European Journal of Biotechnology and Bioscience

European Journal of Biotechnology and Bioscience Online ISSN: 2321-9122, Impact Factor: RJIF 5.44 www.biosciencejournals.com Volume 5; Issue 4, July 2017; Page No. 42-47

Sustainable surface water quality monitoring in () * Eric Foto, Olga Biteman Mobili, Oscar Allahdin, Nicole Poumaye, Joseph Mabingui UNESCO Chair, Lavoisier Hydrosciences Laboratory, University of Bangui, Faculté des Sciences, BP, BANGUI

Abstract The study deals with the evolution of the physicochemical and bacteriological quality parameters that may be sources of surface water pollution in the city of Bangui in the Central African Republic. These parameters were monitored on a seasonal basis and are one of the first investigations to characterize the waters of the two main rivers of the city for their uses for the production of water intended for human consumption. In this context, the results provide a model for the monitoring and preservation of water resources in sub-Saharan regions facing the problem of climate change.

Keywords: pollution, surface waters, quality, physicochemical

1. Introduction in collective sanitation of the neighborhoods, provides ideal Knowing the quality of superficial and underground natural basins for the proliferation of various pathogenic bacteria and waters is an essential element for individuals, economic germs. The malaria pandemic, the leading cause of death in activities, agriculture and communities. The Central African the country, is justified. These waters are naturally sensitive to Republic is a country with a high rate of rainfall. Its area is human pressures. The degradation of these waters is linked, on covered by both forest and savanna. But over the last 30 years, the one hand, to alterations in the physico-chemical quality of there has been a progression of the forest on the savannah, the water and, above all, to changes in their which is a situation currently exceptional in the world. There hydromorphological characteristics. are three seasons: the dry season runs from November to March, the intermediate season runs from April to June and 2. Localisation the rainy season from July to October. Natural water resources In our study, we looked at the (Figure 1a), are abundant: streams, rainwater, marshes and groundwater. which serves as a waterway during high water periods in the Unfortunately, all these resources are confronted with a Central African Republic. It is the main surface water resource problem of quality for human consumption. As the country is used for the drinking water supply of the city of Bangui. The virtually non-industrialized, pollution is mainly bacteriological Mpoko River (Figure 1b) in the southern part of the Bangui and organic. The profusion of water coupled with a deficiency region is smaller.

Fig 1: a) Ubangi river in Bangui. b) Mpoko river

Dupré (1996) [3] reports that the concentrations of dissolved particles are very low because of their high mobility during elements Ca, Na, Sr, K, Ba, Rb and U in the Ubangui and flood periods. Congo are remarkably low compared to other rivers. Patrick Seyler in 1996 [11] compares the dissolved metals of Moreover, the contents of these elements in the suspended the Ubangui and the Amazon with the average contents of the 42

European Journal of Biotechnology and Bioscience major world rivers. It also observes that these rivers whose world's rivers, the Ni, Cd and Rb levels are slightly higher, but basins are little anthropized, are little polluted. Compared to still below the pollution standards (Table 1). the average of the metallic contents in the waters of the

Table 1: Concentrations of different dissolved elements in the Ubangui, Amazon and global averages (Seyler 1996) [11]

To this end, we limited our study specifically to the - Collection: Sodéca collects approximately 1200 m3 / h. physicochemical and bacteriological parameters knowing that There is a ferry used for crossing the two countries. Two large the city does not have an industry. hotels are close to this site. - Upstream slaughterhouse: There is a center of commercial 3. Materials activities, especially for vegetables, fruits, and meat. Some of The following in situ analyzes were carried out on each water the litter related to this activity is discharged into the river point using the following materials: -pH (pH-meter WTW from a stream (Sapeke). A wild slaughter is also sometimes 340i), - Electrical Conductivity and Temperature (WTW 340i improvised on the shore, with washing offal. conductivity meter), -Alkalinity (Alkalinity HACH kit), - Oxi - Aval Abattoir: the only official slaughterhouse in Bangui. 330 / SET WTW Oximeter and then to the analytical Blood, offal and intestinal contents are discharged into the laboratory the devices used are - Hach turbidimeter, Precisa Ubangui through a channel constructed for this purpose. The XT 220A balance, WTW Oxi 330 / SET oximeter, - Uvikon population in this region is very dense. The pollution is mainly 860 Kontran spectrophotometer, Varian Spectra AA 55 atomic of human and animal origin. absorption spectrometer. The following equipment was used - Mpoko: Second River in size after the Ubangi. The samples for bacteriological analyzes: incubators, Petri dishes, filtration were taken about 2 km before the confluence with the ramp, sterile pipettes, filter membranes (0.45 mm), colony Ubangui. This region (south exit of Bangui) is very populated, counters, pliers, water bath and autoclave. A series of samples with no sanitary facilities. has been made for various chemical and bacteriological - Confluence Ubangui / Mpoko: The sampling was carried out analyzes which are then brought back to the laboratory in a in pirogue about 2 km after the mixing of the waters of the cooler Ubangui and the Mpoko at a distance about fifty meters from the bank. This region is sparsely populated. Pollution from the 4. Méthodology Mpoko should be greater during large waters. After a first phase of recognition of the sampling points on the ground by the Lavoisier laboratory team, three sampling 5. Results and Discussions campaigns one in high water on 17 November 2008; The On the samples taken, we carried out various bacteriological second in March 2009 low water; And the third in August and physicochemical analyzes. The results are shown in 2009. Intermediate flows were recorded in 6 sites: Figures 2, 3 and 4. A similarity can be observed between the - Ouango Saô: where the Bangui - Zongo (Democratic waters of the Mpoko and those collected 2 km from the Republic of Congo) river line is located, and there are strong confluence, showing that the mixture of water has not yet commercial activities between the two countries. One can taken place at the sampling point and that this sampling site estimate a crossing of twenty small boats per day, for tourism located 50 m from the right bank After the confluence is and goods. This region is sparsely populated. therefore little affected by the Ubangi. 43

