Assessing the Rate of Remediation of Polycyclic Aromatic Hydrocarbon Contaminated Soil Using Redox Parameters
This paper investigates the use of redox parameters as a measure of the environmental impact assessment of soil contaminated with polycyclic aromatic hydrocarbons. The levels of naphthalene and anthracene which were used as model contaminants in the soil were periodically monitored along with ferric sulphate and nitrate at ambient conditions. The Brucine and Gelatin Barium methods were employed in estimating the nitrate and sulphate reductions. Experimental results revealed that the microbial utilization of nitrate was faster than that of sulphate; an indication that nitrate is the basic nutrient which provides nitrogen for the metabolic processes occurring during soil remediation. The percentage absorption for both nitrate and sulphate was comparatively higher for the soil unimpacted with polycyclic aromatic hydrocarbons, approximately 49.3% and 26.12% respectively. The percentage absorption of nitrate and sulphate for soil spiked independently with naphthalene and anthracene was found to be 42.18%; 31.21% and 22.93%; 19.74% respectively. The percentage reduction of naphthalene and anthracene in the nitrate and sulphate enhanced soil was 47.5%; 43.1% and 42.5%; 36.5% respectively. These results further affirm that the higher the molecular weight of the polycyclic aromatic hydrocarbon, the slower the rate of its degradation.