Greener Journal of Environment Management and Public Safety Vol. 2 (5), pp. 189-194, September 2013.
ISSN: 2354-2276 © 2011 Greener Journals
Manuscript Number: 110113939
Risk Assessment of Raw Effluents Discharged From an Industrial Estate in Lagos, Southwestern Nigeria
Department of Geography and Environmental Sciences, University of Hertfordshire, Hatfield, AL10 9AB, United Kingdom.
Email: omotayoayeni @ yahoo.com
An industrial area was selected for geo-environmental studies in Lagos due to the discharge of raw effluents into the open drains. Effluent samples were collected from nine sites and taken to the analyzing laboratory for chemical analysis. The concentrations of constituent elements were determined using Inductively Coupled Plasma (ICP) and Optical Electro Spectrometer (OES) standard methods. The results obtained for toxic heavy metals show mean concentrations in the order of abundance given as Fe>Mn>Zn>Cu>Pb>Cd.
Physico-chemical parameters, such as electrical conductivity (EC), total dissolved solids (TDS), temperature, pH and elemental composition were obtained and the trend of abundance of elements is given as Na>Ca>Mg>K>P. The coefficient of determination r2= 0.9967 obtained for EC and TDS shows a good positive correlation coefficient between the two parameters while temperature and pH varied anomalously. This study reveals that the concentrations of toxic heavy metals and physico-chemical parameters were significantly higher than the permissible limits of WHO which could pose a huge adverse effect to man and the environment. Therefore, the polluting industries have the duty-of-care to manage their effluent disposal in order to safeguard the aesthetic integrity of the environment and to ensure public safety.
Keywords: risk assessment, raw effluents, industrial estate, heavy metals, pollution, health, environment.