Dear Label_Name,

Greetings! I hope you are well.

I am writing on behalf of an international publishing house, Science and Education Publishing, USA (http://www.sciepub.com).

Science and Education Publishing (SciEP) is a multidisciplinary open access publisher of Journals covering the fields of Science, Technology and Medicine. All SciEP publications are subject to high-quality peer review, editorial and production processes and are freely available online.

Welcome to the April, 2013 edition of SciEP newsletter, providing monthly summaries of articles on science & education related topics of interest to scientist and professionals. The mission of our journals is to provide an open access forum for publishing new findings on issues pertinent to scientific and academic field. We also invite you to submit original research papers, review articles, short reports, or case studies are considered for publication in our Multidisciplinary Journals.

American Journal of Public Health Research
DOI: 10.12691/ajphr-1-1-3

The Implementation of a Tele-Homecare System with Service Oriented Architecture and HL7 Message Transmission Standard
Ching-Sung Wang

American Journal of Medical and Biological Research
DOI: 10.12691/ajmbr-1-1-2

The Influence of Ethanol on Pyruvate Kinases Activity in Vivo, in Vitro, in Silico
Lelevich Sergey Vladimirovich, Khrustalev Vladislav Victorovich, Barkovsky Eugene Victorovich, Shedogubova Tatyana Aleksandrovna

American Journal of Medical Sciences and Medicine
DOI: 10.12691/ajmsm-1-1-1

Clinical and Histological Features in Wegener Granulomatosis
Li Cavoli Gioacchino, Passantino Rita, Bono Luisa, Tortorici Calogera, Ferrantelli Angelo, Giammarresi Carlo, Rotolo Ugo

American Journal of Infectious Diseases and Microbiology
DOI: 10.12691/ajidm-1-1-2

The Curse of Lymphatic Filariasis: Would the Continual Use of Diethylcarbamazine Eliminate this Scourge in Papua New Guinea?
Anne Lanham, Lillian Mwanri

We have released issues of some journals on February 2013.
American Journal of Public Health Research
American Journal of Medical Sciences and Medicine
American Journal of Medical and Biological Research
American Journal of Pharmacological Sciences
American Journal of Clinical Medicine Research
American Journal of Nursing Research
American Journal of Cancer Prevention
American Journal of Medicine Studies
American Journal of Infectious Diseases and Microbiology
American Journal of Cardiovascular Disease Research
American Journal of Biomedical Research
American Journal of Mechanical Engineering
American Journal of Microbiological Research
Journal of Preventive Medicine
American Journal of Food and Nutrition
American Journal of Hypertension Research
American Journal of Sports Science and Medicine
Journal of Cancer Research and Treatment
American Journal of Zoological Research
Journal of Biomedical Engineering and Technology
American Journal of Microbiological Research
Biomedical Science and Engineering

We are pleased to announce that submissions are now being accepted for peer review for all the journals across all our subject areas in SciEP.

Please submit your manuscript via our online submission system:
http://www.sciepub.com/author/signin

To unsubscribe from our mailing list, please click on the following link: unsubscribe

I am looking forward to hearing from you.

Kind regards,

David Rain
Email:join@sciepub.com
Science and Education Publishing (http://www.sciepub.com)

Characterization of Dissolved Organic Matter in the Waters of Lomé Lagoon System (Togo)

Ayah M.*, Grybos M., Bawa L. M., Bril H., Djaneye-Boudjou G.

Laboratoire de Chimie des Eaux, Faculté Des Sciences, Université de Lomé, Lomé, Togo

Abstract: The aims of study is to distinguish the different origins of dissolved organic matter and emphasizes the spatial variations of dissolved organic matter quality in Lomé lagoon system composed by three lakes and Equilibrium canal. The results showed that, the three lakes of Lomé are dominated by biological dissolved organic matter (HIX < 4) except the site O₁₁ (HIX = 5.75) with high biological activity (BIX included between 0.8 and 1). This high biological activity could due to the water contribution from north plateau and offshore bar. Apart from O₁₁ and C₄ the information brought by the ratio Iγ/Iα shows that the dissolved organic matter of the lagoon is autochthonous and composed by labile organic compounds. Lomé lagoon system is composed in majority by humic substances with a small amount of microbial products.

