Environmental impact assessment of two polluting sources on stream in Nigeria
International Agricultural Engineering Journal
Department of Agricultural and Environmental Engineering, Federal University of Technology, Akure, Nigeria; Department of Biological and Agricultural Engineering, Universiti Putra Malaysia (UPM), Malaysia
The environmental impact of locating two polluting sources of landfill (refuse dump) and petrochemicals on Alaba stream in Akure, Nigeria was assessed. Twenty physio-chemical parameters were analyzed for wet and dry seasons respectively with three sampling points within 5m intervals from one another of the two polluting sources on the stream. The parameters include: colour, odour, taste, pH, temperature, turbidity, alkalinity, conductivity, dissolved oxygen (DO), biochemical oxygen demand (BOD5) and total solids (TS). Others were chloride (CL-), total dissolved solids (TDS), total suspended solids (TSS), lead (Pb), nitrate (NO3), sulphate (SO4-2), oil and grease, Escherichia coli (E-coli) and faecal coliform. Some parameters were determined in-situ while others were determined using APHA (2005) standard procedures and results obtained were subjected to statistical analysis. All the samples investigated contained a considerable degree of pollution which asserted the pollution of the stream. The results for dry and wet seasons indicated that the conductivity, 353.33±15.0 and 256.67±26.58, Alkalinity, 52.83±16.0 and 90.90±20.98, DO, 0.33±0.08 and 0.48±0.01mg/l, Turbidity, 57.22±7.15 and 8.10±1.70, BOD, 0.20±0.10 and 0.22±0.11, TDS, 0.18±0.16 and 0.46±0.42. E-coli had values 55.37±7.45 and 8.99±3.23, faecal coliform, 241.50±11.64 and 129.83±35.06 and Pb, 13.72±7.68 and 11.88±5.20 respectively. Others were sulphate, 1298.33±422.52 and 1273.33±423.77, nitrate, 6.40±0.96, chloride, 0.33±0.12. Most of the values (with the exception of pH and alkalinity) were above the maximum permissible levels of FAO, WHO and NSDWQ standards and parameters such as pH, turbidity, DO, BOD, Pb, E-coli and faecal coliform decreased as the distance from the polluting sources increased. Statistical analyses showed significant differences at specific confidence levels while treatment of Alaba stream is required to achieve minimum acceptable level for domestic uses, public awareness on the dangers inherent in polluting the stream should be carried out.
Alkalinity; Biochemical oxygen demand; Chemical analysis; Chlorine compounds; Dissolved oxygen; Environmental impact assessments; Escherichia coli; Land fill; Lead; Nitrates; Petrochemicals; pH; Pollution; River pollution; Statistical methods; Turbidity; Akure; Degree of pollutions; Dry and wet seasons; Micro-biological parameters; Physico - chemical parameters; Stream; Total dissolved solids; Total suspended solids; Environmental impact