Soil sulphur status provides valuable information about its bioavailability and potential environmental consequences. Sulphur forms (total, organic, water soluble, adsorbed, organic matter bound and elemental S) of selected crude oil polluted and unpolluted soils in Bayelsa, Niger Delta, Nigeria were evaluated. Experimental design was a 3 x 2 x 2 factorial of location, soil depth and pollution status arranged in a randomized complete block set-up with 3 replications. Also relationship between S forms and selected soil properties was estimated using correlation and regression analyses. Averaged over soil depths and pollution status, soil S varied distinctly (LSD 0.05) as 1.59, 2.57 and 1.98 (elemental S), 26.25, 35.15 and 25.67 (water soluble S), 6.07, 6.34 and 6.58 (organic matter bound S), 51.71, 58.08 and 53.42 (adsorbed S), 1014.87, 998.90 and 940.13 (organic S) and 1094.92, 1092.14 and 1019.22 mg kg-1 (total S) in Agudama-Epie, Elebele and Imiringi respectively. Also interactions of location x soil depths x pollution status yielded best elemental S (3.79 mg kg-1) in surface depth of polluted soil at Elebele, water soluble S (43.34 mg kg-1), organic matter bound S (10.00 mg kg-1) and adsorbed S (68.00 mg kg-1) in the subsurface depths of unpolluted soils at Agudama-Epie, Imiringi, and Elebele respectively. Best organic (1228.06 mg kg-1) and total S (1296.73 mg kg-1) were in the surface depth of unpolluted soils in Agudama-Epie. Soil OM, pH, sand, silt, clay, P, N, Mg, Ca, K, Na and ECEC correlated with S forms. Besides clay which accounted for more than 40% of water soluble and adsorbed S, other S forms were poorly predicted by the soil properties. In general, concentrations of most S forms were higher in unpolluted than polluted soils, probably due to favourable conditions for S transformation and existence of important S sources other than crude oil in the former than the later.
Keywords: Bayelsa and Niger Delta, Polluted, Sulphur, unpolluted soils
