Hydrochemical and statistical approaches in the evaluation of groundwater quality for drinking and irrigation uses around around Ezzangbo–Ngbo area, Southeastern Nigeria

Assessment of groundwater quality around Ezzangbo–Ngbo area, southeastern part of Nigeria was carried out using hydrochemical and statistical approach with the sole aim of determining its suitability for drinking and irrigation uses. 20 groundwater samples were collected and analyzed in Water Science Laboratory, University of Nebraska, Lincoln, USA, for physicochemical parameters, such as pH, electrical conductivity (EC), total dissolve solid (TDS), total hardness (TH), sodium ion (Na + ), magnesium ion (Mg 2+ ), potassium ion (K + ), chloride ion (Cl − ), sulphate ion (SO 4 2− ), and nitrite ion (NO 3 − ) using the atomic absorption spectrophotometric (AAS), Dionex ICX-90 and potentiometric titration methods. Result of hydrochemical analysis indicated that pH ranges from 6.46 to 7.25; further deductions from pH suggested that base except samples locations BH2, BH4, BH5, HDW1, BH6, BH7, HDW2, BH9, BH10, HDW4, HDW5, BH13, and BH14 which were considered acidic. Total dissolved solid (TDS) for this study ranges from 184 to 447 mg/L, indicating groundwater is considered to be freshwater. Further findings from TH value revealed that TH ranges from 62.11 to 489.03 mg/L, classifying the groundwater as ‘soft’ to ‘very hard’ water. Ca 2+ > Na + > Mg 2+ > K + is the order of main cation concentrations, with mean value of 97.20 mg/L, 75.01 mg/L, 10.17 mg/L, and 1.24 mg/L, respectively, while HCO 3− > Cl − > SO 4 2− > NO 3 − s is the order of main anions concentrations, with mean value of 388.05 mg/L, 14.09 mg/L, 12.04 mg/L, and 0.162 mg/L, respectively. Results from assessment of groundwater for drinking indicates that groundwater fell into the category “excellent” and “good” for drinking use based on WQI and “excellent to unsuitable” for irrigation use based on %Na and SAR.Ca 2+ –Mg 2+ –HCO 3 − and Na 2+ −HCO 3 − hydrochemical facies were identified. Reverse ion exchange, weathering of silicate minerals, and rock–water interactions were identified as the major mechanisms influencing ionic components of groundwater in the area.