Impact of Crude-Oil Spillage Pollution and Chemical Remediation on Agricultural Soil Properties and Crop Growth

Loamy sand of agricultural land in an oil producing and processing area was polluted with crude oil and the fouled soil samples were reclaimed using chemical degreasers and detergents. Both treatments showed significant effect on soil properties and crop growth parameters; however recovery level was 67-100% and significantly (p ≤ 0.01) higher than the level of degradation, except in infiltration rate. Soil pH increased by 26% in fouled soil attributable to bacterial biodegradation of crude oil under the anaerobic conditions present in the soil macro and micro-pores, and indicated the tendency of crude oil spills to buffer acidic soil to neutral. Hydraulic conductivity with 45 – 67% reduction from 82.24 cm/day in the control soil to 39.6 cm/day in polluted soil confirmed the blockage of polluted soils micropores by oil films. Crop growth, indicated by root elongation, diminished to 7.4 ± 0.64 cm in polluted soil compared to13.47 ± 6.40 cm in the control soil. Evapotranspiration and leaf mass water decreased by 90% while fertility indicated 33 – 103% increase in total nitrogen, organic carbon and available phosphorus in the polluted soil. The chemical degreaser/detergent emulsion effectively recovered soil properties and plant growth in the reclaimed soil and is recommended for short-duration restoration of crude-oildegraded soil for productive agriculture. @JASEM J. Appl. Sci. Environ. Manage. December, 2010, Vol. 14 (4) 147 - 154