THE N E W YORK WATER SUPP1.Y.
127
perature of 6 5 O C. f ( ~30 r minutes, be iised, t h w e will be but slight if any differencee in the results, provided that the s mliition of citrate be slightly ammoniacal, and the digestion be tnadr in a closed flask. T o the use of a ci d solutions of citrate, either acid a t the beginning or the digestion or becoming acid during its continuance, are probably due more than to any other cause, the discrepancies in this analytical process.
XVIII. ‘I’HE CONTAMINATION OF THE N E W Y O R K W A T E R SUPPLY. BY
DR ALBERT R. LEEDS
I n this jo.urnal (vol. 111, 98,) I have given under thc title “Relative purity of city watera in the United States,” the analyses of the drinking waters of many of our large cities, as performed by the same methods, and as made upon samples collected a t or near the same date. As a necessary deduction from these results, the drinking waters arranged themselves in a series, in which the Brooklyn water occupied the place of honor as the purest, the Boston water the lowest place, being the most foul. The New P o r k water, No. VI, fell in the middle of the series. The water supplies (judged by the samples analyzed) of Brooklyn, Rochester, Philadelphia, Baltimore and Washington, were pronounced satisfactory. Those of New York, Newark, Jersey City, Hoboken, Cincinnati, Oswego, Wilminpton (Del.) and Boston, were stated to be contaminated. There was no question as to the contamination of the Newark (Passaic) water (No. 7’), because its impurities were established by a multitude of analyses. And with wgard to the Croton water the evidence of contamination was found in the facts : 1st. That its various impurities exceeded the limits which are allowab e i n a pure drinking water. %nd. T h a t its composition approached very closely to that of the Passaic. of whose contamination there could be no question ; 3rd. That the water shed of t h e Croton contained suficient sources of pollution to account for the figures obtained by analysis. The results above summarized have been accepted without cavil, except in the caee of the New York water supply. T h e pollution of the Boston water was so great that 1 could not credit my resulte without making a personal inspection of the sources of the Boston supply. This I did at a later season, and found not only were the first results more than confirmed but that the sources of pollution
128
TI{& N E W YORK WATER SUPPLY.
were unniist:ikablc. They were in the first place, t h e impurities thrown i n b y nranriftlcturing comniunities ; and secondly, the enormous expansion of cacrtain organic growths at favorable seasons of the year T h e i.esult,s ixblnting t o the water snpply ofwilmington, Del., w~1icl),were a t first objected to b y t h e ilniiit’ormed local press of tliat city, W C I Y later on ncknowlcdged by tlie health arid city authorities to be -\varrantctl hy the acatrial facts, and I ani a t prrsent engaged on lwhxlf of this city t o investigate the prt&e nature and extent of the plliitiun. Ur. E Waller i i i this journal (lTol,IV, p. 15), has objected t o t h e New York water supply being characterized as vontamin?trd, on the ground that his results, for a term of .yeais, differ greatly from my own and are of a more tnvorable character. Also, for the reason that the Croton water shed cannot originate any sources of contamination ; and finally, that the health of New York is not, an(1 has never been, siivh as t o iric1ie:ite tire presence of any contamination in tlic water supply. 111 I ~ I ! , I korild state : 1st. ‘I’lrxt the analyses of the New York water, on whicli Dr. W a l l r ~l)ases ~ his opinion, have been incomplete, and data have been lost sight oc, which are of the greatest valuein forming a judgment a8 t o the fact of cwntnmination. 2ntl. That certniii of his methods are erroneons, and of necekjity givc a more f a v o r n h l r impression of the water than it,s true chnractcr \VarrRlltS. 3 r ~ l .‘I’hc analysis of the Cr iton water niade J u n e 231.11, 1887, does not stand alone, but is confirmat,ory of other previous analyses ivliirl~led me t o the conclusion that the Croton water was con ai.iinntecl. I t was not made, as Dr. IValler intimates, upon water turbid with scdinitmt, but upon clear water drawl) from the continuously floivirig faucet in t h e Barclay sweet feiq-house. I took it from this source as affording a very fair average saml’lp of Croton water and I have no reason for supposing that it was otherwi+e. 4th. T l i e a ~ n d i t i o nof the Croton mater shed is sucsh as to account for the figurw given in riiy nnalysis. T h e table of populatioil given b y Dr. Wallcr f u r the, water sheds, does not explain the facts which exi.;t ; for Etocliestcr with b u t /w{f the density of population on its IIernlock Lake water shed, that exists upon the Croton, has a far superior w;itclr supl)ly, while Hrooklyn on the other hand, with dotthk the population, has a better srilqily than either. 5th. There are no clatn given, or so far as I know ever have been
THE NEW YORK WATER SUPPLY.
