Use of Water Pollution Index to Assess the Levels of Dissolved Organic and Inorganic Substances in Nworie River Owerri, Imo State Nigeria

The use of water pollution index to assess the contributions of organic and inorganic parameters in the pollution level of Nworie River was studied in the month of October, 2014. An index represents the results of generated field data in a simple and generalised way by mathematically combining sets of values obtained. The pollution indices of water and sediment samples during dredging of the river in 2010 and in this present study were presented and comparisons made. This investigation surveyed the following parameters for both surface water and sediment samples: pH, Temp, Phosphate, Nitrate, Sulphate, Iron and Lead, while turbidity, conductivity, Alkalinity, Carbonate, Hardness, DO, BOD5 TSS, were included in surface water analysis. Three sampling stations along the stretch of the river were selected: Federal Medical center, Akanchawa Road and Egbeada and standard methods were adopted for their sampling and analysis. The result of the analysis indicates that turbidity and total suspended solids exceeded the standard limits for surface water, while iron exceeded that for sediments. A DO of 5.7mg/l shows that the river could sustain aquatic life. The results of the computed pollution index revealed that the index of organic parameters was 0.42 while that of inorganic was 0.34.During the dredging of the river in 2010 organic parameters had an index of 0.48 while inorganic had 0.30.For sediments, organic variables had a score of 0.08 while inorganic had 0.02 score. During the dredging in 2010, the index of organic parameters for sediments was 0.13, while for inorganic vsariables it was 0.053.The pollution indices strongly implicated pollution by organic wastes which were higher during the dredging of Nworie River. Keywords: Pollution index, organic, inorganic, Nworie River