Aisosa Peace OMOFOMWAN

This study evaluated the effects of spent crude oil on the growth and development of two cocoyam species (Colocasia esculenta [L.] Schott. and Xanthosoma sagitifolim [L.] Schott.] as well as the microbiological, proximate and phytochemical compostion of soil and cocoyam species. Cocoyam corms from both species were collected from different markets in Benin City while the spent crude oil was obtained from mechanic workshop. 250kg of loamy soil was mixed with 10 litres of spent oil, the same treatment was carried out for the other respective treatment 7 litres, 3 litres and the control which was without oil. Then 25kg of the various soil treatment was transferred into the perforated bowls. After which the corm was planted into the bowl, then the plant was monitored for eight months. After eight month the plant that was given control treatment had the highest plant height (75.5 cm). The plants grown on spent oil contaminated soil had better body mass compared to those grown on soil without any contaminants. The microbiological and phytochemical analysis of the control and contaminated soil and cocoyam species was done using standard laboratory methods. The result of the fungi associated with cocoyam revealed a colony-forming unit of between 64×105 and 127×105. The group of fungi mainly associated with the different cocoyam samples obtained from the different markets in Benin City was mainly Aspergillus and Penicillum species. The Aspergillus sp. was more diverse based on their morphological description on PDA when compared to the Penicillum sp. The percentage occurrence of the Penicillium sp. was found to be higher than those of the Aspergillus sp. in all the cocoyam samples analyzed. The results of the proximate values of the Taro samples revealed the presence of carbohydrates, protein, fat, fibre and ash in varying amounts while the results of the phytochemicals revealed the presence of saponin, tannins, alkaloids, flavonoids and polyphenol. Cocoyam contains food compounds that are beneficial and also of economic importance to man. However, there is the need to conserve this food substance against fungal infestation so that its full economic value can be harnessed. Most importantly, the results from the study revealed that the growth and development of cocoyam are affected by spent crude oil pollution of soil. More study is required to elucidate the potential effects and bioremediation potentials of the crops.