Soil fungal population study related to oil pollution along different distances from kawrgosk oil refinery of erbil-iraq

Abstract

Soil fungal population along different distances from Kawrgosk Oil Refinery was analyzed in relation to physicochemical characteristics and residual oil contents. Fourteen species belonging to twelve genera were isolated. The total number of fungi from sixteen studied sites was 243×103 cfu g-1 dry soil. Maximum fungal population 41×103 cfu g-1 dry soil was in site 6 and minimum population 2×103 cfu g-1 dry soil was in the refinery center. The most frequently isolated fungi were yeasts 96×103 cfu.g-1 dry soil with a percentage of occurrence 41.03 %, followed by Aspergillus ochraceous 43×103 cfu.g-1 dry soil (18.38 %), Rhodotorula sp. 24×103 cfu.g-1 dry soil (10.26 %), Penicillium spp. 23×103 cfu g-1 dry soil (9.83 %) and A. niger 12×103 cfu.g-1 dry soil (5.13 %) and the least frequently isolated species was A. terreus 1×103 cfu.g-1 dry soil (0.43 %). The correlation between total cfu of fungi with oil residue was negative by r value of -0.092 and its correlation with silt and clay contents, pH, total P, K, and S were also negative by r values of -0.005, -0.135, -0.290, -0.090, -0.255 and -0.227 respectively (p<0.05). The correlation between total cfu of fungi with moisture, sand, EC, total organic C and total N were positive by r-values of 0.005, 0.143, 0.355, 0.161 and 0.152 respectively.