Environmental Engineering Reference
In-Depth Information
study of their photoinduced and biological changes would gain useful information
by using EEM-PARAFAC.
A few studies have been conducted on the photoinduced and microbial changes
of FDOM in natural waters. It should be important to conduct experiments in Asia,
Africa and Latin America, because in these continents there are regions where
freshwaters are highly contaminated with untreated sewerage and industrial efflu-
ents and few studies are presently available. Emerging contaminants such as phar-
maceuticals, hormones, endocrine disrupting compounds and so on are widely
detected in natural waters (Richardson
2007
). The application of EEM-PARAFAC
to identify emerging contaminants would constitute a new dimension to control
and detect these harmful organic substances in aquatic environments. Finally,
PARAFAC modeling of sample EEM spectra could be a useful parameter for the
identification of DOM components and for the elucidation of photoinduced, bio-
logical and any other changes in the molecular properties of the fluorescent com-
ponents. Some researchers use the Raman Unit fluorescence (nm
−
1
) EEM data for
PARAFAC modeling, which causes significant changes in the component's fluo-
rescence excitation-emission maxima and in the fluorescence intensity compared
to QSU or a.u. calibration. It is strongly suggested to use either QSU or a.u. cali-
bration, which allows a better comparison of the fluorescence properties and their
application to DOM dynamics in natural waters.
8 Nomenclature
a.u.
Arbitrary unit
CDOM
Colored or chromophoric dissolved organic matter
DAS1
Diaminostilbene-type
DOC
Dissolved organic carbon
DOM
Dissolved organic matter
DSBP
Distyryl biphenyl
EEM
Excitation-emission matrix
EEMS
Excitation-emission matrix spectroscopy
FDOM
Fluorescent dissolved organic matter
FI
Fluorescence intensity
F
index
Fluorescence index
Fulvic acids
Two components are identified in standard SRFA
FWAs
Fluorescent whitening agents
Humic acids
Two components are identified in standard SRHA
NoHA
Nordic Reference-humic acid
NoFA
Nordic Reference-fulvic acid
PARAFAC
Parallel factor
QSU
Quinine sulfate unit
RU
Raman Unit