Keywords: dissolved organic carbon, aromaticity, 3D fluorescence, fluorescence indexes

Received May 17, 2015; Revised June 23, 2015; Accepted June 29, 2015

Citation: Ayah M., Grybos M., Bawa L. M., Bril H., Djaneye-Boudjou G., Characterization of Dissolved Organic Matter in the Waters of Lomé Lagoon System (Togo). American Journal of Environmental Protection, 3 (4). 145-150. January 2015. doi:10.12691/env-3-4-5

1. Introduction

In urban cities where naturals waters such as, lakes, rivers, lagoons are presents, the organic matter can have many origins: autochtonous or allochthonous or from to humans activities making it to be very complex. Several techniques such as XAD fractionation, ultrafiltration, GC-MS pyrolysis, UV Visible spectroscopy, mass spectroscopy, 3D fluorescence can helps to get much information about these organic matters. Spectroscopic techniques are widely used to have qualitative information of this kind of complex mixtures of organic compounds. The spectrometry UV Visible informs about the light absorption of a sample. The SUVA index (Specific Ultraviolet Absorbance) is used as an indicator of the chemical composition of dissolved organic matter. Nowadays, a new technique, 3D fluorescence is greatly used to characterize the OM [1]. About 70 % dissolved organic matter from water are able to emit a fluorescence signal. This technique (3D fluorescence), based on excitation and the emission of the molecules, give information about the energy emitted in response to the excitation. By this technique, it is easy to differentiate two molecules having the same emission wavelength and different excitation wavelength. 3D fluorescence excitation-emission matrix spectroscopy is a rapid, selective and sensitive technique. It has been proven to be a useful technique to characterize natural organic matters [2,3,4,5]. Because of it high sensitivity, good selectivity, and non-destructive nature, excitation–emission matrix is also widely used to differentiate the changes and transformations of organic matter in natural environment. For the last decade, excitation–emission matrix and several indexes (HIX, BIX and Iγ/Iα) have been developed to quantify humification degree and origin of humic materials [6,7]. The determination of these indexes is based on the fact that the progress of the humification process is associated with increased carbon and hydrogen (C/H) and the increase results in a shift of the spectrum fluorescence to longer wavelength emission wavelength [3,4,5]. In fact, the index of humification of MOD (index HIX) differentiates MOD sources such as between microbial cell lysis products and more humified compounds [4,5]. The BIX index that characterizes the supply of MOD of indigenous biological activity of an aquatic environment is linked to greater presence of fluorophore β in samples of natural waters [6,7,8]. As for the Iγ/Iα, it allows the identification of protein compounds associated with biological activity mainly to the influence of MOD of marine origin [6,8]. The excitation–emission matrix diagrams of humic substances are scrutinized to establish a complete fluorescence fingerprint (number of peaks, their location and intensities) of this material as well as to identify potential correlations between features and properties of the samples. They can therefore be of great helps to differentiate complex mixtures of fluorophors, based on their specific peaks. The 3D fluorescence is used to study dissolved organic matter from sea waters [8], coastal and deep-sea sediments [9], landfill leachates [10], humic acid [11], farm wastes [3], natural waters [12,13], soil extracts [14], tropical wetlands [15], organic matter produced by algae [16], to trace the origin of individual dissolved organic matter peaks [5,17,18,19,20,21], to monitor organic contamination [22] or the interaction between dissolved organic matter and metals [23]. In practice, the 3D Fluorescence requires a small quantity of volume with a low concentration of organic matter (< 20 mg.L⁻¹) [24,25]. However, the identification of fluorophors is difficult due to the changes in the pH, the temperature and ionic strength, which can affect the fluorescence emission [20,26]. Some fluorescence index such as HIX and BIX and the ratio of fluorescence intensities Iγ/Iα helps to get information about the origins and the characteristics of organic matters. The humification index (HIX) informs about the origins of dissolved organic matter [27,28,29]. It helps to appreciate the condensation degree of the organic matter, its complexity and stability towards the microbial activity [30]. The BIX index is the ratio between the maximum emission intensity at 380 nm and the maximum emission intensity at 430 nm for an excitation intensity of 310 nm. It shows the dissolved organic matter due to autochthonous biological activity in aquatic environment [27,29,31]. The Iγ/Iα helps to identify the proteics compounds due to the biological activity. This ratio can be defined as the ratio between the maximum emission intensity at 460 nm and the maximum emission intensity at 320 nm for an excitation intensity of 250 nm. In Togo, there is no data about organic matter characteristics of Lomé lagoon. So, the objective of this work is to distinguish the different origins of organic compounds and emphasizes the spatial variations of the dissolved organic matter quality.