129
given, upon which conclusions can be based coiinecting the vital statistic* of New P o r k with the character of its water supply. T h e face of Dr.Waller’s assertion is not to be measured by it8 positiveness, but upon the appositeness and weight of the data upon which it is Iiased, and of siich data he has given us none. I t is extremely difficult, unfortriiiately, to connect the various distases of a great commuiiity with the more or less deteriorated cmdition c,f its water supply. Unfortunately. because if the connection were one easily proved, both chcmist and mediva1 practitioner could arrive with eaSe and certainty a t results whiohare now open to more or less criticism. Whilst reiter tting i n vsrioris commnnications the statement that the water supply of Newark x i i d Jersey City is contaminated, and in seasoiis of excessive di-otiglit like the summers of 1881 badly so, I have repeatedly challeiigcd the physicians of tliese towns, to connect by irrefragihle demonstration, the impiirity of the water with any case of diwease, aiid they have professed their inability so t o do. I mention this, inore particulai-ly because tlie chemist is ofteii acciisetl by the l~hysiciaiiof reporting a long series of decimals, withoiit satisfactorily showiiig that any of the sllbstance~reported are specific causea of disease. Here, on the other hand, is a case wliere for years the water has been reported, on the strength of the oxidizable and oxidized nitrogenous matters which it uontairis, to be coi~taminated,and yet no phjsician has proven, or attempted to prove, that any particular case of disease has been due t o dririkiiig it. I n the population of 50,000 people inhahiring the town of Patcrson, which 1~0u1-sall its sewage iiito the Passaic at a point 16 iniles above the inrakes of the pumping stations of Newark and Jersey City, and in the city of Pass.tic with its coiisiderable population likewise sewerilia into the Passaic river a t a point nnly half this distalice, there must be many cases of typhoid fever, yet 110 one has ever shown that a single case of tyl)lioid fever has h e n originated i n Newark and Jersey City b y drinking the Pwssaic water. From what ‘souwe tlieii does Dr. Waller derive the statistics upon whicli lie inl’em the purity of the Croton water from the death-rate of the New York population :J r . 1 o return, however, to the mnre serious sources of error in tt:e methods made use of by Dr. Wallel-. 1st. With reference t o the incompleteness of his analyses. H e h a s charged me with iridefiniteriess in the use of the terms “nitrites" and “ nitrates.” I fail entirely to see any iiidefiiiiteiiess. I used these terms because they were the proper generic names of the sub-
high, the ainount of nitrites is iisuslly quite inappreciable. And tlie Same is generally t i w of river-waters. I n the 23 samples of water, tlie com1)ositioii of wliicli is given ill t,hc table upon the W o m p a r a tive Purity of City Waters in the ITnited States,” no reaction for nitrites Iiappenecl t o be obtained in the case of any one of them. ,4nd yet the Bo3ton water reqiiired t,he eiiormotis amount of 1.77 parts t o the 100,000 of oxygen to effect the oxidation of its organic mat;crs, an11 contained 1.24 parts of nitrates. Sometimes the Passaic water does afford the nitroiis reaction, but in these cases I have attributed it, to the non.oxidized sewage of Newark which has only to flow npward for a couple of miles before reachiiig the intnkei of tlie ~ ~ u m p i i i ~ - s t n t i orather n s , than to the sewage of Paterson, which has t u flow clownward 1G milcs before reacliing the same points, and is iisnally completely oxidized in its long exposure. l‘he fact tliat a t times I have obtained from the Croton the nit r o w reac,tiori, in one iristance a reaction strong enough to aiimit of quantitative estimatiou, has had due weight ill forminq my estimation of its purity. 