Effect of Crude Oil Contaminated Soil on the Growth, Development and Nutritional Composition of Maize (Zea mays L.,)

Abstract

Petroleum hydrocarbon contamination remains a major environmental challenge because of the release of toxic by-products that affect soil quality and plant growth. This study assessed the effect of crude oil on the growth, development, and nutritional composition of maize (Zea mays L.) with a view to evaluating its toxicity. Soil samples were collected, characterized using FTIR, and contaminated with crude oil at varying v/w levels. Maize seeds were planted in pots and monitored for 12 weeks. Two groups were established: an uncontaminated control (20 replicates) and contaminated soils (20 replicates). Key growth parameters, including germination rate, plant height, chlorophyll content, and yield, were monitored, alongside macronutrient and micronutrient composition. Results showed that contaminated soils caused a significant reduction in nutrient availability and uptake compared to controls. During the germination phase (weeks 1–3), there was no significant difference (p>0.05) in plant height, girth, leaf area, and stem diameter. However, as the plants advanced into the vegetative phase, a significant decline (p<0.05) in these parameters was observed in the contaminated group. FTIR analysis further revealed distinct changes in functional groups and hydrocarbon compound presence in contaminated soils, confirming crude oil’s interference with soil chemistry. Overall, the findings indicate that crude oil pollution hampers maize growth, development, and nutritional quality, largely through nutrient depletion and structural alterations in the soil. The study underscores the need for effective remediation strategies to restore soil fertility and sustain agricultural productivity in crude oil-polluted environments.