Seasonal Variation of Nutrient Pollution and Suspended Solids in the Drainage Network of Okpara Basin in Parakou (North-East of Benin)

• 作者: Benjamin K. Yao Fran?ois De Paule Codo Martin P. Aina Maurille P. S. Lanmandjèkpogni
• 来源期刊: 环境保护(英文)
• 学科: 医学
• 关键词: POLLUTION Okpara BASIN NUTRIENTS EUTROPHICATION
• 年，卷（期）: hjbhyw_2018,（13）
• 页码范围: 1359-1371
• 页数: 13页
• 分类号: R73

摘要

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 < pH < 9.14;mean = 7.17) and wet (6.28 < pH < 9.38;mean = 7.45). The reduction potential is lower in rainy season (-89.50 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 < CC < 0.856). In addition, pollutant concentrations vary according to a decreasing gradient between the former urban core, the periphery zone and the ex