of sulphate of iron per gallon). 

 The necessary oxygen of the water was absorbed. Fish were 

 asphyxiated, having no dissolved oxygen to breathe, and, in ad- 

 dition, having their gills clogged with the matter in suspension. 

 The public analysts of Glasgow gave it as their opinion that if 

 the river water, as it then was, were mixed with fifty times its 

 bulk of pure water, fish would still be unable to live in it. 



By degrees the strength of the pollution diminished, remedial 

 measures were entirely abandoned, and the pumps which 

 were working twelve hours daily, and throwing 475 gallons a 



