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Volume 10 March 2005
ISSN 1438-7890
 
African Journal of Environmental Assessment and Management
Revue africaine de gestion et d’évaluation environnementales
 
IMPACT ASSESSMENT OF INDUSTRIAL EFFLUENT ON WATER QUALITY OF THE RECEIVING ALARO RIVER IN IBADAN, NIGERIA
 

Sayo O. Fakayode

Department of Chemistry and Biochemistry, Baylor University

P.O. Box 97348, Waco Texas 76798, U.S.A

E-mail: Sayo_Fakayode@baylor.edu

 

Alaro River is receiving industrial effluent as a point source. The water quality of the river upstream and downstream after the point of effluent discharge was assessed with the view of determining the effect of industrial effluent on the water quality of the river. The water samples were analyzed for dissolved oxygen (DO), pH, alkalinity, electrical conductivity, total solid (TS), chloride, sulphate, phosphate and heavy metals (Pb, Mn, Ni, Cd, Cr and Cu). The average levels of the parameters upstream were: pH (7.8 ± 0.5); DO (7.0 ± 1.3 mg/L); alkalinity (405 ± 103 mg CaCO3/L); TS (328.8 ± 106.7 mg/L); chloride (474.8 ± 154.1 mg/L); sulphate (2.3 ± 0.7 mg/L); phosphate (0.175 ± 0.026 mg/L); Pb (0.023 ± 0.001mg/L); Mn (0.169 ± 0.009 mg/L); Ni (0.011 ± 0.003 mg/L); Cd (0.004 ± 0.002 mg/L); Cr (0.003 ± 0.001 mg/L) and Cu (0.005 ± 0.001 mg/L). Much higher average levels of alkalinity (744 ± 80 mg CaCO3/L); total solids (1379 ± 389 mg/L); chloride (1126 ± 83 mg/L); sulphate (16.4 ± 13.9 mg/L); phosphate (4.62 ± 2.07 mg/L); Pb (0.14 ± 0.03 mg/L); Mn (0.456 ± 0.190 mg/L); Ni (0.03 ± 0.03 mg/L); Cd (0.01 ± 0.001 mg/L); Cr (0.021 ± 0.007 mg/L); Cu (0.0923 ± 0.035 mg/L) and lower average levels of pH (6.5 ± 0.5) and DO (0.63 ± 0.93 mg/L) were obtained downstream. The levels of most parameters in the effluent exceeded the effluent guideline for discharge into surface water. River’s recovery capacities for the water quality parameters were fairly good and ranged between 36 and 90 %.

 
 
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