Nature And Properties Of Soils

Mobil Producing Nigeria Unlimited (MPNU), a subsidiary of ExxonMobil and the highest crude oil & condensate producer in Nigeria has its operational base and an oil terminal, the Qua Iboe terminal (QIT) located at Ibeno, Nigeria. Other oil companies like Network Exploration and Production Nigeria Ltd, Frontier Oil Ltd; Shell Petroleum Development Company Ltd; Elf Petroleum Nigeria Ltd and Nigerian Agip Energy, a subsidiary of the Italian ENI E&P operate onshore, on the continental shelf and in deep offshore of the Atlantic Ocean, respectively with the coastal waters of Ibeno, Nigeria as the nearest shoreline. This study was designed to delineate the oil-polluted sites in Ibeno, Nigeria using microbiological and physico-chemical characterization of soils, sediments and ground and surface water samples from the study area. Results obtained revealed that there have been significant recent hydrocarbon inputs into this environment as observed from the high counts of hydrocarbonoclastic microorganisms in excess of 1% at all the stations sampled. Moreover, high concentrations of THC, BTEX and heavy metals contents in all the samples analyzed corroborate the high recent crude oil input into the study area. The results also showed that the pollution of the different environmental media sampled were of varying degrees, following the trend: ground water > surface water > sediments > soils. Keywords—Microbiological characterization, oil-polluted sites, physico-chemical analyses, total hydrocarbon content.

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Delineation of Oil – Polluted Sites in Ibeno LGA, Nigeria, Using Microbiological and Physicochemical Characterization

The aim of this study was to assess the toxicity of dispersants (OSD/SEACARE and OSD/LT) with different concentrations on the growth of Aspergillus and Rhizopus species in fresh water (Ocdee River) in KegbaraDereGokana Local Government Area, Rivers State. The Fresh water sample was collected by submerging 10liters of jerry Can (sterile) into a depth of 30cm in K-Dere River in Gokana Local Government Area, Rivers State. The samples were transported to the laboratory in sterile containers packed in coolers in an ice pack for analyses within six hours of collection. Oil spill dispersants; OSD/SEACARE and OSD/LT were obtained from Barker and Hughes Nig. Ltd (formally Mil Park Nigeria Limited) in Port Harcourt Rivers State. The toxicity testing was done for the period of days at room temperature. Standard microbiological techniques were used; toxicity testing was prepared by setting up conical flask aseptically covered with cotton wool. For each dispersant (toxicant), the test was carried out in five (5) separate conical flasks containing appropriately sterile habitat water (freshwater). In each of the conical flask, four toxicant concentrations (%); 10, 25, 50, and 75 were added separately. These concentrations were obtained by aseptically transferring 10, 25, 50 and 75 ml of the dispersant into 90, 75, 50, and 25 ml of sterile freshwater. The control contained the water sample (habitat water) and the organism without toxicant. One millilitre (1ml) of the test organism was added to each toxicant concentration in test tubes containing (10, 25, 50, 75% and control respectively). Aliquot (0.1ml) from each concentration was then plated out using spread plate technique on Sabouraud Dextrose Agar immediately after zero (0) hour inoculation was done, inoculation and spreading continued after 4, 8, 12 and 24 hours for short time toxicity (Acute) while for long time (Chronic) inoculation was from 168 (7days), 336 (14days), 504 (21days) and 672 (28days) hours respectively and the plates were incubated for 72 hours at 28± 2oC. After incubation, the total viable count on each plate was taken and converted to log10.This process was repeated for the two test organisms and two dispersants separately giving a total number of twenty (20) experimental set-ups. The result obtained showed that the two dispersants employed in this study pose lethal threats to the biological population of the aquatic environment and tend to seriously alter the overall stability of the river ecosystem [] as observed with the response of Aspergillus and Rhizopus species to the toxicity of dispersant with respect to other forms of life. However, the result of the percentage (%) log survival count showed that Aspergillus and Rhizopus species are quite tolerant to the toxicants at some concentrations and exposure times as seen in table 4.4 and 4.5 which showed that the organisms had reasonable growth at 10% and 25% concentrations of the toxicants at 0, 4, 8 hours, and to some extent, 12 and 24hours. The sensitivity of the fungi; Aspergillus and Rhizopus species to the toxicity of different toxicants (OSD/SEACARE AND OSD/LT) with the fresh water sample decreased in the following order (noting the lower lethal concentration (Lc50), the more toxic the toxicant); Aspergillus in OSD/SEACARE (56.15%), Aspergillus in OSD/LT (58.81%) and Rhizopusin OSD/SEACARE (58.05%), Rhizopusin OSD/LT (58.40%). The study revealed that the fungal species; Aspergillus and Rhizopus species responded differently to different concentrations of the two toxicants from time to time and the response of the organisms due to the presence of the toxicant may alter or affect the process of decomposition, mineralization and nutrient generation which will in turn disturb the nature of the ecosystem and biogeochemical cycle. Furthermore, the study also revealed that dispersants contain some chemical components that can be very hazardous to life, reducing productivity and promoting death of not just the aquatic forms of life (both the micro and macro flora) but also higher forms of life such as humans and other mammals that make use of them as source of food and other means of survival. K e y w o r d s Oil spill dispersant, OSD/SEACARE, OSD/LT, Aspergillus and Rhizopus species Accepted: 22 December 2019 Available Online: 20 January 2020 Article Info Int.J.Curr.Microbiol.App.Sci (2020) 9(1): 2487-2896

