THE WATER SUPPLIES OF ILLINOIS.
IN the latter part of September, 1895, the State of Illinois began a survey of its waters for the purpose of systematically determining the present sanitary condition of the water supplies drawn from lakes, streams, and wells, the
normal condition of the incontaminated water, the formulation of local standards of purity based upon the results of analyses of water derived from unpolluted sources, the provision of such means as shall afford to citizens of the State opportunity to obtain immediate information regarding the wholesomeness of the potable waters in which they are directly interested and the prevention of the development and dissemination of disease from the use of impure water.
The available sources of the State’s water supply are practically limited to rain water, low land surface water from streams and lakes, and ground water from wells of greater or less depth. The water from each one of these sources, and from each class among these sources differs most widely-the result usually of local conditions. The water courses are natural drainage channels, which, as they receive the drainage of all the town and villages situated within their respective watersheds, nearly all, therefore, now consist of diluted sewage. The rain water when kept in cisterns is equally im pure, and the ground water from wells is too often as bad, owing to the propinquity of sources of pollution. The earth ceitainly filters that pollution; but filtration to be effectual must be more or less intermittent-that is, the filtering material must lie fiequcntly renewed either by replacement, or by exposure to the air. In any case well water, even that drawn from a great depth, is deceptive and may be contaminated in most unsuspected ways and may receive dejecta from diseased human beings washed down upon the surface with the rain water from great distances.
In order, therefore, to arrive at a full knowledge of the condition of its water supplics.thc State of Illinois has thoroughly equipped a laboratory for analytical purposes and employed a first-class expert staff to conduct the investigation, which differs from that of ores, etc,, in that the
results of a chemical examination of a water are not in themselves sufficient to indicate the character of the water in any ordinary case * * * The data resulting from a water analysis require interpretation, and it is essential that the one who is to interpret shall have complete information regarding the history of the water its source, the surroundings, also, in case of a well, the nature Of the strata from wh!ch the water comes, as well as the overlying strata, and, in fact, as complete information as it is possiole to obtain. Even with this information the formation of a correct conclusion is in many cases a difficult matter, and is ordinarily er.tirly beyond the powers of the layman. A wholesome water power from a certain source may contain such qualities of the various constituents as would, if found in the water from a different source, serve entirely to condemn the latter. The significance of the results depends usually directly upon the sources of the water.
Qf these substances, the determination of which is most itpportant, some are originally present in minute quantities; but their quantity is easily increased by the use of improper vessels and methods in taking the same.
The most explicit instructions for collecting samples for analysis were, therefore, issued to those intrusted with the task. Every imaginable detail was set down, all tending to secure the desired object.
Regular analysis of the water also included the determination of turbidity,sediment, color, odor, residue on evaporation, loss on ignition, nitrogen in the four different states-e., as free or saline ammonia, as aluminoid ammonia, as nitrites, as nitrates, chlorine contained as chlorides, and oxygen consumed. In the case of turbid waters from rivers, etc., similar determillations were made with the water in its original condition and after it had been filtered, so as to distinguish between constituents contained in solution, and those merely held in solution, the hardness, the determination of the dissolved gases, the degree of alkalinity, the quantity of phosphorus contained as phosphates, etc,-the last, so as to note, if possible, the relation between chlorine and phosphorus in normal and in polluted waters. Quantitative analyses were likewise made in a few cases of the mineral matters contained in the waters. When the water was received at the laboratory it was examined for turbidity and sediment, and again,after standing over night, determination has been made by mere inspection. In the case of certain turbid surface waters and some deep well water, determinations were made of the nitrogen as free and as albuminoid ammonia, the total organic nitrogen, the oxygen consumed, the total solids, and the loss on ignition in the water after it has been filtered, in addition to the determinations made with the water in its original condition. The odor, as a rule, was noted in the original condition of the sample as brought in to the laboratory; sometimes, however, it was put in a covered vessel warmed gently, and brought near to the nostrils just before the cover was removed. The color was determined directly by comparing it to the tint developed in the Nessler standards-the method adopted by the Massachusetts board of health. The hardness was not generally determined; but whenever it seemed especially desirable it was estimated by the use of soap solutions as per Clark’s method Other scientific methods, too long to be described here, were employed for the other determinations.
A large number of the citizens seemed most anxious about the chemical analysis of their wells, as the greater part of the water in the State is drawn from such sources. The statement of results in the report was made in part by weight per million parts of water by weight; hence, one part in the report is equivalent to one ten-thousandth of one percent, or is equivalent to .058335 grain per United States gallon of 231 cubic inches.
So far as concerned standards of purity whereby to establish the condition of potable waters, no hard and fast line could be established. The following limits were, however, adopted provisionally as a reasonable basis for reaching conclusions regarding the wholesomeness of the waters of ordinary shallow wells.
MAX1MUM LIMITS OF IMPURITIES.
