134 



DOMESTIC WATER SUPPLY OF BRISBANE, ETC. 



Here is a list of the amounts of zinc found in various 

 samples of water collected in galvanised iron tanks from 

 galvanised iron roofs : — 



Date. 

 13th February, 1899 

 25th January, 1899 

 16th February, 1899 

 21st September, 1899 

 24th September, 1899 

 7th July, 1898 . . 

 7th July, 1898 .. 

 20th July, 1898 . . 

 6th February, 1898 

 7th November, 1898 

 19th November, 1898 

 16th January, 1899 



All these tank waters were examined in connection with 

 obscure cases of lead poisoning among children, and in no case 

 was lead found — in fact lead cannot remain in solution 

 in presence of metallic zinc, so that one would not expect to 

 find lead in solution in water stored in a galvanised iron tank. 

 Many other waters were examined qualitatively in con- 

 nection with the lead poisoning cases and all were found to 

 contain zinc in solution. On 27th February, 1902, samples 

 were tested as follows : — 



Grains zinc per gallon. 

 2-0 

 10 

 10 



1-0 (Maryborough). 

 10 (Wynnum). 

 0-8 

 0-8 

 1-27 



0-3 (Toowoomba). 

 0-75 

 1-0 

 1-0 



•70 grains zinc per gallon. 

 2"35 ,, ,, ,, 



' ^^ M 11 »» 



1-32 



1-32 



1-00 



Two samples Upper Paddington : — 

 ((() Tank cleaned 9 months before 



Sept. 12, 1902 — from same tank . . 

 (b) Tank not cleaned for at least 5 years 



Sample from Milton : — 



Tank not cleaned for years 



Sample from Kangaroo Point : — 

 Tank not cleaned for years 



Sample from Eagle .Junction : — 

 Tank cleaned 9 months before 



From these and other results it seems that tank waters 

 contain on an average about one grain of zinc per gallon. Just 

 after rain this amount would probably be greater, but is not 

 likely to rise above two grains for any length of time. The metal- 

 lic taste of the zinc in the tank water is very noticeable to any- 

 one not accustomed to drinking it. But for the presence of this 

 zinc ordinary tank water would be a very good drinking water. 

 As it is, thorough boiling of the water throws all the zinc out of 

 solution, and if then filtered and allowed to stand for a day to 



