Investigation of hydrochemical characteristic of groundwater quality of Bogoberi in Calabar Municipality in Cross River State, Southeastern Nigeria

Abstract

A groundwater quality assessment was conducted in the Bogoberi community of Calabar Municipality, Cross River State, Southeastern Nigeria, to evaluate the suitability of groundwater for drinking and other domestic purposes using different indices. A reconnaissance survey of five (5) borehole water samples were collected and analyzed using standard field and laboratory methods to determine various physicochemical properties. The results were compared with guidelines from the World Health Organization (WHO) and Nigerian Standards for Drinking Water Quality. The electrical conductivity varied between 97.2 and 254 μS/cm, while alkalinity levels ranged from 15 to 25 mg/L. Dissolved oxygen levels were between 2.5 and 5.2 mg/L, and biochemical oxygen demand ranged from 0 to 0.06 mg/L. Total dissolved solids were observed between 65.12 and 170.18 mg/L. The nitrate and sulphate ranged from 0.15 to 0.48 and 0 to 10.03 mg/L, respectively. The study area is dominated by the Calabar Flank unit. It is underlained by Teritary and Quarternary to Recent sediments known as the Benin Formation (Coastal Plain sands). The Benin Formation consists of alternating sequences of gravel and sand of various grain size, silt, clay and alluvium. In the area, the alternating sediments built up a multi-aquifer system. The Cretaceous sediments include mostly conglomerate, limestone, sandstone, mudstone, shale and marl of Calabar Flank. Statistical analysis gave significant correlation (at 0.05) between electrical conductivity, total dissolved solids, total hardness, alkalinity, and many other elements. The study aids in the understanding of chemistry of groundwater and setting background for related detailed study for long-term monitoring and management.