During the fifteen months since the work was inaugurated 1,787 samples of water from various sources within the State were examined,a large proportion of which consisted of analyses of single samples of water from house wells or cisterns used for domestic supply-many of which were suspected of being the causes of typhoid or diptheria cases in the localities whence they were taken. In the majority of cases the analyses showed there was only too good ground for this suspicion by revealing evidence of the contamination of the water of the wells by sewage or drainage of refuse matters of animal origin, and (adds the report) “the results of our investigation have in numerous instances led to the condemnation of the sources of supplies being in such condition as to endanger the health of the users.”
These analyses are arranged in three general groups: (1) Analyses of 802 water samples from house wells,cisterns, or springs used for family supply; (2) records of the periodic examinations of the water of certain wells, of which the analyses have been made for the purpose of determining the normal characteristics of some of the ground waters of the State; (3) examinations of certain surface waters, mainly those of the Illinois river and some of its tributaries. The various samples, 1,787 in number, came from 156 towns situated in sixty-eight different counties of the State. A fair idea of the general distribution of the localities of the sources whence the waters came for analysis may be bad by inspection of the accompanying map. The locations of water sources are shown by the heavy black circles.
More than half of the people of Illinois depend upon wells for their water supply, a small part of which is derived from the rock strata; by far the greater part being drawn from the deposits which overlie the rocks, which deposits, with the exception of one small area in the extreme southern end of the State, consist of glacial detritus. These present most varied characteristics, depending upon the nature of the outcrop upon which the waters as originally gathered and the strata with which they come in contact on their way to the point at which they issue from the earth. The artesian wells are as a rule entirely free from impurities derived from the products and wastes of habitation, and contain various substances, medicinal and otherwise, leached from the rock strata and frequently are heavily charged with common salt.
Nearly the whole surface of Illinois is covered with deposits of glacial detritus, the drift and the loess, to depths of from ten to 150 feet-even 250 feet or more These deposits include strata of sand, gravel, and clay in almost infinite variety of character, fineness,and states of admixture with each other, and range from pure, clean-rock fragments, silica, etc., and pure kaolin on the one hand to indeterminate mixtures containing large proportions of organic matters, the remains of vegetable life, on the other. Largely as ancient surface soils, great beds, and the like, have been covered by considerable deposits of sand, gravel, clay, etc., many such buried surface soils containing the remains of the organic matters incident to the luxuriant vegetable growths of past ages lie one below another in some localities and are separated by intervening drift deposits,ranging fronj several feet to fifty or sixty feel in thickness Of these drift strata many are water-bearing and have wells more or less deep sunk in them. These waters, with their almost endless varieties of minor characteristics (depending, of course, upon the composition of the deposits with which they have been in contact), fall naturally into two groups-with referrence to their leading qualities and the relative proportions of their several nitrogenous constituents-(1) shallow drifts, and (2) deep drift waters; the differences manifested depending upon the depth ftom which the waters were drawn.
Normal shallow drift waters contain the various salts and other substances which have been leached from the upper soil, essentially in unchanged condition-i. e., they contain chlorides, sulphates,carbonates and silicates of calcium magnesium, potassium, and sodium, with minute quantities of iron and aluminum compounds, together with considerable quantities of nitrates, but only minute quantities of saline ammonia and albuminoids; organic matters are almost entirely absent. Nitrites are frequently present in notable quantity.
Normal deep drift waters contain in general the same mineral salts as the shallow waters; but usually the quantity of iron is considerable, and the nitrates are either entirely absent or present in but minute quantities, while free ammonia is abundant, and albuminoids ate present in comparatively considerable quantities. “ Oxy en consumed ” is high, and tie water residue blackens upon being heated, showing that much organic matter is contained.
There are marked differences between the two waters in appearance and palatability. Those from shallow wells are well aerated, clear, sparkling and of agreeable taste; those from deeper wells, on the contrary, contain little, or no oxygen, arc of a disagreeable taste, denoting the presence of marsh gas, and occasionally accompanied by minute quantities of sulphuretted t ydrogen. They are either turbid or quickly become so on exposure to the air, owing to the oxidation of the iron carbonate contained in them and the consequent precipitation of insoluble ferric compounds. The precipitating particles are often so minute as to be at first indistinguishable except from the color which they impart to the water; but after a short exposure to the air the water becomes opalescent, then de cidedly turbid; finally a brown deposit, like iron rust, is produced, and after this is separated, the water becomes clear and colorless, nevertheless, such waters from a sanitary standpoint are more wholesome than the more inviting looking waters from the shallow drift wells, which are much more liable than the former to pollution with refuse animal matter, while whatever organic matters the deeper drift wells hide in their waters are derived from the buried vegetable remains already referred to and are comparatively harmless.
The surface waterof Illinois which have been subjected to ex-. amination were chiefly sampled from the Illinois river and several of its tributaries, including the Illinois and Michigan canal -some samples, however, were from the Mississipi at Alton, Golden Eagle and Quincy and from the Vermilion river at La Salle, The details of these analyses will follow in another report-n fact the present is but a preliminary report, though, so far as concerns the wells it is thoroughly exhaustive.
