Evaluation of the efficacy of soil flushing remediation method on crude oil-spilled mangrove sediment at Bodo Creek, Gokana, Nigeria

Abstract

The efficacy of soil flushing remediation method of a crude oil spilled mangrove sediment at Bodo creek, Bodo, Nigeria was evaluated. Field observation revealed that after soil flushing remediation operation of the Bodo crude oil-spilled site in 2018 by Shell Petroleum Development Company of Nigeria, no post-remediation assessment was carried out to determine the effectiveness of the technique as a remediation strategy. This study was carried out to ascertain the effectiveness of soil flushing remediation method for decontamination of hydrocarbon-spilled mangrove environment. Sediment samples were collected from 3 stations within the creek which were non-remediated crude oil-polluted station, soil flushing remediated station and non-polluted station, at depths of 0 – 15 cm and analysed for sediment temperature, pH, conductivity, Total Petroleum Hydrocarbon (TPH), Total Hydrocarbon Content (THC) and microbial properties. Results showed significant decrease in TPH and THC (1241.71 mg/kg and 1755.45 mg/kg, respectively) in the soil flushing remediated station when compared with non-remediated polluted station (1792.93 mg/kg and 28261.5 mg/kg, respectively). Despite the significant decrease in THC and TPH in the soil flushing station, the values were still above environmentally permissible limits. This implies that other remediation techniques should be adopted after the soil flushing approach.