Microbial evaluation and deterioration of paints and paint-products.

The microbial quality of materials and final products of a reputable paint industry in Lagos area were analysed. The bacterial contaminants isolated in the paint-products included Bacillus brevis, B. polymyxa, B. laterosporus, Lactobacillus gasseri, L. brevis, Esherichia coli and Proteus mirabilis. The fungal contaminants detected in the paints were mainly Aspergillus niger, A. flavus and Penicillium citrinum. The microbial populations in the raw materials ranged from 1.0 x 106 – 9.5 x 106 cfu g-1 for bacteria and between 1.25 x 104 and 6.8 x 104 cfu g-1 for fungi while those present in packaging materials ranged from 3.45 x 106 – 7.65 x 106 cfu g-1 for bacteria and 2.4 x103 – 2.8 x 103 cfu g-1 for fungi respectively. The bacterial populations in the fresh paint samples monitored every two weeks from the time of production ranged from 1.6 x 101 – 4.7 x 105 cfu ml-1 while the fungal populations ranged from 1.0 x 101 – 5.5 x 103 cfu ml-1 over a ten-month study period. The optical density at 600 nm increased while transmittance, pH, specific gravity and viscosity of the paint samples decreased over the period suggesting gradual deterioration of the aesthetic qualities of the paint-products with time as indicated by the measured parameters.

Impact of refined petroleum spills on water quality, macro-invertebrate and microbial communities of a tropical aquatic environment.

Water quality characteristics, benthic macro-invertebrates and microbial communities of three first order streams in South West Nigeria were investigated to assess the effects of refined petroleum five months after spillage. All physical and chemical conditions except temperature and pH were significantly different (P<0.01) at the upstream control stations and impacted stations reflecting the perturbational stress. The benthic macro-invertebrate fauna were dominated by arthropods, but the faunal spectrum was dissimilar at all the stations studied. Sampling stations at the epicentre of the spill showed considerable reduction in faunal compositions and relative abundance. Generally, the microbial density and diversity were highest in both soil and water samples from impacted sites than in control sites. There was a significantly higher proportion (P < 0.05) of hydrocarbon utilizers in soil than in water samples in all stations except in samples from stations (P<0.05).

Inorganic nutrient utilisation by "adapted" Pseudomonas putida strain used in the bioremediation of agricultural soil polluted with crude petroleum.

Garden soil samples polluted with crude petroleum were bioremediated by inorganic nutrient monitoring with appropriate adjustment and inoculation with crude oil-adapted strain of Pseudomonasputida (PP) isolated from oil-impacted soils. Soil samples without PP inoculation served as the control samples to compare the abilities of the native soil microflora with the adapted PP strain in biodegrading crude oil pollutant. In the experimental samples, oil concentration and all the inorganic nutrient sources tested decreased more rapidly with a proportional increase in the population densities of both PP and the native soil microflora than were observed in the control samples. This trend was particularly strong for PO4(3-) and NO3- which eventually became limiting both in all the experimental samples and in some control samples. Inoculation of crude oil-impacted agricultural soils by oil -adapted PP strain with nutrient monitoring and adjustment can be effective as bioremediation methods of agricultural land upon pollution with petroleum or petroleum products.

Impacts of crude oil on the germination and growth of cress seeds (Lepidium sp.) after bioremediation of agricultural soil polluted with crude petroleum using "adapted" Pseudomonas putida.

The impacts of crude oil on the germination, growth and morphology of cress seeds (Lepidium sp.) after bioremediation of agricultural soil polluted with crude petroleum using "adapted" Pseudomonas putida (PP) were examined for 15 days. At day 15 there was 100% germination in the untreated control samples, the mean height of the seedlings was 75.8 +/- 2.6 mm and all appeared to have grown morphologically normal. In the experimental samples treated with oil and PP inoculation, there was 98% germination and the seedlings reached a height of 63.8 +/- 6.9 mm; again, morphologically the seedlings appeared normal. However, in the control samples treated with oil but without PP inoculation, there was 31-38% germination and seedling heights of 34.2 +/- 11.4-42.3 +/- 8.5 mm with abnormal morphology. Treatment of oil-impacted agricultural soil with PP as a bioremediation agent does produce soil which is capable of growing larger and healthier plants than where bioremediation has not taken place.