An interesting instance of the effect of the purification of the water supply is shown in the cases of Jersey City and Newark, N. J-two cities practically under the same climatic and geographical conditions, being separated by the lersey meadows. Upto April, 15,1893.the I’assaic river was the source of the water supply of each city. This water was greatly contaminated by sewage. Up to that date the annual deaths from typhoid fever during three years were as follows:
In April, 1893, Newrrk began using I’-quannock from a watershed unexposed to pollution; Jersey City continuing to use the I’assaic water. The result was a diminution in the death rate from typhoid fever to one-fifth of its formei proportions in Newark as the following table shows:
An abundant water supply alone, does not diminish the death rate front typhoid fever. This is shown in the case of Dantzic, a very badly sewered city, which in 1869 had an annual death rate from typhoid fever of ten. An abundant supply of pure water was introduced, but no marked’eduction in the death rate occurred until the city was sewered in 1872, when it fell to 1.5.
New York has less than one half the amount of water supply per capita than Washington, and yet its death rate from typhoid fever is just one-half of the latter city.
The experiences of other foreign cities furnish statistics going to prove the close relation of pure drinking water to the health of the community.
From 1841 to 1850, the deccnnium previous to the adoption of sand filtration for the purification of the Thames, l.ea, and New River waters, the average annual death rate from typhoid fever in London was 9 8. During the next ten years, which embraced eight to nine years’use of the now well known lamdon filter beds, the death rate from typhoid fever wan 8.7. That is, for the first decade during which the filters were in use the reduction of the mortality was about fourteen per cent. For the decade 1871-1880 It dropped to 2.4, for that from 1881-1890, to 1.9. and for the past five years it has fallen as low as 1.4. This is a reduction in the death rate from typhoid fever alone of eighty six per cent, since the introduction of the I-ondon filters.
At Munich, Vienna, and Berlin,the death rates from typhoid fever arc very low. The following table compares the death rate in these cities as compared to those in three American cities:
The fact that the population in these cities are great beer drinkers may, perhaps, have some influence in bringing about the low death rates from typhoid fever; but the main factor is the pure water supply. Vienna at present gels its water from the Schnceburg. through an aqueduct fifty miles long. Up to 1874 well water was used almost exclusively. Owing to defective diainage this was very impure, and the annual death rate from typhoid fever was. very high-10 to 34.
Berlin gets its water from the river Spree and lake Tegel. the waters of both being passed through sand filters.
Munich from 1854 to 1859, had a death rate from typhoid fever of 24. In i860 the sides and bottoms of the privy pits were cemented and the death rate fell to 16.80 Between that time and 1864. good sewerage was introduced and the rate fell to 1.75.
In Stockholm, before sewers were introduced the death rate from typhoid fever »as 5.1. As the number of metres of sewer pipes increased, the death rate from typhoid fever steadily diminished, until in 1887, with 65,701) metres of sewers, the death rate was only 1.7.
Breslau, before being sewered, had a death rate from typhoid fever of 15 2. Ten years later, after proper sewers had been introduced, the death rate had fallen to 5.5.
A FILTRATION EXPERIMENT.
Marshal Pridham,a graduate of the Pennsylvania University, claims to have discovered a perfect method of filtering the water of the Schuylkill. The following is an abridged account of a recent experimental trial of his system.
In the upper floor of a Philadelphia syrup refinery were built three wooden reservoirs, near which was a simple electrical apparatus. Into the first of the reservoirs were dumped seventy-five pounds of sewer mud, coal dust and other refuse. Then about sixty gallons of Schuylkill water were turned on from a hydrant through a hose. The first reservoir was connected with the second by a long glass tube. After it had been filled the mixtnre (very filthy and evil smelling) of Schuylkill water, sewer mud, eti., was thoroughly stirred up with a pole and then allowed to flow through the glass tube into the second reservoir. As it passed through the tube, nothing could look blacker or more full of corruption. The second reservoir was fitted up with a series of metal plates set edge wise. As soon as the plates had been colored with the dark colored fluid, Mr. I’ridham turned on the electrical current, which found its way to the Second reservoir through a series of wires. In about two minutes a valve at the lower end of the second reservoir was opened, and at the same time an electrical generator of ozone was started,and almost immediately a stream of clear sparkling water began to flow through a second glass tube into the third reservoir, and was drawn from there into small glass receptacles and passed around among the spectators -all o f whom before drinking it smelled nothing disagreeable, and in drinking it no approach to an unpleasant taste. The inventor claimed that all the bacteria had been killed by the application of his system. According to his method of purification, when the impure water reaches the second reservoir, it is decomposed by the electricity and the heavier impurities sink to the bottom: the lighter foreign matter meanwhile forming a scum on the top. In passing to the third reservoir, the ozone which is introduced sterilizes it so that when it reaches the third reservoir it is as pure as any water can be, though retaining all of it natural qualities.
The company which owns the patents on the process would like to have it tried on a large scale on the Schuylkill water,and claims that an experimental plant, with a capacity of 25,000, >000 gallons a day can be built for about $65,000, and further that the entire water consumption of the city, 400,000,000 gallons daily, can be filtered and rendered perfectly pure, it is claimed, at an expense of less than seventy cents per million gallons or a little over $100,000 per annum. The cost of erecting filtration plants of sufficient capacity to do this would be, according to estimates made, not over $750,000.