Small-Scale Industrial Village in Benin City,Nigeria: Establishment,Failure and Phytotoxicity Assessment of Soils from the Abandoned Site

In 1986, the then Nigerian Military Governmentpromulgated a decree stipulating that all small-scaleindustries be moved out of the city centres to designatedlocations in the more remote areas or villages. In linewith that decree, the then Edo State Government decidedto create the Small-scale Industrial village at Ogbesan,near Benin City, Nigeria. This article summarises thesituation leading to the establishment of a typicalsmall-scale industrial site (Ogbesan), its failure andthe current state of the abandoned site. To test thephytotoxic effect of soils taken from the impacted areain the abandoned site at Ogbesan, seeds of Arachishypogaea were used for experiments. Growth of test plantwas generally depressed by soils from the impacted area.One hundred percent germination inhibition was observedin sub-soil obtained from the centrally located plot (D3)in the study area. Twenty eight days after sowing, plantheight, root elongation and leaf area values wereconsistently lower in plants from almost all theexperimental plots than the control and this effect wasmore in the subsoil samples. In the most affected plots,plant height, root elongation and leaf area were 83, 100 and 87% (B5) and 94, 67 and 71% (C1),respectively, lower than the control. The resultsindicate clearly that the activities and wastes dumped atthe sites adversely affect the ability of soils from thesite to support plant growth.     

Sensitivity Studies of the Common Bean (Vigna unguiculata) and Maize (Zea mays) to Different Soil Types from the Crude Oil Drilling Site at Kutchalli, Nigeria (7 pp)

Background, Aims and Scope   The economic growth that Nigeria has enjoyed as a result of oil revenue has its drawback through exposure of people in the oil producing areas to environmental contamination, due largely to the increase in the movement of oil. Activities associated with oil well drilling on agricultural lands have led to serious economic losses on the communities affected. The local people in most of these communities are peasants who do not know how to react to drilling wastes or polluted fields where they have their crops. A case under study is the Kutchalli oil drilling area. Methods   Waste pit soil from drilling waste dumps in Kutchalli oil drilling area was tested whole and in combinations with 'clean' soil for their abilities to support plant growth and development in common bean (Vigna unguiculata) and maize (Zea mays). Seed germination, plant height, leaf area, biomass accumulation, respiratory activity as well as soil chemical analysis were used to access the ability of waste pit soil to support plant growth and development in the test plants. Results   Discussion and Conclusions. Waste pit soil completely inhibited the germination of bean and maize seeds. Waste pit soil in combinations with different proportions of Kutchalli soil gave growth (germination, height of plants, number of leaves, leaf area, etc.) values that were inferior to the control soil (Kutchalli) and the independent control soil (Monguno). Seeds planted in the test soil combinations containing waste pit soil showed significantly low respiratory activity. Waste pit soil seems to be toxic to plant growth and development. Drilling mud in combination with native Kutchalli soil significantly enhanced plant growth and development. Recommendations and Outlook   The seed germination, growth and development inhibition by waste pit soil suggests its toxicity. We want to suggest the need for strict control and monitoring of waste pit soil in oil drilling sites.     

Bioremediation of engine oil polluted soil by the tropical white rot fungus, Lentinus squarrosulus Mont. (Singer)

This study was conducted to test the efficacy of an indigenous white rot fungus Lentinus squarrosulus in degrading engine oil in soil. Flasks containing sterilized garden soil (100 g) moistened with 75% distilled water (w/v) were contaminated with engine oil 1, 2.5, 5, 10, 20 and 40% w/w concentrations, inoculated with L. squarrosulus and incubated at room temperature for 90 days. Levels of organic matter, pH, total hydrocarbon and elemental content (C, Cu, Fe, K, N, Ni, Zn and available P) were determined post-fungal treatment. Results indicate that contaminated soils inoculated with L. squarrosulus had increased organic matter, carbon and available phosphorus, while the nitrogen and available potassium was reduced. A relatively high percentage degradation of Total Petroleum Hydrocarbon (TPH) was observed at 1% engine oil concentration (94.46%), which decreased to 64.05% TPH degradation at 40% engine oil contaminated soil after 90 days of incubation. The concentrations of Fe, Cu, Zn and Ni recovered from straw/fungal biomass complex increased with the increase of engine-oil contamination and bio-accumulation by the white-rot fungus. The improvement of nutrient content values as well as the bioaccumulation of heavy metals at all levels of engine oil concentrations tested through inoculations with L. squarrosulus is of importance for the bioremediation of engine-oil polluted soils.