Natural Stream Water Research Articles

Solubility of Atmospheric Oxygen in Water: Twenty-Ninth Progress Report of the Committee on Sanitary Engineering Research of the Sanitary Engineering Division

Group of researchers in England conducted experiments that showed significant differences from previously accepted saturation concentrations of gaseous oxygen dissolved in distilled water; based on these observations, paper derives true saturation values throughout normal range of natural stream water temperatures; table lists values which are considered most satisfactory for application to natural stream conditions.

Rapid Estimation of Water Pollution from Paper and Pulp Wastes

The fact that the pollution of waste water from paper manufacturing plant, especially that of sulfite pulp waste liquor, in natural water streams causes rapid foaming is utilized for a proposed method of rapid estimation of the polution of waters. Approximately 50cc sample water in an oxygen bottle, s shaken and the duration of time for disappearance of the risen foam is measured to make possible for semiquantitative determination to the extent of dilution of 10ppm of the waste liquor. The sensitivity for estimation is higher by using the sample water with lower temperature, also there are some differences between fresh water and sea water, but no remarkable difference is observed when the sea water is diluted to one-half. Since there is some difference in the stability of foam depending upon the kinds of waste waters, it is necessary to make previous test on the relation of duration and stability of foam for a particular water to be tested. By use of this technique, it is possible to estimate the degree of pollution by measuring the durability of foam without measuring the consumption of KMnO4.

THE EFFECT OF AGAR ON THE GROWTH OF NITZSCHIA LINEARIS

THE DIATOM, Nitzschia linearis W. Sm., is one of the common diatoms found in the eastern United States growing in shallow water on mud in streams not adversely affected by pollution. In 1947 an effort was made to culture this diatom in the laboratory. Various types of culture media, such as aqueous solutions, silica gels, and agar were tried. The nutrient solutions used were a modification of Miquel's medium (Miquel, 1892), Chu's number 14 (Chu, 1942), and Ketchum and Redfield (1938) ,medium added to natural stream water. In a series of experiments in which the above nutrients were added to the various media, Nitzschia linearis consistently grew better on the agar medium regardless of the type of nutrient solution used for enrichment. Experiments were then conducted to see if the substance producing the stimulating effect could be pyridine extracted from the agar as described by Robbins (1939). The extract obtained from the pyridine-treated agar was added to agar enriched with Miquel's nutrients and to agar enriched with Chu 14. The agar to which the nutrients were added was purified with Chlorox (sodium hypochlorite) as described by G. W. Beadle (personal communication, 1947). This was done in order to remove any growth-promoting substances such as biotin which might be present. It was found that a stimulating effect upon the growth of Nitzschia linearis was produced when the quantity of extract per 100 ml. of medium was equivalent to that obtained from 1-5 g. of agar. However, due to the difficulty of counting diatoms on an agar medium to determine the amount of growth, no precise results were obtained. Therefore, these experiments were repeated using an aqueous medium. MATERIALS AND METHODS.-The pyridine extraction of the agar was conducted as follows: Glassware, linen, and all equipment used in the extraction were treated with a 5 per cent aqueous pyridine solution for 48 hr. before beginning the agar extraction. The equipment was then washed and rinsed with glass distilled water. The agar was put in linen bags allowing ample room for the expansion of the agar. Difco agar was extracted with a 5 per cent aqueous solution of pyridine over a period of 48 hr. The pyridine solution was changed three times during this 48-hr. period. At the end of 48 hr. the extracts were combined and vacuum distilled at 28?C. until all the pyridine was removed. The extract was then concentrated by evaporating it at 28?C. The extract was refrigerated and experiments were started as