ABSTRACT
Wetlands are very important ecological units that are rich in
fauna and flora. They provide many goods and services directly usable by the
local population (wood, fish products,...) and multi-functional resources (the
aesthetics of the landscape, the protection of biodiversity and habitat...).
The interest of wetlands is confirmed by the inscription of the lagoon system
of southern Benin on the list of the sites of the 'RAMSAR' convention. In
Benin, the valorisation of these waters still remains a major problem because
of the anarchic and uncontrolled of invasive species (Eichhornia
crassipes) multiplication. To assess the environmental and socio-economic
impacts related to its proliferation, physico-chemical analyses and field
surveys were conducted. It is clear from the analysis that physico-chemical
results from human activities release to promote the proliferation of the water
hyacinth. However, the statistical analysis of the results showed a significant
difference between the parameters (dissolved oxygen, turbidity, suspended
solids, total phosphorus) circles as hyacinth and those in open water to the 5
% threshold. Also, of field investigations showed that incomes in period
decreased (934,67 CFA francs) were 2.67 times higher than those obtained in the
flood period (351,67 CFA francs).
The statistical study does not indicate a significant
difference in the threshold of 5% for daily income of socio-professional groups
to flood and recession. At the end of the study, solutions have been proposed
to reduce the degradation of water bodies and to improve the living conditions
of populations in the Commune of Sô - Ava.
Keywords : Eichhornia.
crassipes, physicochemical parameters, eutrophication, environmental
impacts, socioeconomic impacts, So-Ava
LISTE DES FIGURES
Titres Pages
Figure 1.1 Jacinthe d'eau sur le lac
Nokoué
..............................................................................6
Figure 1.2 Meubles et objets artisanaux issus
des cordes de jacinthe .... .............................16
Figure 2.1 : Carte de la commune de Sô-Ava
indiquant les sites de prélèvement ............ 21
Figure 2.2: pH mètre et
conductimètre
..............................................................
...................25 Figure 2.3 : spectrophotomètre DR
2800
................................................................................25
Figure 3.1 : Variation de la température sur les sites
de prélèvement ...........................32 Figure 3.2
: Variation du pH sur les sites de prélèvement
......................................................33 Figure 3.3
: Variation de l'oxygène dissous sur les sites de
prélèvement ............................34
Figure 3.4 Variation de la conductivité
électrique et de la salinité sur les sites de
prélèvement............................................
..................................................................................35
Figure 3.5 : Variation de la turbidité
sur les sites de prélèvement
.......................................36
Figure 3.6 :
Variation des matières en suspension sur les sites de
prélèvement ................37
Figure 3.7 : Variation des nitrites sur les
sites de prélèvement ...............
.............................38
Figure 3.8 : Variation des nitrates sur les
sites de prélèvement ..............
.............................39
Figure 3.9 : Valeurs moyennes d'ammonium sur
les sites de prélèvement
.........................40
Figure 3.10 : Valeurs moyennes
du phosphore total sur les sites de prélèvement
.............41
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