TITLE:
Seasonal Variation of Nutrient Pollution and Suspended Solids in the Drainage Network of Okpara Basin in Parakou (North-East of Benin)
AUTHORS:
Maurille P. S. Lanmandjèkpogni, François De Paule Codo, Benjamin K. Yao, Martin P. Aina
KEYWORDS:
Pollution, Okpara, Basin, Nutrients, Eutrophication
JOURNAL NAME:
Journal of Environmental Protection,
Vol.9 No.13,
December
11,
2018
ABSTRACT: This
work presents mainly, the seasonal variation of pollution by nutrients and
suspended solids thresholds between the old urban core and the peripheral areas
of the city of Parakou on the Okpara basin. The city of Parakou has been
experiencing strong demographic and socio-economic growth for about two
decades. A total of sixty wastewater samples from twelve sampling sites were
collected in 2016 according to the AFNOR standards, between the months of March
and April in the dry season, then August, September and October in the rainy season. The descriptive statistic of data
(minima-maxima) indicates variations of the parameters as follows: The
temperature varies between 27.05 and 30.82, the water is a highly variable pH
in the dry season (5.84 5 respectively reach the highest ratio (55 mg/L O2 and 232.08 mg/LO2)
in the dry season than in the wet season (12.00 mg/L O2 and 202.40
mg/L O2). Nitrates have reached a maximum of 12.60 mg/L in the rainy
season against 5.40 mg/L in the dry season. For nitrite, yielded 3.34 mg/L
against 0.45 mg/L for conversely, phosphates are at 6.45 mg/L in the dry season
against 2.32 mg/L in the rainy season. The mean concentrations of suspended
solids are between 40 mg/L in the rainy season and 0.52 mg/L in the dry season.
From the physico-chemical characterization and the chi-square independent test,
this work shows mainly two results: On the one hand, apart from phosphates,
concentrations of nitrates, nitrites and suspended solids on the Okpara basin
in Parakou, are higher in the rainy season than in dry season. This can be
explained by the variability of soil leaching and thus shows a relative link
between the quality of surface water and the hydrogeomorphic basin conditions
shown by the independence test (0.456