2. Materials and Methods

2.1. Study Area

The studies were undertaken in Lomé lagoon with a length of 8 Km near the sea of Togo (Atlantic Ocean). The lagoon is composed by three lakes. West lake, East lake and lake of Bè. West lake and East lake are connected by Equilibrum canal. All the analyses was done in LCE (Laboratoire de Chimie des Eaux de l’Université de Lomé, Togo) and GRESE (Groupement de Recherche Eau Sol Environnement, Université de Limoges, France). Water samples were collected in September 2011 in Lomé lagoon system (West lake, East lake, lake of Bè and in Equilibrum canal). For each hydrological unit two representatives’ samples were taken: sites O₁₁ and O₅ for West lake, sites C₄ and C₂ for Equilibrum canal, E₃ and E1 for East lake and B₆ and B₃ for lake of Bè. The location of each site is shown in Figure 1 and Table 1.

Table 1. Geographical location of sampled sites

Figure 1. Location of site in Lomé lagoon system

Water samples were collected in plastic bottles of 1.5 L, previously rinsed with distillated water and then with sampled natural freshwater. Smart et al., [32] and Patel-Sorrentino et al., [26] reported that evolution of water samples may occur after collection. For this reason, once collected, the samples were immediately filtered and acidified to avoid both coagulation and alteration of the characteristic peaks position of humics compounds. However, parameters such as temperature, pH and the electric conductivity were determined in-situ by a multimeter ‘‘Type WTW Multi 3420’’ and The redox potential was determined using a potentiometer ‘‘PHM210 Type MeterLab’’.

2.3. Characterization of Dissolved Organic Matter

Dissolved organic matter (DOM) were determined by a TOC-L analyser 5000 (Shimadzu) with a precision of ± 50µgC.L⁻¹. All the samples have been acidified with HCl 1M and sparged with high purity air (quality: 5.0) to removed inorganic carbon and volatile organic compounds. Non organic volatile carbon was then combusted at 720°C to produce CO₂ which is detected by infrared Spectroscopy. The SUVA is defined as the ratio of UV absorbance to DOC value (Absorbance /DOC). It helps to estimate the rate of aromatic and hydrophobic compounds found in the water [33; 34]. The absorbance at 254 nm which is characteristic of phenolics compounds was measured using a UV Varian Cary 50 Probe spectrophotometer. This measurement was performed on samples previously filtered at 0.45 µm. The precision was ± 0.005 cm⁻¹ and the cell use was in quartz with double beam and 1 cm of length. The SUVA index, defined by the ratio UV₂₅₄ nm and COD can be also expressed as a percentage of aromaticity (ARO) of the substance. The aromaticity of MOD in the waters was estimated using the following equation [33]:

Where the SUVA₂₅₄ represents the UV absorbance at 254 nm of samples Standardized water to the organic carbon concentration dissolved (COD).

The 3D fluorescence was determined by a Shimadzu FP-5301 PC spectrofluorometer. The data was treated by Panorama Fluorescence 2.1 software. The samples were previously diluted by buffer phosphate pH 7 to obtain 5mgC.L⁻¹. HIX index was determined by taking the ratio of the areas defined between the emission wavelengths of 300 and 345 nm and those defined between 435 and 480 nm for an excitation wavelength at 254 nm [27,28,29,30]. The BIX index is the ratio between the maximum emission intensity at 380 nm and the maximum emission intensity at 430 nm for an excitation intensity of 310 nm. It shows that the dissolved organic matter due to autochthonous biological activity in aquatic environment [27,29,31]. The ratio Iγ/Iα can be defined as the ratio between the maximum emission intensity at 460 nm and the maximum emission intensity at 320 nm for an excitation intensity of 250 nm.

