Abstract—The experiment conducted in the study aimed at the utilization of the Cypress (Cupressus sempervirens) seedlings to phytoremediate soil polluted with crude oil. One- and 2-year-old seedlings were grown in soil polluted with 0.5 and 1.5% weight-to-weight (w/w) crude oil. Plant growth parameters, crude oil degradation, hydrocarbons, soil parameters, nitrogen (N), phosphorus (P), and potassium (K) were measured. The results showed a successful plant growing in crude oil-polluted soil, with no poisonous symptoms or recorded mortality cases. Chlorophyll b, the shoots’ biomass, and plant height showed a significant reduction. The pH decreased while both Electrical Conductivity (EC) and Organic Matter (OM) of the soil increased significantly. The pH reduction recorded 0.2 degrees, soil EC, and OM in soil containing 0.5% crude oil marked 811.167 µS/cm and 1.578%; in soil polluted with 1.5% crude oil, the results read differently, marking 889.667 µS/cm and 1.942% respectively. Regarding the Total Petroleum Hydrocarbons (TPH), Gas Chromatography Technique analysis of soil showed that a total of 10 different hydrocarbons (3C–8C and 10C–13C) had vanished. Additionally, Petroleum degradation was found to be in the range of (35.98–37.881%) after 4 months of planting, while reaching (87.333–87.831%) after eight months. N concentration in soil and plant tissues also showed a significant increase. In general, 1- and 2-year-old seedlings showed insignificant results in most of the studied traits, apart from the plant growth parameters. The study provided evidence of this plant’s capacity to grow in soil polluted with 0.5% and 1.5% crude oil, and it also exhibited a strong ability to remediate the soil from crude oil.
Keywords—phytoremediation, crude oil pollution, hydrocarbons, Cupressus sempervirens
Cite: Ramadhan Omer Hussain, "Evaluating the Phytoremediation Capacity of Cupressus Sempervirens in Crude Oil-contaminated Soils: A Study of Growth Parameters and Hydrocarbon Removal Efficiency," International Journal of Environmental Science and Development vol. 17, no. 4, pp. 415-426, 2026.
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