Irrigation and Drinking Water Quality Index Determination for Groundwater Quality Evaluation in Akoko Northwest and Northeast Areas of Ondo State, Southwestern Nigeria

摘要

The water quality index (WQI) obtained for the water samples ranges between 22.7 and 88.6. The water quality index classified the water into "excellent" and "good" drinking water and account for about 85% and 15% of the study area respectively. The % Na of the samples varies between 49 and 79%. Sodium Absorption Ratio (SAR) of the studied water samples varies from 1.40 to 3.56 with a mean of 2.44. The values are within 0 - 10 specified as excellent water for irrigation purpose. The Residual Sodium Carbonate (RSC) values ranges between - 51.6 and +10.57, with an average of -14.5, which agrees with less than 2.5 specified for the purpose of irrigation. The permeability index (PI) of the water varies from 2.27 to 19.9, with an average of 7.93. The values fall within the Third category of 0 - 25 irrigation water which is rated as poor. The electrical conductivity of the water ranges from 117 to 789 μs/cm with an average of 378 μs/cm which corresponds to moderate (medium salinity). Also, the water in the study area shows variation of low salinity to high salinity. The Wilcox plot showed that the water samples have excellent - good irrigation potential except a sample taken from Arigidi Akoko which fall within "good to permissible limit." Therefore combine all these results the water are moderately suitable for irrigation purpose and good for drinking.