Journal of Environment and Earth Science www.iiste.org ISSN 2224-3216 (Paper) ISSN 2225-0948 (Online) Vol.5, No.20, 2015 80 Physico-chemical properties of soil polluted with petroleum crankcase oil and chlorophyll concentration of Abelmoschus esculentus (okra). * Onyegeme-Okerenta B. M., Alozie, S. C., Wegwu M. O. Department of Biochemistry, Faculty of Biological and Chemical Sciences, College of Natural and Applied Sciences, University of Port Harcourt, PMB 5323, Choba, Rivers State, Nigeria. Abstract Effect of petroleum crankcase oil (PCO) on soil physico-chemical parameters and chlorophyll content of Abelmoschus esculentus (Okra) was investigated. Garden topsoil was collected from Obingwu, Ohii in Owerri West Local Government Area of Imo State, Nigeria tested for soil physico-chemical parameters, weighed and polluted with different volumes of PCO to give the various percentage pollutions. Five viable seeds of A. esculentus were planted in each. An unpolluted soil sample served as the control for the investigation. Harvest of the leaves and fruits was done immediately after fruiting and taken to the laboratory for the assessment of soil physico-chemical parameters and chlorophyll concentration. Results obtained for soil pH and soil phosphate show there was no significant difference (p>0.05) at the various levels of PCO pollution. However, there was a significant increase (p<0.05) in the percentage moisture content and calcium carbonate with respective increase in PCO pollution while a significant decrease (p<0.05) was observed in organic carbon, nitrogen and chlorophyll content of the PCO polluted samples when compared with the control. Furthermore, at 6% PCO pollution, only two seeds sprouted and leaf growth was not sustained till the end of the experiment. These results indicate that soil physico-chemical parameters and chlorophyll concentration of A. esculentus leaves were responsive to the detrimental effects of PCO in areas where it is disposed indiscriminately. Keywords: Abelmoschus esculentus, pollution, petroleum crankcase oil (PCO), soil, chlorophyll. 1. Introduction Nigeria is a major world producer of crude oil. Pollution of the environment due to crude oil spillage and its allied products has steadily increased as a result of oil exploration, industrialisation and incessant disposal of crude products and wastes by road side automobile mechanics, maintenance workshops, and dealers (Kori – Siakpere, 1998). The role of oil and gas industries in improving the quality of life and economic development in Nigeria cannot be overemphasized. Alongside the good things that brought an enhancement in the standard of living was the emergence of deleterious substances in the environment following oil and gas activities (Nwaogu et al 2012). These industrial pollutants, including CO 2 from exhausts of automobiles and other pollutants such as heavy metals, constitute an important source of environmental pollution. In oil and gas operations, crude oil, corrosive acid waste, toxic chemicals and other harmful industrial wastes are intermittently released into the environment (air, soil and water) (Rowell, 1977). Sulphur and other toxic gases by oil companies are usually released into the atmosphere. These, together with injected particulates and unburned hydrocarbons undergo series of chemical reactions in the presence of sunlight, resulting in dense characteristic smog (Bamidele, 2000). The implication of petroleum hydrocarbon pollution in agricultural production system and the environmental impact associated with the exploration and exploitation of crude oil has been an area of great interest in the last three decades. The increase in demand for petroleum and its products as a source of energy and primary raw material for petrochemical industries has resulted in a corresponding increase in the harm caused by crude oil and its allied products like petroleum crank case oil (Odiete, 1999). Abelmoschus esculentus (okra), known in many English-speaking countries as lady's fingers or gumbo is a flowering plant in the mallow family. It is one of the most important fruit vegetable crops and a source of calorie (4550kcal/kg) for human consumption and ranks first before other vegetable crops (Babatunde et al. 2007). It is an important vegetable and widely distributed from Africa to Asia, Southern Europe and America (Khomsug et al. 2010). Abelmoschus esculentus is cultivated throughout the tropical and warm temperate regions of the world for its fibrous fruits or pods containing round, white seeds. It is among the most heat- and drought-tolerant vegetable species in the world and will tolerate soils with heavy clay and intermittent moisture, but frost can damage the pods (Okafor & Fernandes 1987), Okra cultivation and production has been widely practiced because of its importance to the economy development and can be found in almost every market in Africa. Varieties vary by plant height, size of fruit, colour, early or late maturing etc., (Udoh et al. 2005). CORE Metadata, citation and similar papers at core.ac.uk Provided by International Institute for Science, Technology and Education (IISTE): E-Journals