History of the Water Supply of the World / arranged in a comprehensive form from eminent authorities, containing a description of the various methods of water supply, pollution and purification of waters, and sanitary effects, with analyses of potable waters, also geology and water strata of Hamilton county, Ohio, statistics of the Ohio river, proposed water supply of Cincinnati.

by Thomas J. Bell

QUALITY OF POLLUTION.

Scientists tell us that it is not so much the quantity as the quality of the sewage:

“It is true a large amount of refuse material is of such character as to be, except in excessive quantities, of no appreciable influence on the human system; the addition of the inorganic compounds of lime, soda, potash, etc., would have no deleterious effect; in fact, although the lime compounds increase the hardness of water, and make it less desirable for washing, the presence of a moderate amount of mineral substance makes the water more palatable and very probably more wholesome.

“Then, in case of many waste liquors, which appear to be very offensive, the matter which really could be regarded as injurious is comparatively small in amount. If we consider the character of the substances discharged by different manufacturing establishments, we shall find them very different. Some of them are such as to be universally regarded as unfit to admit to any stream; those, for instance, containing lead, arsenic, etc.; others, such as salts of iron, are scarcely regarded as injurious; thus, the discharge of sulphate of iron (copperas) into a stream already polluted with sewage matter, might, within certain limits, be of positive advantage. Again, in the case of some of the vegetable dye-stuffs, the weak-spent dye liquors, although they communicate a very foul appearance to the water for some distance, yet contain a comparatively small amount of solid matter, and, if discharged into a stream of considerable size, as soon as disseminated through it, are diluted to a very great extent.

“Different in character, however, from much of the refuse of manufacturing establishments is the sewage coming from dwellings, or the sewage (in its more restricted sense of excremental matter from animal sources) which comes from our manufactories. In fact, this foul material, coming from establishments employing a large number of operators, is likely, in many cases, to have a more injurious effect upon the stream into which it is thrown than refuse from the manufacturing operations. There are, however, some branches of industry which discharge refuse material offensive and dangerous to health. Such material is discharged from tanneries, wool-pulling and hide-dressing establishments, slaughter-houses and rendering-houses. ‘Too much stress can not be laid upon the importance of preventing the discharge of such refuse.’”—(Prof. Nichols, in Fifth Annual Report of Massachusetts State Board of Health.)

“The discharge of gas works is known to kill fish and destroy lower forms of animal life, which are important agents in preserving the purity of fresh water.

“One would not assert that the drainage of a single house would contaminate the water of a large river like the Merrimack so as to make it unfit for domestic use, yet we must beware how we depreciate the effect of sewage matter, even in a large stream.”—(Prof. Nichols, in Fifth Annual Report of Massachusetts State Board of Health, 1875.)

“With small amount of sewage the chances are favorable for the action of atmospheric influences, and particles of undecomposed material-propagating disease are rendered proportionally small, owing to the great dilution.

“A minute quantity may do much harm, because it is now generally believed, that it may hold the specific thing that propagates specific diseases.

“Rice water evacuations, of a cholera patient, however much diluted, still remains in liquid, although chemical test fails to detect it.

“The carcass of a dead animal, thrown into a river or pond, and confined there, so as not to be borne off bodily, gradually wastes away, and, in a longer or shorter time, the main part of the carcass has disappeared. What has become of it? A part has been converted into gaseous products of decomposition, as the offensive odors observed during the decay will testify; but another portion has been carried off by the stream as soluble nitrogenous organic matter. This nitrogenous matter would be detected a short distance away, with greater or less ease, according to the volume of water present; but in a stream of large size, or in a lake at no very great distance from the source of contamination, it would be impossible to discover any offensive matter. There is a limit to the delicacy of our tests: there is a point beyond which, at the present, we are not able to go. At the present time, a chemical analysis alone is not sufficient to determine the desirability of a given water-supply.”—(Rivers Pollution Commission, 1874.)

“The action of a float, upon or near the surface of the water, is no indication of the movement, back and forth, of the sewage in suspension. Portions of fresh sewage, it is true, will float, but after maceration the sewage has a specific gravity of about 1.325, and will sink, in still water, or very slow currents, at the rate of one foot per minute; but in a current of 170 feet a minute, it will not sink, but remain in suspension.”—(J. W. Adams, C. E., Water Supply Commission of Philadelphia, 1874.)

“This evidence, taken in connection with our own investigations, appear to us, conclusively, to prove:

“1st. That there is, at certain times, in human excreta, some material capable of producing disease, of a very fatal character, in human subjects.

“2d. That this morbific matter can be detected only by its specific action upon human subject, and can not be distinguished, either by chemical or microscopical analysis, even in the concentrated excreta, much less in water mixed with the excreta.

“3d. That, inasmuch as the organic matters of sewage are oxidized and destroyed with extreme slowness in running water, there is great probability that morbific matter will escape destruction and be conveyed to great distances in rivers and streams.”—(Rivers Pollution Commission, 1874.)

“Carbonates of calcium and lime produce temporary hardness; while sulphate of lime and calcium and salts of magnesium produce permanent hardness.

“Temporary hardness is objectionable for culinary and manufacturing purposes, and excessive hardness is productive of disease known as gravel. Magnesium salts are especially objectionable, because they cause diarrhœa and dyspepsia. Goitre, or swelling of the glands and cretinism, a kind of insanity, are charged to this impurity.

“Frequently, the water happens to be a little off color, especially after a heavy storm, and the consumers get an idea that the water is poisoned, and no amount of re-assuring will prove the reverse. Such cases occurred in New York City, once or twice, during the late war with the South. A little investigation will show the absurdity of such a thing.

“One-sixteenth of a grain of strychnine is necessary to poison a person. It would, therefore, require three and one-half tons of strychnine to have poisoned the Croton water effectually—a quantity not to be had in the world, and to procure it would take about three years.

“If arsenic was desirable, two grains for each person would be required, or 114 tons for the whole population of the city at that time. Living animals, when seen under the microscope, are very formidable in appearance and frightful in motion, yet they are not objectionable. They only inhabit very pure water. It sometimes happens, owing, perhaps, to some peculiarity of the season, that these little animals multiply to such an extent as to produce serious annoyance.

“It is stated that one-sixth of the deaths in Iceland are caused by little animals being taken into the system. Young leeches, contained in drinking water, sometimes fix themselves on the pharynx. In Algiers, 400 French soldiers were sick at one time from this cause.”—(From Prof. Foote’s lecture.)