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Abstract
The characterization of the pollution of water source, or of a waste stream, by specific compounds is frequently impossible. Many organic materials entering the streams are readily apparent by their effect on quality. Organic materials may cause offensive odour, or a disagreable taste and colour changes. Non-biodegradable organic waste consstituents may accumulate, causing potential health hazards. The pollutional characteristics of water may be classified, according to their physical state (dissolved, suspended, colloidal, etc.) and according to their nature (inorganic, organic, gases and living organisms).
The present study 1S devoted for the determination of certain undesirable organic and inorganic compounds in drinking water supplies with special emphasis on Dakahlia Governorate water. These are phenols, urea and fluoride.
The toxic nature of phenolic compounds has made it necessary to detect and determine accurately very low concentrations of these compounds. By nitrosation with nitrous acid and using resorcinol or 8-hydroxyquinoline
as chromogenic agents, methods for determination of phenol and some alkyl derivatives (o,m and p-cresols) have been proposed. Accurate and precise results were obtained by both methods.
For the analysis of phenol and it’s alkyl derivatives In a mixture form using four colorimetric procedures has been recommended. Although the results obtained seem to be less accurate than any of four procedures when used singly, yet the proposed method enjoys applicability in small water<laboratories.
Urea is one of the oldest organlc constitutents (~ known in natural waters. Both p-dimethylaminobenzaldehyde and p-dimethylaminocinnamaldehyde are used for the produution of coloured products with urea that can be measured spectrophotometrically. The recovery values range from 98.3 % to 100.5% and from 98.1% to 100.5% with standard deviations of 0.77 and 1.01 for the pdehyde and p-dimethylaminocinnamaldehyde methods respectiively. The methods are sensitive and urea in water samples can be assayed with good accuracy and reproducibility.
The reaction of urea and diacetyldioxirne has been also used for the same purpose, after studying the effect of different oxidizing agents on the reaction. As a result, a method based upon reaction with diacetyldioxime In preesence of carric sulphate and semicarbazide has been prooposed. Both phenols and urea are possible contaminants
of Dakahlia water resources due to the presence of the Granular Wood, and Resines Factory as well as Talkha Fertiliser’s Factory. Some of their exudates may contamiinate the neighbouring water resources.
Inorganic fluorides, on the other hand, are desira-
e constituents in drinking water in trace concentrations prevent dental caries. High concentrations cause deleerious effects leading to fluorosis and teeth fragility.
indirect potentiometric method using calcium ion seleccve electrode has been proposed to replace the more penslve fluoride ion selective electrode.
reover, a colorimetric method using thorium nitrate, and Lenol orange has been developed. The results obtained
~ both accurate and precise.