3. Results and Discussion

Table 2 shows the values of physicochemical parameters, permanganate index, dissolved organic carbon, the SUVA and aromaticity of samples lakes. It is found that C₄ site present higher levels of permanganate index (IP = 40 mg.L⁻¹) and dissolved organic carbon (DOC = 91.11 mg / L) follow to C2 site (IP = 31.0 and COD = 20.83 mg.L⁻¹). However, the percentage of aromaticity of organic molecules for the two sites is the lowest and is located for C₄ and C₂ respectively between 14 and 16%. It was proved that, the aromaticity percent of the aromatics molecules such as humics substances were situated between 20 and 40% in opposite to microbial metabolites with about 16 % [35]. The low SUVA (< 2) of C₄ and C₂ is another parameter which confirms the humics acids absence [36; 37; 34]. It means that the dissolved organic matter of equilibrium canal (site C₄) is composed of microbial metabolites molecules. The COD of sites O₁₁ and O₅ is low (11 mg.L⁻¹). But, aromaticity of the molecules is very high (22 %). This imply that, the dissolved organic matter of these points is characteristics of humics substances with bigs molecules. Some recent studies [34,37,38], reported that SUVA > 2.2 is characteristic of humics acids. For the sites O₅, E₃, E₁, B₆ and B₃, the values of dissolved organic matter and permanganate index are low. Their organic matter could come in part from microbial metabolites due to the percent of aromaticity (16 %). The production of microbial metabolites could due to the lyses of bacterial playing a rule in much ecological and biogeochemical process, like nutrients recycling (nitrogen fixation).

Table 2. Physicochemicals and spectrocopics parameters

So, the dissolved organic matter could be degrade in the lagoon (sites C₄, C₂, O₅, E₁ and B₃), characterized by the increases of the nutrients amount for microorganisms. For the site O₁₁, the lagoon deposits due to runoff waters could be rich in aromatics humics substances. Two maxima (peaks A and C) are observed with a remarkable constancy in all excitation-emission matrixes in this study.

The general fluorescence properties of samples are illustrated in Figure 2. Qualitatively, the 3D fluorescence matrixes show three intensities (I) excitation/emission (Ex/Em. They are I(285/310), I(230/280) and I(230/340) respectively in relation with microbial products, and proteins such as tyrosine and tryptophane likes. About, the peaks, the maximum fluorescence intensity are detected, at the λ excitation 245 nm (peak A), and at 325 nm (peak C) and both have an emission maximum at 425 nm. Thus, the humic substances show at least, two kinds of fluorophores with different chemical and spectroscopic behaviors. These results are similar to those described in some previous studies [8,11,24,39]. Table 3 distinguishes the site where the fluorophores have been detected or not.

Table 3. Relation between the sites and the fluorophores

Figure 2. Excitation/emission fluorescence matrix of the samples

Table 4. Fluorescence indexes values

The fluorescence indexes and the ratio Iγ/Iα showing the spatial variations of dissolved organic matter (Table 4) will give more information about previous results.

The high HIX index (5.75 > 4) is only found in site O₁₁. This humification index means the low humic terrigenous nature with news autochtonous dissolved organic matter present in this lake. The others parts of the lakes shows HIX indexes of 2 and 3. This indicates that the dissolved organic matter is due to biological or bacterial activities. But, the BIX index prove that sites O₁₁, E₃ and B₆ situated between 0,7 and 0,8 revealed a low bacterial activity [27; 29] in opposite of the sites (O₅, C₄, C₂, E₁ and B₃). The dissolved organic matter of O₁₁ is charcateristic of humic substances with a ratio Iγ/Iα < 0.75 [29]. This result is also confirmed by the SUVA, Aromaticity and absorbance 254 nm. The ratio Iγ/Iα = 2 > 1.4 confirmed that the organic matter of C₄ is due to aquatic biological or bacterial activities. The others sites are composed of labiles autochtonous organic compounds. The results illustrated that, the three lakes of Lomé are dominated by some biological dissolved organic matter (HIX < 4). This high biological activity may be influence by the water comes from north plateau and offshore bar.

4. Conclusion

The results showed that, the three lakes of Lomé are dominated by biological dissolved organic matter with high biological activity. This high biological activity may be due to contribution of water from north plateau and offshore bar. A part sites O₁₁ and C₄, the information brought by the ratio Iγ/Iα showed that the dissolved organic matter of the lagoon is autochthonous and composed by labile organic compounds. The SUVA, aromaticity values and HIX, BIX and Iγ/Iα indexes are well-correlated.

