Potential benefits and inherent dangers in cropping municipal waste dump sites – case studies in the City of Ibadan, Nigeria

Abstract

The benefits derivable to crops from the high fertility status of municipal wastes dump sites and the dangers of heavy metal accumulation in crops planted therein were examined in three municipal refuse dumpsites namely, [Eleiyele (Site 1), Ring Road, (Site 2) and Bere (Site 3)] in Ibadan, Nigeria.


The response of maize (Zea mays) to the soil nutrients and heavy metals were examined in the greenhouse and in the field. The plant nutrients in the three dump sites were quite adequate for maize growth and development but no germination of the test crop was observed in Site 3. Water (absorbed) and potassium nitrate (KNO3) (exchangeable) fractions of the heavy metals in the soils of the three sites were lower than the critical levels considered to be phytotoxic. However, the total extractable copper (Cu) (20.42mgkg-1) and zinc (Zn) (39.44mgkg-1) in the soils were higher in Site 3 than in the other dump sites. Site 3 soil also contained the highest population of cellulose degrading microorganisms. The concentrations of the heavy metals in plant tissue planted in the greenhouse experiment were low but high in plant tissue harvested in the field. Refuse dump site soils are important in Ibadan agricultural production but it is necessary that cropping is preceeded by soil test to determine nutrient and heavy metal concentrations.



Keywords:Soil nutrients; Fertility status; Heavy metals; Municipal wastes

[Global Jnl Environ Sci Vol.2(2) 2003: 102-105]