Analyzing Fluorescent Dissolved Organic Matter

This assignment delves into the analysis of Fluorescent Dissolved Organic Matter (FDOM) using the PARAFAC method. It explores how PARAFAC effectively processes excitation-emission matrix data for FDOM characterization. The document highlights the advantages of PARAFAC in understanding FDOM's role in various environmental processes and provides a comprehensive overview of its applications.

Literature review of
organic matter
fluorescence in
groundwater

Table of Contents
Theme 1: Overview of environmental geophysics technique..........................................................3
Theme 2: Organic matter florescence in groundwater.....................................................................3
Theme 3: Importance of organic matter florescence in groundwater-Technique involved in
organic matter florescence in groundwater......................................................................................4
Theme 4: Application of the PARAFAC technique used in organic matter florescence in
groundwater.....................................................................................................................................5
CONCLUSION................................................................................................................................7
REFERENCES................................................................................................................................8

Theme 1: Overview of environmental geophysics technique
With the rapid development of industries in the past decades, there has been a serious
threat to the environment. These threats have led to many consequences that have posed harm to
the human life, natural resource, ecosystem, utilisation of land and to natural and human
heritage. Thus, there is need of site restoration and rehabilitation projects that will help in the
proper management of environmental degradation which is key need of today's society.
Environmental Geophysics consists of the modern geographic discipline whose main aim is to
determine the physical properties of the shallow surfaces with the use on non invasive high
resolution geophysical techniques (Graham, Baker and Andersen, 2015). This study of the sub
surface help in study of the shallow earth crust which have direct relation to the human activities.
The main purpose of the environment geophysics is to handle the technical problems that mainly
arises due to constructions activities such as landslides, fault zones, evaporite sinkholes, kart
collapse and mine subsidence. Furthermore, geophysical techniques also help in exploring the
places having buried waste, sites of aquifers and surrounding places having contaminants in their
subsurface than at last the mapping work is performed of these selected sites.
Theme 2: Organic matter florescence in groundwater
Organic matter is the heterogeneous mixture of the various substance that can be
classifies on the basis of their sources. In the recent years many researches are performed on the
variation of the concentration of organic matter in the ground water. The main reason that came
forward for these changes are intensive rain, increase in the acidity of soil and severity of
drought. The increase concentration of organic matter have adverse effect on the quality of
water i.e. it effects the taste, colour and change the odour. Fluorescent dissolved organic matter
is the source of carbon that are environment pollutant and mainly arises by human activities such
as pesticides, herbicides, insecticides and fungicides (Fluorescent Dissolved Organic Matter,
2017). There are many other sources of carbon that fall under the one group known as Total
Organic Carbon (TOC) that mainly includes naturally occurring humic acids and fulvic acids
which are derived from the debris of decaying plants. It is a fact that most of the organic carbons
easily absorb the ultra violet lights and their presence can be detected under the water by UVA or
UVT measurement. Measurement of the fluorescence of organic matter that is dissolved in
ground water can provide the new information regarding how surface water get infiltrated in the
aquifers and also help in determining the quality of the groundwater.

The most common and well know approach used for the characterisation of the organic
matter is florescence of organic matter. In this approach an electron form atom or molecule is
excited to very high energy level by making that electron absorb the photon energy from its
ground state. Then florescence occur when the energy of electron is lost in the form of photon
when it again returns to its ground state. As per the views of Coble and et.al., (2014), recent
studies have shown that this approach is a useful tool that help in the determination of the
concentration of organic matter and its character. However according to Graham and et.al.,
(2015) organic matter concentration is not stable in the ground water and can be degraded by the
microorganisms. Although use of florescence for the measurement of amount of organic matter
and its character provides an effective information regarding the hydro geological functioning of
the groundwater.
The process of organic matter florescence in ground water help in the analysis of
vulnerability of the contaminants that are present in groundwater. Farmers use large amount of
pesticides, herbicides and fungicides in order to produce the good quality of crops. But this in
turn when surface water travels in the ground water system it infiltrates through the soil. Then
water soluble carbon sources along with the organic matter are transported to the groundwater by
this process of infiltration and this results in the contamination of the ground water. It is known
that large amount of organic matter that is dissolved into the groundwater is fluorescent i.e. if
this organic matter is illuminated with help of high energy source of light than a fraction of this
energy is absorbed by them and then re-emit the lower amount of energy as florescence. With the
help of various techniques the absorptions and florescence can be conducted in order to detect
even the presence of very low amount of organic matter present in the ground water (Marini,
2013).
Theme 3: Importance of organic matter florescence in groundwater-
Technique involved in organic matter florescence in groundwater
It is clear from the above discussion that florescence of organic matter help in tracing the
sources of ground water. This is performed by detecting the presence of amount of organic
matter in the ground water. And secondly it helps in determining the vulnerability of the
contaminants that are present within the groundwater. Now after getting the florescent data there
is need of processing this data is order to interpret the result of research performed. There are
various techniques available for the florescence data processing which mainly includes peak