Response of Aspergillus and Rhizopus species to the Toxicity of Dispersants

Aim: To investigate bioremediation potentiality of Pseudomonas aeruginosa KX828570 on crude oil Polluted Marshland and Terrestrial Soil treated with oil spill dispersant 
Study Design: The study employs experimental design, statistical analysis of data and interpretation. 
Place and Duration of the Study: Soil samples were collected from K-Dere, Gokana L.G.A, and were transported to the Microbiology Laboratory of Rivers State University, Port Harcourt, Nigeria for analyses while Oil spill dispersant (OSD/LT and OSD/Seacare) were from Barker and Hughes Nig Ltd (formally mil park Nigeria limited), all in Rivers state, Nigeria. This investigation study lasted for 28 days and sampling was done every 7day period. 
Methodology: Eight experimental set up were carried out using Pseudomonas aeruginosa KX828570 as the bio-augmenting organism in terrestrial and marshland soil contaminated with two Oil spill dispersant (OSD/LT and OSD/Seacare) separately. Controls for the two soil types were made without organism and treatment. Its bioremediation potential on the pollutants and two types of soil were monitored for 28 days. The setup was tilled twice a week to provide moisture and more oxygen for the organisms to thrive. Analysis of pH, Temperature, Moisture content, Total Hydrocarbon Content, Total Heterotrophic Bacteria, Dispersant Utilizing Bacteria was carried out at weekly intervals. 
Results: The pH of both soils ranged from 5.75 to 7.37; temperature from 270C to 340C; moisture content 03 to 0.6 across the soil samples. Total Hydrocarbon Content (THC) showed a steady decline from day 1 – 28. The percentage (%) bioremediation rates of polluted soils were as follows: Terrestrial soil+OSD/Seacare+Pseudomonas aeruginosa KX828570 69.4% > Terrestrial soil+OSD/LT+ Pseudomonas aeruginosa KX828570 65.9% > Marshland soil+OSD/Seacare+ Pseudomonas aeruginosa KX828570 52.6% > Marshland soil+OSD/Seacare+ Pseudomonas aeruginosa KX828570 47.6%. Dispersant utilizing bacterial count in marshland and terrestrial soil ranged from 6.013 to 7.338 log10Cfu/g and 6.045 to 7.301 log10Cfu/g respectively from Day 1 to 28. 
Conclusion:  From the investigation, it revealed that Oil spill dispersants are more degradable in terrestrial soil than marshland soil. OSD/Seacare is more biodegradable than OSD/LT in both terrestrial and marshland soil augmented with Pseudomonas aeruginosa KX828570. Thus, Pseudomonas aeruginosa KX828570 have been found to be a potential bioremediation agent in oil spill dispersant polluted marshland and terrestrial soil.

