MACROINVERTEBRATE DIVERSITY AND WATER QUALITY PATTERN OF A MUNICIPAL STREAM IN DOKO DISTRICT, NIGER STATE, NIGERIA

Abstract

Abstract Macroinvertebrates organisms form significant part of an aquatic ecosystem which are of ecological and economic importance because they maintain various levels of interaction within aquatic environment. Emikpata stream in Doko district, Niger State, Nigeria is used for a variety of purposes such as irrigation, cattle drinking and domestic purposes. The macroinvertebrate diversity and water quality patterns of the stream were evaluated for a period of eight months using the standard experimental techniques. Four different study stations were selected along the course of the stream designated as Stations 1, 2, 3, 4, respectively. A total of 625 individuals from 28 species and 19 families of invertebrate were recorded. Significantly higher (P<0.05) macro-invertebrate abundance was recorded from dry season than in the wet season. The results of the physicochemical parameters showed that temperature (23.0 - 27.0 0C), flow velocity (0.29-0.30 m/s), conductivity (49.1 - 110.0 us/cm), dissolve oxygen (5.97 - 6.35 mg/L), total hardness (12.3-18.0 mg/L), total alkalinity (13.0-20.5 mg/l), phosphate (0.60 - 1.12 mg/L) , potassium (1.74 - 1.92 mg/L) was not significant (P>0.05) among the sample stations while biological oxygen demand (3.25-3.87 mg/L), pH value (6.0 - 6.32), chlorine (10.71 - 32.79 mg/L), nitrate (1.83 - 3.69 mg/L), sodium (7.24 - 9.02 mg/L), showed significant differences (P<0.05) between the sample station.. The CCA result showed strong relationships between species abundance and measured environmental variables. Emikpata Stream is found to be under minimum anthropogenic impact and is impaired in the downstream sections. Higher population of pollution tolerant macroinvertebrates groups and the tasting water quality of the surface water during the sampling period were implications of pollution stress caused by anthropogenic activities, decomposing domestic wastes and inorganic fertilizer washed into the stream from various nearby farms.