Water quality. Determination of the growth inhibition effects of waste waters, natural waters and chemicals on the duckweed Spirodela polyrhiza. Method using a stock culture independent microbiotest

2017 ◽  
2002 ◽  
Vol 2 (2) ◽  
pp. 213-221 ◽  
Author(s):  
N. Kishimoto ◽  
I. Somiya ◽  
R. Taniyama

An improved UV spectrophotometric method for determination of nitrate in natural waters was proposed and the determination accuracy of the method was discussed in this study. As a result of estimation of the proposed method, adoption of 215 and 220 nm for detection of nitrate and interfering substances resulted in decreasing standard error to about a half of that of a conventional spectrophotometric method. One of the reasons was thought that the coefficient of variation of relative absorbance of interfering substances (rs) at 215 nm was smaller and more stable than that at 275 nm, which was used in the conventional method. The other reason inferred was that most of the interfering substances absorbed UV light at wavelengths of 215 and 220 nm. Although rs has to be renewed when targeted water quality is under extreme conditions, the procedure of the proposed method is very simple, namely only measuring two UV absorbances of a filtrated sample, and more accurate than the conventional spectrophotometric method. Consequently, the proposed method is available for rapid determination of nitrate in natural waters.


2013 ◽  
Vol 14 (1) ◽  
pp. 40-47

The procedure for the reliable determination of Be in natural waters by ETAAS was elaborated. Various modifiers (EDTA, Ca(NO3)2, Mg(NO3)2, Pd(NO3)2 and the mixture of Pd(NO3)2 and Mg(NO3)2) for the determination of beryllium was examined. The applicability of the selected Mg(NO3)2 as the appropriate and generally used modifier for the determination of Be in the different types of natural waters by ETAAS has been confirmed. The accuracy of the method was verified by analyzing of the certified reference material of drinking water ("Trace Metals in Drinking Water"). The real drinking waters and waste waters with the reference values of Be concentration, spiked tap water, mineral waters and model river water were utilized for the determination of Be. Using Mg(NO3)2 for modification, the detection limit of 0.07 μg L-1, the quantification limit of 0.22 μg L-1 and characteristic mass of 3.7 pg of Be were obtained. The recovery was in the range 95–111% and (%) RSD value was less than 8%.


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