2nd. The method which Dr. Waller employed of determining the :imount of oxygen required to oxidize the org iiiic matter is erroncoils, and of necessity gives a more fitvomble impitssion of the watcr than its true character deserves. I n m:iking tliis statement, I am aware of what has been written in favor of th s metlioil, b u t see no reason for regarding it otherwise than erroneoiis. If it is desired to oxidize tho organic matter in drinking waters by Imtassium perinaiiganntv, so as to destroy the 1)ossihly noxious sultstances, the wat1-r to which tlie potassium pcrmniigaiiate has Lecn ;iddud ie boiled before it is tliotight entirely safe to drink. If the potassium permangiuiate is to be standaidized by an orgnnic substance, as i t is in this instance Ly oxalic:. acid, thc stantlnrdization is performed by heating the solution of oxalic adid or of pyrin:mgannte. But, in making the cleteimiitiatioii of the organic matter in the water itself, tliis method proposes it should be done a t a variable comnion temperature. Of coiirse. only a small aniourit (If tlie organic matter in the water is thus oxidized, and althoiigh it is claimed that this part is the really dangeroiis putrescible portion, the fact still iemains that only a part of the orgaiiic matter is ,attacked b y the permanganate in‘ the cold, and the method is thus far erroneous. Still more, the method lacks t h e esseiitials of an accurate Jolumetric estimation, and does not admit. of arriving a t a certain end reaction. I tried the method, and after satisfying myself of its essential
13%
T H E NEW YOBK WATER SUPPLY.
inaccuracy, adopted what appehred to me the mqst fiatisfactory a n d definite process, tliat of titration at t,he boiling point. Dr. Waller's objections to this method are f;irloit'ul rather than real. The impurities i l l the y e r i n a n ~ a n a t cand sulphuric acid, though actually present, are too small to adliiii, of any aliprwiahle iiiflueiioe on tlie results. The objection that t l i c h ctiloi~ictesi i i the \v:Lter would affect t h e results has greater weight, but i i i pi.autioe these eri'oi's, like those produced i i i Tidy's rnoditicatiori of the periliariganate process 1)s the pixseiice of clilorides, are t o o miall t o bc coiisidei,cLd. I a m fortiinately able to bring ati cJxpcrirnetit, perfoi,med UII p.,lliited iiat ural waters tlielnselvcs, to cwtiti~~m this statemeut. The Passaic water (Yept. tith, ISSl), at tlic iiitake of the Jersey City Rcservoir, contained in 100,000 parts: LOW TIDE. HIGH TIDE. Chlorine, Oxygen required
1
E. Biiiik. ~litltlle. JV, Batik. 5.73 2.10 3.40 0.55
0.44
E. B ; I I I ~Miiltllc. . W.Btink, 55.88 44.76 60.?5
0.44
0.47
0.60
0.76
T h e differences had been caused by the backing up of the river waters, on meeting the tidal wave f r u m the sea. Ori the same day, and iipon t,he same two tides, the differences for the corresponding points a t tlie Newark Reservoir, threc-quarters of a iriile further u p stream, were : LOW TIDE. HIGH TIDE. E. B:iiik. ?:litltlle. W. Bwk. E. Brltik. Mitlillc. W. B:iiik. Chlorine, 2.185 1.17 2.505 21.13 25.00 14.50 Oxy. required, 0.62 0.56 0.43 1.80 2.82 2.82
But it may be objected to these resiilts, that the oxydizahle organic matters i i i the various samples varied greatly, RO tliat n o inferrnce could be rlisawn with regard to the iiiflueiice of tlie chloi.irie itself. This objeotioii does riot aliply to the water taken at iir~ervslsof about a mile down tlic stream, u1)on the same cl ~y (Sept. 6 t h , 'SI). Beginning at a point below tlie Tail Race at Passaic Nills, m e found for samples : NI). 7.5
76
77
78
70
80
81
82
83
84
0 . 5 3 0.liO 0.94 0.57 1.57 1.005 0.90 0.5fi 1.10 %.505 Chlorine, Oxy. required 0.53 0.50 0.49 0.52 0.51 0.59 0.47 0.47 0.44 0.43
It mzy be objected, however, that. all these reRiilts merely raise a strong presumption in favor of the propositioli that tLe sinall
THE NEW YORK WATER SUPPLY.