European Journal of Biotechnology and Bioscience

Fig 2: Variation of temperature in the different sites. Fig 3 Variation of conductivity in the different sites

Fig 4: Variation of pH in the different sites.

The temperature of the water, between 25 and 29 ° C, varies supply decreases. little with the season for the zones of Ouango Saö and the The directive of the European Communities on the quality of catchment by the Water distribution company (Sodéca). water intended for human consumption indicates a guideline For sites in the vicinity of the abattoir, the temperature is level of 400 μS/cm for conductivity. Mineralization of water higher during high water because of greater streams or small would therefore need to be increased during the treatment of releases. water, if one wants to reduce its aggressiveness. The Mpoko passes through a zone with strong vegetation The buffering capacity of these weakly mineralized waters is cover before Bangui, which is responsible for lower low, resulting in relatively low pH values. The lowest pH temperatures for the waters of the Mpoko and the Mpoko / values (5

Fig 5: Evolution of turbidity at different sites Fig 6: Evolution of suspended solids content at different sites 44

European Journal of Biotechnology and Bioscience

It is noted that the waters are more turbid during high water content: (a) all points, (b) except values for high water at the due to a higher suspended solids content due to high runoff. Aval Abattoir; Figure 7 Change in turbidity as a function of suspended solids

Fig 7: Change in turbidity as a function of suspended solids content: (a) all points, (b)

Figure 7 shows that there is a linear relationship between Incident light). Light scattering is related to the number and turbidity and suspended solids (TSS). If the value size of the particles. The slaughterhouse throws into the river, corresponding to the downstream waters near the the blood and the viscera of the killed animals, compounds slaughterhouse is eliminated, a line with a correlation which give more adsorbent particles and therefore responsible coefficient R² = 0.81 is obtained. The principle of measuring for a decrease in the value of the turbidity downstream of the turbidity is to measure the scattered light (Tyndall effect) at slaughterhouse. It can therefore be concluded that, apart from 860 nm laterally at 90 ° by particles under the effect of a light the waters near the slaughterhouse, the Ubangui particles have source (1 unit of NTU corresponds to 0.02% diffusion of the similar origins.

Fig 8: Variation of O2 levels at different sites Fig 9: Variation of CO2 levels at different sites

Fig 10: Variation of BOD5 levels at different sites 45

European Journal of Biotechnology and Bioscience

The phenomena of self-purification in surface waters result [10]. The oxygen content in the water is therefore affected by an from the degradation of organic polluting loads under the increase in BOD5: the oxygen content in the water increases if action of microorganisms. BOD5 is low, ie if the quantity of organic material to be This results in an oxygen consumption which is expressed by oxidized decreases. Figure 11 et 12. Evolution of the Oxygen the biochemical demand for oxygen or BOD5. (Rodier, 1984) (a) and CO2 (b) content with the BOD5 of the analyzed waters.

Fig 11: Evolution of the Oxygen content with the BOD5 of the Fig 12: Evolution of the CO2 content with the BOD5 of the analyzed analyzed waters waters

We note in Figure 12 (if the values corresponding to the The CO2 concentration is higher when the easily reducible waters near the catchment where some of the carbon dioxide is organic species (low BOD5) have been transformed into eliminated due to the agitation of the water caused by carbon dioxide. pumping and the downstream waters Of the slaughterhouse We depict in Figure 13 the bacteriological contamination during high water, (undergoing very organic pollution) that the (Coliforms and faecal streptococci) in the waters of the CO2 contents decrease if the BOD5 increases. different sampling sites.

Fig 13: Coliform contents in different waters. Fig 14: Faecal streptococcal contents in different waters.

