On May 19th 2016, a lecture was delivered at the main auditorium of the University of Benin by Prof. Geoffrey O. Anoliefo on Man and His Environment: Unsustainable exploitation of the land. The lecture anchored on how man?s activities have resulted in the degradation of the environment, how the soil can be reverted to its pristine state and how to avoid further soil damage.

Soil degradation is a serious environmental problem especially in the Niger Delta region of Nigeria, where the soil has be polluted with crude oil spills and toxic chemicals from industries. Soil degradation can also result from excessive erosion brought about by deforestation, indiscriminate buildings which block natural drain routes, overgrazing and improper disposal of non-degradable wastes. Degradation of the soil makes the soil unable to support the growth of crops, which results in reduction in biodiversity and affects the general sustenance of life.

Due to the adverse effects of soil degradation, the need for remediation of the soil has been emphasized over the years. The conventional physical methods of remediation involving excavation of the polluted soil to an offsite location for treatment and/or disposal is cost extensive and time consuming hence it is often never done.

The biological method of soil remediation (bioremediation) uses the biodegradative potentials of naturally occurring organisms to remove or break down harmful substances in the soil. This can be done with plants, fungus or microbes. Studies have shown that microbes are the major drivers of bioremediation. However, the major limitation is that microbial metabolism of certain substances may produce toxic intermediates.

Bioremediation can also be achieved by the use of certain plants. Plants such as Chromolaena odorata (locally called ?Awolowo weed?) and Vernonia amygdalina (bitter leaf), both Asteraceae, has been shown to be able to remove pollutants from the soil, especially crude oil spills. Other plants that have been studied as potential good phytoremediation agents for the clean-up of crude oil contaminated soils include Panicum maximum (Guinea grass) and Water leaf (Talinum triangulare). Studies have also shown that plants such as Africa lettuce and Alstonia boonei (De wild) can take up heavy metals such as Lead, Cadmium and Iron from the soil and store in their leaves. Further research is still on-going regarding plants that can be employed to clean up the environment.