fitting and regional integration, in which the particular pair of excitation and emission
wavelength is first identified after that the florescent intensity is deducted from excitation-
emission matrix (EEM) of an optical region that is of important concern (Yamashita, Boyer and
Jaffe 2013). Second technique is the multivariate excitation emission matrix analysis which
includes three approaches namely self organising map, in this method the high dimensional data
on statistical relationship is converted into simple geometric relation ship on low dimensional
map. Second approach is principal component analysis, in this technique of data processing the
identification of the uncorrelated variation is done from the given dataset. The third and most
popular approach is parallel factor analysis (PARAFAC) it is a highly efficient technique for
EEM data processing. According to Singh, Inamdar and Scott, (2013) in more than 500 journals
that were published between 2004-2014 all the researchers have used this technique for
excitation-emission matrix data processing. One of the main reason for the acceptance of
PARAFAC as an approach or EEM modelling is that, in case when non-negative constraint are
used during the procedure of the modelling it provides an advantage over self organising map
techniques and principal component analysis technique by allowing the quantification of the
florescence spectra. Thus, considering the available information this literature will focus on the
PARAFAC as an important method used in the organic matter florescence in groundwater by
using the spectroflourometre.
Theme 4: Application of the PARAFAC technique used in organic matter
florescence in groundwater
The PARAFAC technique is used for the decomposition of fluorescence excitation-
emission matrix. As per the views of Coble and et.al., (2014) it is the best available technique
that is used in organic fluorescence of the ground watery through multivariate excitation
emission matrix analysis. It provides both qualitative and quantitative model of the available data
and then separates the measured signals with the help of specified excitation and emission
spectra into the individual fluorescent phenomenon. If this is compared to the principal
component analysis technique than it is found that PCA only provides the qualitative data in
which the PCA model consists of principle components such as abstract mathematical entities
and chemical information. According to Tareq, Maruo and Ohta, (2013) in some cases there
some issue that interfere with above made assumption of the PARAFAC. This includes the
presence of the strong components with the similar fluorescence properties. Thus, it creates

difficulties in the quantification of some compounds that are found in the organic matter in case
when their specific analysis is not performed. But this issue can be easily solved if proper care is
taken while using the PARAFAC as the process for data interpretation.
Along with the use in ground water PARAFAC has showed the good results in marine,
fresh water and in waste water system. This technique of PARAFAC have become more efficient
after the invention of the online database known as openflour. This is the database of organic
florescent spectra that are already published and allows the user for the quantitative comparison
between the available PARAFAC models and linking them with available literature. There are
number of components that are identified along with their excitation and emission positioning
that are linked to the changes that occur in the concentration and character of the organic matter.
Characterisation of the Fluorescent Dissolved Organic Matter by using the PARAFAC is
also used for accessing the variability in the dissolved organic matter in the ground water.
According to El Halabi and et.al., (2013) there is relation between the spectroscopic
measurement, PARAFAC modelling and the Open flour database. The fluorescence excitation
emission matrix data is collected by using the fluorescence spectrometer after that EEM are
corrected for the inner filter effect than the components of the fluorescent are separated by using
the PARAFAC modelling using the spectroflourometre. In this method first PARAFAC fits were
identified and then spilt half analysis take place. According to Xu and et.al., (2013) in this
procedure identical models were produced from the dataset that were randomly generated. After
that fluorescent components that were derived from the PARAFAC modelling was compared
with the other available PARAFAC components by using the open flour database.
Another major application of the PARAFAC while doing the analysis of fluorescent
dissolved organic matter is that it is able to identify the three important component of the
available data. These three components are: excitation emission wavelength i.e. terrestrial
derived humic material, second is reprocessed allochthonous humic material and microbial or
protein type material. Along with this application of the PARAFAC approach help in the
removal of artifacts that are present in the dataset for analysis.
As per the views of Wilderjans and Ceulemans, (2013) it can be easily found that
PARAFAC analysis is highly complexed procedure, so it can be inferred that despite the
presence of relative easy data acquisition, the presence of the highly complicated post processing
tends to limit the wider application of this approach of EEM spectroscopy for the organic matter