References

[1]   | Powe A. M., Flandcher K. A., St Luce N. N., Lowry M., Neal S., Mc Carroll M. (2004). Molecular fluorescence, phosphorescence, and chemiluminescence spectromandry. Anal Chem; 76:4614-34.
[2]   | Antunes, M. C. G., Esteves da Silva, J. C. G. (2005). Multivariate curve resolution analysis excitation-emission matrices of fluorescence of humic substances. Anal. Chim. Acta 546, 52-59.
[3]   | Baker A. (2002). Fluorescence properties of some farm wastes: implications for water quality monitoring. Water Res; 36:189-95.
[4]   | Fu, P. Q., Wu, F. C., Liu, C. Q. (2004). Fluorescence excitation–emission matrix characterization of a commercial humic acid. Chin. J. Geochem. 23: 309-318.
[5]   | Sierra M. M. D., Giovanela M., Parlanti E., Soriano-Sierra E. J. (2005). Fluorescence fingerprint of fulvic and humic acids from varied origins as viewed by single-scan and excitation/emission matrix techniques. Chemosphere; 58:715-33.
[6]   | Larsson, T., Wedborg, M., Turner, D. (2007). Correction of inner-filter effect in fluorescence excitation–emission matrix spectromandry using Raman scatter. Anal. Chim. Acta; 583: 357-363.
[7]   | Richard C., Guyot G., Trubandskaya O., Trubandskoj O., Grigatti M., Cavani L. (2009). Fluorescence analysis of humic-like substances extracted from composts: influence of composting time and fractionation. Environ. Chem. Landt.; 7: 61-65.
[8]   | Coble PG, Green SA, Blough NV, Gagosian RB. (1990). Characterization of dissolved organic matter in the Black Sea by fluorescence spectroscopy. Nature; 348:432-4.
[9]   | Sierra M. M. D., Donard O. F. X., Andcheber H., Soriano-Sierra E. J., Ewald M. (2001). Fluorescence and DOC contents of porewaters from coastal and deepsea sediments in the Gulf of Biscay. Org Geochem; 32: 1319-28.
[10]   | Baker A, Curry M. (2004). Fluorescence of leachates from three contrasting landfills. Water Res; 38: 2605-13.
[11]   | Matthews B. J. H., Jones A. C., Theodorou N. K., Tudhope A. W. (1996). Excitation– emission-matrix fluorescence spectroscopy applied to humic acid bands in coral reefs. Mar Chem; 55: 317-32.
[12]   | Marhaba T. F., Van D., Lippincott R. L. (2000). Rapid identification of dissolved organic matter fractions in water by spectral fluorescent signatures. Water Res; 34: 3543-50.
[13]   | Parlanti E., Morin B., Vacher L. (2002). Combined 3D-spectrofluorimandry, high performance liquid chromatography and capillary electrophoresis for the characterization of dissolved organic matter in natural waters. Org Geochem; 33: 221-36.
[14]   | Cannavo P., Dudal Y., Boudenne J. L., Lafolie F. (2004). Potential for fluorescence spectroscopy to assess the quality of the soil waterextracted organic matter. Soil Sci; 169: 688-96.
[15]   | Mladenov N., Mc Knight D. M., Wolski P., Ramberg L. (2005). Effects of annual flooding on dissolved organic carbon dynamics within a pristine wandland, theOkavango Delta, Botswana. Wandlands; 25:622-38.
[16]   | Leloup M., Nicolau R., Pallier V., Yépremian C., Feuillade G-C. (2013). Organic matter produced by algae and cyanobacteria: quantitative and qualitative characterization. Journal of Environmental Sciences; 26 (6) 1089-1097.
[17]   | Katsuyama M., Ohte N. (2002). Dandermining the sources of stormflow from the fluorescence properties of dissolved organic carbon in a forested headwater catchment. J Hydrol; 268:192-202.
[18]   | Stedmon C. A., Markager S., Bro R. (2003). Tracing dissolved organic matter in aquatic environments using a new approach to fluorescence spectroscopy. Mar Chem; 82:239-54.
[19]   | Alberts J .J., Takacs M. (2004). Total luminescence spectra of IHSS standard and reference fulvic acids, humic acids and natural organic matter: comparison of aquatic and terrestrial source terms. Org Geochem; 35:243-56.
[20]   | Baker A. (2005). Fluorescence tracing of diffuse landfill leachate contamination in rivers. Water Air Soil Pollut; 163: 229-44.
[21]   | Mariot M., Dudal Y., Furian S., Sakamoto A., Vallès V., Fort M., Barbiero L. (2007). Dissolved organic matter fluorescence as a water-flow tracer in the tropical wandland of Pantanal of Nhecolândia, Brazil. Science of the Total Environment 388: 184-193
[22]   | Jiji R. D., Cooper G. A., Booksh K. (1999). Excitation–emission matrix fluorescence based dandermination of carbamate pesticides and polycyclic aromatic hydrocarbons. Anal Chim Acta; 397: 61-72.
[23]   | Dudal Y, Holgado R, Maestri G, Dupont L, Guillon E. (2006). Rapid screening of DOM's mandal-binding abilitiy using a fluorescence-based microplate assay. Sci Total Environ; 354: 286-91.
[24]   | Coble PG. (1996). Characterization of marine and terrestrial DOM in seawater using excitation–emission matrix spectroscopy. Mar Chem; 51:325-46.
[25]   | Chen, W., Westerhoff, P., Leenheer, J. A., Booksh, K. (2003). Fluorescence excitation– emission matrix regional integration to quantify spectra for dissolved organic matter. Environ. Sci. Technol.; 37: 701-5710.
[26]   | Patel-Sorrentino N. , Mounier S., Benaim J.Y. (2002). Excitation–emission fluorescence matrix to study pH influence on organic matter fluorescence in the Amazon basin rivers. Water Research; 36 : 2571-2581.
[27]   | Zsolnay A., Baigar E., Jimenez M., Steinweg B., Saccomandi F. (1999). Differentiating with fluorescence spectroscopy the sources of dissolved organic matter in soils subjected to drying. Chemosphere 38, 45-50.
[28]   | Zsolnay A. (2003). Dissolved organic matter: artefacts, definitions and functions. Geoderma 113 : 187-209
[29]   | Vacher L. (2004). Andude par fluorescence des propriétés de la la matière organique dissoute dans les systèmes estuariens. Cas des estuaires de la Gironde and de la Seine. Ph.D. Thesis, Université Bordeaux 1.
[30]   | Kalbitz, K., Schmerwitz, J., Schwesig, D., Matzner, E. (2003a): Biodegradation of soil-derived dissolved organic matter as related to its properties. Geoderma 113: 273-291.
[31]   | Parlanti, E., Worz, K., Geoffroy, L., and Lamotte, M. (2000). Dissolved organic matter fluorescence spectroscopy as a tool to estimate biological activity in a coastal zone submitted to anthropogenic inputs. Organic Geochemistry 31, 1765-1781.
[32]   | Smart P. L., Finlayson B. L., Rylands W. D., Ball C. M. (1976). The relation of fluorescence to dissolved organic carbon in surface waters. Water Res; 10:805-11.
[33]   | Weishaar J. L., Aiken G. R., Bergamaschi B. A., Fram M. S., Fujij R., Mopper K. (2003). Evaluation of specific ultravioland absorbance as an indicator of the chemical composition and reactivity of dissolved organic carbon. Environmental Science & Technology 37: 4702-4708.
[34]   | Labanowski J., Feuillade G. (2011). Dissolved organic matter: Precautions for the study of hydrophilic substances using XAD resin. Water Research, vol. 45, pp. 315-327.

