ASSESSMENT OF POLYCYCLIC AROMATIC HYDROCARBONS IN SOIL AND WATER OF AGBABU BITUMEN DEPOSIT IMPACTED AREA

Abstract

The bitumen, soil and water samples collected within a distance of 100 metre from the borehole bitumen located at E004o68-96l and N06o34-66l in Agbabu village were analyzed for polycyclic aromatic hydrocarbon (PAH) concentrations. The possible sources of the PAHs in the samples were also investigated and classified. The PAHs content of the sample was determined using gas chromatographic technique. The total concentration of PAHs was noted to be 8750.06ppm in the bitumen sample, 625.12ppm in soil sample and 68.62ppm in the water sample. Generally, the concentrations of indenol(1,2,3-cd) pyrene and naphthalene were observed to be on the lower and upper limits of the PAHs determined in all the samples , that is for bitumen sample, the PAH concentrations ranged between 44.13ppm (Indenol(1, 2, 3-cd)pyrene to 1231.53ppm (naphthalene), the soil sample showed a similar trend with indenol(1,2,3-cd)pyrene having a concentration of 22ppm (Indenol(1, 2, 3-cd)pyrene and 176.32ppm (naphthalene). The water also showed PAH constituents with a concentration of 0.44ppm (Indenol(1, 2, 3-cd)pyrene and 8.06ppm (naphthalene), The PAH concentrations of all the samples were compared with some standard values such as: Canadian Soil Quality Guideline to protect portable water (SOIL A), Canadian Soil Quality Guidelines for Agriculture and residential/parkland sites (SOIL B), Canadian Soil Quality Guidelines for commercial and industrial sites (SOIL C), USEPA Maximum Contaminant Level for water (WAT A), WHO guidelines (WAT B) and Wisconsin Department of Natural Resources’ regulation for drinking water (WAT C). The result showed that the concentrations of PAHs present in the soil and water samples were relatively higher than their corresponding values given in the standards. Statistical correlation analysis was conducted on the PAHs and showed a strong correlation between the PAHs within the soil, water and the bitumen deposit samples. Also, the possible sources of the PAHs in the samples were investigated and classified as either petrogenic or pyrogenic sources by evaluating the low molecular weight and high molecular weight ratio i.e. parameter HMWLMW . Following the values of 33.96 and 4.96 obtained for soil and water samples respectively using the parameter HMW LMW, It followed that PAHs in the soil and water samples were of petrogenic origin since the evaluated values were greater than1. Therefore all animals living within the bitumen deposit area are at a risk of high level exposure to polycyclic aromatic hydrocarbons The data serve as information for the uses to which the soil and water of the village should be put and when the need arises the treatment of the soil and water to suit the desired usage.