Water quality index and correlation study for the assessment of water quality and its parameters in Etim Ekpo, Nigeria

Abstract Water bodies can be polluted by the addition of nutrients such as nitrates, phosphates, sulphates and chlorides through urbanization, agricultural, industrial and domestic activities. This study was aimed at determining the pollution status of EtimEkpo River, AkwaIbom State, Nigeria, during wet and dry seasons. Physicochemical parameters of water including, temperature, pH, dissolved oxygen (DO), biochemical oxygen demand (BOD), and conductivity, were measured using USEPA protocol. Other parameters were determined using UV-Visible spectrophotometric techniques. They were nitrates (NO₃^–), sulphates (SO₄^2-), phosphates (PO₄^3-), carbonates (CO₃^2-) and chlorides (Cl^–). Mean temperature were of 27.87^oC and 27.98^oC for wet and dry seasons respectively. The pH of the river water samples during the wet season ranged from 6.90 to 7.83 while the pH during the dry season ranged from 6.63 to 7.73.Mean values of dissolved oxygen ranged from 12.41mgIl – 15.32 mg/l for wet season and 12.94mg/l – 13.98mg/l for the dry season. Mean BOD were 4.75mg/l and 4.15mg/l respectively for wet and dry season. The conductivity levels ranged from 13.09µScm^-1to 19.04µScm^{-1 in the wet season and 12.12µScm-1} to 13.90µScm^{-1 in the dry season. Concentrations of PO}₄^3-, SO₄^2-, NO₃^–, CO₃^2- and Cl^– in the samples were within safe limits. The Pearson’s correlation coefficient revealed weak correlations amongst the parameters measured, indicating different sources of their input to the water body. Over-all the study revealed a low pollution status of the river under study. The results from the present study serve as a base-line for future researches. Continuous monitoring of the river is encouraged, as anthropogenic activities in the area increases.

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