[35]  
Davranche, M., Dia, A., Fakih, M., Nowack, B., Gruau, G., Ona-nguema, G., Petitjean, P., Martin, S., Hochreutener, R., (2012) Organic matter control on the reactivity of Fe(III)-oxyhydroxides and associated As in wetland soils: A kinetic modeling study a Géosciences. Chemical Geology 335 (2013) 24-35.

[36]   | Kang K-H., Shin H. S., Park H. (2002). Characterization of humic substances present in landfill leachates with different landfill ages and its implications. Wat. Res.; 36(16): 4023-4032.
[37]   | Berthe C., Redon E., Feuillade G. (2008). Fractionation of the organic matter contained in leachate resulting from two modes of landfilling: An indicator of waste degradation. Journal of Hazardous Materials, vol. 154, pp. 262-271.
[38]   | Tcha-Thom M. (2014). Evaluation de l’impact des fractions de matières organiques extraites de lixiviats de déchets ménagers et assimilés sur les caractéristiques des sols agricoles togolais et français. Mémoire de Master 2, Université de Limoges; 36p.
[39]   | Mounier S., Patel N., Quilici L., Benaim J. Y., Benamou C. (1999). Fluorescence 3D de la matière organique dissoute du fleuve Amazone. Water Res; 33(6):1523-33.