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Bioremediation Potential of Pseudomonas aeruginosa KX828570 on Crude Oil Spill Polluted Marshland and Terrestrial Soil Treated with Oil Spill Dispersant

Crude oil exploration has been beneficial to our economy but detrimental to our environment with the artisanal refineries further compounding the challenge. This research was aimed at investigating the microbiology and heavy metal pollution of three crude oil polluted rivers in Rivers State, Nigeria and effects on living organisms inhabiting that environment. This study was carried out in three locations in South-South Nigeria (Eagle Island, Iwofe and Chokocho rivers). A total of 64 water samples (upstream and downstream points) were collected using appropriate containers and sterile polyethene bags for 6 crab samples for a period of three months. Water and crab samples were analyzed for heavy metals using Atomic Absorption Spectrophotometric method while microbiological analysis involved isolation and enumeration of microbial populations of the water and crab samples as well as characterization and identification of the isolates using standard methods Results showed Total Heterotrophic bacteria (THB) ranged from 6.0 × 10 6 cfu/ml to 9.0 × 10 8 cfu/ml for the downstream locations and 1.7 × 10 6 cfu/ml to 3.5 × 10 7 cfu/ml for the upstream locations. Total Heterotrophic Fungi (THF) ranged from 2.0 × 10 4 cfu/ml to 1.1 × 10 5 cfu/ml for downstream locations and 0.1 × 10 4 cfu/ml to 4.0 × 10 4 cfu/ml for upstream locations, Hydrocarbon Utilizing Bacteria (HUB) ranged from 0.8 × 10 3 cfu/ml to 4.0 × 10 3 cfu/ml in downstream locations and 2.0 × 10 3 cfu/ml to 7.4 × 10 3 cfu/ml in upstream locations, Hydrocarbon Utilizing Fungi (HUF) Case Study Precious et al.; SAJRM, 11(3): 1-11, 2021; Article no.SAJRM.78200 2 ranged from 1.0 × 10 3 cfu/ml to 6.0 × 10 3 cfu/ml for downstream locations and 5.0 × 10 2 cfu/ml to 8.0 × 10 3 cfu/ml for upstream locations. The bacteria identified biochemically included Serratia sp., Enterobacter sp. and Salmonella sp. for the crab samples and Bacillus sp. was dominant in the water samples (Bacillus subtilis, Bacillus cereus, Bacillus carboniphilus). The heavy metals (Fe, Ni, Zn, Cd, Cu, Mn, Cr and Pb) were below the DPR permissible limit but are likely to increase since the activities leading to pollution are still ongoing. The crab as a filter feeder, had higher concentration of heavy metals and microbial population and the location with the highest crude oil pollution (14.5mg/l) had the lowest THB (6.0 × 10 6 cfu/ml) as physicochemical parameters like the amount of Dissolved Oxygen had been altered.

Microbiological Characteristics and Heavy Metal Pollution of Crude Oil Contaminated Water Bodies in Port Harcourt Metropolis, Nigeria

Wetland soils constitute vast, under-exploited and sometimes undiscovered ecologies in many countries of the World, including Nigeria. A total of 54 wetland soil samples including surface and subsurface soil at depths of 0-15 cm and 15-30 cm were collected using a sterile hand auger for a period of three months between August and October and subjected to standard and analytical microbiological procedures. The wetland soil samples were further subjected to atomic absorption spectroscopy (AAS) to check for presence and concentration of heavy metals. Results obtained showed that apart from heterotrophic bacterial and fungal counts, hydrocarbon utilizing bacteria (HUB) counts were higher in the surface soil ranging from 12.06±3.43X10 cfu/g at Iwofe to 6.19±2.67 a X10 7 cfu/g at Chokocho while subsurface soil had HUB ranging from 8.91±6.67 a X10 3 cfu/g at Eagle Island to 4.93±3.95X10cfu/g at Chokocho. Heavy metals such as Fe, Pb, Cd and Ni were recorded in concentrations above FEPA permissible limit in the surface and subsurface soil across the three wetlands. The heavy metal concentration in each wetland however, decreased with an increase in soil depth. According to literatures, elevated levels of heavy metals in soils decrease Original Research Article Chibuike et al.; MRJI, 31(2): 53-63, 2021; Article no.MRJI.66612 54 microbial population, diversity and activities. However, the microbial population in this study increased with increasing heavy metal concentration which indicates that the microbes can tolerate or utilize heavy metals in their systems; as such can be used for bioremediation of heavy metal polluted soils.

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N. David Ogbonna

Papers

Microbiology and Heavy Metal Content of Wetlands Impacted by Crude Oil Pollution in Rivers State, Southern Nigeria