online monitoring. One of the main reason for the use of PARAFAC as an approach or EEM
modelling is that, in case when non-negative constraint are used during the procedure of the
modelling it provides an advantage over self organising map techniques and principal component
analysis technique by allowing the quantification of the florescence spectra. As per the views of
Murphy and et.al., (2013) PARAFAC model is the best available model that can help in
determining the variability in the organic matter by using the excitation-emission wavelength
pairs. According to Marini, (2013) there is the presence of some assumptions that should be
considered while applying the concept of PARAFAC modelling. The first available assumption
is variability it means no two components have same spectra. Second assumption is trilinearity, it
means that same component have chemical variation in different dimensions of datasets. Third
and final assumption is additivity, in which one complete signal is considered to be a linear
superposition of the available number of components.
CONCLUSION
From the above discussion, it can be concluded that, increase in the urbanisation has
cause serious threat to the natural environment along with life of humans. And to overcome the
effect of this threat various environmental geophysics technique are identified to solve various
occurring technical problems that mainly arises due to constructions activities such as landslides,
fault zones, evaporite sinkholes, kart collapse and mine subsidence. Along with this, these
techniques also help in the identification of the sites have buried waste and aquifers. It can also
be inferred that from various available techniques of data processing PARAFAC stands out to be
one of the effective approach for the organic matter florescence in groundwater. It was also
found that when compared to other available technique PARAFAC gives both quantitative and
qualitative characteristics of data on the other hand self organising map and principal component
analysis can only provide with the quantitative data. Thus, at the end it can be concluded that
PARAFAC is perfect approach for the excitation-emission matrix data processing.

REFERENCES
Books and journals
Coble, P. G. and et.al., 2014. Aquatic organic matter fluorescence. Cambridge University Press.
El Halabi, F. and et.al., 2013. Multiparametric response surface construction by means of proper
generalized decomposition: An extension of the PARAFAC procedure. Computer
Methods in Applied Mechanics and Engineering. 253. pp.543-557.
Graham, P. W. and et.al., 2015. Field measurements of fluorescent dissolved organic material as
a mean of early detection of leachate plumes. Water Air and Soil Pollution. 226(7). pp
1-18.
Graham, P. W., Baker, A. and Andersen, M. S., 2015. Dissolved organic carbon mobilisation in
a groundwater system stressed by pumping. Scientific Reports, 18487.
Marini, F., 2013. Chemometrics in food chemistry (Vol. 28). Newnes.
Murphy, K. R. and et.al., 2013. Fluorescence spectroscopy and multi-way techniques.
PARAFAC. Analytical Methods. 5(23). pp.6557-6566.
Singh, S., Inamdar, S. and Scott, D., 2013. Comparison of two PARAFAC models of dissolved
organic matter fluorescence for a mid-Atlantic forested watershed in the USA. Journal
of Ecosystems, 2013.
Tareq, S. M., Maruo, M. and Ohta, K., 2013. Characteristics and role of groundwater dissolved
organic matter on arsenic mobilization and poisoning in Bangladesh. Physics and
Chemistry of the Earth, Parts A/B/C. 58. pp.77-84.
Wilderjans, T. F. and Ceulemans, E., 2013. Clusterwise Parafac to identify heterogeneity in
three-way data. Chemometrics and Intelligent Laboratory Systems. 129. pp.87-97.
Xu, H. and et.al., 2013. Insights into extracellular polymeric substances of cyanobacterium
Microcystis aeruginosa using fractionation procedure and parallel factor analysis. water
research. 47(6). pp.2005-2014.
Yamashita, Y., Boyer, J. N. and Jaffe, R., 2013. Evaluating the distribution of terrestrial
dissolved organic matter in a complex coastal ecosystem using fluorescence
spectroscopy. Continental shelf research. 66. pp.136-144.
Online

Fluorescent Dissolved Organic Matter (FDOM). 2017. [Online]. Available through
<http://www.zapstechnologies.com/parameters/fluorescent-dissolved-organic-matter/>.
[Accessed on 7th October 2017].