TITLE:
Assessment of the Physico-Chemical Quality of Irrigation Water Used in the Niaye of Patte d’Oie (Dakar)
AUTHORS:
Mariama Bakhoum, Tidiane Diop, Mor Wade, Adrienne Ndiolene, Mor Diop, Mouhamadou Abdoulaye Diallo, Cheikh Abdoul Khadir Diop
KEYWORDS:
Niaye, Irrigation Water, Water Quality Indices, Sodicity, Geochemistry
JOURNAL NAME:
Journal of Agricultural Chemistry and Environment,
Vol.15 No.1,
January
7,
2026
ABSTRACT: Urban market gardening plays an essential role in meeting the food needs of Dakar’s rapidly growing population. This high population density generates significant wastewater discharges in the study area, thereby increasing the risk of contamination of surface and groundwater. This study aims to assess the physico-chemical quality of irrigation water used at the market gardening site of the Niaye of Patte d’Oie (Dakar), in order to evaluate its suitability for irrigation and its potential effects on soils and crops. Three water samples were collected from different points across the site. The collected samples were analyzed for several physico-chemical parameters, including pH, electrical conductivity (EC), total dissolved solids (TDS), major cations (Na+, K+, Ca2+, Mg2+ and
NH
4
+
), and major anions (
HCO
3
−
,
PO
4
3−
,
SO
4
2−
,
Cl
−
,
NO
3
−
and
F
−
). The obtained values were compared with FAO guideline values for irrigation water. Irrigation water quality indices (SAR, RSC, SSP, KI, and PI) were calculated to evaluate the overall water quality. The results show that most major ions exhibit concentrations within the recommended limits, except for K+, Na+,
NO
3
−
,
NH
4
+
, and
PO
4
3−
, whose levels locally exceed the guidelines. Most samples show moderate salinity, with TDS values below 2000 mg/L, indicating that the water generally meets irrigation standards. The low to moderate SAR values indicate a limited sodicity risk, while the dominance of Na+ and
Cl
−
suggests the influence of salt dissolution. The maximum SAR value (below 10) and RSC value (below 1.25) confirm good water quality for irrigation. Hydrochemical analysis reveals two types of facies: a sodium-potassium bicarbonate-chloride facies and a sodium-potassium sulfate facies. According to the Riverside classification diagram, the irrigation water from the Niaye of Patte d’Oie ranges from medium to poor quality, requiring cautious use. Overall, the water quality in the Niaye of Patte d’Oie is acceptable for irrigation, but regular monitoring remains necessary to prevent salt accumulation in soils and to preserve the sustainability of market gardening production.