TITLE:
Qualitative Assessment and Typology of the Water Resource Used for the Production of Drinking Water in Duékoué, Western Côte d’Ivoire
AUTHORS:
Kouamé Kouakou Benoit, Konan Kouakou Séraphin, Attoungbre Kouakou Severin, Konan Koffi Félix, Boussou Koffi Charles, Kouamé Kouamé Martin
KEYWORDS:
Dohou Lake, Water Quality, Coliform, Fecal Coliform, Physico-Chemical Parameters, Typology and Variation
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.7 No.5,
May
30,
2019
ABSTRACT: The objective of this study was to evaluate the
typology of water through physicochemical and bacteriological characterization
with the aim of highlighting its vulnerability as a drinking water resource.
The methodology adopted was to evaluate the level of pollution by monitoring
the spatiotemporal variation of the water pollution indicator levels of Lake
Dohou. The sampling frequency is monthly for one year, from November 2017 to
October 2018, in order to obtain a fairly representative image of water quality
and its seasonal evolution in eight (8) well-defined stations. The parameters
were determined using the standard methods defined by the French Association
for Standardization (AFNOR). This study shows that the waters are acidic, with
an average pH of 5.81 and a low electrical conductivity of between 42.67 ± 4.30
and 59.62 ± 21.84 μS.cm-1. At all stations, seasonal mean water transparencies are
low (L-1. All of the
lake’s waters have non-compliant BOD5 (2.L-1) for raw water intended for the production of drinking
water. Sites D6 and D7 have COD/BOD5 ratio greater than 3, which indicates the
presence of non-biodegradable organic matter in these areas. Total coliforms, Escherichia coli and Enterococci were
present in 100% (28/28) water samples at
concentrations ranging from 2300 to 173,000 CFU/100 mL, from 100 to 1650 CFU/100 mL and from 20 to 1140 CFU 1/100 mL respectively. For Salmonella pathogens, they were detected in 50% of
the dry season samples and in 100% of the rainy season samples. This almost
permanent presence of this pathogenic germ denotes a poor quality of water with
reference to this parameter. The presence of total coliform and other microbial
contaminants suggests that supplied water is
highly contaminated with pathogens and great reservoirs for them. Principal component analysis (PCA) of the physicochemical data set
allowed defining three different classes of water on the Dohou Lake. Outside
the upstream zone (D6 and D8), water could continue
to be used for the production of drinking water.