Report of streams examination, chemic and bacteriologic : of the waters between lake Michigan at Chicago and the Mississippi river at St. Louis, for the purpose of determining their condition and quality before and after the opening of the drainage channel / Made under the direction of Arthur R. Reynolds, M. D., commissioner of health ... pub. by authority of the trustees of the Sanitary district of Chicago.

  • Chicago (Ill.). Department of Health.
Date:
1902
Catalogue details

Licence: In copyright

Credit: Report of streams examination, chemic and bacteriologic : of the waters between lake Michigan at Chicago and the Mississippi river at St. Louis, for the purpose of determining their condition and quality before and after the opening of the drainage channel / Made under the direction of Arthur R. Reynolds, M. D., commissioner of health ... pub. by authority of the trustees of the Sanitary district of Chicago. Source: Wellcome Collection.

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    corresponding bottle for the chemical samples, fitted into a wooden box, one such outfit being shipped to the collector each week. Great pains were taken to insure that the sample was obtained with due bacterial precau- tions, and in order to emphasize the instructions given to the collector personal visits, involving careful supervision and recurrent demonstration, were made frequently to all the more important points of collection. The water sample was always taken at a point about eight inches below the surface and in midstream, except at Joliet and save where cross-sections were taken. The bottle of water was placed in its covered case as soon as collected, and this case was then packed in the canister and completely surrounded with ice. The hour of collection was always timed to permit of as speedy shipment as possible. The chemical samples were collected in glass-stoppered bottles of one-gallon capacity. These were cleaned with chromic acid cleaning mix- ture each time before being sent out from the laboratory, thoroughly rinsed with ammonia-free water and drained. The stoppers were secured in place by tying tightly over them a piece of rubber cloth. After filling the bottle the cloth cap was fastened in place with wire which was sealed with stamped metal. (b) Methods of Physical and Chemical Analysis. A serial number was assigned to each sample immediately upon its receipt in the laboratory, and this number was also placed upon the collector's certificate. The seal was then broken and the cover of the stopper removed. Any dust adher- ing was carefully wiped away, and a few cubic centimeters of tbe sample were poured out to wash the lip of the bottle. About 1,500 c.c. of the water were then filtered through a double filter (Munchfilter, Xo. o), which had been carefully washed with a half liter or more of pure water. The determinations of the nitrites” and nitrates” have been made first, followed by the ammonias’’ and oxygen consumed. The date of collec- tion” recorded in the table is takai from the collector's certificate that accompanies each sample; the date of examination” refers to the date of making the nitrate and nitrite determinations and the ammonia analyses. I'he determinations of the residue and chlorine have been completed as soon as practical)le. The results are all expressed in parts per million. 1 he loss on ignition of the residue on evaporation was omitted, since analysts are now generally agreed that the information furnished bv this determination is not valuable enough to compensate for the labor involved. Turbidity and Sediment.—The turl)idity and sediment have been determined in the laboratory merely by ocular inspection and are ex- pressed by the conventional adjectives slight.” distinct.” decided” or muddy,” as regards turbidity ; very little.” little.” considerable” or “much,” to indicate tbe sediment. In the absence of anv recognized standard at tbe time this investiga- tion was undertaken this seemed to be the best method available, although it proved far from satisfactory. Color.— b'or the sake of uniformity with previous examinations of the waters ('ealt with, tbe color of the filtered water has been tiscertained by