Petroleum hydrocarbons content in the soil and its accumulation in grasses from oil spill site at Isoko North LGA of Delta State, Nigeria

Abstract

This study was done to evaluate the concentration of petroleum hydrocarbons in an oil spill site in Ozoro, Isoko North Local Government Area, Delta State of Nigeria. The study area was affected by the crude oil spill in early 2019, and the cleanup of the site was carried out almost immediately by the oil company. Five soil samples were collected randomly at two soil depths, the soil surface (0- 5 cm) and 40 cm soil depth. In addition, two kinds of grass, Nettle-leaf goosefoot (Chenopodium murale) and Guinea grass (Megathyrsus Maximus) were collected from the points the soil samples were collected, during January 2020. All the samples collected were analyzed for total hydrocarbon content (THC) using standard procedures. The results showed significant concentration in the soil samples; and accumulation of THC in the roots and leaves of the grasses. At the soil surface, the THC ranged between 9,075 and 13,563 mg/kg; while at a depth of 40 cm below the soil surface, the THC ranged between 6,518 and 13,004 mg/kg. The Guinea grass had a higher accumulation of THC (mean = 1258 mg/kg), compared to the Nettle-leaf goosefoot (an average of 922.8 mg/kg). The significant accumulation in the guinea grass is an indication of its phytoremediation. The results will be helpful in planning and monitoring of remediation programmes for crude oil spills sites.