Q. Can you give me any opinion as to danger of water-poisoning from the use of galvanized pipes for soft spring-water?

A. We referred this question to Prof. William Ripley Nichols, whom we consider an authority. The following is his reply:

"It would be difficult to give an opinion of any value without more knowledge of the character of the water than is conveyed by the term 'soft.' If the water is what we should consider soft in this region, if a fair proportion of the dissolved salts consists of carbonates, and if there is no excess of carbonic-acid, the so-called galvanized pipe can, no doubt, be used with perfect safety; if the water is effervescent, or contains an excess of carbonic-acid without actually effervescing, especially if chlorides are present (or sulphates other than sulphate of lime), it would perhaps be better not to use the pipes. Even in the latter case, however, if in the morning or whenever the water has remained for any considerable length of time in the pipes, enough water is wasted to thoroughly flush the pipes before any is used for drinking or cooking, there will probably be no danger. In this case a filter of bone-coal would be an additional safeguard.

"As to the general question of the action of water on zinc, the matter was quite fully studied a few years after the manufacture of articles of the so-called ' galvanized ' iron began, and the experiments of Mallet (British Association Reports, 1838 and 1840) are justly considered classic. All ordinary waters act more or less on galvanized-iron with the formation, as a rule, of oxide of zinc, which is subsequently changed to a hydrated carbonate. This coating may be to a certain extent protective, and, when once formed, it may check the corrosion of the underlying metal. It is not, however, very coherent, and where there is a flow of continually renewed water, as in the interior of a pipe, the coating is continually removed and reformed. Water drawn from such pipes, especially after standing for some hours, usually contains more or less oxide or carbonate of zinc in suspension, and, at the same time, some zinc in solution. It is stated - and it is the experience of the writer - that the corrosion from the first takes place irregularly in patches; at any rate, after a longer or shorter time, depending upon the quality of the pipe and the character of the water, the iron becomes exposed in spots; then the corrosion proceeds more rapidly, and after a time - in fact, from that time - the pipe has no superiority over a plain iron pipe.

"As to the danger to health: Although certain compounds of zinc are known to be poisonous if taken in sufficient quantity, it is generally held by those who have given particular attention to the subject, that ordinary water may be conveyed with perfect safety through zincked pipes. Some chemists have reported finding so much sulphate and so much chloride of zinc in a given water, but, as any one acquainted with chemistry knows, these compounds cannot be identified as such when they occur in small quantity, and the cases are exceptional where it is not erroneous to regard the zinc as thus existing. In most waters it is justifiable to regard the dissolved zinc as existing as carbonate, and the amount, at the most, is so small that the action on the system is not to be feared, at least from an allopathic point of view. It is said that 'there are on record a number of cases of zinc-poisoning from the use of galvanized-iron pipes.' This may be so, but in some of the cases, at any rate, the records are decidedly open to criticism. The question of the use of galvanized pipes, tanks, etc., was investigated quite thoroughly in 1873 for the Massachusetts State Board of Health by Dr. W. E. Boardman, who gives the pros and cons in the matter. No doubt the investigation was undertaken partly because of the then somewhat recent occurrence in the neighborhood of Boston of cases of sickness and death which were ascribed to the drinking of water which had passed through 'galvanized' pipe. Dr. Boardman and other competent physicians concluded that there was not in 'these cases adequate evidence to establish the correctness of the opinion given as to the nature of the illness in the way of cause and effect,' and other cases were investigated with a similar result.

"The writer would not wish to be understood as implying that there may not be cases of well-authenticated ill effects; he is familiar with waters in connection with which he certainly would not advise the use of zincked pipe, but these waters would not be recommended for domestic use. The largest amount of zinc in solution which the writer remembers at the moment to have met with was 0.85 grains to the gallon; this would correspond to nearly 1.1 grain of oxide of zinc. A much larger amount could exist in solution, even in the form of the difficultly soluble carbonate. As much as six grains has been reported in solution and suspension together, but in such cases probably the larger part was in suspension. For the particulars of the effects of the different compounds of zinc, the size of doses given medicinally or for experimental purposes, and for other similar data any persons interested are referred to the paper of Dr. Boardman alluded to above."