Coliform pollution is especially important at the more fragile. When the ratio of coliforms / faecal streptococci slaughterhouse (upstream and downstream) and by is greater than 4, pollution is likely to be of mainly human streptococci downstream of the slaughterhouse. Fecal origin (sewers). When it is less than 0.7, animal origin and coliforms and streptococci live abundantly in the fecal matter especially livestock appear to play a predominant role in the of warm-blooded men and animals. Some streptococci may be contamination of water (Rodier, 1984) [10]. rare in humans but abundant in animals. Fecal coliforms are

Table 2: Report Fecal coliforms / faecal streptococci.

Sites /saison Ouango saô captage Sodeca Upstream Abattoir Downstream Abattoir Mpoko Ubangui- Mpoko Flood 0,50 2,00 0,43 1,12 5,00 4,00 Inter Season 0,33 3,00 0,30 1,00 3,00 0,67 etiage 0,38 3,00 0,30 1,00 2,50 1,33

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European Journal of Biotechnology and Bioscience

From these remarks, we can draw the following conclusions: 5. Vernick G, Van Hoogstraten TL, O’TOOLE JSF, TE. The ratio of fecal coliforms to faecal streptococci is low in Encyclopedia Britannica, Central African Republic, with Ouango Sao. This region, which is sparsely populated and the primary contributions, 2012. bacterial pollution very low, would be mainly of animal 6. Gao Y. Trace Metal behavior in sedimentary origin. environments, PhD thesis. This ratio increases near capture and is predominantly of 7. Jacques Bordet. leau dans son environnement rural human origin (sewers). There are two hotels with sewers Edition Joanet, paris, 2007. dumped into the river near the catchment area. 8. Laraque A, Bellanger M, et al. Évolution récentes des The ratio of faecal coliforms / faecal streptococci in the débits du Congo, de l’Oubangui, et de la Sangha. Recent waters around the slaughterhouse (upstream downstream) is Evolution of Congo, oubangui and Sangha rivers flows low and therefore of animal origin. We have no interpretations Geo-Eco-Trop. 37(I):93-100. to justify the lower values observed upstream. 9. LeChevallier MW. et al. Effect of turbidity on The ratio values are high in the Mpoko waters. This pollution chlorination efficiency and bacterial persistence in would therefore be of human origin in view of a large and drinking water. Applied and Environmental microbiology, anarchic urbanization. 42: 159-167 ommunity Health. 1981; 54(1):45-51. The faecal coliform / faecal streptococci ratio in the waters 2 10. Rodier J. L’analyse de l’eau : eaux naturelles, eaux km from the confluence is high during the high water period résiduaires, eaux de mer. Water analysis: natural water, and then decreases. These waters are particularly affected by wastewater, sea water. Dunod Edition. 1984, 113, 193, the Mpoko during the high water period. For low water, 198, 240, 793, 808,823, 820. pollution would therefore be more of animal origin, the 11. Seyler P, Elbaz- Poulichet F, Biogéochimique contrôle population on the shores being low. sur la variabilité temporelle des concentrations en éléments traces dans la rivière Oubangui République 6. Conclusion centrafricaine, 1996. This study has generally laid the foundation for an 12. Sondag F, Laraque a, Riandey C. Chimie des eaux du understanding of the characteristics of the waters of the fleuve Congo à et de l’Ubangui a Bangui. Ubangui River at the level of the agglomeration of Bangui. Grands Bassins Fluviaux, Paris. 1993, 22-24. From a bacteriological point of view, the extreme sensitivity 13. Viland MC, Montiel A, pS- Eau. Eau et Santé, Guide of surface water to human pollution has been highlighted, and pratique pour les intervenants en milieu rural africain “ our results highlight the health hazards associated with the use coll. Etudes et travaux, n° 21. R. Eau, Environnement et of this resource. They can be potabilized at lower cost for the Santé Publique. 2003, 2. populations. With this in mind and in order to supply the most deprived sections of the population with drinking water, it is important for now to focus our efforts on easily accessible surface waters. Since well water is very often contaminated by bacteria, we consider it necessary that, therefore, from the waters of the Ubangi River, one can validly use for the treatment of water intended for human consumption.

7. Acknowledgments The authors are also grateful to the French Embassy in Bangui, Nord Pas-de-Calais Region, Nord Pas-de-Calais Water Agency, UNESCO, and University of Lille1and University of Bangui.

8. Références 1. Association Française de Normalisation French Standards Association Eaux méthodes-d’essai Methods for testing water Paris. 1990 ; 1:73. 2. Cardot C. Les Traitements de l'eau Procédés physico- chimiques et biologiques Cours et problèmes résolus. Ed. Ellipses, Techno sup. 1999, 297. 3. Dupré BJ, et al. Major and trace elements of river-borne material: The Congo Basin. Geochemical et Cosmochimica Acta. 1996; 60(8):1301-1321. 4. Foto E, Malenguinza J, Nguerekossi B, Boughriet A, Louche B, Poumaye N, ET AL. -Élimination de la turbidité et de la pollution bactérienne dans les eaux naturelles Cas du Fleuve Ubangui, Centre Afrique, Field Actions Science Reports The journal of field actions. 2014 ; 7.

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