emoto 
Serra 
ipais 
asil, 
asil, 
LASER FLUORESCENT DIAGNOSTIC OF DISSOLVED 
ORGANIC MATTER IN NATURAL WATER. 
Elena M. Filippova 
Quantum Radiophysics Chair, 
Department of Physics, Moscow State University, 
Moscow 119899 GSP, Russia. 
Comission: VII. 
ABSTRACT: 
Important problems of environment control demand 
elaboration of remote methods for dissolved 
organic matter (DOM) diagnostics in natural water. 
Currently fluorescent methods using Raman, 
scattering signal as an internal standard are 
widely applied for environment control DOM in 
water. 
In this paper temperature variations and 
ultraviolet irradiation (both lamp and laser 
sources) influence on fluorescence excitation and 
emission spectra of water samples have been 
investigated. Photo chemical processes under laser 
excitation and effect of fluorescence saturation 
have been studied. The obtained results give a 
chance to support the hypothesis of the nature of 
fluorescence band of dissolved organic matter in 
water. 
KEY WORDS: Remote Sensing, Water, Fluorescence 
Spectra. 
1. INTRODUCTION. 
The dissolved organic matter is a 
significantingredient of natural water systems and 
determines its ecological state. That is why the 
creation of the precise and sensitive methods to 
control the presence of DOM total quantity in 
water is now as the actual problem as before. One 
of such method is the fluorescent analysis based 
on the hypothesis that the correlation between 
fluorescent intensity (Ig1) and DOM concentration 
(C) exists. However, more careful investigation of 
DOM spectral characteristics led us to conclusion 
that the relation between Ici and C is practically 
much more complex that one could anticipate a 
priori. There are many factors which break this 
correlation. These factors are: 
631 
1) random changes of the fluorescent source 
intensity; 
2) dependence of fluorescent signal level on 
the experimental conditions and as well as the 
conditions of the waves propagation; 
3) temperature changes of the water; 
4) changes of pH values in water; 
5) presence of metal ions in water; 
6) ultraviolet (UV) radiation from the Sun 
and excitation radiation of laser or lamp sources. 
The first two factors can be removed using the 
method with calibration of fluorescent signal 
according to Raman scattering (RS) signal of 
water and parallel detection of these signals 
(Fadeev, 1983). Parameter F=l RS doesn’t depend 
on fluctuations of radiation source power, 
experimental conditions and is used in our case as 
a parameter correlating with concentration of 
organic pollutions (DOM in our case). 
It is important to emphasize that the use of RS 
signal as an internal standard is the basic 
principle for remote sensing, when some parameters 
can not be controlled. 
Influence of metal ions on fluorescence spectra of 
DOM has been studied in (Safronova, 1989). Changes 
of the fluorescent intensity connected with 
variations of pH values and temperature ( in range 
8...42 C) have been investigated in detail in 
(Smart, 1976). Influence of UV sunlight radiation 
on fluorescence spectra of DOM are described in 
(Samokhina, 1989). 
The goal of this paper is to study the general 
appropriateness of the spectral characteristic of 
DOM under temperature variations ( in wide range 
0...30°C) and UV radiation excitation by both lamp 
and laser sources. During these experiments we 
supposed to estimate an influence of factors 
mentioned above on the spectral characteristics of 
DOM (to correct fluorescence spectra obtained in 
situ). Moreover new experimental results extend 
our knowledge about the nature fluorescence band 
of DOM.