133
amounts of salt i n river water d o not appreciably raise the figures obtained by permanganate at the boiling point. They do not prove it ; for proof a suitable experiment is demanded. I n the first plar-e, it was necessary to determitie the coefficient of change, when potassium permangirnate i3 boiled with distilled water. Both in the cold and on heatiiig, potassiiim permanganate changes in acidulated solution with distilled water, and the amount of this change has to be determined in both cases, and a corresponding deduction has to be made from the amount obtained with an equal volume of the natural water nnder examination, I thus obtained : 100 cc. distilled water, Miller’s method (3 hr.) 0.9 cc. permanganate. 100 cc. diatilled water, Kubel’s method, - - 0.9 cc. permanganate. Another test by Kitbel’a method on a different, fiample of distilled water, and with different pcrmanganate solution, gave 1.15 cc. permanganate. I n otlier words, in order to make use of Miller’s method with any expectation of arriving a t accurate results, it is necessary in each case to apl’ly a correctiott due to the alteration of the permanganate alone. . This and many other p:ecautions C. M. Tidy (Jour. London Chem. Soc., xxxv., p. 46) has tak-n, i n order if possible t o bring Miller’s process into a form capable of yielding regular and accurate results. Elit I do not find in Dr. Wnller’s account of Mil!er’s method, as he employed it, that any such precautions were taken. The influence of these corrections may be perceived by considering the great changes thereby produced in Dr. Waller’s results. For illstance, for the first five months of the year 1879, he obtained 0.072 parts of oxygen per 100,000, aa the ar,nount required to oryitize the organic matter. This would be eqiial to 0.72 cc. permanganate solution used. If, as is possible, lie had obtained 0.9 cc. as tlie correction t o be applied by the use of the permatiganate solution with distilled water alone, there would have been left a minus quantity, o r 0.018 parts of oxygen, as the amount required t o oxydize the organic matters in the Croton water. Dr. Tidy has endeavored to find the extent to which the chlorides affect the accuracy of the modified Miller’s method, and has found that their iufluence, even when present in very large quantities, practically nil. A similar remark applies to the effect of chlorides o n the results afforded by Kubel’s method. F o r instauce, in an experiment in which 100 cc. of distilled water decolorized on boiling 1.15 00. permanganate, i t decolorized only 1.3 cc. permanganate
Free ;ttninoniiL. . . . . . . . . . . Albuminoid amniunia. . . . . . Or;yg(*ii wqiiired. . . . . . . . . . ?ii tri .................. S i t r:i t c!s . . . . . . . . . . . . . . . . . . Cli1ori ti e . . . . . . . . . . . . . . . . . . 'I'utnl Iiardness. . . . . . . . . . . . ttb.
1'criii;i; I en t 1iai.dness . . . . . . . 'l'eiiiporary hardiicss. . . . . . . . '1'0 t a1 s( 1 i t i s . . . . . . . . . . . . . )
Jliriei a1 matters. . . . . . . . . . .
Organic and volatile mattel,?;
