ABSTRACT

Bioaugumentation with selected bacteria in regenerating soil degraded by granite at umuoghara Ezza, Nigeria.  The study aimed to identify and characterize the dominant bacteria specie in the degraded soils of the study area, to determine the composition and population of bacteria community in the quarry area and to evaluate comparative effectiveness of enhanced bioremediation (bio-augmentation) and natural attenuation of soils degraded by granite quarrying. Soil samples were collected round the quarry site using a radii sampling technique, at 50m away from the quarry pit by the north(A); south (B); east (C) and west (D) positions with the aid of Global position System (GPS). In each of the positions A-D above, soils were collected at 4 sampling points 50m apart. A non-quarry soil was collected as control. Thus, all a total of 17 soil samples were collected. The bacteria species identified and characterized were staphylococcus aureus with microbial count of 2.6x108; Micrococcus spp with microbial count of 3.32 x108; pseudomonas spp with microbial count of 4.21x108 and Escherichia coli with microbial count of 3.12x108, the bacterial isolate  Pseudomonas Spp was  selected out of four 4 bacterial isolates owing to its relative growth and abundance.  A strain of Pseudomonas was isolated from the rhizosphere of cocoyam plant and was inoculated on the soil samples following a pre inoculation analysis and post inoculation analysis on soil samples for selected heavy metal (lead, zinc, copper, and chromium) and selected physicochemical analysis. The result showed that mean concentration of metals in the quarry site were pre-treatment for zinc 0.25(mg/l); lead 0.08(mg/l); Cr 3.25(mg/l); and Cu 0.63(mg/l) and control (1.80, 0.12, 4.08, 1.24) respectively. After 10 weeks of inoculation, the mean concentration of post -treatment for zinc 0.21(mg/l); lead 0.05(mg/l); Cr 2.14(mg/l); Cu 0.44 and control (0.84, 0.08, 3.12,0.8) comparison of the Mean concentration and SD of heavy metals in the soil environment showed that it was in the order chromium  3.25 (mg/l ) to  2.54(mg/l) >Cu 0.63(mg/l) to 0.44(mg/l) >Zn 0.25(mg/l)  to 0.21(mg/l) >Pb 0.08(mg/l) to  0.05(mg/l).The mean concentration of Chromium and zinc were above the prescribed limits of WHO, FEMEV, FAO and EU. On the other hand, mean concentration lead was equal to the standards-implying that a little increment could lead to above existing international limits. Copper on the other hand was lower than the standards. The mean concentration for Ca 2+, Mg 2+, Na+ and .k+ has showed that pre- treatment had Ca 2+ (6.18), Mg 2+ (1.17), k+(0.21 ),Na+ (11.75) and control (10.12, 3.7, 1.10, 1.43) respectively for the exchangeable bases. The mean concentration for Ca 2+ ,Mg 2+  Na+ and .k+  showed that post- treatment had Ca 2+ (2.42), Mg 2+ (1.17), Na+ (0.14) K (O.15) and control (8.24, 2.0, 0.8, 0.10) respectively for the exchangeable bases. The mean concentration for PH,OC,OM has showed that pre- treatment had pH(5.07), OC(1.09), k+(0.21 )and OM (1.83).others are  N(0.09mg/l), P(20.19mg/l)  The mean concentration for pH(5.07), OC(1.09), k+(0.21 ),OM (1.83), N(0.09mg/l) and P(20.19mg/l)  showed that post-treatment had pH(5.48), OC(1.43), OM (2.34), N(0.015mg/l) and P(20.78mg/l). From the results, there was a significant decrease in the mean and SD concentration of the micro elements and heavy metal toxicity in post treatments. The high content of these toxic metals in the soil may have adverse effects on soil quality and on human health if they get into the food chain. In order to reduce the likelihood of this occurring, illegal quarrying and the consumption of contaminated plant and water close to the quarry pit should be strongly discouraged