Thesis Abstract

Abstract
This study aimed to investigate the effects of spent engine oil pollution on the germination of Arachis hypogaea (groundnut) seeds. The experiment was conducted using a randomized block design with three replicates. Different concentrations of spent engine oil (0%, 2.5%, 5%, 7.5%, and 10%) were applied to the soil where the seeds were planted. The germination rate, seedling growth, and biochemical parameters of the plants were assessed after a specified period. Results showed that the germination rate decreased significantly with increasing concentrations of spent engine oil. Seeds planted in soil with higher oil concentrations exhibited delayed germination and lower overall germination rates compared to those in uncontaminated soil. Seedling growth was also adversely affected by the oil pollution, with reduced shoot and root lengths observed in plants grown in oil-contaminated soil. Biochemical analysis revealed that the presence of spent engine oil in the soil led to increased levels of oxidative stress in the plants. This was evident from higher levels of reactive oxygen species (ROS) and malondialdehyde (MDA) in the leaves of plants exposed to oil pollution. Conversely, the activities of antioxidant enzymes such as superoxide dismutase (SOD) and catalase (CAT) were reduced in the contaminated plants, indicating a compromised antioxidant defense system. Overall, the findings suggest that spent engine oil pollution has detrimental effects on the germination and early growth stages of Arachis hypogaea seeds. The presence of oil in the soil hinders seed germination, impairs seedling growth, and disrupts the antioxidant defense mechanisms of the plants. These effects are likely due to the toxic components present in the spent engine oil, which induce oxidative stress and inhibit normal plant physiological processes. In conclusion, the study highlights the importance of monitoring and mitigating spent engine oil pollution in agricultural environments to safeguard plant growth and productivity. Further research is needed to explore the long-term effects of oil contamination on plant development and to develop sustainable remediation strategies for oil-polluted soils.

Thesis Overview

Groundnuts (Arachis hypogeal) also known as peanuts are considered a very healthy snack. They belong to the family Fabaceae and are native of regions like South America, Mexico and Central America (FAO, 2002). It is successfully grown in other parts of the world as well. It is one of World’s principal oilseed Crops (Mukher et al., 2010). It ranks fourth in oil production after Soybean, Cotton seed and rapeseed. Major groundnut producers in the World are China (40.1%), India 16.4%) Nigeria (8.2%), USA (5.9%) Indonesia (4.1%) and Sudan (5.23%) (FAO, 2002). Groundnut kernels are consumed directly as raw, roasted or boiled kernels or oil extracted from the kernel is used as culinary oil. Nigeria is the largest groundnut producer in Africa (Sokoto et al, 2010). The nuts are also used as animal feed and industrial raw materials (oil, cake and fertilizers). These multiple uses of this crop make it an excellent cash crop for both domestic and foreign trade in several developing and developed countries (Olawale and Ayo, 2000; Mukhter et al., 2009). Groundnuts and groundnut products are very beneficial in the treatment of hemophilia and other such inherited blood disorders. People suffering from nose bleeding also benefit from eating groundnut and it is also helpful in reducing excessive menstruation bleeding in Women (FAO, 2002). Groundnuts are rich in vitamins, contain at least 13 different types of vitamins that include vitamin A, B, C and E together with 26 essential minerals like calcium, zinc, iron, boron, potassium, phosphorus, manganese, magnesium, copper, fat, sodium, water, proteins, carbohydrate and fibre (Iwo and Obok, 2008). Many of these materials help in brain function and development and also assist in the maintenance of strong bone. They are also rich in anti-oxidants which help in reducing the risk of contracting cardiovascular diseases, cancer risk and anti-ageing, keeping the body young and fit. Groundnuts are also very rich in five main nutrients required by the body to maintain and repair the tissues namely; food energy, protein, prosperous, thiamin and niacin hence they are highly recommended to growing children expecting and nursing mothers. (Obasi, 2008). Spent engine oil also called used lubricating oil is obtained after serving and subsequently during oil from motor automobiles. The disposal of spent engine oil into gutter, water drains, open vacant plots and farms in Nigeria is a common occurrence and this is mostly done by automobile and allied artisans with workshops on roadsides and open places. Agbogidi (2011a) reported that spent oil is the commonest soil contaminant in the rural areas of Nigeria where agriculture/farming forms the mainstay of the rural inhabitants. The used oil may contain some toxic materials including heavy metals that could affect growth, yield and general performance of plants (Agbogidi and Egbuchua, 2010). Although studies have been conducted on spent oil contamination by  Anoliefo and Edegbai (2000), Vwioko and Fashemi (2005), Agbogidi (2009a), Agbodigi (2010a), Agbogidi (2010b) and Agbogidi (2011b) on the growth of plants, oil in soil has been shown to have significant impact on plant growth, yield and performance (Inoni et al., 2006, Ngoku et al., 2008 and Agbogidi, 2009b). There is however, paucity of documented information on the effect of oil on the growth of groundnut. It is against this background that a study as this has been embarked on. The present study has been designed to assess the effects of spent engine oil pollution on the germination, growth and development of groundnut (Arachis hypogeal).

 

1.2 JUSTIFICATION

The uses of Arachis hypogaea (Groundnut) in our time cannot be underestimated as it serves as alternative means for vegetable oil production which is heart friendly, has a wide range of health benefits, serves as food to both man and animals, moreover it generates fund to Nigeria as a country as well as to the commercial and substantial farmers. Hence the need for this research works.

It is hoped that the result of this research will reveal the effects of spent engine oil pollution on the germination, growth and development of Arachis hypogaea (Groundnut) and thus make recommendations that will ensure proper production of Arachis hypogaea.

1.3 AIMS AND OBJECTIVES

1. To determine the effects of spent engine oil pollution on the germination of Arachis hypogaea
2. To identify the effects of spent engine oil on the growth of Arachis hypogaea plants.
3. To identify the effects of spent engine oil on leaf area, number of leaves and plant height.