The use of land for field evaluations of the impact of crude oil on the biotic and abiotic factors in developing bioremediation strategies for agricultural land upon pollution with crude petroleum or petroleum products.

A small piece of land in the Garden of the University of Lagos, Nigeria, wa s deliberately contaminated with crude petroleum and the oil impact on both the biotic and abiotic factors monitored for 129 days with a view to devel oping strategies for bioremediation of agricultural land upon pollution wit h crude oil. Between days 0 and 12, the total heterotrophs (TH) and hydroca rbon utilizers (THCU) dropped significantly alongside with the dissolved ox ygen and the concentration of inorganic nutrient sources such as PO4-3, SO4 -2, HCO3-1 and N-2. However, between days 12 and 120 when the trends in the TH, THCU and nitrogen sources increased, the oil concentration decreased s ignificantly as reflected by both the GC and gravimetric data. On applicati on of data generated to model equations, approximately 329 days would elaps e before the contaminated land could recover from the impact of the oil pol lutant. Therefore, in bioremediation of agricultural land polluted with cru de oil, it may be necessary to monitor the levels of inorganic nutrient sou rces and adjust same appropriately to enhance microbial growth particularly that of the HCU hence the biodegradation of oil pollutant. The use of mode l equations to predict the recovery time of the contaminated land was consi dered a good index for reference purposes, policies and action plans partic ularly for impact assessment in bioremediation programmes of land polluted with crude oil.