COMPARATIVE STUDIES ON THE HEAVY METAL CONCENTRATION IN LEAF, STEM AND ROOT OF CORCHORUS OLITORIUS L. IRRIGATED WITH SEWAGE WATER AND TAP WATER RESPECTIVELY, A RESEARCH PROJECT TOPIC ON PLANT SCIENCE
The level of accumulation of heavy chemicals in the leaves, stem and roots of Corchorusolitorius seedlings irrigated with sewage (Sewage effluent) and tap water to maturity respectively was investigated. Prior to irrigation, water quality indicators and physico-chemical properties of the two water sources were analysed. The experiment, a completely randomized design was carried out in a screen house in the Botanic Garden of the Department of Plant Science and Biotechnology, University of Nigeria, Nsukka and lasted for four months. The results showed that sewage water had higher values of biochemical oxygen demand (BOD), chemical oxygen demand (COD), and temperature than tap water. The results also showed that tap water had higher values of dissolved oxygen (DO) and transparency than sewage water. The results further showed that sewage water had higher values of the analysed physico-chemical properties than tap water. Again, it showed that sewage water enhanced better seedling growth than tap water. Cadmium, Mercury, Zinc, Copper, Lead and Arsenic accumulation in the leaves, stem and roots were higher in seedlings irrigated with sewage water when compared with those irrigated with tap water. The results further showed that the accumulation of heavy chemicals in the leaves, stem and roots of the seedlings irrigated with both water sources, (Sewage and tap) were higher than the accepted standard of the Federal Environmental Protection Agency (FEPA). Based on the results obtained, it is recommended that continued production of leaf vegetables off-season using sewage water be avoided, because of possible health hazards posed by continued consumption of such vegetables.
Globally, water has been a major requirement for the growth and development of biotic life. Water has for long exerted strong influence on the choice of place for human settlement. Of all human activities, agriculture and industrial activities have been identified as the highest consumer of water (Nweze and Chimboh, 2003). With time, increase in population and sophisticated advancements in man’s industrial sectors have resulted in drastic scarcity of available natural/clean water.