Eco-Toxicological Assessment of Local and Industrial Refined Kerosene on Pollution Bio-Monitor Pseudomonas sp. in Tri-Aquatic Ecosystem

Abstract

Aim: To investigate eco-toxicity of local and industrial refined kerosene on pollution bio-monitor Pseudomonas sp. in tri-aquatic ecosystem (Marine, brackish and freshwater). Study Design: The study employs experimental examination and statistical analysis of the data and interpretation. It was designed to evaluate the different kerosene concentration and the duration of exposure that could cause potential toxicological effect on Pseudomonas sp. in tri-aquatic ecosystem. Place of Study: Fresh water, brackish water, and marine water samples were collected in four litre (4L) sterile containers. Fresh water sample was collected from Asarama Andoni; brackish water from Eagle Island while marine water was collected from Bonny River in Bonny L.G.A., all in Rivers state, Southern, Nigeria. The locally refined kerosene was gotten from Okrika mainland, while the industrially refined kerosene was obtained from Chinda filling station, UST roundabout, Mile 3 Port Harcourt. The study lasted for three months. Methodology: Standard microbiological techniques were used; toxicity procedure were applied using local and industrial refined kerosene; prepared at concentrations of 1.625%, 3.25%, 6.5%, 12.5% and 25% in fresh, brackish and marine water. These were tested with Pseudomonas sp. for 0, 4, 8, 12, and 24h separately for each toxicant. The cultures were incubated at 35°C for 24 hours. The median lethal concentration (LC50) was employed to compute the toxicities of the different toxicants on the test organism. Results: The results specify that percentage (%) logarithm of mortality of Pseudomonas sp. increases with increased toxicants concentration and exposure time. The pollution bio-monitor Pseudomonas sp. demonstrated sensitivity to the toxicity of local and industrially refined kerosene. The sensitivity showed variations, toxic level decreased in the following order (noting that the lower the LC50, the more toxic the toxicants): Industrial refined kerosene in fresh water (18.80%) > Industrial refined kerosene in brackish water (20.81%) > Local refined kerosene in brackish water (21.48%) > Industrial refined kerosene in marine water (22.20%) > Local refined kerosene (24.26) > Local refined kerosene in marine water (24.92%).  Industrial refined kerosene was seen to be more toxic in fresh water and local refined kerosene was found to be least toxic in marine water. Conclusion: The study showed that industrial refined kerosene in fresh water (LC50 = 18.8%) has the highest toxicity strength while local refined kerosene in marine water (LC50 = 24.92%) has the least toxicity strength on Pseudomonas sp. in the tri-aquatic ecosystem. These results show that local and industrial refined kerosene can inhibit the growth of Pseudomonas sp. in an aquatic ecosystem; noting that Pseudomonas sp. is one of the most effective biodegrading bacteria in ecological biogeochemical cycles, pollutant removal/remediation and a key pollution bio-monitor.