A multivariate approach to assessing the water quality of the Bamako reach of the Niger River in Mali as irrigation water.

Abstract

Agricultural production in the Bamako region has been raised, and its output quality has been questionable due to the discharge of wastewater into the Niger River. This study assessed the Niger River water body variations for irrigation application temporally and spatially. Thirteen parameters, potential of hydrogen, electrical conductivity, nitrate, total dissolved solids, phosphate, sulfate, chloride, ammonium, calcium, magnesium, potassium, sodium, and bicarbonate, were analyzed at the 15 sampling locations. Parameters examination indicated that most pollutants had higher concentrations over the high-flow phase than in the low-flow period. All parameters were within the Food and Agriculture Organization's recommended values levels. Irrigation variables, sodium adsorption ratio, sodium percentage, soluble sodium percentage, residual sodium bicarbonate, Kelly's ration, permeability index, total hardness, and potential salinity showed the water samples' convenience for irrigation. However, the magnesium hazard concentration exceeded the recommended values levels. Besides, the chloroalkaline indices indicated a trend of degradation that should be addressed. Therefore, a river management plan and regular irrigation water quality monitoring are needed to reduce water hardness in Bamako. The Niger River's sustainable management process must be thrived on all actors' participation. A scientific assessment will be conducted using appropriate methods to identify pollution sources in Bamako. The results of this study will serve as a cornerstone for future investigations concerning the quality of surface water, which is essential for irrigation purposes. PRACTITIONER POINTS: Human activities affected the Niger River water bodies in Bamako city. Quantitative and qualitative assessments reveal the pollution status and trend of the Niger River. The water quality trend is better in the low-flow season, which is an ideal period for vegetable production in Bamako. Most multivariate approaches indicated that the Niger River water is healthy for irrigation purposes. Magnesium hazard exceeded the standard levels, and the chloroalkaline indices indicated a trend of the Niger River water quality deterioration.