Latitudinal Transects and Quantitative Ecological Risk Assessments of Polycyclic Aromatic Hydrocarbons in Terrestrial Soils of Pakistan and King George Island, Antarctica

Polycyclic aromatic hydrocarbons (PAHs) were carefully analyzed from terrestrial soils collected at numerous sites in Pakistan and King George Island (sub-Antarctica) and compared with other data around the world. The mean concentrations of An, Pyr, B[a]A, Chry, B[b + k]F, B[a]P, Ind, D[a,h]A, and B[g,h,i]P of world terrestrial soils were significantly (p < 0.05) greater than those of samples collected at King George Island and Pakistan. We found that a comparatively high percentage contribution of Σ5,6-ring PAHs was detected at terrestrial soils of Pakistan (i.e., 48%), indicating that high molecular weight PAHs as the main composition of carcinogenic substances. On the contrary, a relatively high percentage contribution of Σ3,4-ring PAHs was observed at KGS (i.e., 89%) and in good agreement with earlier studies in a similar areas. A simple linear regression analysis indicated that no significant relationships between latitude/longitude and PAH contents were observed in Pakistan. Applications of diagnostic binary ratios coupled with advanced statistical tools highlight the importance of vehicle exhausts as one of the main contributors of PAH congeners in terrestrial soils of Pakistan. It is also crucial to underline that cancer risk levels of terrestrial soils collected at Pakistan and King George Island fall into “acceptable level” range.